This database catalogues publications of the ECCO Project and those that employ ECCO's products. Click the read more buttons for full citation, abstract, links to corresponding publications, and a list of ECCO products employed. Please acknowledge the ECCO project when utilizing our products and let us know of any publications that are missing from this list. You might be interested in our "Research Roundup" StoryMaps for 2024, 2023, 2022, 2021 and 2020.
Tian, Zhongxiang; Liang, Xi; Zhao, Fu; Liu, Na; Li, Ming; Li, Chunhua (2025). On the effects of the timing of an intense cyclone on summertime sea-ice evolution in the Arctic, Annals of Glaciology (65), e20, 10.1017/aog.2024.15.
Formatted Citation: Tian, Z., X. Liang, F. Zhao, N. Liu, M. Li, and C. Li, 2025: On the effects of the timing of an intense cyclone on summertime sea-ice evolution in the Arctic. Annals of Glaciology, 65, e20, doi:10.1017/aog.2024.15
Abstract:
This study investigates the impacts of the timing of an extreme cyclone that occurred in August 2012 on the sea-ice volume evolution based on the Arctic Ice Ocean Prediction System (ArcIOPS). By applying a novel cyclone removal algorithm to the atmospheric forcing during 4-12 August 2012, we superimpose the derived cyclone component onto the atmospheric forcing one month later or earlier. This study finds that although the extreme cyclone leads to strong sea-ice volume loss in all runs, large divergence occurs in sea-ice melting mechanism in response to various timing of the cyclone. The extreme cyclone occurred in August, when enhanced ice volume loss is attributed to ice bottom melt primarily and ice surface melt secondarily. If the cyclone occurs one month earlier, ice surface melt dominates ice volume loss, and earlier appearance of open water within the ice zone initiates positive ice-albedo feedback, leading to a long lasting of the cyclone-induced impacts for approximately one month, and eventually a lower September ice volume. In contrast, if the cyclone occurs one month later, ice bottom melt entirely dominates ice volume loss, and the air-open water heat flux in the ice zone tends to offset ice volume loss.
Title: Multi-decadal collapse of East Antarctica’s Conger-Glenzer Ice Shelf
Type: Journal Article
Publication: Nature Geoscience
Author(s): Walker, Catherine C.; Millstein, Joanna D.; Miles, Bertie W. J.; Cook, Sue; Fraser, Alexander D.; Colliander, Andreas; Misra, Sidharth; Trusel, Luke D.; Adusumilli, Susheel; Roberts, Chancelor; Fricker, Helen A.
Year: 2024
Formatted Citation: Walker, C. C. and Coauthors, 2024: Multi-decadal collapse of East Antarctica's Conger-Glenzer Ice Shelf. Nature Geoscience, 17(12), 1240-1248, doi:10.1038/s41561-024-01582-3
Li, Ming; Liang, Xi; Liu, Na; Zhao, Fu; Tian, Zhongxiang (2024). Responses of the Arctic sea ice drift to general warming and intraseasonal oscillation in the local atmosphere, Climate Dynamics, 9 (62), 9303-9318, 10.1007/s00382-024-07395-9.
Formatted Citation: Li, M., X. Liang, N. Liu, F. Zhao, and Z. Tian, 2024: Responses of the Arctic sea ice drift to general warming and intraseasonal oscillation in the local atmosphere. Climate Dynamics, 62(9), 9303-9318, doi:10.1007/s00382-024-07395-9
Fluegel, Bailey L.; Walker, Catherine (2024). The Two-Decade Evolution of Antarctica’s Hektoria Glacier and Its 2022 Rapid Retreat From Satellite Observations, Geophysical Research Letters, 22 (51), 10.1029/2024GL110592.
Title: The Two-Decade Evolution of Antarctica’s Hektoria Glacier and Its 2022 Rapid Retreat From Satellite Observations
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Fluegel, Bailey L.; Walker, Catherine
Year: 2024
Formatted Citation: Fluegel, B. L., and C. Walker, 2024: The Two-Decade Evolution of Antarctica's Hektoria Glacier and Its 2022 Rapid Retreat From Satellite Observations. Geophys. Res. Lett., 51(22), doi:10.1029/2024GL110592
Abstract:
Beginning in March 2022, the Antarctic Peninsula's Hektoria Glacier experienced an unprecedented retreat of ∼23 km over 1.5 years, one of the fastest observed glacier retreats on record. Improving constraints on the drivers of such extreme events is key to understanding glacier change around the continent and future sea-level rise. We use satellite remote sensing and reanalysis data to characterize changes in Hektoria, a former Larsen B Ice Shelf tributary, over the last ∼20 years and document a period of retreat from 2002 to 2011, and readvancement from 2011 to 2022. We find that the long-term ice front and velocity response (2002-2022) correlated more strongly with changes in modeled ocean temperatures compared to surface air temperatures. However, the acute loss of buttressing support following fast ice collapse paired with a near-contemporaneous extreme atmospheric river in the region likely catalyzed the unprecedented 2022-2023 retreat.
Formatted Citation: Chen, R., Y. Yang, Q. Geng, A. Stewart, G. Flierl, and J. Wang, 2024: Diagnostic Framework Linking Eddy Flux Ellipse with Eddy-Mean Energy Exchange. Ocean-Land-Atmosphere Research, 3, doi:10.34133/olar.0072
Abstract:
The design of non-eddy-resolving numerical models requires a good understanding and an appropriate representation of the eddy-mean flow feedback. To understand this feedback, we propose a diagnostic framework that links eddy geometry with the eddy-mean energy exchange terms in the Lorenz energy diagram. This framework provides explicit mathematical formulas that link eddy-mean energy exchange rates with both the mean state structure and the properties of eddy momentum ellipses and eddy buoyancy ellipses. Considering that the mean flow contains both along- and cross-stream variations, we decompose the eddy-mean kinetic energy exchange term into 3 components: one associated with the cross-stream variation in mean flow (MC), one associated with the along-stream variation in mean flow (MA), and one associated with the variation in mean flow (MR). We also state the corresponding geometric formulas. The geometric interpretation of MC is consistent with barotropic instability theories and the literature on eddy geometry. As for MA , the weakening (strengthening) of mean flow in the along-stream direction corresponds to eddy kinetic energy generation (decay) through MA. MA and a portion of MR are related under the quasi-geostrophic assumption. From a global integral perspective, both the along-stream and cross-stream variations in the mean flow contribute considerably to eddy-mean kinetic energy exchange. At the Kuroshio Extension, both the mean state energy level and eddy energy level are key to shaping the spatial pattern of eddy-mean energy exchange. This framework offers a tool for geometrically interpreting eddy-mean energy exchange, which may offer guidance for eddy parameterizations.
Ma, Yuanyuan; Wang, Zemin; Zhang, Baojun; An, Jiachun; Geng, Hong; Li, Fei (2024). The Spatiotemporal Surface Velocity Variations and Analysis of the Amery Ice Shelf from 2000 to 2022, East Antarctica, Remote Sensing, 17 (16), 3255, 10.3390/rs16173255.
Formatted Citation: Ma, Y., Z. Wang, B. Zhang, J. An, H. Geng, and F. Li, 2024: The Spatiotemporal Surface Velocity Variations and Analysis of the Amery Ice Shelf from 2000 to 2022, East Antarctica. Remote Sensing, 16(17), 3255, doi:10.3390/rs16173255
Abstract:
The surface velocity of the Amery Ice Shelf (AIS) is vital to assessing its stability and mass balance. Previous studies have shown that the AIS basin has a stable multi-year average surface velocity. However, spatiotemporal variations in the surface velocity of the AIS and the underlying physical mechanism remain poorly understood. This study combined offset tracking and DInSAR methods to extract the monthly surface velocity of the AIS and obtained the inter-annual surface velocity from the ITS_LIVE product. An uneven spatial distribution in inter-annual variation in the surface velocity was observed between 2000 and 2022, although the magnitude of variation was small at less than 20.5 m/yr. The increase and decrease in surface velocity on the eastern and western-central sides of the AIS, respectively, could be attributed to the change in the thickness of the AIS. There was clear seasonal variation in monthly average surface velocity at the eastern side of the AIS between 2017 and 2021, which could be attributed to variations in the area and thickness of fast-ice and also to variations in ocean temperature. This study suggested that changes in fast-ice and ocean temperature are the main factors driving spatiotemporal variation in the surface velocity of the AIS.
Formatted Citation: Zhang, X., F. Li, Z. Jing, B. Zhang, X. Ma, and T. Du, 2024: Detecting marine heatwaves below the sea surface globally using dynamics-guided statistical learning. Communications Earth & Environment, 5(1), 616, doi:10.1038/s43247-024-01769-x
Formatted Citation: Liang, X., Z. Tian, F. Zhao, M. Li, N. Liu, and C. Li, 2024: Evaluation of the ArcIOPS sea ice forecasts during 2021-2023. Frontiers in Earth Science, 12, doi:10.3389/feart.2024.1477626
Abstract:
The operational sea ice forecasts from the Arctic Ice Ocean Prediction System (ArcIOPS) during 2021-2023 are validated against satellite-retrieved sea ice concentration and drift data, in situ and reanalyzed sea ice thickness data. The results indicate that the ArcIOPS has a reliable capacity on the Arctic sea ice forecasts for the future 7 days. Over the validation period, the root mean square error (RMSE) of the ArcIOPS sea ice concentration forecasts at a lead time of up to 168 h ranges between 8% and 20%, and the integrated ice edge error (IIEE) is lower than 1.6 × 106 km2 with respect to the Hai Yang 2B (HY-2B) sea ice concentration data. Compared to the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS), sea ice volume evolution from the ArcIOPS forecasts is closer to that derived from the CS2SMOS sea ice thickness observations, which have been assimilated into the ArcIOPS. Sea ice thickness comparisons at three locations in the Beaufort Sea between the ArcIOPS forecasts and in situ mooring observations also prove that the sea ice thickness forecasts are credible, which sets a solid basis for supporting ice-breaker navigation in the Arctic thick ice zone. The sea ice drift deviations between the ArcIOPS forecasts and the National Snow and Ice Data Center (NSIDC) data are lower than 4 cm/s in most of the months. Future work will emphasize on developing multi-variable data assimilation scheme and fully coupled air-ice-ocean forecasting system for the Arctic sea ice forecasts.
Zhao, Zhangzhe; Sprintall, Janet; Du, Yan (2024). Large Mixed Layer Salinity Variation in the Southern Tropical Indian Ocean Due To the Blending of Water Masses, Geophysical Research Letters, 21 (51), 10.1029/2024GL110569.
Title: Large Mixed Layer Salinity Variation in the Southern Tropical Indian Ocean Due To the Blending of Water Masses
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Zhao, Zhangzhe; Sprintall, Janet; Du, Yan
Year: 2024
Formatted Citation: Zhao, Z., J. Sprintall, and Y. Du, 2024: Large Mixed Layer Salinity Variation in the Southern Tropical Indian Ocean Due To the Blending of Water Masses. Geophys. Res. Lett., 51(21), doi:10.1029/2024GL110569
Abstract:
The southern tropical Indian Ocean (TIO) displays large mixed layer salinity (MLS) variation. Circulation in this region is governed by the Indian Ocean tropical gyre (IOTG), where the source water proportion and associated mixing remain unclear. Particles integrating into the IOTG and entering the central southern TIO originate from the Bay of Bengal, Malacca Strait, western Indian Ocean, and Indonesian Throughflow. Surprisingly, cross-equatorial advection is particularly important, implying a significant connection between both the Bay of Bengal and the South China Sea via Malacca Strait into the southern TIO. The anomalous anticlockwise circulation weakens the IOTG during positive Indian Ocean Dipole (IOD). An opposite pattern is observed in the negative IOD. A particle experiment reveals that water masses are modulated by the anomalous circulation that drives the redistribution of MLS by changing the proportion of the different source waters. This represents a potential predictability for the southern TIO MLS variability.
Li, Zhao; Jiang, Weiping; van Dam, Tonie; Zou, Xiaowei; Chen, Qusen; Chen, Hua (2024). Advances in Modeling Environmental Loading Effects: A Review of Surface Mass Distribution Products, Environmental Loading Products, and Their Contributions to Nonlinear Variations of Global Navigation Satellite System (GNSS) Coordinate Time Series, Engineering, 10.1016/j.eng.2024.09.001.
Title: Advances in Modeling Environmental Loading Effects: A Review of Surface Mass Distribution Products, Environmental Loading Products, and Their Contributions to Nonlinear Variations of Global Navigation Satellite System (GNSS) Coordinate Time Series
Formatted Citation: Li, Z., W. Jiang, T. van Dam, X. Zou, Q. Chen, and H. Chen, 2024: Advances in Modeling Environmental Loading Effects: A Review of Surface Mass Distribution Products, Environmental Loading Products, and Their Contributions to Nonlinear Variations of Global Navigation Satellite System (GNSS) Coordinate Time Series. Engineering, doi:10.1016/j.eng.2024.09.001
Woods, K.; Wallace, L. M.; Williams, C. A.; Hamling, I. J.; Webb, S. C.; Ito, Y.; Palmer, N.; Hino, R.; Suzuki, S.; Savage, M. K.; Warren-Smith, E.; Mochizuki, K. (2024). Spatiotemporal Evolution of Slow Slip Events at the Offshore Hikurangi Subduction Zone in 2019 Using GNSS, InSAR, and Seafloor Geodetic Data, Journal of Geophysical Research: Solid Earth, 8 (129), 10.1029/2024JB029068.
Title: Spatiotemporal Evolution of Slow Slip Events at the Offshore Hikurangi Subduction Zone in 2019 Using GNSS, InSAR, and Seafloor Geodetic Data
Type: Journal Article
Publication: Journal of Geophysical Research: Solid Earth
Author(s): Woods, K.; Wallace, L. M.; Williams, C. A.; Hamling, I. J.; Webb, S. C.; Ito, Y.; Palmer, N.; Hino, R.; Suzuki, S.; Savage, M. K.; Warren-Smith, E.; Mochizuki, K.
Year: 2024
Formatted Citation: Woods, K. and Coauthors, 2024: Spatiotemporal Evolution of Slow Slip Events at the Offshore Hikurangi Subduction Zone in 2019 Using GNSS, InSAR, and Seafloor Geodetic Data. Journal of Geophysical Research: Solid Earth, 129(8), doi:10.1029/2024JB029068
Abstract:
Detecting crustal deformation during transient deformation events at offshore subduction zones remains challenging. The spatiotemporal evolution of slow slip events (SSEs) on the offshore Hikurangi subduction zone, New Zealand, during February-July 2019, is revealed through a time-dependent inversion of onshore and offshore geodetic data that also accounts for spatially varying elastic crustal properties. Our model is constrained by seafloor pressure time series (as a proxy for vertical seafloor deformation), onshore continuous Global Navigation Satellite System (GNSS) data, and Interferometric Synthetic Aperture Radar displacements. Large GNSS displacements onshore and uplift of the seafloor (10-33 mm) require peak slip during the event of 150 to >200 mm at 6-12 km depth offshore Hawkes Bay and Gisborne, comparable to maximum slip observed during previous seafloor pressure deployments at north Hikurangi. The onshore and offshore data reveal a complex evolution of the SSE, over a period of months. Seafloor pressure data indicates the slow slip may have persisted longer near the trench than suggested by onshore GNSS stations in both the Gisborne and Hawkes Bay regions. Seafloor pressure data also reveal up-dip migration of SSE slip beneath Hawke Bay occurred over a period of a few weeks. The SSE source region appears to coincide with locations of the March 1947 Mw 7.0-7.1 tsunami earthquake offshore Gisborne and estimated great earthquake rupture sources from paleoseismic investigations offshore Hawkes Bay, suggesting that the shallow megathrust at north and central Hikurangi is capable of both seismic and aseismic rupture.
Formatted Citation: Huang, H., K. Huang, L. Yang, Z. Liang, W. Song, and D. Wang, 2024: Negative Surface Chlorophyll Concentration Anomalies in the Southeast Arabian Sea During Summer in 2015 and 2019. J. Geophys. Res. Ocean., 129(10), doi:10.1029/2024JC021154
Abstract:
Satellite observations revealed two extremely low surface chlorophyll concentration (SCC) events with a warm sea surface temperature anomaly in the southeastern Arabian Sea (SEAS, 6°-15°N, 72°-77°E) during the summer (July-August-September) in 2015 and 2019. We find that the physical processes leading to these two similar low SCC events are remarkably different. The low SCC in the SEAS during summer 2019 is mainly related to the weakened upwelling and deepening of the thermocline depth due to the combined effects of the local wind anomalies and the arrival of westward-propagating downwelling coastal Kelvin wave driven by easterly anomalies near the eastern Sri Lanka during an extreme positive Indian Ocean Dipole (IOD) event. In summer 2015, a weaker positive IOD-induced easterly anomalies in the southern Bay of Bengal also drives downwelling coastal Kelvin waves westward, deepening the thermocline in the SEAS. But unlike that in summer 2019, the local wind stress curl anomalies in the SEAS during summer 2015 favors upwelling, which counteracts the downward motion of the coastal Kelvin waves, leading to weaker downward transport (one-third of that in 2019). Meanwhile, the upper ocean layer in the SEAS experiences extreme warming during summer owing to the development of 2015/2016 super El Niño. This substantial warming enhances upper oceanic stratification, which results in weaker vertical mixing and reduces the SCC to an extremely low level despite the much weaker IOD strength in 2015.
Zhao, Fu; Liang, Xi; Tian, Zhongxiang; Li, Ming; Liu, Na; Liu, Chengyan (2024). Southern Ocean Ice Prediction System version 1.0 (SOIPS v1.0): description of the system and evaluation of synoptic-scale sea ice forecasts, Geoscientific Model Development, 17 (17), 6867-6886, 10.5194/gmd-17-6867-2024.
Formatted Citation: Zhao, F., X. Liang, Z. Tian, M. Li, N. Liu, and C. Liu, 2024: Southern Ocean Ice Prediction System version 1.0 (SOIPS v1.0): description of the system and evaluation of synoptic-scale sea ice forecasts. Geoscientific Model Development, 17(17), 6867-6886, doi:10.5194/gmd-17-6867-2024
Abstract:
Abstract. An operational synoptic-scale sea ice forecasting system for the Southern Ocean, namely the Southern Ocean Ice Prediction System (SOIPS), has been developed to support ship navigation in the Antarctic sea ice zone. Practical application of the SOIPS forecasts had been implemented for the 38th Chinese National Antarctic Research Expedition for the first time. The SOIPS is configured on an Antarctic regional sea ice-ocean-ice shelf coupled model and an ensemble-based localized error subspace transform Kalman filter data assimilation model. Daily near-real-time satellite sea ice concentration observations are assimilated into the SOIPS to update sea ice concentration and thickness in the 12 ensemble members of the model state. By evaluating the SOIPS performance in forecasting sea ice metrics in a complete melt-freeze cycle from 1 October 2021 to 30 September 2022, this study shows that the SOIPS can provide reliable Antarctic sea ice forecasts. In comparison with non-assimilated EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF) data, annual mean root mean square errors in the sea ice concentration forecasts at a lead time of up to 168 h are lower than 0.19, and the integrated ice edge errors in the sea ice forecasts in most freezing months at lead times of 24 and 72 h maintain around 0.5×106 km2 and below 1.0×106 km2, respectively. With respect to the scarce Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) observations, the mean absolute errors in the sea ice thickness forecasts at a lead time of 24 h are lower than 0.3 m, which is in the range of the ICESat-2 uncertainties. Specifically, the SOIPS has the ability to forecast sea ice drift, in both magnitude and direction. The derived sea ice convergence rate forecasts have great potential for supporting ship navigation on a fine local scale. The comparison between the persistence forecasts and the SOIPS forecasts with and without data assimilation further shows that both model physics and the data assimilation scheme play important roles in producing reliable sea ice forecasts in the Southern Ocean.
Guillermo-Montiel, Juan Carlos; Martínez-López, Benjamín; Ochoa-Moya, Carlos Abraham; Quintanar, Ignacio Arturo; Cabos-Narváez, William David (2024). Why did numerical weather forecasting systems fail to predict the Hurricane Otis’s development?, Atmósfera (38), 10.20937/ATM.53367.
Title: Why did numerical weather forecasting systems fail to predict the Hurricane Otis’s development?
Type: Journal Article
Publication: Atmósfera
Author(s): Guillermo-Montiel, Juan Carlos; Martínez-López, Benjamín; Ochoa-Moya, Carlos Abraham; Quintanar, Ignacio Arturo; Cabos-Narváez, William David
Year: 2024
Formatted Citation: Guillermo-Montiel, J. C., B. Martínez-López, C. A. Ochoa-Moya, I. A. Quintanar, and W. D. Cabos-Narváez, 2024: Why did numerical weather forecasting systems fail to predict the Hurricane Otis's development? Atmósfera, 38, doi:10.20937/ATM.53367
Abstract:
Hurricane Otis (HO) occurred in the eastern tropical Pacific (ETP), intensifying rapidly and unexpectedly, making landfall near Acapulco at 06:25 UTC on October 25, 2023 as a category five hurricane. Official and unofficial national weather forecasts (NWF) failed to predict HO's development, trajectory, and intensification. To analyze the reasons for the failure of the NWF, we conducted two experiments using the Weather Research and Forecasting (WRF) model, with Global Forecast System (GFS) and fifth-generation ECMWF atmospheric reanalysis (ERA5) data as initial condition (IC). Our results showed that some fields in the GFS data, such as relative humidity, convective available potential energy, and even sea surface temperature, were more favorable for the development and intensification of the disturbance compared to ERA5. However, the three-dimensional structure of the wind field in the ETP in GFS did not contribute to the initial development of HO. Additionally, we explored the WRF's sensitivity to different model configurations to simulate the trajectory and intensity of the hurricane using a coupled ocean-atmosphere system composed of WRF and a three-dimensional upper-ocean circulation model based on Price-Weller-Pinkel. Our numerical experiments involve modifications in the IC, cumulus parameterizations (CP), roughness coefficients, spatial resolutions, different time steps, and an idealized coupled model. The sensitivity test reveals the significance of the CP scheme, where the Kain-Fritsch was the only one that helped simulate the HO properly, altogether with increased spatial resolution. Furthermore, ocean-atmosphere coupling improves the prediction of the landfall time and location of the HO. However, no experiment captured the intensity or rapid intensification of HO.
Jiang, Huidong; Ye, Zhenjiang; Zhang, Yixiao; Zhang, Wenchao; Tian, Yongjun; Li, Jianchao; Liu, Yang; Yu, Haiqing; Zhang, Xingui (2024). The integration of diel vertical migration and hydrodynamic process influences the transport of swimming crab zoea (Portunus trituberculatus), Fisheries Oceanography, 10.1111/fog.12695.
Formatted Citation: Jiang, H. and Coauthors, 2024: The integration of diel vertical migration and hydrodynamic process influences the transport of swimming crab zoea (Portunus trituberculatus). Fisheries Oceanography, doi:10.1111/fog.12695
Abstract:
Vertical migration and dispersal processes during the marine crab larval stage markedly affect transport, habitat selection, population connectivity, and resource replenishment success rates. However, not much is known of the reproductive ecology of swimming crabs in the nearshore waters of the northwest Pacific shelf. Here, we investigated the diel vertical migration (DVM) characteristics and transport patterns of the swimming crab zoea (Portunus trituberculatus) in this area. A Lagrangian particle-tracking algorithm coupled with a hydrodynamic model, incorporating a DVM pattern of zoeae based on observations from a field survey of the diurnal distribution of swimming crab zoea, was used to simulate the transport of zoeae, and the impact of zoeal transport on population connectivity was explored. The results revealed that particles were predominantly transported in a nearshore direction from the particle release point, with short dispersal distances during the zoeal stages. In nearshore waters on the continental shelf, the swimming crab zoeae are exposed to shoreward-moving currents with the aid of prolonged daytime locations in the lower water column, whereas larvae migrate upward to the middle and upper layers of the water column at night rather than the most superficial layer, potentially avoiding surface offshore-moving currents that may be responsible for the retention and shoreward transport of larvae. Most zoeae are transported to shallow waters, and the contribution of transport to population connectivity during the zoeal stages is relatively limited. The findings here have considerable implications for understanding the mechanisms governing the early recruitment dynamics of this species, as well as for fisheries management and conservation of marine biodiversity.
Cai, Yiting; Mouyen, Maxime (2024). Loading-induced stress variation on active faults and seismicity modulation in the Kuril Islands-Japan region, Earth and Planetary Science Letters (643), 118904, 10.1016/j.epsl.2024.118904.
Title: Loading-induced stress variation on active faults and seismicity modulation in the Kuril Islands-Japan region
Type: Journal Article
Publication: Earth and Planetary Science Letters
Author(s): Cai, Yiting; Mouyen, Maxime
Year: 2024
Formatted Citation: Cai, Y., and M. Mouyen, 2024: Loading-induced stress variation on active faults and seismicity modulation in the Kuril Islands-Japan region. Earth and Planetary Science Letters, 643, 118904, doi:10.1016/j.epsl.2024.118904
Yang, Lu; Fu, Hongli; Luo, Xiaofan; Zhang, Xuefeng (2024). Reconstruction of Arctic Sea Ice Thickness and Its Impact on Sea Ice Forecasting in the Melting Season, Journal of Atmospheric and Oceanic Technology, 7 (41), 685-704, 10.1175/JTECH-D-23-0049.1.
Formatted Citation: Yang, L., H. Fu, X. Luo, and X. Zhang, 2024: Reconstruction of Arctic Sea Ice Thickness and Its Impact on Sea Ice Forecasting in the Melting Season. Journal of Atmospheric and Oceanic Technology, 41(7), 685-704, doi:10.1175/JTECH-D-23-0049.1
Abstract:
Generally, sea ice prediction skills can be improved by assimilating available observations of the sea ice concentration (SIC) and sea ice thickness (SIT) into a numerical forecast model to update the initial conditions. However, due to inadequate daily SIT satellite observations in the Arctic melting season, the SIC fields in forecast models are usually directly updated, which causes mismatch of SIC and SIT in dynamics and affects the model prediction accuracy. In this study, a statistically based bivariate regression model of SIT (BRMT) is tentatively established based on the grid reanalysis data of SIC and SIT to reconstruct daily Arctic SIT data. The results show that the BRMT can reproduce the spatial and temporal changes in the SIT in the melting season and capture the variation trend of SIT in some periods. Compared with the SIT observations from buoy and satellite, the reconstructed SIT shows better performance in the central Arctic than other datasets. Furthermore, when the reconstructed SIT is added to the forecast model with only assimilated SIC, the forecast accuracy of SIC, sea ice extent, and SIT in the Arctic melting season is improved and does not weaken with the increase in the forecast time. Especially in the central Arctic, the average absolute deviation between 24-h SIT forecast results and observations is only 0.16 m. The results indicate great potential for applying the reconstructed SIT to the operational forecast of Arctic sea ice during the melting season in the future.
Leng, Hengling; He, Hailun; Chen, Dake; Lin, Peigen; Yang, Yang; Wang, Zhaomin (2024). Bathymetry-constrained ocean geostrophic currents play a key role in shaping the sea ice circulation in the Canada Basin, Arctic Ocean, Environmental Research Letters, 10.1088/1748-9326/ad6baa.
Formatted Citation: Leng, H., H. He, D. Chen, P. Lin, Y. Yang, and Z. Wang, 2024: Bathymetry-constrained ocean geostrophic currents play a key role in shaping the sea ice circulation in the Canada Basin, Arctic Ocean. Environmental Research Letters, doi:10.1088/1748-9326/ad6baa
Abstract:
Satellite-based observations and a pan-Arctic coupled sea ice-ocean model are utilized to study the effect of ocean geostrophic currents on large-scale sea ice circulation in the Canada Basin, Arctic Ocean. We find that surface winds primarily drive sea ice drifts in the west-east direction, while the geostrophic currents in the Beaufort Gyre promote north-south ice drifts. Wind fluctuations can create variable ice drifts, yet geostrophic currents respond more slowly due to their larger vertical scale, serving as a slowly-evolving conveyor belt for maintaining the anticyclonic ice circulation. It is further demonstrated that the bathymetry can regulate the movement of sea ice via constraining the expansion of ocean circulation. This mechanism is indirect in the sense that the ice is far from the seafloor. Our research underscores the necessity of considering the bathymetry-constrained geostrophic currents in understanding Arctic sea ice dynamics. With the rapid retreat of Arctic sea ice, the multi-scale interactions between ice drifts and ocean currents may have significant implications for the Arctic ecosystem, climate, and shipping corridors.
Formatted Citation: Song, R., L. Mu, S. N. Loza, F. Kauker, and X. Chen, 2024: Assimilating Summer Sea-Ice Thickness Observations Improves Arctic Sea-Ice Forecast. Geophys. Res. Lett., 51(13), doi:10.1029/2024GL110405
Abstract:
Accurate Arctic sea-ice forecasting for the melt season is still a major challenge because of the lack of reliable pan-Arctic summer sea-ice thickness (SIT) data. A new summer CryoSat-2 SIT observation data set based on an artificial intelligence algorithm may alleviate this situation. We assess the impact of this new data set on the initialization of sea-ice forecasts in the melt seasons of 2015 and 2016 in a coupled sea ice-ocean model with data assimilation. We find that the assimilation of the summer CryoSat-2 SIT observations can reduce the summer ice-edge forecast error. Further, adding SIT observations to an established forecast system with sea-ice concentration assimilation leads to more realistic short-term summer ice-edge forecasts in the Arctic Pacific sector. The long-term Arctic-wide SIT prediction is also improved. In spite of remaining uncertainties, summer CryoSat-2 SIT observations have the potential to improve Arctic sea-ice forecast on multiple time scales.
Chau, Thi-Tuyet-Trang; Chevallier, Frédéric; Gehlen, Marion (2024). Global Analysis of Surface Ocean CO2 Fugacity and Air-Sea Fluxes With Low Latency, Geophysical Research Letters, 8 (51), 10.1029/2023GL106670.
Title: Global Analysis of Surface Ocean CO2 Fugacity and Air-Sea Fluxes With Low Latency
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Chau, Thi-Tuyet-Trang; Chevallier, Frédéric; Gehlen, Marion
Year: 2024
Formatted Citation: Chau, T., F. Chevallier, and M. Gehlen, 2024: Global Analysis of Surface Ocean CO2 Fugacity and Air-Sea Fluxes With Low Latency. Geophys. Res. Lett., 51(8), doi:10.1029/2023GL106670
Abstract:
The Surface Ocean CO2 Atlas (SOCAT) of CO2 fugacity (fCO2) observations is a key resource supporting annual assessments of CO2 uptake by the ocean and its side effects on the marine ecosystem. SOCAT data are usually released with a lag of up to 1.5 years which hampers timely quantification of recent variations of carbon fluxes between the Earth System components, not only with the ocean. This study uses a statistical ensemble approach to analyze fCO2 with a latency of one month only based on the previous SOCAT release and a series of predictors. Results indicate a modest degradation in a retrospective prediction test for 2021-2022. The generated fCO2 and fluxes for January-August 2023 show a progressive reduction in the Equatorial Pacific source following the La Niña retreat. A breaking-record decrease in the northeastern Atlantic CO2 sink has been diagnosed on account of the marine heatwave event in June 2023.
Ren, Hengye; Lu, Wenfang; Xiao, Wupeng; Zhu, Qing; Xiao, Canbo; Lai, Zhigang (2024). Intraseasonal response of marine planktonic ecosystem to summertime Madden-Julian Oscillation in the South China Sea: A model study, Progress in Oceanography (224), 103251, 10.1016/j.pocean.2024.103251.
Formatted Citation: Ren, H., W. Lu, W. Xiao, Q. Zhu, C. Xiao, and Z. Lai, 2024: Intraseasonal response of marine planktonic ecosystem to summertime Madden-Julian Oscillation in the South China Sea: A model study. Progress in Oceanography, 224, 103251, doi:10.1016/j.pocean.2024.103251
Song, Qianghua; Wang, Chunzai; Yao, Yulong; Fan, Hanjie (2024). Unraveling the Indian monsoon’s role in fueling the unprecedented 2022 Marine Heatwave in the Western North Pacific, npj Climate and Atmospheric Science, 1 (7), 90, 10.1038/s41612-024-00645-x.
Formatted Citation: Song, Q., C. Wang, Y. Yao, and H. Fan, 2024: Unraveling the Indian monsoon's role in fueling the unprecedented 2022 Marine Heatwave in the Western North Pacific. npj Climate and Atmospheric Science, 7(1), 90, doi:10.1038/s41612-024-00645-x
Abstract:
An unprecedented marine heatwave (MHW) event occurred in the middle-high latitudes of the western North Pacific during the summer of 2022. We demonstrate that excessive precipitation thousands of kilometers away fuels this extreme MHW event in July 2022. In the upper atmosphere, a persistent atmospheric blocking system, forming over the MHW region, reduces cloud cover and increases shortwave radiation at the ocean surface, leading to high sea surface temperatures. Atmospheric perturbations induced by latent heat release from the extreme precipitation in the Indian summer monsoon region enhance this atmospheric blocking through the propagation of quasi-stationary Rossby waves. Our hypothesis is verified by using a numerical model that is forced with the observed atmospheric anomalous diabatic heating. This study sheds light on how a subtropical extreme event can fuel another extreme event at middle-high latitudes through an atmospheric teleconnection.
Formatted Citation: Liang, X. and Coauthors, 2024: The linkage between wintertime sea ice drift and atmospheric circulation in an Arctic ice-ocean coupled simulation. Ocean Modelling, 189, 102362, doi:10.1016/j.ocemod.2024.102362
Formatted Citation: Liu, Y., Z. Zhang, Q. Yuan, and W. Zhao, 2024: Decadal trends in the Southern Ocean meridional eddy heat transport. J. Clim., doi:10.1175/JCLI-D-23-0462.1
Abstract:
Meridional heat transport induced by oceanic mesoscale eddies (EHT) plays a significant role in the heat budget of Southern Ocean (SO) but the decadal trends in EHT and its associated mechanisms are still obscure. Here, this scientific issue is investigated by combining concurrent satellite observations and Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2) reanalysis data over the 24 years between 1993-2016. The results reveal that the surface EHT from both satellite and ECCO2 data consistently show decadal poleward increasing trends in the SO, particularly in the latitude band of Antarctic Circumpolar Current (ACC). In terms of average in the ACC band, the ECCO2-derived EHT over the upper 1000 m has a linear trend of 1.1×10−2 PW per decade or 16% per decade compared with its time-mean value of 0.07 PW. Diagnostic analysis based on "mixing length" theory suggests that the decadal strengthening eddy kinetic energy (EKE) is the dominant mechanism for the increase of EHT in the SO. By performing energy budget analysis, we further find that the decadal increase of EKE is mainly caused by the strengthened baroclinic instability of large-scale circulation that converts more available potential energy to EKE. For the strengthened baroclinic instability in the SO, it is attributed to the increasing large-scale wind stress work on the large-scale circulation corresponding to the positive phase of Southern Annular Mode between 1993-2016. The decadal trends in EHT identified here may help understand decadal variations of heat storage and sea-ice extent in the SO.
Wu, Yang; Wang, Zhaomin; Liu, Chengyan; Yan, Liangjun (2024). Impacts of Ice-Ocean Stress on the Subpolar Southern Ocean: Role of the Ocean Surface Current, Advances in Atmospheric Sciences, 2 (41), 293-309, 10.1007/s00376-023-3031-8.
Formatted Citation: Wu, Y., Z. Wang, C. Liu, and L. Yan, 2024: Impacts of Ice-Ocean Stress on the Subpolar Southern Ocean: Role of the Ocean Surface Current. Advances in Atmospheric Sciences, 41(2), 293-309, doi:10.1007/s00376-023-3031-8
Title: A Synthesis of Global Coastal Ocean Greenhouse Gas Fluxes
Type: Journal Article
Publication: Global Biogeochemical Cycles
Author(s): Resplandy, L.; Hogikyan, A.; Müller, J. D.; Najjar, R. G.; Bange, H. W.; Bianchi, D.; Weber, T.; Cai, W.-J.; Doney, S. C.; Fennel, K.; Gehlen, M.; Hauck, J.; Lacroix, F.; Landschützer, P.; Le Quéré, C.; Roobaert, A.; Schwinger, J.; Berthet, S.; Bopp, L.; Chau, T. T. T.; Dai, M.; Gruber, N.; Ilyina, T.; Kock, A.; Manizza, M.; Lachkar, Z.; Laruelle, G. G.; Liao, E.; Lima, I. D.; Nissen, C.; Rödenbeck, C.; Séférian, R.; Toyama, K.; Tsujino, H.; Regnier, P.
Year: 2024
Formatted Citation: Resplandy, L. and Coauthors, 2024: A Synthesis of Global Coastal Ocean Greenhouse Gas Fluxes. Global Biogeochemical Cycles, 38(1), doi:10.1029/2023GB007803
Abstract:
The coastal ocean contributes to regulating atmospheric greenhouse gas concentrations by taking up carbon dioxide (CO2) and releasing nitrous oxide (N2O) and methane (CH4). In this second phase of the Regional Carbon Cycle Assessment and Processes (RECCAP2), we quantify global coastal ocean fluxes of CO2, N2O and CH4 using an ensemble of global gap-filled observation-based products and ocean biogeochemical models. The global coastal ocean is a net sink of CO2 in both observational products and models, but the magnitude of the median net global coastal uptake is ∼60% larger in models (−0.72 vs. −0.44 PgC year−1, 1998-2018, coastal ocean extending to 300 km offshore or 1,000 m isobath with area of 77 million km2). We attribute most of this model-product difference to the seasonality in sea surface CO2 partial pressure at mid- and high-latitudes, where models simulate stronger winter CO2 uptake. The coastal ocean CO2 sink has increased in the past decades but the available time-resolving observation-based products and models show large discrepancies in the magnitude of this increase. The global coastal ocean is a major source of N2O (+0.70 PgCO2-e year−1 in observational product and +0.54 PgCO2 -e year−1 in model median) and CH4 (+0.21 PgCO2-e year−1 in observational product), which offsets a substantial proportion of the coastal CO2 uptake in the net radiative balance (30%-60% in CO2-equivalents), highlighting the importance of considering the three greenhouse gases when examining the influence of the coastal ocean on climate.
Guo, Haihong; Cai, Jinzhuo; Yang, Haiyuan; Chen, Zhaohui (2024). Observations reveal onshore acceleration and offshore deceleration of the Kuroshio Current in the East China Sea over the past three decades, Environmental Research Letters, 2 (19), 024020, 10.1088/1748-9326/ad1d3b.
Formatted Citation: Guo, H., J. Cai, H. Yang, and Z. Chen, 2024: Observations reveal onshore acceleration and offshore deceleration of the Kuroshio Current in the East China Sea over the past three decades. Environmental Research Letters, 19(2), 024020, doi:10.1088/1748-9326/ad1d3b
Abstract:
The Kuroshio Current (KC) in the East China Sea is one of the most prominent components of the ocean circulation system in the North Pacific. The onshore intensification of the KC is found to drive nutrient-rich upwelling in the shelf regions, induce anomalous warming that leads to coastal marine heatwaves, and reduce the ability of the oceans to absorb anthropogenic carbon dioxide. Based on altimeter and in situ observations, we find an onshore acceleration and offshore deceleration of the KC over the past three decades. This intensification is characterized by a spatial mean onshore acceleration (offshore deceleration) of 0.39 (−0.63) cm s−1 per decade. This phenomenon can be attributed to changes in wind stress curl (WSC) and oceanic stratification over the subtropical North Pacific. The weakened WSC decreases the vertical extent of the KC by reducing its transport and contributes to the offshore deceleration, whereas the enhanced stratification drives the uplift of the KC and contributes to the onshore acceleration. Our findings underscore the importance of establishing and maintaining a long-term monitoring network for the zonal variations of the KC in the future to obtain a comprehensive understanding of the associated impacts.
Wang, Tianyu; Du, Yan; Liao, Xiaomei; Zhou, Runjie; Adeagbo, Ogooluwa Samuel (2024). Influence of rossby wave in southern Indian Ocean on the low frequency variability of eddy kinetic energy within agulhas current system, Deep Sea Research Part I: Oceanographic Research Papers (203), 104218, 10.1016/j.dsr.2023.104218.
Title: Influence of rossby wave in southern Indian Ocean on the low frequency variability of eddy kinetic energy within agulhas current system
Type: Journal Article
Publication: Deep Sea Research Part I: Oceanographic Research Papers
Author(s): Wang, Tianyu; Du, Yan; Liao, Xiaomei; Zhou, Runjie; Adeagbo, Ogooluwa Samuel
Year: 2024
Formatted Citation: Wang, T., Y. Du, X. Liao, R. Zhou, and O. S. Adeagbo, 2024: Influence of rossby wave in southern Indian Ocean on the low frequency variability of eddy kinetic energy within agulhas current system. Deep Sea Research Part I: Oceanographic Research Papers, 203, 104218, doi:10.1016/j.dsr.2023.104218
Huneke, Wilma G. C.; Hobbs, William R.; Klocker, Andreas; Naughten, Kaitlin A. (2023). Dynamic Response to Ice Shelf Basal Meltwater Relevant to Explain Observed Sea Ice Trends Near the Antarctic Continental Shelf, Geophysical Research Letters, 24 (50), 10.1029/2023GL105435.
Title: Dynamic Response to Ice Shelf Basal Meltwater Relevant to Explain Observed Sea Ice Trends Near the Antarctic Continental Shelf
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Huneke, Wilma G. C.; Hobbs, William R.; Klocker, Andreas; Naughten, Kaitlin A.
Year: 2023
Formatted Citation: Huneke, W. G. C., W. R. Hobbs, A. Klocker, and K. A. Naughten, 2023: Dynamic Response to Ice Shelf Basal Meltwater Relevant to Explain Observed Sea Ice Trends Near the Antarctic Continental Shelf. Geophys. Res. Lett., 50(24), doi:10.1029/2023GL105435
Abstract:
Observed Antarctic sea ice trends up to 2015 have a distinct regional and seasonal pattern, with a loss during austral summer and autumn in the Bellingshausen and Amundsen Seas, and a year-round increase in the Ross Sea. Global climate models generally failed to reproduce the magnitude of sea ice trends implying that the models miss relevant mechanisms. One possible mechanism is basal meltwater, which is generally not included in the current generation of climate models. Previous work on the effects of meltwater on sea ice has focused on thermodynamic processes. However, local freshening also leads to dynamic changes, affecting ocean currents through geostrophic balance. Using a coupled ocean/sea-ice/ice-shelf model, we demonstrate that basal melting can intensify coastal currents in West Antarctica and the westward transport of sea ice. This change in transport results in sea ice anomalies consistent with observations, and may explain the disparity between climate models and observations.
Title: Impact of sea ice transport on Beaufort Gyre liquid freshwater content
Type: Journal Article
Publication: Climate Dynamics
Author(s): Cornish, Sam B.; Muilwijk, Morven; Scott, Jeffery R.; Marson, Juliana M.; Myers, Paul G.; Zhang, Wenhao; Wang, Qiang; Kostov, Yavor; Johnson, Helen L.; Marshall, John
Year: 2023
Formatted Citation: Cornish, S. B. and Coauthors, 2023: Impact of sea ice transport on Beaufort Gyre liquid freshwater content. Climate Dynamics, 61(3-4), 1139-1155, doi:10.1007/s00382-022-06615-4
Abstract:
The Arctic Ocean's Beaufort Gyre (BG) is a wind-driven reservoir of relatively fresh seawater, situated beneath time-mean anticyclonic atmospheric circulation, and is covered by mobile pack ice for most of the year. Liquid freshwater accumulation in and expulsion from this gyre is of critical interest due to its potential to affect the Atlantic meridional overturning circulation and due to the importance of freshwater in modulating vertical fluxes of heat, nutrients and carbon in the ocean, and exchanges of heat and moisture with the atmosphere. Here, we investigate the hypothesis that wind-driven sea ice transport into/from the BG region influences the freshwater content of the gyre and its variability. To test this hypothesis, we use the results of a coordinated climate response function experiment with four ice-ocean models, in combination with targeted experiments using a regional setup of the MITgcm, in which we rotate the surface wind forcing vectors (thereby changing the ageostrophic component of these winds). Our results show that, via an effect on the net thermodynamic growth rate, anomalies in sea ice transport into the BG affect liquid freshwater adjustment. Specifically, increased ice import increases freshwater retention in the gyre, whereas ice export decreases freshwater in the gyre. Our results demonstrate that uncertainty in the ageostrophic component of surface winds, and in the dynamic sea ice response to these winds, has important implications for ice thermodynamics and freshwater. This sensitivity may explain some of the observed inter-model spread in simulations of Beaufort Gyre freshwater and its adjustment in response to wind forcing.
Formatted Citation: Sun, D., F. Li, Z. Jing, S. Hu, and B. Zhang, 2023: Frequent marine heatwaves hidden below the surface of the global ocean. Nature Geoscience, doi:10.1038/s41561-023-01325-w
Abstract:
Marine heatwaves are extreme warm water events that can cause devastating impacts on ecosystems and have complex socio-economic ramifications. Surface signals and drivers of marine heatwaves have been extensively investigated based on satellite observations, whereas their vertical structure in the global ocean remains unclear. In this study, we identify marine heatwave events in the epipelagic zone (0-200 m) using a four-dimensional spatio-temporal framework based on three ocean reanalysis datasets. We find that only about half of the marine heatwave events have continuous surface signals during their life cycles and around one-third always reside in the subsurface ocean without any imprint on sea surface temperature. The annual number of these subsurface marine heatwave events shows a significant increase in response to subsurface mean-state warming during the past three decades. Our findings reveal the limitation of identifying marine heatwaves solely based on the sea surface temperature and underscore the necessity of subsurface observations for monitoring marine heatwaves.
Tommaso, Pivetta; Carla, Braitenberg; Franci, Gabrovšek; Gerald, Gabriel; Bruno, Meurers (2023). Gravimetry and hydrologic data to constrain the hydrodynamics of a Karstic area: the Škocjan Caves study case, Journal of Hydrology, 130453, 10.1016/j.jhydrol.2023.130453.
Formatted Citation: Tommaso, P., B. Carla, G. Franci, G. Gerald, and M. Bruno, 2023: Gravimetry and hydrologic data to constrain the hydrodynamics of a Karstic area: the Škocjan Caves study case. Journal of Hydrology, 130453, doi:10.1016/j.jhydrol.2023.130453
Formatted Citation: Yasunaka, S. and Coauthors, 2023: An Assessment of CO2 Uptake in the Arctic Ocean From 1985 to 2018. Global Biogeochemical Cycles, 37(11), doi:10.1029/2023GB007806
Abstract:
As a contribution to the Regional Carbon Cycle Assessment and Processes phase 2 (RECCAP2) project, we present synthesized estimates of Arctic Ocean sea-air CO2 fluxes and their uncertainties from surface ocean pCO2 -observation products, ocean biogeochemical hindcast and data assimilation models, and atmospheric inversions. For the period of 1985-2018, the Arctic Ocean was a net sink of CO2 of 116 ± 4 TgC yr−1 in the pCO2 products, 92 ± 30 TgC yr−1 in the models, and 91 ± 21 TgC yr−1 in the atmospheric inversions. The CO2 uptake peaks in late summer and early autumn, and is low in winter when sea ice inhibits sea-air fluxes. The long-term mean CO2 uptake in the Arctic Ocean is primarily caused by steady-state fluxes of natural carbon (70% ± 15%), and enhanced by the atmospheric CO2 increase (19% ± 5%) and climate change (11% ± 18%). The annual mean CO2 uptake increased from 1985 to 2018 at a rate of 31 ± 13 TgC yr−1 dec−1 in the pCO2 products, 10 ± 4 TgC yr−1 dec −1 in the models, and 32 ± 16 TgC yr−1 dec−1 in the atmospheric inversions. Moreover, 77% ± 38% of the trend in the net CO2 uptake over time is caused by climate change, primarily due to rapid sea ice loss in recent years. Furthermore, true uncertainties may be larger than the given ensemble standard deviations due to common structural biases across all individual estimates.
Formatted Citation: Zhu, S., P. Wu, S. Zhang, O. Jahn, S. Li, and Y. Zhang, 2023: A high-resolution marine mercury model MITgcm-ECCO2-Hg with online biogeochemistry. Geoscientific Model Development, 16(20), 5915-5929, doi:10.5194/gmd-16-5915-2023
Abstract:
Abstract. Mercury (Hg) is a global persistent contaminant. Modeling studies are useful means of synthesizing a current understanding of the Hg cycle. Previous studies mainly use coarse-resolution models, which makes it impossible to analyze the role of turbulence in the Hg cycle and inaccurately describes the transport of kinetic energy. Furthermore, all of them are coupled with offline biogeochemistry, and therefore they cannot respond to short-term variability in oceanic Hg concentration. In our approach, we utilize a high-resolution ocean model (MITgcm-ECCO2, referred to as "high-resolution-MITgcm") coupled with the concurrent simulation of biogeochemistry processes from the Darwin Project (referred to as "online"). This integration enables us to comprehensively simulate the global biogeochemical cycle of Hg with a horizontal resolution of 1/5°. The finer portrayal of surface Hg concentrations in estuarine and coastal areas, strong western boundary flow and upwelling areas, and concentration diffusion as vortex shapes demonstrate the effects of turbulence that are neglected in previous models. Ecological events such as algal blooms can cause a sudden enhancement of phytoplankton biomass and chlorophyll concentrations, which can also result in a dramatic change in particle-bound mercury (HgaqP ) sinking flux simultaneously in our simulation. In the global estuary region, including riverine Hg input in the high-resolution model allows us to reveal the outward spread of Hg in an eddy shape driven by fine-scale ocean currents. With faster current velocities and diffusion rates, our model captures the transport and mixing of Hg from river discharge in a more accurate and detailed way and improves our understanding of Hg cycle in the ocean.
Formatted Citation: Xu, W., G. Wang, X. Cheng, X. Xing, J. Qin, G. Zhou, L. Jiang, and B. Chen, 2023: Mesoscale Eddy Modulation of Subsurface Chlorophyll Maximum Layers in the South China Sea. Journal of Geophysical Research: Biogeosciences, 128(11), doi:10.1029/2023JG007648
Abstract:
Subsurface chlorophyll maximum (SCM) layers contribute considerably to the integrated biomass of the water column and can be strongly modulated by mesoscale eddies that are ubiquitous in the global ocean. The mechanisms of eddy-induced surface chlorophyll concentration have been extensively examined in the South China Sea (SCS). However, the potential impact of mesoscale eddies on SCM layers remains unclear. We examined the influence of mesoscale eddies on the depth, thickness and magnitude of SCM layers in the SCS using output from an eddy-permitting biological-physical coupled model over a 22-year period. Our study shows that nutrient distribution is largely driven by eddy dynamics, with cyclonic eddies enhancing the supply of inorganic nutrients in the upper layers by uplifting the thermocline, and downward displacement of the thermocline in anticyclonic eddies, reducing the nutrient supply into the euphotic zone from the depth. We found that anticyclonic (cyclonic) eddies are responsible for increased (decreased) SCM depth and decreased (increased) SCM magnitude; SCM thickness decreased in cyclonic eddies but slightly increased in anticyclonic eddies. The effects of mesoscale eddies depend on eddy amplitude. Maximal anomalies in depth, thickness and magnitude always occur near the center of eddies. Phytoplankton community structure at SCM layers is also affected by eddies, with more diatoms in cyclonic eddies and more coccolithophores in anticyclonic eddies. Our study will advance our understanding of mesoscale physical-biogeochemical interactions.
Das, Bijan Kumar; Anandh, T.S.; Chakraborty, Arun; Kuttippurath, J. (2023). Summertime discontinuity of Western Boundary Current in the Bay of Bengal during contrasting Indian Ocean Dipole events of 2008 and 2010, Regional Studies in Marine Science (64), 103049, 10.1016/j.rsma.2023.103049.
Title: Summertime discontinuity of Western Boundary Current in the Bay of Bengal during contrasting Indian Ocean Dipole events of 2008 and 2010
Type: Journal Article
Publication: Regional Studies in Marine Science
Author(s): Das, Bijan Kumar; Anandh, T.S.; Chakraborty, Arun; Kuttippurath, J.
Year: 2023
Formatted Citation: Das, B. K., T. Anandh, A. Chakraborty, and J. Kuttippurath, 2023: Summertime discontinuity of Western Boundary Current in the Bay of Bengal during contrasting Indian Ocean Dipole events of 2008 and 2010. Regional Studies in Marine Science, 64, 103049, doi:10.1016/j.rsma.2023.103049
Ma, Kai; Liu, Chuanyu; Xu, Junli; Wang, Fan (2023). Contrasts of bimodal tropical instability waves (TIWs)-induced wind stress perturbations in the Pacific Ocean among observations, ocean models, and coupled climate models, Journal of Oceanology and Limnology, 10.1007/s00343-023-2326-z.
Title: Contrasts of bimodal tropical instability waves (TIWs)-induced wind stress perturbations in the Pacific Ocean among observations, ocean models, and coupled climate models
Type: Journal Article
Publication: Journal of Oceanology and Limnology
Author(s): Ma, Kai; Liu, Chuanyu; Xu, Junli; Wang, Fan
Year: 2023
Formatted Citation: Ma, K., C. Liu, J. Xu, and F. Wang, 2023: Contrasts of bimodal tropical instability waves (TIWs)-induced wind stress perturbations in the Pacific Ocean among observations, ocean models, and coupled climate models. Journal of Oceanology and Limnology, doi:10.1007/s00343-023-2326-z
Formatted Citation: Min, C., Q. Yang, H. Luo, D. Chen, T. Krumpen, N. Mamnun, X. Liu, and L. Nerger, 2023: Improving Arctic sea-ice thickness estimates with the assimilation of CryoSat-2 summer observations. Ocean-Land-Atmosphere Research, doi:10.34133/olar.0025
Kun, Zhang; Qiang, Wang; Baoshu, Yin; Dezhou, Yang; Lina, Yang (2023). Contribution of deep vertical velocity to deficiency of Sverdrup transport in the low-latitude North Pacific, Journal of Physical Oceanography, 10.1175/JPO-D-23-0006.1.
Formatted Citation: Kun, Z., W. Qiang, Y. Baoshu, Y. Dezhou, and Y. Lina, 2023: Contribution of deep vertical velocity to deficiency of Sverdrup transport in the low-latitude North Pacific. Journal of Physical Oceanography, doi:10.1175/JPO-D-23-0006.1
Abstract:
Deep vertical velocity is a critical factor causing deficiencies in Sverdrup theory. However, few studies have focused on its influence in the low-latitude western Pacific. Through multiple analyses of observational, reanalysis, and simulation data, this study explored the contribution of deep non-zero vertical velocity to the Sverdrup transport inaccuracy in the low-latitude North Pacific. The vertical velocities inducing relatively small non-Sverdrup transport exist within 1500-2500 m, which exhibit similar patterns with opposite values to the south and north of 13°N. The zonally integrated meridional volume transport associated with these vertical velocities displays non-negligible dipolar zonal bands west of approximately 150°W. The positive and negative transport bands, centered at 11°N and 17°N, can reach an amplitude of approximately 8.0 Sv when integrated from the eastern boundary to 140°E. On average, such integrated meridional transport makes up roughly half of the prominent Sverdrup transport discrepancies in the central-western Pacific. Further investigation indicated that the spatial pattern of these vertical velocities is modulated by ocean topography and deep southward currents. Moreover, a near-global test suggested that the meridional non-Sverdrup transport related to deep vertical velocity is widespread and undergoes remarkable multidecadal variation. This study reveals the disruptive role of deep vertical velocity in disturbing the Sverdrup balance and emphasizes the consideration of its long-term variation when diagnosing wind-driven circulation changes using Sverdrup theory.
Qian, Jiangchao; Zhai, Xiaoming; Wang, Zhaomin; Jochum, Markus (2023). Distribution and Trend of Wind Power Input to Near-Inertial Motions in the Southern Ocean, Geophysical Research Letters, 18 (50), 10.1029/2023GL105411.
Title: Distribution and Trend of Wind Power Input to Near-Inertial Motions in the Southern Ocean
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Qian, Jiangchao; Zhai, Xiaoming; Wang, Zhaomin; Jochum, Markus
Year: 2023
Formatted Citation: Qian, J., X. Zhai, Z. Wang, and M. Jochum, 2023: Distribution and Trend of Wind Power Input to Near-Inertial Motions in the Southern Ocean. Geophys. Res. Lett., 50(18), doi:10.1029/2023GL105411
Abstract:
Wind power input to near-inertial motions is an important energy source for generating diapycnal mixing in the ocean. However, the distribution and long-term trend of this input over the Southern Ocean have yet to be quantified. In this study, we investigate the near-inertial wind power input (WPI i ) to the Southern Ocean using a global eddy-permitting coupled ocean-sea ice model forced by a high-resolution atmospheric reanalysis product. Our results reveal a zonally asymmetric distribution of WPI i in the Southern Ocean, with the strongest input in the South Indian Ocean and the weakest in the South Pacific. The integrated WPI i between 30°S and 60°S exhibits a significant positive trend over the past four decades due to the intensification of mesoscale weather systems. The surface mixed-layer depth is found to modulate the spatial pattern and trend of WPI i by altering the surface near-inertial currents.
Title: Reduction of non-tidal oceanographic fluctuations in ocean-bottom pressure records of DONET using principal component analysis to enhance transient tectonic detectability
Formatted Citation: Otsuka, H., Y. Ohta, R. Hino, T. Kubota, D. Inazu, T. Inoue, and N. Takahashi, 2023: Reduction of non-tidal oceanographic fluctuations in ocean-bottom pressure records of DONET using principal component analysis to enhance transient tectonic detectability. Earth, Planets and Space, 75(1), 112, doi:10.1186/s40623-023-01862-z
Abstract:
Ocean bottom pressure-gauge (OBP) records play an essential role in seafloor geodesy. Oceanographic fluctuations in OBP data, however, pose as a significant noise source in seafloor transient crustal deformation observations, including slow slip events (SSEs), making it crucial to evaluate them quantitatively. To extract the significant fluctuation phenomena common to multiple observation networks, including oceanographic fluctuations and tectonic signals, we applied principal component analysis (PCA) to the 3-year Dense Oceanfloor Network System for Earthquakes and Tsunamis (DONET) OBP time series for 40 stations during 2016-2019. PCA could separate several oceanographic signals based on the characteristics of their spatial distributions, although evident transient tectonic signals could not be confirmed from the observed pressure records during this observed period. The spatial distribution of the first four principal components (PCs) reflected the common component, inclined component along sea depth, longitude component, and parabola-like pattern, respectively. By subtracting each PC (in particular, PC-2 and PC-4) from the time series, we could significantly reduce the sea depth dependence of OBP records, which has been highlighted in several previous studies and is also evident in this region. We interpreted PCs 2-4 as the reflection of the strength and meandering of ocean geostrophic currents based on a comparison with the PC spatial distribution of the numerical oceanographic models. In addition, to evaluate the ability of PCA to separate transient tectonic signal from OBP time series, including oceanographic fluctuations, we conducted a synthetic ramp assuming an SSE by rectangular fault and then applied PCA. The assumed synthetic tectonic signal could be separated from the oceanographic signals and included in the principal component independently depending on its amplitude, suggesting that the spatial distribution of each PC would change if the amplitude of the synthetic signal were sufficiently large. We propose a transient event-detection method based on the spatial distribution difference of a specific PC with or without a tectonic signal. We used the normalized inner product (NIP) between these PCs as the indicator of their similarities. This method can detect transient tectonic signals more significantly than the moment-magnitude scale of 5.9 from OBP records.
Kuhn, Angela M.; Mazloff, Matthew; Dutkiewicz, Stephanie; Jahn, Oliver; Clayton, Sophie; Rynearson, Tatiana; Barton, Andrew D. (2023). A Global Comparison of Marine Chlorophyll Variability Observed in Eulerian and Lagrangian Perspectives, Journal of Geophysical Research: Oceans, 7 (128), 10.1029/2023JC019801.
Title: A Global Comparison of Marine Chlorophyll Variability Observed in Eulerian and Lagrangian Perspectives
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Kuhn, Angela M.; Mazloff, Matthew; Dutkiewicz, Stephanie; Jahn, Oliver; Clayton, Sophie; Rynearson, Tatiana; Barton, Andrew D.
Year: 2023
Formatted Citation: Kuhn, A. M., M. Mazloff, S. Dutkiewicz, O. Jahn, S. Clayton, T. Rynearson, and A. D. Barton, 2023: A Global Comparison of Marine Chlorophyll Variability Observed in Eulerian and Lagrangian Perspectives. J. Geophys. Res. Ocean., 128(7), doi:10.1029/2023JC019801
Abstract:
Ocean chlorophyll time series exhibit temporal variability on a range of timescales due to environmental change, ecological interactions, dispersal, and other factors. The differences in chlorophyll temporal variability observed at stationary locations (Eulerian perspective) or following water parcels (Lagrangian perspective) are poorly understood. Here we contrasted the temporal variability of ocean chlorophyll in these two observational perspectives, using global drifter trajectories and satellite chlorophyll to generate matched pairs of Eulerian-Lagrangian time series. We found that for most ocean locations, chlorophyll variances measured in Eulerian and Lagrangian perspectives are not statistically different. In high latitude areas, the two perspectives may capture similar variability due to the large spatial scale of chlorophyll patches. In localized regions of the ocean, however, chlorophyll variability measured in these two perspectives may significantly differ. For example, in some western boundary currents, temporal chlorophyll variability in the Lagrangian perspective was greater than in the Eulerian perspective. In these cases, the observing platform travels rapidly across strong environmental gradients and constrained by the shelf topography, potentially leading to greater Lagrangian variability in chlorophyll. In contrast, we found that Eulerian chlorophyll variability exceeded Lagrangian variability in some key upwelling zones and boundary current extensions. In these cases, variability in the nutrient supply may generate intermittent chlorophyll anomalies in the Eulerian perspective, while the Lagrangian perspective sees the transport of such anomalies off-shore. These findings aid with the interpretation of chlorophyll time series from different sampling methodologies, inform observational network design, and guide validation of marine ecosystem models.
Thankaswamy, Anandh; Xian, Tao; Wang, Lian-Ping (2023). Typhoons and their upper ocean response over South China Sea using COAWST model, Frontiers in Earth Science (11), 10.3389/feart.2023.1102957.
Formatted Citation: Thankaswamy, A., T. Xian, and L. Wang, 2023: Typhoons and their upper ocean response over South China Sea using COAWST model. Frontiers in Earth Science, 11, doi:10.3389/feart.2023.1102957
Abstract:
The formation and intensification of typhoons is a complex process where energy and mass exchanges happen between the ocean and the atmosphere. In most typhoon numerical studies, a static ocean and a dynamic atmosphere are used to reduce the complexity of modeling. Using the COAWST model, we studied the air-sea interactions of Typhoon Mujigae in 2015, Typhoon Merbok in 2017, and Typhoon Hato in 2017 over the South China Sea. With different translation speeds, track shapes, and intensities between these cyclones, they act as an excellent case study to analyze the air-sea coupling in the models. The inclusion of coupling between the ocean and atmosphere is found to improve the typhoon track simulation significantly. The bias in the cyclone tracks is reduced by 10%-40% in the coupled model. The upper ocean response to the typhoon was also analyzed using the coupled model output. The coupled simulations show that the major energy extraction occurs to the right of the track, which is consistent with satellite observation and latent heat release analysis. The coupling process shows the air-sea interactions and exchanges in the upper ocean along with the energy released during the passage of typhoons. The heat budget analysis shows that the cooling of the upper ocean is mainly attributed to the advection associated with the typhoon forcing. This study shows that it is necessary to include ocean feedback while analyzing a typhoon, and the application of coupled models can improve our understanding as well as the forecasting capability of typhoons.
Avila-Alonso, Dailé; Baetens, Jan M.; Cardenas, Rolando; De Baets, Bernard (2023). Response of phytoplankton functional types to Hurricane Fabian (2003) in the Sargasso Sea, Marine Environmental Research, 106079, 10.1016/j.marenvres.2023.106079.
Title: Response of phytoplankton functional types to Hurricane Fabian (2003) in the Sargasso Sea
Type: Journal Article
Publication: Marine Environmental Research
Author(s): Avila-Alonso, Dailé; Baetens, Jan M.; Cardenas, Rolando; De Baets, Bernard
Year: 2023
Formatted Citation: Avila-Alonso, D., J. M. Baetens, R. Cardenas, and B. De Baets, 2023: Response of phytoplankton functional types to Hurricane Fabian (2003) in the Sargasso Sea. Marine Environmental Research, 106079, doi:10.1016/j.marenvres.2023.106079
Title: Subglacial Freshwater Drainage Increases Simulated Basal Melt of the Totten Ice Shelf
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Gwyther, David E.; Dow, Christine F.; Jendersie, Stefan; Gourmelen, Noel; Galton-Fenzi, Benjamin K.
Year: 2023
Formatted Citation: Gwyther, D. E., C. F. Dow, S. Jendersie, N. Gourmelen, and B. K. Galton-Fenzi, 2023: Subglacial Freshwater Drainage Increases Simulated Basal Melt of the Totten Ice Shelf. Geophys. Res. Lett., 50(12), doi:10.1029/2023GL103765
Yang, Lina; Zhao, Xinyang; Liang, Peng; Zhang, Tianyu; Xie, Lingling; Murtugudde, Raghu (2023). Wind and heat forcings of the seasonal and interannual sea level variabilities in the southwest Pacific, Journal of Physical Oceanography, 10.1175/JPO-D-23-0018.1.
Formatted Citation: Yang, L., X. Zhao, P. Liang, T. Zhang, L. Xie, and R. Murtugudde, 2023: Wind and heat forcings of the seasonal and interannual sea level variabilities in the southwest Pacific. Journal of Physical Oceanography, doi:10.1175/JPO-D-23-0018.1
Abstract:
Sea level variabilities in the southwest Pacific contribute to the variations of equatorial current bifurcation and the Indonesian Throughflow transport. These processes are closely related to the recharge/discharge of equatorial heat content and dynamic distribution of anthropogenic ocean heating over the Indo-Pacific basin, thus being of profound significance for climate variability and change. Here we identify the major features of seasonal and interannual sea level variabilities in this region, confirming the dominance of the first baroclinic mode in the tropics (contributing 60-80% of the variances) and higher baroclinic modes in the extra-tropics (40-60% of the seasonal variance). Seasonally, except in the western Coral Sea where the Ekman pumping is significant, the wind-driven first-mode baroclinic Rossby waves originating to the east of the dateline control the sea level variations over most tropical Pacific regions. In the domain where the 1.5-layer reduced gravity model becomes deficient, the surface heat fluxes dominate, explaining ~40-80% of sea level variance. For interannual variability, ~40-60% of the variance are El Niño-Southern Oscillation (ENSO)-related. The wind-driven Rossby and Kelvin waves east of the dateline explain ~40-78% of the interannual variance in the tropical Pacific. Outside the tropics, small-scale diffusive processes are presumed critical for interannual variability according to a thermodynamic analysis using an eddy-permitting ocean model simulation. Further process and predictive understandings can be achieved with the coupled climate models properly parameterizing the sub-grid-scale processes.
Wu, Yang; Zhao, Xiangjun; Qi, Zhengdong; Zhou, Kai; Qiao, Dalei (2023). Relative Contribution of Atmospheric Forcing, Oceanic Preconditioning and Sea Ice to Deep Convection in the Labrador Sea, Journal of Marine Science and Engineering, 4 (11), 869, 10.3390/jmse11040869.
Formatted Citation: Wu, Y., X. Zhao, Z. Qi, K. Zhou, and D. Qiao, 2023: Relative Contribution of Atmospheric Forcing, Oceanic Preconditioning and Sea Ice to Deep Convection in the Labrador Sea. Journal of Marine Science and Engineering, 11(4), 869, doi:10.3390/jmse11040869
Abstract:
The relative contribution of atmospheric forcing, oceanic preconditioning, and sea ice to Labrador Sea Deep Convection (LSDC) is investigated by conducting three ensemble experiments using a global coupled sea ice-ocean model for the first time. Simulated results show that the atmospheric activities dominate the interannual and decadal variability, accounting for 70% of LSDC. Oceanic preconditioning is more significant in the shallow LSDC years that the water column is stable, accounting for 21%, especially in the central Labrador Sea and Irminger Sea. Moreover, the sea ice contribution is negligible over the whole Labrador Sea, while its contribution is significant in the sea ice-covered slope regions, accounting for 20%. The increasingly importance of sea ice on LSDC and the water mass transformation will be found in the North Atlantic Ocean, if the Arctic sea ice declines continuously. Additionally, there is a 10 Sv increase (85%) in atmospheric forcing to the subpolar gyre in the North Atlantic Ocean, while oceanic preconditioning contributes a 7 Sv decrease (12%). These findings highlight the importance of summer oceanic preconditioning to LSDC and the subpolar gyre, and therefore it should be appropriately accounted for in future studies.
Boeira Dias, Fabio; Rintoul, Stephen R.; Richter, Ole; Galton-Fenzi, Benjamin Keith; Zika, Jan D.; Pellichero, Violaine; Uotila, Petteri (2023). Sensitivity of simulated water mass transformation on the Antarctic shelf to tides, topography and model resolution, Frontiers in Marine Science (10), 10.3389/fmars.2023.1027704.
Title: Sensitivity of simulated water mass transformation on the Antarctic shelf to tides, topography and model resolution
Type: Journal Article
Publication: Frontiers in Marine Science
Author(s): Boeira Dias, Fabio; Rintoul, Stephen R.; Richter, Ole; Galton-Fenzi, Benjamin Keith; Zika, Jan D.; Pellichero, Violaine; Uotila, Petteri
Year: 2023
Formatted Citation: Boeira Dias, F., S. R. Rintoul, O. Richter, B. K. Galton-Fenzi, J. D. Zika, V. Pellichero, and P. Uotila, 2023: Sensitivity of simulated water mass transformation on the Antarctic shelf to tides, topography and model resolution. Frontiers in Marine Science, 10, doi:10.3389/fmars.2023.1027704
Abstract:
Water mass transformation (WMT) around the Antarctic margin controls Antarctica Bottom Water formation and the abyssal limb of the global meridional overturning circulation, besides mediating ocean-ice shelf exchange, ice sheet stability and its contribution to sea level rise. However, the mechanisms controlling the rate of WMT in the Antarctic shelf are poorly understood due to the lack of observations and the inability of climate models to simulate those mechanisms, in particular beneath the floating ice shelves. We used a circum-Antarctic ocean-ice shelf model to assess the contribution of surface fluxes, mixing, and ocean-ice shelf interaction to the WMT on the continental shelf. The salt budget dominates the WMT rates, with only a secondary contribution from the heat budget. Basal melt of ice shelves drives buoyancy gain at lighter density classes (27.2<σθ<27.6 kg m-3 ), while salt input associated with sea-ice growth in coastal polynyas drives buoyancy loss at heavier densities (σθ > 27.6). We found a large sensitivity of the WMT rates to model horizontal resolution, tides and topography within the Filchner-Ronne, East and West Antarctica ice shelf cavities. In the Filchner-Ronne Ice Shelf, an anticyclonic circulation in front of the Ronne Depression regulates the rates of basal melting/refreezing and WMT and is substantially affected by tides and model resolution. Model resolution is also found to affect the Antarctic Slope Current in both East and West Antarctica, impacting the on-shelf heat delivery, basal melt and WMT. Moreover, the representation of the ice shelf draft associated with model resolution impacts the freezing temperature and thus basal melt and WMT rates in the East Antarctica. These results highlight the importance of resolving small-scale features of the flow and topography, and to include the effects of tidal forcing, to adequately represent water mass transformations on the shelf that directly influence the abyssal global overturning circulation.
Verjans, Vincent; Robel, Alexander; Thompson, Andrew F.; Seroussi, Helene (2023). Bias Correction and Statistical Modeling of Variable Oceanic Forcing of Greenland Outlet Glaciers, Journal of Advances in Modeling Earth Systems, 4 (15), 10.1029/2023MS003610.
Title: Bias Correction and Statistical Modeling of Variable Oceanic Forcing of Greenland Outlet Glaciers
Type: Journal Article
Publication: Journal of Advances in Modeling Earth Systems
Author(s): Verjans, Vincent; Robel, Alexander; Thompson, Andrew F.; Seroussi, Helene
Year: 2023
Formatted Citation: Verjans, V., A. Robel, A. F. Thompson, and H. Seroussi, 2023: Bias Correction and Statistical Modeling of Variable Oceanic Forcing of Greenland Outlet Glaciers. Journal of Advances in Modeling Earth Systems, 15(4), doi:10.1029/2023MS003610
Manizza, Manfredi; Carroll, Dustin; Menemenlis, Dimitris; Zhang, Hong; Miller, Charles E. (2023). Modeling the recent changes of phytoplankton blooms dynamics in the Arctic Ocean, Journal of Geophysical Research: Oceans, 10.1029/2022JC019152.
Title: Modeling the recent changes of phytoplankton blooms dynamics in the Arctic Ocean
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Manizza, Manfredi; Carroll, Dustin; Menemenlis, Dimitris; Zhang, Hong; Miller, Charles E.
Year: 2023
Formatted Citation: Manizza, M., D. Carroll, D. Menemenlis, H. Zhang, and C. E. Miller, 2023: Modeling the recent changes of phytoplankton blooms dynamics in the Arctic Ocean. J. Geophys. Res. Ocean., doi:10.1029/2022JC019152
Jung, Yong Woo; Kim, Beom Sik; Jung, Hae Kun; Lee, Chung Il (2023). Distributional Changes in Fishery Resource Diversity Caused by Typhoon Pathways in the East/Japan Sea, Fishes, 5 (8), 242, 10.3390/fishes8050242.
Title: Distributional Changes in Fishery Resource Diversity Caused by Typhoon Pathways in the East/Japan Sea
Type: Journal Article
Publication: Fishes
Author(s): Jung, Yong Woo; Kim, Beom Sik; Jung, Hae Kun; Lee, Chung Il
Year: 2023
Formatted Citation: Jung, Y. W., B. S. Kim, H. K. Jung, and C. I. Lee, 2023: Distributional Changes in Fishery Resource Diversity Caused by Typhoon Pathways in the East/Japan Sea. Fishes, 8(5), 242, doi:10.3390/fishes8050242
Abstract:
Typhoons disturb the upper ocean, weaken the physical stratification, and induce temporal and spatial changes in primary production, which rapidly alter the distribution and diversity of fishery resources. This study analyzed the response of oceanic conditions and fishery resources on the sea area of the typhoon pathway in the East/Japan Sea (Type A: typhoon passed from southwest to northeast; Type B: typhoon dissipated in the southwest; Type C: typhoon passed from southeast to northeast; and Type D: typhoons passed from southwest to northwest). For Types A and B, the sea surface temperature (SST) decreased in all areas, and Chl-a showed the largest fluctuations in the southwest. For Type C, the SST variation was reduced in the eastern part, stratification was strengthened, and Chl-a did not differ significantly in each area. For Type D, SST and Chl-a showed significant variations in the western part. The biomass of fishery resources increased along the typhoon path for each type, and the diversity increased for Types A and D but decreased for Type B; however, the diversity and catch of fishery resources increased in the northeast for Type C. This study contributes to understanding the impact of typhoon pathway changes on the marine environment and ecosystem.
Zhao, Rongjie; Zhao, Feng; Feng, Ling; Fang, James Kar-Hei; Liu, Chuanyu; Xu, Kuidong (2023). A Deep Seamount Effect Enhanced the Vertical Connectivity of the Planktonic Community Across 1,000 m Above Summit, Journal of Geophysical Research: Oceans, 3 (128), 10.1029/2022JC018898.
Formatted Citation: Zhao, R., F. Zhao, L. Feng, J. K. Fang, C. Liu, and K. Xu, 2023: A Deep Seamount Effect Enhanced the Vertical Connectivity of the Planktonic Community Across 1,000 m Above Summit. J. Geophys. Res. Ocean., 128(3), doi:10.1029/2022JC018898
Guo, Yaru; Li, Yuanlong; Wang, Fan (2023). Destinations and Pathways of the Indonesian Throughflow Water in the Indian Ocean, Journal of Climate, 11 (36), 3717-3735, 10.1175/JCLI-D-22-0631.1.
Title: Destinations and Pathways of the Indonesian Throughflow Water in the Indian Ocean
Type: Journal Article
Publication: Journal of Climate
Author(s): Guo, Yaru; Li, Yuanlong; Wang, Fan
Year: 2023
Formatted Citation: Guo, Y., Y. Li, and F. Wang, 2023: Destinations and Pathways of the Indonesian Throughflow Water in the Indian Ocean. J. Clim., 36(11), 3717-3735, doi:10.1175/JCLI-D-22-0631.1
Abstract:
Passage of the Indonesian Throughflow (ITF) water through the Indian Ocean constitutes an essential section of the upper limb of the global ocean conveyor belt. Although existing studies have identified a major exit of the ITF water to the Atlantic Ocean through the Agulhas Current system, our knowledge regarding other possible destinations and primary pathways remains limited. This study applies the Connectivity Modeling System (CMS) particle tracking algorithm to seven model-based ocean current datasets. The results reveal a robust return path of the ITF water to the Pacific Ocean. The partition ratio between the Atlantic and Pacific routes is 1.60 ± 0.54 to 1, with the uncertainty representing interdataset spread. The average transit time across the Indian Ocean is 10-20 years to the Atlantic and 15-30 years to the Pacific. The "transit velocity" is devised to describe the three-dimensional pathways in a quantitative sense. Its distribution demonstrates that the recirculation structures in the southwestern subtropical Indian Ocean favor the exit to the Atlantic, while the Antarctic Circumpolar Current in the Southern Ocean serves as the primary corridor to the Pacific. Our analysis also suggests the vital impact of vertical motions. In idealized tracing experiments inhibiting vertical currents and turbulent mixing, more water tends to linger over the Indian Ocean or return to the Pacific. Turbulence mixing also contributes to vertical motions but only slightly affects the destinations and pathways of ITF water.
Keywords:
ECCO Products Used: ECCO2;GECCO2
URL:
Other URLs:
Lang, Yandong (2023). Mathematical and Physical Methods to Construct Approximately Neutral Surfaces.
Title: Mathematical and Physical Methods to Construct Approximately Neutral Surfaces
Type: Thesis
Publication:
Author(s): Lang, Yandong
Year: 2023
Formatted Citation: Lang, Y., 2023: Mathematical and Physical Methods to Construct Approximately Neutral Surfaces. http://hdl.handle.net/1959.4/101076.
Abstract: The magnitude of the diffusivity that characterizes lateral mixing in the ocean is about 106 -108 times larger than that of vertical mixing. The lateral direction is along the direction of the neutral tangent plane (same as the direction of the locally referenced potential density surface). However, due to the helical nature of the neutral trajectories (the normal vector of the neutral tangent plane is not curl-free), well-defined neutral surfaces do not exist. Well-defined but only approximately neutral surfaces have traditionally been chosen based on either (i) constructing a three-dimensional density variable whose iso-surface (the surface with a constant density value of the density variable) describes the lateral direction, or (ii) creating a two-dimensional approximately neutral surfaces (ANS), which are normally more neutral than the iso-surfaces of the three-dimensional density variable A three-dimensional neutral density variable is here derived called rSCV, which is an improvement on the neutral density rn of Jackett and McDougall (1997). Compared with rn, rSCV is independent of pressure and thus is insensitive to the ubiquitous vertical heaving motions of waves and eddies, and has similar neutrality as rn. The material derivatives (the rate of change of the density variables) of rSCV and rn have also been derived using numerical methods. The material derivative of rSCV is shown to be close to that of rn. Oceanographers have traditionally estimated the quality of an ANS by focusing on the fictitious vertical diffusion caused by lateral diffusion being applied in the wrong direction. This thesis shows that the spurious advection through an ANS is another important consideration that limits the accuracy and usefulness of an ANS. Because of this concern, a two-dimensional approximately neutral surface is constructed called the Wu.s-surface, which minimizes the spurious dia-surface advection through the surface. The spurious dia-surface advection through the Wu.s-surface is more than a hundred times smaller than that on the most neutral ANS to date, however, the fictitious diapycnal diffusion on it is larger. Therefore, the Wu.s+s2-surface is created to control both the spurious dia-surface advection and the fictitious diapycnal diffusion on the surface. It is shown that minimizing the fictitious diffusion and the spurious dia-surface advection is important for using such surfaces in inverse studies. Hence the Wu.s+s2-surface is the best choice of surface for such studies.
Hay, H. C. F. C.; Fenty, I.; Pappalardo, R. T.; Nakayama, Y. (2023). Turbulent Drag at the Ice-Ocean Interface of Europa in Simulations of Rotating Convection: Implications for Nonsynchronous Rotation of the Ice Shell, Journal of Geophysical Research: Planets, 3 (128), 10.1029/2022JE007648.
Title: Turbulent Drag at the Ice-Ocean Interface of Europa in Simulations of Rotating Convection: Implications for Nonsynchronous Rotation of the Ice Shell
Type: Journal Article
Publication: Journal of Geophysical Research: Planets
Author(s): Hay, H. C. F. C.; Fenty, I.; Pappalardo, R. T.; Nakayama, Y.
Year: 2023
Formatted Citation: Hay, H. C. F. C., I. Fenty, R. T. Pappalardo, and Y. Nakayama, 2023: Turbulent Drag at the Ice-Ocean Interface of Europa in Simulations of Rotating Convection: Implications for Nonsynchronous Rotation of the Ice Shell. Journal of Geophysical Research: Planets, 128(3), doi:10.1029/2022JE007648
Formatted Citation: Xue, A., F. Jin, W. Zhang, J. Boucharel, and J. Kug, 2023: Parameterizing the nonlinear feedback on ENSO from tropical instability waves (TIWs) by nonlinear eddy thermal diffusivity. Climate Dynamics, doi:10.1007/s00382-023-06744-4
Formatted Citation: Ibarbalz, F. M. and Coauthors, 2023: Pan-Arctic plankton community structure and its global connectivity. Elementa: Science of the Anthropocene, 11(1), doi:10.1525/elementa.2022.00060
Abstract: The Arctic Ocean (AO) is being rapidly transformed by global warming, but its biodiversity remains understudied for many planktonic organisms, in particular for unicellular eukaryotes that play pivotal roles in marine food webs and biogeochemical cycles. The aim of this study was to characterize the biogeographic ranges of species that comprise the contemporary pool of unicellular eukaryotes in the AO as a first step toward understanding mechanisms that structure these communities and identifying potential target species for monitoring. Leveraging the Tara Oceans DNA metabarcoding data, we mapped the global distributions of operational taxonomic units (OTUs) found on Arctic shelves into five biogeographic categories, identified biogeographic indicators, and inferred the degree to which AO communities of unicellular eukaryotes share members with assemblages from lower latitudes. Arctic/Polar indicator OTUs, as well as some globally ubiquitous OTUs, dominated the detection and abundance of DNA reads in the Arctic samples. OTUs detected only in Arctic samples (Arctic-exclusives) showed restricted distribution with relatively low abundances, accounting for 10-16% of the total Arctic OTU pool. OTUs with high abundances in tropical and/or temperate latitudes (non-Polar indicators) were also found in the AO but mainly at its periphery. We observed a large change in community taxonomic composition across the Atlantic-Arctic continuum, supporting the idea that advection and environmental filtering are important processes that shape plankton assemblages in the AO. Altogether, this study highlights the connectivity between the AO and other oceans, and provides a framework for monitoring and assessing future changes in this vulnerable ecosystem.
Formatted Citation: Su, F. and Coauthors, 2023: Widespread global disparities between modelled and observed mid-depth ocean currents. Nature Communications, 14(1), 2089, doi:10.1038/s41467-023-37841-x
Abstract:
The mid-depth ocean circulation is critically linked to actual changes in the long-term global climate system. However, in the past few decades, predictions based on ocean circulation models highlight the lack of data, knowledge, and long-term implications in climate change assessment. Here, using 842,421 observations produced by Argo floats from 2001-2020, and Lagrangian simulations, we show that only 3.8% of the mid-depth oceans, including part of the equatorial Pacific Ocean and the Antarctic Circumpolar Current, can be regarded as accurately modelled, while other regions exhibit significant underestimations in mean current velocity. Knowledge of ocean circulation is generally more complete in the low-latitude oceans but is especially poor in high latitude regions. Accordingly, we propose improvements in forecasting, model representation of stochasticity, and enhancement of observations of ocean currents. The study demonstrates that knowledge and model representations of global circulation are substantially compromised by inaccuracies of significant magnitude and direction, with important implications for modelled predictions of currents, temperature, carbon dioxide sequestration, and sea-level rise trends.
Formatted Citation: Pascual-Ahuir, E. G., and Z. Wang, 2023: Optimized sea ice simulation in MITgcm-ECCO2 forced by ERA5. Ocean Modelling, 183, 102183, doi:10.1016/j.ocemod.2023.102183
Formatted Citation: Wang, C., S. Wang, Z. Jing, T. Geng, H. Wang, and L. Wu, 2023: Equatorial Submesoscale Eddies Contribute to the Asymmetry in ENSO Amplitude. Geophys. Res. Lett., 50(5), doi:10.1029/2022GL101352
Song, Xiangzhou (2023). Observed Opposite Fall-to-Winter Variations in the Air-Sea Latent Heat Flux Between the Western Boundary Currents and Coastal Seas, Geophysical Research Letters, 2 (50), 10.1029/2022GL100875.
Title: Observed Opposite Fall-to-Winter Variations in the Air-Sea Latent Heat Flux Between the Western Boundary Currents and Coastal Seas
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Song, Xiangzhou
Year: 2023
Formatted Citation: Song, X., 2023: Observed Opposite Fall-to-Winter Variations in the Air-Sea Latent Heat Flux Between the Western Boundary Currents and Coastal Seas. Geophys. Res. Lett., 50(2), doi:10.1029/2022GL100875
Formatted Citation: Yang, H., C. Yang, Y. Liu, and Z. Chen, 2023: Energetics during eddy shedding in the Gulf of Mexico. Ocean Dynamics, 73(2), 79-90, doi:10.1007/s10236-023-01538-y
Abstract: Using the Estimating Circulation and Climate of the Ocean (ECCO) Phase II product, this study investigates the energetic characteristics during eddy shedding in the Gulf of Mexico. Based on the sea level anomaly data between 1992 and 2016, a total of 34 eddy shedding events are identified. Drawing on multiscale energy and vorticity analysis method, the eddy kinetic energy (EKE) budgets are diagnosed based on the ensemble of 34 eddy shedding events. During the stage of eddy shedding, barotropic instability (BT) dominates the energy budget. Meanwhile, energy transfers from upper layer to the deep layer by vertical pressure work (PW), which is the main source of abyssal EKE. Before eddy detachment, cyclonic eddy appears at the southeastern side of the Loop Current. Even though buoyancy forcing (BF) dominates the energy budget, BT makes considerable contribution to the generation of cyclonic eddy. Baroclinic instability (BC) shares the similar horizontal distribution with BF which accounts for 32% of the value of BC.
Praetorius, Summer K.; Alder, Jay R.; Condron, Alan; Mix, Alan C.; Walczak, Maureen H.; Caissie, Beth E.; Erlandson, Jon M. (2023). Ice and ocean constraints on early human migrations into North America along the Pacific coast, Proceedings of the National Academy of Sciences, 7 (120), 10.1073/pnas.2208738120.
Title: Ice and ocean constraints on early human migrations into North America along the Pacific coast
Type: Journal Article
Publication: Proceedings of the National Academy of Sciences
Author(s): Praetorius, Summer K.; Alder, Jay R.; Condron, Alan; Mix, Alan C.; Walczak, Maureen H.; Caissie, Beth E.; Erlandson, Jon M.
Year: 2023
Formatted Citation: Praetorius, S. K., J. R. Alder, A. Condron, A. C. Mix, M. H. Walczak, B. E. Caissie, and J. M. Erlandson, 2023: Ice and ocean constraints on early human migrations into North America along the Pacific coast. Proceedings of the National Academy of Sciences, 120(7), doi:10.1073/pnas.2208738120
Abstract: Founding populations of the first Americans likely occupied parts of Beringia during the Last Glacial Maximum (LGM). The timing, pathways, and modes of their southward transit remain unknown, but blockage of the interior route by North American ice sheets between ~26 and 14 cal kyr BP (ka) favors a coastal route during this period. Using models and paleoceanographic data from the North Pacific, we identify climatically favorable intervals when humans could have plausibly traversed the Cordilleran coastal corridor during the terminal Pleistocene. Model simulations suggest that northward coastal currents strengthened during the LGM and at times of enhanced freshwater input, making southward transit by boat more difficult. Repeated Cordilleran glacial-calving events would have further challenged coastal transit on land and at sea. Following these events, ice-free coastal areas opened and seasonal sea ice was present along the Alaskan margin until at least 15 ka. Given evidence for humans south of the ice sheets by 16 ka and possibly earlier, we posit that early people may have taken advantage of winter sea ice that connected islands and coastal refugia. Marine ice-edge habitats offer a rich food supply and traversing coastal sea ice could have mitigated the difficulty of traveling southward in watercraft or on land over glaciers. We identify 24.5 to 22 ka and 16.4 to 14.8 ka as environmentally favorable time periods for coastal migration, when climate conditions provided both winter sea ice and ice-free summer conditions that facilitated year-round marine resource diversity and multiple modes of mobility along the North Pacific coast.
Formatted Citation: Huang, M., Y. Yang, and X. Liang, 2023: Seasonal Eddy Variability in the Northwestern Tropical Atlantic Ocean. Journal of Physical Oceanography, doi:10.1175/JPO-D-22-0200.1
Abstract: Eddies in the northwestern tropical Atlantic Ocean play a crucial role in transporting the South Atlantic Upper Ocean Water to the North Atlantic and connect the Atlantic and the Caribbean Sea. Although surface characteristics of those eddies have been well studied, their vertical structures and governing mechanisms are much less known. Here, using a time-dependent energetics framework based on the multiscale window transform, we examine the seasonal variability of the eddy kinetic energy (EKE) in the northwestern tropical Atlantic. Both altimeter-based data and ocean reanalyses show a substantial EKE seasonal cycle in the North Brazil Current Retroflection (NBCR) region that is mostly trapped in the upper 200 m. In the most energetic NBCR region, the EKE reaches its minimum in April-May-June and maximum in July-August-September. By analyzing six ocean reanalysis products, we find that barotropic instability is the controlling mechanism for the seasonal eddy variability in the NBCR region. Nonlocal processes, including advection and pressure work, play opposite roles in the EKE seasonal cycle. In the eastern part of the NBCR region, the EKE seasonal evolution is similar to the NBCR region. However, it is the nonlocal processes that control the EKE seasonality. In the western part of the NBCR region, the EKE magnitude is one order of magnitude smaller than in the NBCR region and shows a different seasonal cycle, which peaks in March and reaches its minimum in October-November. Our results highlight the complex mechanisms governing eddy variability in the northwestern tropical Atlantic and provide insights into their potential changes with changing background conditions.
Formatted Citation: Li, M., C. Pang, X. Yan, L. Zhang, and Z. Liu, 2023: Energetics of Multiscale Interactions in the Agulhas Retroflection Current System. Journal of Physical Oceanography, 53(2), 457-476, doi:10.1175/JPO-D-21-0275.1
Abstract: Using the recently developed multiscale window transform and multiscale energy and vorticity analysis methods, this study diagnoses the climatological characteristics of the nonlinear mutual interactions among mesoscale eddies, low-frequency (seasonal to interannual) fluctuations, and the decadally modulating mean flow in the Agulhas Retroflection Current System (ARCS). It is found that mesoscale eddies are generated primarily in the retroflection region by mixed barotropic and baroclinic instabilities. The barotropic instability dominates the generation of eddy kinetic energy (EKE) here, contributing power roughly 10 times larger than the baroclinic one. These locally generated eddies are transported away. In the rings drift and meanders regions, the nonlocal transport serves as an important energy source for the eddy field, making a contribution comparable to that of the baroclinic instability for the EKE production. Contrarily, in the stable region, the EKE is generated mainly due to the baroclinic instability. In most of the ARCS area, the kinetic energy (KE) is further transferred inversely from mesoscale eddies to other lower-frequency motions. In particular, in the retroflection, rings drift, and stable regions, the inverse KE cascade plays a leading role in generating seasonal-interannual fluctuations, providing roughly 3-5 times as much power as the forward KE cascade from the mean flow and the advection effect. In the meanders region, however, the forward cascade contributes 4 times more KE to the low-frequency variabilities than the inverse one. All the results provide a model-based benchmark for future studies on physical processes and dynamics at different scales in the ARCS.
Title: Towing icebergs to arid regions to reduce water scarcity
Type: Journal Article
Publication: Scientific Reports
Author(s): Condron, Alan
Year: 2023
Formatted Citation: Condron, A., 2023: Towing icebergs to arid regions to reduce water scarcity. Scientific Reports, 13(1), 365, doi:10.1038/s41598-022-26952-y
Abstract: Expanding agriculture, rising global population, and shifts in climate are placing increasing demands on existing water resources, especially in regions currently experiencing extreme drought. Finding new and reliable water sources is an urgent challenge. A long-held idea is that icebergs could be towed to arid coastal regions and harvested to help alleviate water stress. Here, a numerical model is used to simulate the deterioration of icebergs towed to Cape Town, South Africa and the United Arab Emirates (UAE). Moved at a speed of 0.5 m/s, an iceberg able to reach Cape Town must be at least ~300 m long and ~200 m thick at its time of capture. An iceberg this size would only require ~1 to 2 vessels to move and would deliver ~2.4 million liters of water. Placing an insulating material around the same iceberg to inhibit wave-induced erosion results in 4.5 billion liters of deliverable water. To reach the UAE, an unprotected iceberg needs to be at least ~2000 m long and 600 m thick, or 1250 m long and 600 m thick if insulated from wave-induced erosion. Icebergs of these dimensions would require ~10 to 20 vessels to move. Results are discussed in terms of the size and number of icebergs needed to help alleviate drought. In theory, small icebergs can easily be moved to South Africa; the challenge is likely to be harvesting the water as icebergs left offshore in a subtropical environment melt after a few days to weeks.
Stell, Angharad C.; Bertolacci, Michael; Zammit-Mangion, Andrew; Rigby, Matthew; Fraser, Paul J.; Harth, Christina M.; Krummel, Paul B.; Lan, Xin; Manizza, Manfredi; Mühle, Jens; O'Doherty, Simon; Prinn, Ronald G.; Weiss, Ray F.; Young, Dickon; Ganesan, Anita L. (2022). Modelling the growth of atmospheric nitrous oxide using a global hierarchical inversion, Atmospheric Chemistry and Physics, 19 (22), 12945-12960, 10.5194/acp-22-12945-2022.
Title: Modelling the growth of atmospheric nitrous oxide using a global hierarchical inversion
Type: Journal Article
Publication: Atmospheric Chemistry and Physics
Author(s): Stell, Angharad C.; Bertolacci, Michael; Zammit-Mangion, Andrew; Rigby, Matthew; Fraser, Paul J.; Harth, Christina M.; Krummel, Paul B.; Lan, Xin; Manizza, Manfredi; Mühle, Jens; O'Doherty, Simon; Prinn, Ronald G.; Weiss, Ray F.; Young, Dickon; Ganesan, Anita L.
Year: 2022
Formatted Citation: Stell, A. C. and Coauthors, 2022: Modelling the growth of atmospheric nitrous oxide using a global hierarchical inversion. Atmospheric Chemistry and Physics, 22(19), 12945-12960, doi:10.5194/acp-22-12945-2022
Abstract:
Abstract. Nitrous oxide is a potent greenhouse gas (GHG) and ozone-depleting substance, whose atmospheric abundance has risen throughout the contemporary record. In this work, we carry out the first global hierarchical Bayesian inversion to solve for nitrous oxide emissions, which includes prior emissions with truncated Gaussian distributions and Gaussian model errors, in order to examine the drivers of the atmospheric surface growth rate. We show that both emissions and climatic variability are key drivers of variations in the surface nitrous oxide growth rate between 2011 and 2020. We derive increasing global nitrous oxide emissions, which are mainly driven by emissions between 0 and 30°N, with the highest emissions recorded in 2020. Our mean global total emissions for 2011-2020 of 17.2 (16.7-17.7 at the 95 % credible intervals) Tg N yr−1, comprising of 12.0 (11.2-12.8) Tg N yr−1 from land and 5.2 (4.5-5.9) Tg N yr−1 from ocean, agrees well with previous studies, but we find that emissions are poorly constrained for some regions of the world, particularly for the oceans. The prior emissions used in this and other previous work exhibit a seasonal cycle in the extra-tropical Northern Hemisphere that is out of phase with the posterior solution, and there is a substantial zonal redistribution of emissions from the prior to the posterior. Correctly characterizing the uncertainties in the system, for example in the prior emission fields, is crucial for deriving posterior fluxes that are consistent with observations. In this hierarchical inversion, the model-measurement discrepancy and the prior flux uncertainty are informed by the data, rather than solely through "expert judgement". We show cases where this framework provides different plausible adjustments to the prior fluxes compared to inversions using widely adopted, fixed uncertainty constraints.
Nguyen, Nguyet-Minh; San, Dinh Cong; Nguyen, Kim Dan; Pham, Quoc Bao; Gagnon, Alexandre S.; Mai, Son T.; Anh, Duong Tran (2022). Region of freshwater influence (ROFI) and its impact on sediment transport in the lower Mekong Delta coastal zone of Vietnam, Environmental Monitoring and Assessment, 7 (194), 463, 10.1007/s10661-022-10113-9.
Title: Region of freshwater influence (ROFI) and its impact on sediment transport in the lower Mekong Delta coastal zone of Vietnam
Type: Journal Article
Publication: Environmental Monitoring and Assessment
Author(s): Nguyen, Nguyet-Minh; San, Dinh Cong; Nguyen, Kim Dan; Pham, Quoc Bao; Gagnon, Alexandre S.; Mai, Son T.; Anh, Duong Tran
Year: 2022
Formatted Citation: Nguyen, N., D. C. San, K. D. Nguyen, Q. B. Pham, A. S. Gagnon, S. T. Mai, and D. T. Anh, 2022: Region of freshwater influence (ROFI) and its impact on sediment transport in the lower Mekong Delta coastal zone of Vietnam. Environmental Monitoring and Assessment, 194(7), 463, doi:10.1007/s10661-022-10113-9
Formatted Citation: Wang, H., Z. You, H. Guo, W. Zhang, P. Xu, and K. Ren, 2022: Quality Assessment of Sea Surface Salinity from Multiple Ocean Reanalysis Products. Journal of Marine Science and Engineering, 11(1), 54, doi:10.3390/jmse11010054
Abstract: Sea surface salinity (SSS) is one of the Essential Climate Variables (ECVs) as defined by the Global Climate Observing System (GCOS). Acquiring high-quality SSS datasets with high spatial-temporal resolution is crucial for research on the hydrological cycle and the earth climate. This study assessed the quality of SSS data provided by five high-resolution ocean reanalysis products, including the Hybrid Coordinate Ocean Model (HYCOM) 1/12° global reanalysis, the Copernicus Global 1/12° Oceanic and Sea Ice GLORYS12 Reanalysis, the Simple Ocean Data Assimilation (SODA) reanalysis, the ECMWF Oceanic Reanalysis System 5 (ORAS5) product and the Estimating the Circulation and Climate of the Ocean Phase II (ECCO2) reanalysis. Regional comparison in the Mediterranean Sea shows that reanalysis largely depicts the accurate spatial SSS structure away from river mouths and coastal areas but slightly underestimates the mean SSS values. Better SSS reanalysis performance is found in the Levantine Sea while larger SSS uncertainties are found in the Adriatic Sea and the Aegean Sea. The global comparison with CMEMS level-4 (L4) SSS shows generally consistent large-scale structures. The mean ΔSSS between monthly gridded reanalysis data and in situ analyzed data is −0.1 PSU in the open seas between 40° S and 40° N with the mean Root Mean Square Deviation (RMSD) generally smaller than 0.3 PSU and the majority of correlation coefficients higher than 0.5. A comparison with collocated buoy salinity shows that reanalysis products well capture the SSS variations at the locations of tropical moored buoy arrays at weekly scale. Among all of the five products, the data quality of HYCOM reanalysis SSS is highest in marginal sea, GLORYS12 has the best performance in the global ocean especially in tropical regions. Comparatively, ECCO2 has the overall worst performance to reproduce SSS states and variations by showing the largest discrepancies with CMEMS L4 SSS.
Wang, Teng; Zhang, Haofei; Gao, Lei; Zhu, Lixin (2022). Comparison of physical and biological responses to tropical cyclones between the low and middle latitude zones of the western North Pacific, Regional Studies in Marine Science (55), 102535, 10.1016/j.rsma.2022.102535.
Formatted Citation: Wang, T., H. Zhang, L. Gao, and L. Zhu, 2022: Comparison of physical and biological responses to tropical cyclones between the low and middle latitude zones of the western North Pacific. Regional Studies in Marine Science, 55, 102535, doi:10.1016/j.rsma.2022.102535
Formatted Citation: Tian, Z., X. Liang, J. Zhang, H. Bi, F. Zhao, and C. Li, 2022: Thermodynamical and Dynamical Impacts of an Intense Cyclone on Arctic Sea Ice. J. Geophys. Res. Ocean., 127(12), doi:10.1029/2022JC018436
Hornschild, Aaron; Baerenzung, Julien; Saynisch-Wagner, Jan; Irrgang, Christopher; Thomas, Maik (2022). On the detectability of the magnetic fields induced by ocean circulation in geomagnetic satellite observations, Earth, Planets and Space, 1 (74), 182, 10.1186/s40623-022-01741-z.
Formatted Citation: Hornschild, A., J. Baerenzung, J. Saynisch-Wagner, C. Irrgang, and M. Thomas, 2022: On the detectability of the magnetic fields induced by ocean circulation in geomagnetic satellite observations. Earth, Planets and Space, 74(1), 182, doi:10.1186/s40623-022-01741-z
Abstract: Due to their sensitivity to conductivity and oceanic transport, magnetic signals caused by the movement of the ocean are a beneficial source of information. Satellite observed tidal-induced magnetic fields have already proven to be helpful to derive Earth's conductivity or ocean heat content. However, magnetic signals caused by ocean circulation are still unobserved in satellite magnetometer data. We present a novel method to detect these magnetic signals from ocean circulation using an observing system simulation experiment. The introduced approach relies on the assimilation of satellite magnetometer data based on a Kalman filter algorithm. The separation from other magnetic contributions is attained by predicting the temporal behavior of the ocean-induced magnetic field through presumed proxies. We evaluate the proposed method in different test case scenarios. The results demonstrate a possible detectability of the magnetic signal in large parts of the ocean. Furthermore, we point out the crucial dependence on the magnetic signal's variability and show that our approach is robust to slight spatial and temporal deviations of the presumed proxies. Additionally, we showed that including simple prior spatial constraints could further improve the assimilation results. Our findings indicate an appropriate sensitivity of the detection method for an application outside the presented observing system simulation experiment. Therefore, we finally discussed potential issues and required advances toward the method's application on original geomagnetic satellite observations.
Moteki, Qoosaku (2022). Validation of satellite-based sea surface temperature products against in situ observations off the western coast of Sumatra, Scientific Reports, 1 (12), 92, 10.1038/s41598-021-04156-0.
Title: Validation of satellite-based sea surface temperature products against in situ observations off the western coast of Sumatra
Type: Journal Article
Publication: Scientific Reports
Author(s): Moteki, Qoosaku
Year: 2022
Formatted Citation: Moteki, Q., 2022: Validation of satellite-based sea surface temperature products against in situ observations off the western coast of Sumatra. Scientific Reports, 12(1), 92, doi:10.1038/s41598-021-04156-0
Abstract: This study validated the sea surface temperature (SST) datasets from the Group for High-Resolution SST Multi Product Ensemble (GMPE), National Oceanic and Atmospheric Administration (NOAA) Optimal Interpolation (OI) SST version 2 and 2.1 (OIv2 and OIv2.1), and Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2) in the area off the western coast of Sumatra against in situ observations. Furthermore, the root mean square differences (RMSDs) of OIv2, OIv2.1, and ECCO2 were investigated with respect to GMPE, whose small RMSD < 0.2 K against in situ observations confirmed its suitability as a reference. Although OIv2 showed a large RMSD (1-1.5 K) with a significant negative bias, OIv2.1 (RMSD < 0.4 K) improved remarkably. In the average SST distributions for December 2017, the differences among the 4 datasets were significant in the areas off the western coast of Sumatra, along the southern coast of Java, and in the Indonesian inland sea. These results were consistent with the ensemble spread distribution obtained with GMPE. The large RMSDs of OIv2 corresponded to high clouds, and it was suggested that the change in the satellites used for SST estimation contributed to the improvement in OIv2.1.
Zhong, Guorong; Li, Xuegang; Song, Jinming; Qu, Baoxiao; Wang, Fan; Wang, Yanjun; Zhang, Bin; Tian, Detong; Ma, Jun; Yuan, Huamao; Duan, Liqin; Li, Ning; Wang, Qidong; Xing, Jianwei (2022). The increasing big gap of carbon sink between the western and eastern Pacific in the last three decades, Frontiers in Marine Science (9), 10.3389/fmars.2022.1088181.
Formatted Citation: Zhong, G. and Coauthors, 2022: The increasing big gap of carbon sink between the western and eastern Pacific in the last three decades. Frontiers in Marine Science, 9, doi:10.3389/fmars.2022.1088181
Abstract: The Pacific Ocean is one of the important carbon sink regions, and there is a significant west-east difference in sea-air CO2 flux. However, the influence of the long-standing greater CO2 uptakes in the western Pacific than in the east and the dynamic change of this west-east difference remain unclear. In this paper, using the gridded surface ocean pCO2 product constructed by the stepwise FFNN algorithm, we reported an increasing west-east CO2 flux difference from 0.41 PgC yr-1 in 1992 to 0.73 PgC yr-1 in 2020. This increase was mainly attributed to the strengthening western Pacific carbon sink and relatively stable eastern Pacific carbon source. During El Nino events, the west-east CO2 flux difference decreased significantly in a few years, and it then rose back rapidly when El Nino events ended. In addition, the increasing west-east difference in CO2 uptakes during the last three decades did not lead to a higher acidification speed in the western surface temperate Pacific than the east. The greater CO2 absorbed in the west was mainly transported to the deeper waters and caused a more significant carbon inventory change at 200-600 m than the eastern Pacific.
Pratolongo, P; Pan, J. (2022). Introduction to the Marine Environment from Physical and Chemical Perspectives, Marine Biology A Functional Approach to the Oceans and their Organisms, 21-39, 10.1201/9780429399244.
Title: Introduction to the Marine Environment from Physical and Chemical Perspectives
Type: Book Section
Publication: Marine Biology A Functional Approach to the Oceans and their Organisms
Author(s): Pratolongo, P; Pan, J.
Year: 2022
Formatted Citation: Pratolongo, P. P., 2022: Introduction to the Marine Environment from Physical and Chemical Perspectives. Marine Biology A Functional Approach to the Oceans and their Organisms, J. P. Pan, Eds., CRC Press, 21-39, doi:10.1201/9780429399244
Title: Ocean Circulation and Air-Sea Interaction in the South China Sea
Type: Book
Publication:
Author(s): Wang, Dongxiao
Year: 2022
Formatted Citation: Wang, D., 2022: Ocean Circulation and Air-Sea Interaction in the South China Sea. Springer Nature Singapore, Singapore doi:10.1007/978-981-19-6262-2.
Pandey, Lokesh Kumar; Dwivedi, Suneet; Mishra, Alok Kumar (2022). Diagnosing the upper ocean variability in the Northern Bay of Bengal during the super cyclone Phailin using a high-resolution regional ocean model, Theoretical and Applied Climatology, 10.1007/s00704-022-04275-2.
Title: Diagnosing the upper ocean variability in the Northern Bay of Bengal during the super cyclone Phailin using a high-resolution regional ocean model
Formatted Citation: Pandey, L. K., S. Dwivedi, and A. K. Mishra, 2022: Diagnosing the upper ocean variability in the Northern Bay of Bengal during the super cyclone Phailin using a high-resolution regional ocean model. Theoretical and Applied Climatology, doi:10.1007/s00704-022-04275-2
Woods, K.; Webb, S. C.; Wallace, L. M.; Ito, Y.; Collins, C.; Palmer, N.; Hino, R.; Savage, M. K.; Saffer, D. M.; Davis, E. E.; Barker, D. H. N. (2022). Using Seafloor Geodesy to Detect Vertical Deformation at the Hikurangi Subduction Zone: Insights From Self-Calibrating Pressure Sensors and Ocean General Circulation Models, Journal of Geophysical Research: Solid Earth, 12 (127), 10.1029/2022JB023989.
Title: Using Seafloor Geodesy to Detect Vertical Deformation at the Hikurangi Subduction Zone: Insights From Self-Calibrating Pressure Sensors and Ocean General Circulation Models
Type: Journal Article
Publication: Journal of Geophysical Research: Solid Earth
Author(s): Woods, K.; Webb, S. C.; Wallace, L. M.; Ito, Y.; Collins, C.; Palmer, N.; Hino, R.; Savage, M. K.; Saffer, D. M.; Davis, E. E.; Barker, D. H. N.
Year: 2022
Formatted Citation: Woods, K. and Coauthors, 2022: Using Seafloor Geodesy to Detect Vertical Deformation at the Hikurangi Subduction Zone: Insights From Self-Calibrating Pressure Sensors and Ocean General Circulation Models. Journal of Geophysical Research: Solid Earth, 127(12), doi:10.1029/2022JB023989
Formatted Citation: Kuang, F., J. Cha, J. Zhang, A. Pan, H. Chen, X. Zhou, C. Jing, and X. Guo, 2022: Intra-seasonal variability of the abyssal currents in COMRA's contract area in the Clarion-Clipperton Zone. Acta Oceanologica Sinica, 41(11), 1-11, doi:10.1007/s13131-021-1945-5
Xu, Zhipeng; Yang, Chengcheng; Chen, Xiao; Qi, Yiquan (2022). Seasonal Variation of Intra-Seasonal Eddy Kinetic Energy along the East Australian Current, Water, 22 (14), 3725, 10.3390/w14223725.
Formatted Citation: Xu, Z., C. Yang, X. Chen, and Y. Qi, 2022: Seasonal Variation of Intra-Seasonal Eddy Kinetic Energy along the East Australian Current. Water, 14(22), 3725, doi:10.3390/w14223725
Abstract: By using satellite altimeter observations and the eddy-permitting Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2), the seasonal variation of eddy kinetic energy (EKE) along the East Australian Current (EAC) is investigated. Both observations and ECCO2 outputs indicate active intra-seasonal EKE along the EAC path. The ECCO2 result reveals that the intra-seasonal EKE is mainly concentrated in the upper 500 m layer, and shows a prominent seasonal cycle, strong in austral summer and weak in austral winter. Eddy energy budget diagnosis reveals that the evolution of EKE is controlled by barotropic instability of the mean EAC. The seasonal variation of baroclinic instability is opposite to the barotropic instability variation, but of a much smaller magnitude. Further analysis indicates that the seasonal cycle of mesoscale signals in this region is related to the transport variability of the EAC.
Fendrock, Michaela; Condron, Alan; McGee, David (2022). Modeling Iceberg Longevity and Distribution During Heinrich Events, Paleoceanography and Paleoclimatology, 6 (37), 10.1029/2021PA004347.
Title: Modeling Iceberg Longevity and Distribution During Heinrich Events
Type: Journal Article
Publication: Paleoceanography and Paleoclimatology
Author(s): Fendrock, Michaela; Condron, Alan; McGee, David
Year: 2022
Formatted Citation: Fendrock, M., A. Condron, and D. McGee, 2022: Modeling Iceberg Longevity and Distribution During Heinrich Events. Paleoceanography and Paleoclimatology, 37(6), doi:10.1029/2021PA004347
Wu, Qiong; Wang, Xiaochun; Xiu, Peng; Chai, Fei; Chen, Zhongxiao (2022). Sensitivity of Chlorophyll Variability to Specific Growth Rate of Phytoplankton Equation over the Yangtze River Estuary in a Physical-Biogeochemical Model, Atmosphere, 11 (13), 1748, 10.3390/atmos13111748.
Title: Sensitivity of Chlorophyll Variability to Specific Growth Rate of Phytoplankton Equation over the Yangtze River Estuary in a Physical-Biogeochemical Model
Formatted Citation: Wu, Q., X. Wang, P. Xiu, F. Chai, and Z. Chen, 2022: Sensitivity of Chlorophyll Variability to Specific Growth Rate of Phytoplankton Equation over the Yangtze River Estuary in a Physical-Biogeochemical Model. Atmosphere, 13(11), 1748, doi:10.3390/atmos13111748
Abstract: In addition to nutrients and light, temperature plays a crucial role in marine biogeochemical processes. In this study, the sensitivity of the growth rate of phytoplankton to temperature was systematically studied by using a two-level nested physical-biogeochemical coupled model for the Yangtze River estuary of the East China Sea. The physical component of the coupled model is configured from the Regional Ocean Modeling System (ROMS) with the highest horizontal resolution of 3 km. The biogeochemical component of the coupled model is based on the carbon, silicon and nitrogen ecosystem model (CoSiNE). Five specific growth rate of phytoplankton equations with different relation to temperature were tested with the objective of reproducing the temporal evolution of chlorophyll concentration as observed by SeaWiFS. Our results indicate that the specific growth rate of phytoplankton equation which is from Geider's work, reaches a maximum at 22 °C and remains constant with higher temperature, can reproduce the seasonal variation of chlorophyll very well, and may be suitable for application in the physical-biogeochemical coupled model (ROMS-CoSiNE) of the Yangtze River estuary.
Baldacchino, Francesca; Morlighem, Mathieu; Golledge, Nicholas R.; Horgan, Huw; Malyarenko, Alena (2022). Sensitivity of the Ross Ice Shelf to environmental and glaciological controls, The Cryosphere, 9 (16), 3723-3738.
Formatted Citation: Baldacchino, F., M. Morlighem, N. R. Golledge, H. Horgan, and A. Malyarenko, 2022: Sensitivity of the Ross Ice Shelf to environmental and glaciological controls. Cryosph., 16(9), 3723-3738, doi:10.5194/tc-16-3723-2022
Abstract: The Ross Ice Shelf (RIS) is currently stable but recent observations have indicated that basal melt rates beneath the ice shelf are expected to increase. It is important to know which areas of the RIS are more sensitive to enhanced basal melting as well as other external forcings or internal material properties of the ice to understand how climate change will influence RIS mass balance. In this paper, we use automatic differentiation and the Ice Sheet and Sea-level System Model to quantify the sensitivity of the RIS to changes in basal friction, ice rigidity, surface mass balance, and basal melting. Using volume above flotation (VAF) as our quantity of interest, we find that the RIS is most sensitive to changes in basal friction and ice rigidity close to grounding lines and along shear margins of the Siple Coast Ice Streams and Transantarctic Mountains Outlet Glaciers. The RIS sensitivity to surface mass balance is uniform over grounded ice, while the sensitivity to basal melting is more spatially variable. Changes in basal melting close to the grounding lines of the Siple Coast Ice Streams and Transantarctic Mountains outlet glaciers have a larger impact on the final VAF compared to elsewhere. Additionally, the pinning points and ice shelf shear margins are highly sensitive to changes in basal melt. Our sensitivity maps allow areas of greatest future vulnerability to be identified.
He, Liyin; Byrne, Brendan; Yin, Yi; Liu, Junjie; Frankenberg, Christian (2022). Remote-Sensing Derived Trends in Gross Primary Production Explain Increases in the CO2 Seasonal Cycle Amplitude, Global Biogeochemical Cycles, 9 (36), 10.1029/2021GB007220.
Formatted Citation: He, L., B. Byrne, Y. Yin, J. Liu, and C. Frankenberg, 2022: Remote-Sensing Derived Trends in Gross Primary Production Explain Increases in the CO2 Seasonal Cycle Amplitude. Global Biogeochemical Cycles, 36(9), doi:10.1029/2021GB007220
Formatted Citation: Meng, Z., L. Zhou, R. Murtugudde, Q. Yang, K. Pujiana, and J. Xi, 2022: Tropical oceanic intraseasonal variabilities associated with central Indian Ocean mode. Climate Dynamics, 58(3-4), 1107-1126, doi:10.1007/s00382-021-05951-1
Liu, Yuqing; Losch, Martin; Hutter, Nils; Mu, Longjiang (2022). A New Parameterization of Coastal Drag to Simulate Landfast Ice in Deep Marginal Seas in the Arctic, Journal of Geophysical Research: Oceans, 6 (127), 10.1029/2022JC018413.
Formatted Citation: Liu, Y., M. Losch, N. Hutter, and L. Mu, 2022: A New Parameterization of Coastal Drag to Simulate Landfast Ice in Deep Marginal Seas in the Arctic. J. Geophys. Res. Ocean., 127(6), doi:10.1029/2022JC018413
He, Yuefan; Nie, Guigen; Wu, Shuguang; Li, Haiyang (2022). Comparative analysis of the correction effect of different environmental loading products on global GNSS coordinate time series, Advances in Space Research, 10.1016/j.asr.2022.08.009.
Title: Comparative analysis of the correction effect of different environmental loading products on global GNSS coordinate time series
Type: Journal Article
Publication: Advances in Space Research
Author(s): He, Yuefan; Nie, Guigen; Wu, Shuguang; Li, Haiyang
Year: 2022
Formatted Citation: He, Y., G. Nie, S. Wu, and H. Li, 2022: Comparative analysis of the correction effect of different environmental loading products on global GNSS coordinate time series. Advances in Space Research, doi:10.1016/j.asr.2022.08.009
Gupta, Mukund; Williams, Richard G.; Lauderdale, Jonathan M.; Jahn, Oliver; Hill, Christopher; Dutkiewicz, Stephanie; Follows, Michael J. (2022). A nutrient relay sustains subtropical ocean productivity, Proceedings of the National Academy of Sciences, 41 (119), 10.1073/pnas.2206504119.
Title: A nutrient relay sustains subtropical ocean productivity
Type: Journal Article
Publication: Proceedings of the National Academy of Sciences
Author(s): Gupta, Mukund; Williams, Richard G.; Lauderdale, Jonathan M.; Jahn, Oliver; Hill, Christopher; Dutkiewicz, Stephanie; Follows, Michael J.
Year: 2022
Formatted Citation: Gupta, M., R. G. Williams, J. M. Lauderdale, O. Jahn, C. Hill, S. Dutkiewicz, and M. J. Follows, 2022: A nutrient relay sustains subtropical ocean productivity. Proceedings of the National Academy of Sciences, 119(41), doi:10.1073/pnas.2206504119
Abstract: The expansive gyres of the subtropical ocean account for a significant fraction of global organic carbon export from the upper ocean. In the gyre interior, vertical mixing and the heaving of nutrient-rich waters into the euphotic layer sustain local productivity, in turn depleting the layers below. However, the nutrient pathways by which these subeuphotic layers are themselves replenished remain unclear. Using a global, eddy-permitting simulation of ocean physics and biogeochemistry, we quantify nutrient resupply mechanisms along and across density surfaces, including the contribution of eddy-scale motions that are challenging to observe. We find that mesoscale eddies (10 to 100 km) flux nutrients from the shallow flanks of the gyre into the recirculating interior, through time-varying motions along density surfaces. The subeuphotic layers are ultimately replenished in approximately equal contributions by this mesoscale eddy transport and the remineralization of sinking particles. The mesoscale eddy resupply is most important in the lower thermocline for the whole subtropical region but is dominant at all depths within the gyre interior. Subtropical gyre productivity may therefore be sustained by a nutrient relay, where the lateral transport resupplies nutrients to the thermocline and allows vertical exchanges to maintain surface biological production and carbon export.
Formatted Citation: Richter, D. J. and Coauthors, 2022: Genomic evidence for global ocean plankton biogeography shaped by large-scale current systems. eLife, 11, doi:10.7554/eLife.78129
Abstract: Biogeographical studies have traditionally focused on readily visible organisms, but recent technological advances are enabling analyses of the large-scale distribution of microscopic organisms, whose biogeographical patterns have long been debated. Here we assessed the global structure of plankton geography and its relation to the biological, chemical, and physical context of the ocean (the 'seascape') by analyzing metagenomes of plankton communities sampled across oceans during the Tara Oceans expedition, in light of environmental data and ocean current transport. Using a consistent approach across organismal sizes that provides unprecedented resolution to measure changes in genomic composition between communities, we report a pan-ocean, size-dependent plankton biogeography overlying regional heterogeneity. We found robust evidence for a basin-scale impact of transport by ocean currents on plankton biogeography, and on a characteristic timescale of community dynamics going beyond simple seasonality or life history transitions of plankton.
Yang, Zhibin; Jing, Zhao; Zhai, Xiaoming (2022). Effect of Small-Scale Topography on Eddy Dissipation in the Northern South China Sea, Journal of Physical Oceanography, 10 (52), 2397-2416, 10.1175/JPO-D-21-0208.1.
Formatted Citation: Yang, Z., Z. Jing, and X. Zhai, 2022: Effect of Small-Scale Topography on Eddy Dissipation in the Northern South China Sea. Journal of Physical Oceanography, 52(10), 2397-2416, doi:10.1175/JPO-D-21-0208.1
Abstract: Mesoscale eddies are ubiquitous dynamical features, accounting for over 90% of the total kinetic energy of the ocean. However, the pathway for eddy energy dissipation has not been fully understood. Here we investigate the effect of small-scale topography on eddy dissipation in the northern South China Sea by comparing high-resolution ocean simulations with smooth and synthetically generated rough topography. The presence of rough topography is found to 1) significantly enhance viscous dissipation and instabilities within a few hundred meters above the rough bottom, especially in the slope region, and 2) change the relative importance of energy dissipation by bottom frictional drag and interior viscosity. The role of lee wave generation in eddy energy dissipation is investigated using a Lagrangian filter method. About one-third of the enhanced viscous energy dissipation in the rough topography experiment is associated with lee wave energy dissipation, with the remaining two-thirds explained by nonwave energy dissipation, at least partly as a result of the nonpropagating form drag effect.
Yang, Yi; Chen, Ru (2022). Spectral Kinetic-Energy Fluxes in the North Pacific: Definition Comparison and Normal- and Shear-Strain Decomposition, Journal of Marine Science and Engineering, 8 (10), 1148.
Title: Spectral Kinetic-Energy Fluxes in the North Pacific: Definition Comparison and Normal- and Shear-Strain Decomposition
Type: Journal Article
Publication: Journal of Marine Science and Engineering
Author(s): Yang, Yi; Chen, Ru
Year: 2022
Formatted Citation: Yang, Y., and R. Chen, 2022: Spectral Kinetic-Energy Fluxes in the North Pacific: Definition Comparison and Normal- and Shear-Strain Decomposition. Journal of Marine Science and Engineering, 10(8), 1148, doi:10.3390/jmse10081148
Abstract: The spectral kinetic-energy flux is an effective tool to analyze the kinetic-energy transfer across a range of length scales, also known as the kinetic-energy cascade. Three methods to calculate spectral energy fluxes have been widely used, hereafter the ΠA, ΠF, and ΠQ definitions. However, the relations among these three definitions have not been examined in detail. Moreover, the respective contribution of the normal strain and shear strain of the flow field to kinetic-energy cascade has not been estimated before. Here, we use the kinetic energy equations to rigorously compare these definitions. Then, we evaluate the spectral energy fluxes, as well as its decomposition into the normal-strain and shear-strain components for the North Pacific, using a dynamically consistent global eddying state estimate. We find that the data must be preprocessed first to obtain stable results from the ΠF and ΠQ definitions, but not for the ΠA definition. For the upper 500 m of the North Pacific, in the wavenumber ranges with inverse kinetic-energy cascade, both the normal and shear-strain flow components contribute significantly to the spectral energy fluxes. However, at high wavenumbers, the dominant contributor to forward kinetic-energy cascade is the normal-strain component. These results should help shed light on the underlying mechanism of inverse and forward energy cascades.
Formatted Citation: Zhao, F., X. Liang, Z. Tian, C. Liu, X. Li, Y. Yang, M. Li, and N. Liu, 2022: Impacts of the long-term atmospheric trend on the seasonality of Antarctic sea ice. Climate Dynamics, doi:10.1007/s00382-022-06420-z
Chau, Thi Tuyet Trang; Gehlen, Marion; Chevallier, Frédéric (2022). A seamless ensemble-based reconstruction of surface ocean pCO2 and air-sea CO2 fluxes over the global coastal and open oceans, Biogeosciences, 4 (19), 1087-1109, 10.5194/bg-19-1087-2022.
Formatted Citation: Chau, T. T. T., M. Gehlen, and F. Chevallier, 2022: A seamless ensemble-based reconstruction of surface ocean pCO2 and air-sea CO2 fluxes over the global coastal and open oceans. Biogeosciences, 19(4), 1087-1109, doi:10.5194/bg-19-1087-2022
Abstract: We have estimated global air-sea CO2 fluxes (fgCO2) from the open ocean to coastal seas. Fluxes and associated uncertainty are computed from an ensemble-based reconstruction of CO2 sea surface partial pressure (pCO2) maps trained with gridded data from the Surface Ocean CO2 Atlas v2020 database. The ensemble mean (which is the best estimate provided by the approach) fits independent data well, and a broad agreement between the spatial distribution of model-data differences and the ensemble standard deviation (which is our model uncertainty estimate) is seen. Ensemble-based uncertainty estimates are denoted by ±1σ. The space-time-varying uncertainty fields identify oceanic regions where improvements in data reconstruction and extensions of the observational network are needed. Poor reconstructions of pCO2 are primarily found over the coasts and/or in regions with sparse observations, while fgCO2 estimates with the largest uncertainty are observed over the open Southern Ocean (44° S southward), the subpolar regions, the Indian Ocean gyre, and upwelling systems. Our estimate of the global net sink for the period 1985-2019 is 1.643±0.125 PgC yr−1 including 0.150±0.010 PgC yr−1 for the coastal net sink. Among the ocean basins, the Subtropical Pacific (18-49° N) and the Subpolar Atlantic (49-76° N) appear to be the strongest CO2 sinks for the open ocean and the coastal ocean, respectively. Based on mean flux density per unit area, the most intense CO2 drawdown is, however, observed over the Arctic (76° N poleward) followed by the Subpolar Atlantic and Subtropical Pacific for both open-ocean and coastal sectors. Reconstruction results also show significant changes in the global annual integral of all open- and coastal-ocean CO2 fluxes with a growth rate of +0.062±0.006 PgC yr−2 and a temporal standard deviation of 0.526±0.022 PgC yr−1 over the 35-year period. The link between the large interannual to multi-year variations of the global net sink and the El Niño-Southern Oscillation climate variability is reconfirmed.
Dushaw, Brian D. (2022). Surprises in Physical Oceanography: Contributions from Ocean Acoustic Tomography, Tellus A: Dynamic Meteorology and Oceanography, 2022 (74), 33, 10.16993/tellusa.39.
Title: Surprises in Physical Oceanography: Contributions from Ocean Acoustic Tomography
Type: Journal Article
Publication: Tellus A: Dynamic Meteorology and Oceanography
Author(s): Dushaw, Brian D.
Year: 2022
Formatted Citation: Dushaw, B. D., 2022: Surprises in Physical Oceanography: Contributions from Ocean Acoustic Tomography. Tellus A: Dynamic Meteorology and Oceanography, 74(2022), 33, doi:10.16993/tellusa.39
Afroosa, M.; Rohith, B.; Paul, Arya; Durand, Fabien; Bourdallé-Badie, Romain; Joseph, Sudheer; Prerna, S.; Shenoi, S. S. C. (2022). Investigating the robustness of the intraseasonal see-saw in the Indo-Pacific barotropic sea level across models, Ocean Dynamics, 10.1007/s10236-022-01518-8.
Title: Investigating the robustness of the intraseasonal see-saw in the Indo-Pacific barotropic sea level across models
Type: Journal Article
Publication: Ocean Dynamics
Author(s): Afroosa, M.; Rohith, B.; Paul, Arya; Durand, Fabien; Bourdallé-Badie, Romain; Joseph, Sudheer; Prerna, S.; Shenoi, S. S. C.
Year: 2022
Formatted Citation: Afroosa, M., B. Rohith, A. Paul, F. Durand, R. Bourdallé-Badie, S. Joseph, S. Prerna, and S. S. C. Shenoi, 2022: Investigating the robustness of the intraseasonal see-saw in the Indo-Pacific barotropic sea level across models. Ocean Dynamics, doi:10.1007/s10236-022-01518-8
Title: Subsurface phytoplankton vertical structure observations using offshore fixed platform-based lidar in the Bohai Sea for offshore responses to Typhoon Bavi
Type: Journal Article
Publication: Optics Express
Author(s): Chen, Peng
Year: 2022
Formatted Citation: Chen, P., 2022: Subsurface phytoplankton vertical structure observations using offshore fixed platform-based lidar in the Bohai Sea for offshore responses to Typhoon Bavi. Optics Express, 30(12), 20614, doi:10.1364/OE.458796
Yang, Lina; Murtugudde, Raghu; Zheng, Shaojun; Liang, Peng; Tan, Wei; Wang, Lei; Feng, Baoxin; Zhang, Tianyu (2022). Seasonal variability of the Pacific South Equatorial Current during the Argo era, Journal of Physical Oceanography, 10.1175/JPO-D-21-0311.1.
Formatted Citation: Yang, L., R. Murtugudde, S. Zheng, P. Liang, W. Tan, L. Wang, B. Feng, and T. Zhang, 2022: Seasonal variability of the Pacific South Equatorial Current during the Argo era. Journal of Physical Oceanography, doi:10.1175/JPO-D-21-0311.1
Abstract: The tropical Pacific currents from January 2004 to December 2018 are computed based on the gridded Argo temperatures and salinities using the P-vector method on an f-plane and the geostrophic approximation on a β-plane. Three branches of the SEC are identified, i.e., SEC(N) (2°S-5°N), SEC(M) (7°S-3°S), and SEC(S) (20°S-8°S), with the maximum zonal velocity of −55 cm s −1 and total volume transport of −49.8 Sv occurring in the central-east Pacific. The seasonal variability of each branch shows a distinct and different westward propagation of zonal current anomalies, which are well mirrored by the SLA differences between 2°S and 5°N, between 3°S and 6°S, and between 8°S and 15°S, respectively. Most of the seasonal variations are successfully simulated by a simple analytical Rossby wave model, highlighting the significance of the first-mode baroclinic, linear Rossby waves, particularly those driven by the wind stress curl in the central-east Pacific. However, the linear theory fails to explain the SEC(M) variations in certain months in the central-east Pacific, where the first baroclinic mode contributes only around 50% of the explained variance to the equatorial surface currents. A nonlinear model involving higher baroclinic modes is suggested for a further diagnosis. Considering the crucial role played by the tropical Pacific in the natural climate variability via the El Niño-Southern Ocean dynamics and the ocean response to anthropogenic forcing via the ocean heat uptake in the eastern tropical Pacific, advancing the process understanding of the SEC from observations is critical.
Formatted Citation: Xiu, Y., H. Luo, Q. Yang, S. Tietsche, J. Day, and D. Chen, 2022: The Challenge of Arctic Sea Ice Thickness Prediction by ECMWF on Subseasonal Time Scales. Geophys. Res. Lett., 49(8), doi:10.1029/2021GL097476
Delman, Andrew; Landerer, Felix (2022). Downscaling Satellite-Based Estimates of Ocean Bottom Pressure for Tracking Deep Ocean Mass Transport, Remote Sensing, 7 (14), 1764, 10.3390/rs14071764.
Title: Downscaling Satellite-Based Estimates of Ocean Bottom Pressure for Tracking Deep Ocean Mass Transport
Type: Journal Article
Publication: Remote Sensing
Author(s): Delman, Andrew; Landerer, Felix
Year: 2022
Formatted Citation: Delman, A., and F. Landerer, 2022: Downscaling Satellite-Based Estimates of Ocean Bottom Pressure for Tracking Deep Ocean Mass Transport. Remote Sensing, 14(7), 1764, doi:10.3390/rs14071764
Abstract: Gravimetry measurements from the GRACE and GRACE-Follow-On satellites provide observations of ocean bottom pressure (OBP), which can be differenced between basin boundaries to infer mass transport variability at a given level in the deep ocean. However, GRACE data products are limited in spatial resolution, and conflate signals from many depth levels along steep continental slopes. To improve estimates of OBP variability near steep bathymetry, ocean bottom pressure observations from a JPL GRACE mascon product are downscaled using an objective analysis procedure, with OBP covariance information from an ocean model with horizontal grid spacing of ∼18 km. In addition, a depth-based adjustment was applied to enhance correlations at similar depths. Downscaled GRACE OBP shows realistic representations of sharp OBP gradients across bathymetry contours and strong currents, albeit with biases in the shallow ocean. In validations at intraannual (3-12 month) timescales, correlations of downscaled GRACE data (with depth adjustment) and in situ bottom pressure recorder time series were improved in ∼79% of sites, compared to correlations that did not involve downscaled GRACE. Correlations tend to be higher at sites where the amplitude of the OBP signal is larger, while locations where surface eddy kinetic energy is high (e.g., Gulf Stream extension) are more likely to have no improvement from the downscaling procedure. The downscaling procedure also increases the amplitude (standard deviation) of OBP variability compared to the non-downscaled GRACE at most sites, resulting in standard deviations that are closer to in situ values. A comparison of hydrography-based transport from RAPID with estimates based on downscaled GRACE data suggests substantial improvement from the downscaling at intraannual timescales, though this improvement does not extend to longer interannual timescales. Possible efforts to improve the downscaling technique through process studies and analysis of alongtrack GRACE/GRACE-FO observations are discussed.
Sharp, Jonathan D.; Fassbender, Andrea J.; Carter, Brendan R.; Lavin, Paige D.; Sutton, Adrienne J. (2022). A monthly surface pCO2 product for the California Current Large Marine Ecosystem, Earth System Science Data, 4 (14), 2081-2108, 10.5194/essd-14-2081-2022.
Title: A monthly surface pCO2 product for the California Current Large Marine Ecosystem
Type: Journal Article
Publication: Earth System Science Data
Author(s): Sharp, Jonathan D.; Fassbender, Andrea J.; Carter, Brendan R.; Lavin, Paige D.; Sutton, Adrienne J.
Year: 2022
Formatted Citation: Sharp, J. D., A. J. Fassbender, B. R. Carter, P. D. Lavin, and A. J. Sutton, 2022: A monthly surface pCO2 product for the California Current Large Marine Ecosystem. Earth System Science Data, 14(4), 2081-2108, doi:10.5194/essd-14-2081-2022
Richter, Ole; Gwyther, David E.; King, Matt A.; Galton-Fenzi, Benjamin K. (2022). The impact of tides on Antarctic ice shelf melting, The Cryosphere, 4 (16), 1409-1429, 10.5194/tc-16-1409-2022.
Title: The impact of tides on Antarctic ice shelf melting
Type: Journal Article
Publication: The Cryosphere
Author(s): Richter, Ole; Gwyther, David E.; King, Matt A.; Galton-Fenzi, Benjamin K.
Year: 2022
Formatted Citation: Richter, O., D. E. Gwyther, M. A. King, and B. K. Galton-Fenzi, 2022: The impact of tides on Antarctic ice shelf melting. Cryosph., 16(4), 1409-1429, doi:10.5194/tc-16-1409-2022
Abstract: Tides influence basal melting of individual Antarctic ice shelves, but their net impact on Antarctic-wide ice-ocean interaction has yet to be constrained. Here we quantify the impact of tides on ice shelf melting and the continental shelf seas using a 4 km resolution circum-Antarctic ocean model. Activating tides in the model increases the total basal mass loss by 57 Gt yr−1 (4 %) while decreasing continental shelf temperatures by 0.04 °C. The Ronne Ice Shelf features the highest increase in mass loss (44 Gt yr−1, 128 %), coinciding with strong residual currents and increasing temperatures on the adjacent continental shelf. In some large ice shelves tides strongly affect melting in regions where the ice thickness is of dynamic importance to grounded ice flow. Further, to explore the processes that cause variations in melting we apply dynamical-thermodynamical decomposition to the melt drivers in the boundary layer. In most regions, the impact of tidal currents on the turbulent exchange of heat and salt across the ice-ocean boundary layer has a strong contribution. In some regions, however, mechanisms driven by thermodynamic effects are equally or more important, including under the frontal parts of Ronne Ice Shelf. Our results support the importance of capturing tides for robust modelling of glacier systems and shelf seas, as well as motivate future studies to directly assess friction-based parameterizations for the pan-Antarctic domain.
Formatted Citation: Bouchat, A. and Coauthors, 2022: Sea Ice Rheology Experiment (SIREx), Part I: Scaling and statistical properties of sea-ice deformation fields. J. Geophys. Res. Ocean., doi:10.1029/2021JC017667
Abstract: As the sea-ice modeling community is shifting to advanced numerical frameworks, developing new sea-ice rheologies, and increasing model spatial resolution, ubiquitous deformation features in the Arctic sea ice are now being resolved by sea-ice models. Initiated at the Forum for Arctic Modeling and Observational Synthesis, the Sea Ice Rheology Experiment (SIREx) aims at evaluating state-of-the-art sea-ice models using existing and new metrics to understand how the simulated deformation fields are affected by different representations of sea-ice physics (rheology) and by model configuration. Part 1 of the SIREx analysis is concerned with evaluation of the statistical distribution and scaling properties of sea-ice deformation fields from 35 different simulations against those from the RADARSAT Geophysical Processor System (RGPS). For the first time, the viscous-plastic (and the elastic-viscous-plastic variant), elastic-anisotropic-plastic, and Maxwell-elasto-brittle rheologies are compared in a single study. We find that both plastic and brittle sea-ice rheologies have the potential to reproduce the observed RGPS deformation statistics, including multi-fractality. Model configuration (e.g., numerical convergence, atmospheric representation, spatial resolution) and physical parameterizations (e.g., ice strength parameters and ice thickness distribution) both have effects as important as the choice of sea-ice rheology on the deformation statistics. It is therefore not straightforward to attribute model performance to a specific rheological framework using current deformation metrics. In light of these results, we further evaluate the statistical properties of simulated Linear Kinematic Features in a SIREx Part 2 companion paper.
Qin, Jianhuang; Meng, Ze; Xu, Wenlong; Li, Baosheng; Cheng, Xuhua; Murtugudde, Raghu (2022). Modulation of the Intraseasonal Chlorophyll-a Concentration in the Tropical Indian Ocean by the Central Indian Ocean Mode, Geophysical Research Letters, 7 (49), 10.1029/2022GL097802.
Formatted Citation: Qin, J., Z. Meng, W. Xu, B. Li, X. Cheng, and R. Murtugudde, 2022: Modulation of the Intraseasonal Chlorophyll-a Concentration in the Tropical Indian Ocean by the Central Indian Ocean Mode. Geophys. Res. Lett., 49(7), doi:10.1029/2022GL097802
Formatted Citation: Hutter, N. and Coauthors, 2022: Sea Ice Rheology Experiment (SIREx), Part II: Evaluating linear kinematic features in high-resolution sea-ice simulations. J. Geophys. Res. Ocean., doi:10.1029/2021JC017666
Koulali, Achraf; Whitehouse, Pippa L.; Clarke, Peter J.; Broeke, Michiel R.; Nield, Grace A.; King, Matt A.; Bentley, Michael J.; Wouters, Bert; Wilson, Terry (2022). GPS-Observed Elastic Deformation Due to Surface Mass Balance Variability in the Southern Antarctic Peninsula, Geophysical Research Letters, 4 (49), 10.1029/2021GL097109.
Title: GPS-Observed Elastic Deformation Due to Surface Mass Balance Variability in the Southern Antarctic Peninsula
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Koulali, Achraf; Whitehouse, Pippa L.; Clarke, Peter J.; Broeke, Michiel R.; Nield, Grace A.; King, Matt A.; Bentley, Michael J.; Wouters, Bert; Wilson, Terry
Year: 2022
Formatted Citation: Koulali, A. and Coauthors, 2022: GPS-Observed Elastic Deformation Due to Surface Mass Balance Variability in the Southern Antarctic Peninsula. Geophys. Res. Lett., 49(4), doi:10.1029/2021GL097109
Wu, Yusheng; Zhou, Guidi; Wang, Guifen; Cheng, Xuhua (2022). Forced vs. Intrinsic Wintertime Submonthly Variability of Sea Surface Temperature in the Midlatitude Western North Pacific, Frontiers in Marine Science (9), 10.3389/fmars.2022.847144.
Formatted Citation: Wu, Y., G. Zhou, G. Wang, and X. Cheng, 2022: Forced vs. Intrinsic Wintertime Submonthly Variability of Sea Surface Temperature in the Midlatitude Western North Pacific. Frontiers in Marine Science, 9, doi:10.3389/fmars.2022.847144
Abstract: The relative importance of wintertime forced and intrinsic SST variability in the Kuroshio-Oyashio Extension (KOE) region on submonthly timescales (2-10 and 10-30 days) is evaluated based on theoretical, observational, and modeling analysis. It is shown that the theoretical framework extended from the stochastic climate model has difficulties in representing observed SST variability on such short scales. We then employ the single-column General Ocean Turbulence Model (GOTM) to explicitly evaluate the SST variability forced by atmospheric disturbances. Results show that in the KOE region forced SST variability is responsible for a very small fraction of the total variability (<10%) on the submonthly scales, indicating the dominance of intrinsic oceanic processes. Outside the KOE forced variability dominates. By means of sensitivity experiments, the key physical factors are identified: upper ocean vertical mixing, wind stress forcing (mainly for outside KOE), and latent heat flux, the former two of which are not considered in the theoretical framework. The above results are robust against different levels of submonthly SST variability.
Prakash, Kumar Ravi; Pant, Vimlesh; Udaya Bhaskar, T. V. S.; Chandra, Navin (2022). What Made the Sustained Intensification of Tropical Cyclone Fani in the Bay of Bengal? An Investigation Using Coupled Atmosphere-Ocean Model, Atmosphere, 4 (13), 535, 10.3390/atmos13040535.
Title: What Made the Sustained Intensification of Tropical Cyclone Fani in the Bay of Bengal? An Investigation Using Coupled Atmosphere-Ocean Model
Type: Journal Article
Publication: Atmosphere
Author(s): Prakash, Kumar Ravi; Pant, Vimlesh; Udaya Bhaskar, T. V. S.; Chandra, Navin
Year: 2022
Formatted Citation: Prakash, K. R., V. Pant, T. V. S. Udaya Bhaskar, and N. Chandra, 2022: What Made the Sustained Intensification of Tropical Cyclone Fani in the Bay of Bengal? An Investigation Using Coupled Atmosphere-Ocean Model. Atmosphere, 13(4), 535, doi:10.3390/atmos13040535
Abstract: The extremely severe tropical cyclone Fani (25 April-5 May 2019) unusually sustained high intensity for a prolonged duration over the Bay of Bengal (BoB). A regional coupled atmosphere-ocean model was used to investigate the atmospheric and oceanic conditions and processes responsible for the sustained intensification of the tropical cyclone (TC) Fani. The coupled model simulated the track and intensification/weakening stages of the cyclone reasonably well. A reduction in sea surface temperature (by −2°C) and an increase in sea surface salinity due to cyclone-induced upwelling and inertial mixing was noticed in both observations and model. The passage of TC Fani over two geostrophic mesoscale warm-core eddies along the cyclone track was found to supply the necessary energy for the intensification of TC Fani. The sea surface height anomaly and tropical cyclone heat potential (TCHP) were higher during TC Fani than other pre-monsoon cyclones in the BoB. The anomalous TCHP in the warm-core eddy zones (i.e., in excess of >160 kJ cm−2) maintained the warm surface temperature and high air-sea heat fluxes. The air-sea latent heat flux and atmospheric wind shear were favourable for the intensification of the cyclone. The atmospheric moist static energy enhanced up to 360 kJ kg−1 with a deep vertical extension in the atmospheric column supporting the further intensification of TC Fani. Therefore, the unusual oceanic TCHP associated with mesoscale eddies, higher latent heat flux, and enhanced moist static energy in the atmosphere contributed to the sustained intensification of TC Fani for a prolonged period in the BoB.
Barone, Benedetto; Church, Matthew J.; Dugenne, Mathilde; Hawco, Nicholas J.; Jahn, Oliver; White, Angelicque E.; John, Seth G.; Follows, Michael J.; DeLong, Edward F.; Karl, David M. (2022). Biogeochemical Dynamics in Adjacent Mesoscale Eddies of Opposite Polarity, Global Biogeochemical Cycles, 2 (36), 10.1029/2021GB007115.
Title: Biogeochemical Dynamics in Adjacent Mesoscale Eddies of Opposite Polarity
Type: Journal Article
Publication: Global Biogeochemical Cycles
Author(s): Barone, Benedetto; Church, Matthew J.; Dugenne, Mathilde; Hawco, Nicholas J.; Jahn, Oliver; White, Angelicque E.; John, Seth G.; Follows, Michael J.; DeLong, Edward F.; Karl, David M.
Year: 2022
Formatted Citation: Barone, B. and Coauthors, 2022: Biogeochemical Dynamics in Adjacent Mesoscale Eddies of Opposite Polarity. Global Biogeochemical Cycles, 36(2), doi:10.1029/2021GB007115
Title: Enhanced Methane Emission from Arctic Seas in Winter: Satellite Data
Type: Book Section
Publication:
Author(s): Yurganov, Leonid; Muller-Karger, Frank; Leifer, Ira
Year: 2022
Formatted Citation: Yurganov, L., F. Muller-Karger, and I. Leifer, 2022: Enhanced Methane Emission from Arctic Seas in Winter: Satellite Data., 41-44, doi:10.1007/978-3-030-72543-3_10
Formatted Citation: Zhong, G. and Coauthors, 2022: Reconstruction of global surface ocean pCO2 using region-specific predictors based on a stepwise FFNN regression algorithm. Biogeosciences, 19(3), 845-859, doi:10.5194/bg-19-845-2022
David, Carmen L.; Ji, Rubao; Bouchard, Caroline; Hop, Haakon; Hutchings, Jeffrey A. (2022). The interactive effects of temperature and food consumption on growth of larval Arctic cod ( Boreogadus saida ), Elementa: Science of the Anthropocene, 1 (10), 10.1525/elementa.2021.00045.
Title: The interactive effects of temperature and food consumption on growth of larval Arctic cod ( Boreogadus saida )
Type: Journal Article
Publication: Elementa: Science of the Anthropocene
Author(s): David, Carmen L.; Ji, Rubao; Bouchard, Caroline; Hop, Haakon; Hutchings, Jeffrey A.
Year: 2022
Formatted Citation: David, C. L., R. Ji, C. Bouchard, H. Hop, and J. A. Hutchings, 2022: The interactive effects of temperature and food consumption on growth of larval Arctic cod ( Boreogadus saida ). Elementa: Science of the Anthropocene, 10(1), doi:10.1525/elementa.2021.00045
Abstract: Understanding larval growth, mediated by the interaction of early life traits and environmental conditions, is crucial to elucidate population dynamics. We used a bioenergetic model as an integrative tool to simulate the growth of Arctic cod (Boreogadus saida) larvae and to test the sensitivity of modeled growth to temperature and food quantity and quality. The growth was computed as the energy gained through food consumption minus the energy lost through respiration and other metabolic processes. We extended a previously published bioenergetic model to cover the full range of larval length and used a simplified feeding module. This simplification allowed us to build a predictive tool that can be applied to larval Arctic cod at a large spatial scale. Our model suggested that with subzero temperatures in the High Arctic, larvae need to increase food consumption in order to reach the observed length-at-age in late summer. The modeled growth agreed well with the field observations in the High Arctic but was 2-3 times higher than the laboratory-derived growth rate, probably due to differences in food type and selective mortality. Our study reveals important knowledge gaps in our understanding of larval cod growth in the High Arctic, including the lack of empirical estimations of daily ration and respiration for larvae under the natural habitat temperatures.
Richter, Ole; Gwyther, David E.; Galton-Fenzi, Benjamin K.; Naughten, Kaitlin A. (2022). The Whole Antarctic Ocean Model (WAOM v1.0): development and evaluation, Geoscientific Model Development, 2 (15), 617-647, 10.5194/gmd-15-617-2022.
Title: The Whole Antarctic Ocean Model (WAOM v1.0): development and evaluation
Type: Journal Article
Publication: Geoscientific Model Development
Author(s): Richter, Ole; Gwyther, David E.; Galton-Fenzi, Benjamin K.; Naughten, Kaitlin A.
Year: 2022
Formatted Citation: Richter, O., D. E. Gwyther, B. K. Galton-Fenzi, and K. A. Naughten, 2022: The Whole Antarctic Ocean Model (WAOM v1.0): development and evaluation. Geoscientific Model Development, 15(2), 617-647, doi:10.5194/gmd-15-617-2022
Abstract: The Regional Ocean Modeling System (ROMS), including an ice shelf component, has been applied on a circum-Antarctic domain to derive estimates of ice shelf basal melting. Significant improvements made compared to previous models of this scale are the inclusion of tides and a horizontal spatial resolution of 2 km, which is sufficient to resolve on-shelf heat transport by bathymetric troughs and eddy-scale circulation. We run the model with ocean-atmosphere-sea ice conditions from the year 2007 to represent nominal present-day climate. We force the ocean surface with buoyancy fluxes derived from sea ice concentration observations and wind stress from ERA-Interim atmospheric reanalysis. Boundary conditions are derived from the ECCO2 ocean state estimate; tides are incorporated as sea surface height and barotropic currents at the open boundary. We evaluate model results using satellite-derived estimates of ice shelf melting and established compilations of ocean hydrography. The Whole Antarctic Ocean Model (WAOM v1.0) qualitatively captures the broad scale difference between warm and cold regimes as well as many of the known characteristics of regional ice-ocean interaction. We identify a cold bias for some warm-water ice shelves and a lack of high-salinity shelf water (HSSW) formation. We conclude that further calibration and development of our approach are justified. At its current state, the model is ideal for addressing specific, process-oriented questions, e.g. related to tide-driven ice shelf melting at large scales.
Title: Argo-Two Decades: Global Oceanography, Revolutionized
Type: Journal Article
Publication: Annual Review of Marine Science
Author(s): Johnson, Gregory C.; Hosoda, Shigeki; Jayne, Steven R.; Oke, Peter R.; Riser, Stephen C.; Roemmich, Dean; Suga, Tohsio; Thierry, Virginie; Wijffels, Susan E.; Xu, Jianping
Year: 2022
Formatted Citation: Johnson, G. C. and Coauthors, 2022: Argo-Two Decades: Global Oceanography, Revolutionized. Annual Review of Marine Science, 14(1), 379-403, doi:10.1146/annurev-marine-022521-102008
Abstract: Argo, an international, global observational array of nearly 4,000 autonomous robotic profiling floats, each measuring ocean temperature and salinity from 0 to 2,000 m on nominal 10-day cycles, has revolutionized physical oceanography. Argo started at the turn of the millennium, growing out of advances in float technology over the previous several decades. After two decades, with well over 2 million profiles made publicly available in real time, Argo data have underpinned more than 4,000 scientific publications and improved countless nowcasts, forecasts, and projections. We review a small subset of those accomplishments, such as elucidating remarkable zonal jets spanning the deep tropical Pacific; increasing understanding of ocean eddies and the roles of mixing in shaping water masses and circulation; illuminating interannual to decadal ocean variability; quantifying, in concert with satellite data, contributions of ocean warming and ice melting to sea level rise; improving coupled numerical weather predictions; and underpinning decadal climate forecasts.
Xia, Ruibin; He, Yijun; Yang, Tingting (2021). Simulation and future projection of the mixed layer depth and subduction process in the subtropical Southeast Pacific, Acta Oceanologica Sinica, 12 (40), 104-113, 10.1007/s13131-021-1877-0.
Title: Simulation and future projection of the mixed layer depth and subduction process in the subtropical Southeast Pacific
Type: Journal Article
Publication: Acta Oceanologica Sinica
Author(s): Xia, Ruibin; He, Yijun; Yang, Tingting
Year: 2021
Formatted Citation: Xia, R., Y. He, and T. Yang, 2021: Simulation and future projection of the mixed layer depth and subduction process in the subtropical Southeast Pacific. Acta Oceanologica Sinica, 40(12), 104-113, doi:10.1007/s13131-021-1877-0
Formatted Citation: Zhou, J., G. Zhou, H. Liu, Z. Li, and X. Cheng, 2021: Mesoscale Eddy-Induced Ocean Dynamic and Thermodynamic Anomalies in the North Pacific. Frontiers in Marine Science, 8, doi:10.3389/fmars.2021.756918
Abstract: Oceanic mesoscale eddies are associated with large thermodynamic anomalies, yet so far they are most commonly studied in terms of surface temperature and in the sense of composite mean. Here we employ an objective eddy identification and tracking algorithm together with a novel matching and filling procedure to more thoroughly examine eddy-induced thermodynamic anomalies in the North Pacific, their relationship with eddy amplitude (SSH), and the percentage of variability they explain on various timescales from submonthly to interannual. The thermodynamic anomalies are investigated in terms of sea surface temperature (SST), isothermal layer depth (ITD), and upper ocean heat content (HCT). Most eddies are weak in amplitude and are associated with small thermodynamic anomalies. In the sense of composite mean, anticyclonic eddies are generally warm eddies with deeper isothermal layer and larger heat content, and the reverse is true for cyclonic eddies. A small fraction of eddies, most probably subsurface eddies, exhibits the opposite polarities. Linear relationships with eddy amplitude are found for each of the thermodynamic parameters but with different level of scatter and seasonality. HCT-amplitude relation scatters the least and has the smallest seasonal difference, ITD-amplitude relation has the largest scatter and seasonality, while SST-amplitude relation is in between. For the Kuroshio and Oyashio Extension region, the most eddy-rich region in the North Pacific, eddies are responsible for over 50% of the total SSH variability up to the intra-seasonal scale, and ITD and HCT variability up to interannual. Eddy-induced SST variability is the highest along the Oyashio Extension Front on the order of 40-60% on submonthly scales. These results highlight the role of mesoscale eddies in ocean thermodynamic variability and in air-sea interaction.
Xie, Jiping; Mu, Longjiang; Han, Bo; Yang, Qinghua (2021). Evaluation of sea-ice thickness reanalysis data from the coupled ocean-sea-ice data assimilation system TOPAZ4, Journal of Glaciology, 1-13, 10.1017/jog.2020.110.
Formatted Citation: Xie, J., L. Mu, B. Han, and Q. Yang, 2021: Evaluation of sea-ice thickness reanalysis data from the coupled ocean-sea-ice data assimilation system TOPAZ4. Journal of Glaciology, 1-13, doi:10.1017/jog.2020.110
Abstract: With the assimilation of satellite-based sea-ice thickness (SIT) data, the new SIT reanalysis from the Towards an Operational Prediction system for the North Atlantic European coastal Zones (TOPAZ4) was released from 2014 to 2018. Apart from assimilating sea-ice concentration and oceanic variables, TOPAZ4 further assimilates CS2SMOS SIT. In this study, the 5-year reanalysis is compared with CS2SMOS, the Pan-Arctic Ice-Ocean Modeling and Assimilating System (PIOMAS) and the Combined Model and Satellite Thickness (CMST). Moreover, we evaluate TOPAZ4 SIT with field observations from upward-looking sonar (ULS), ice mass-balance buoys, Operation IceBridge Quicklook and Sea State Ship-borne Observations. The results indicate TOPAZ4 well reproduces the spatial characteristics of the Arctic SIT distributions, with large differences with CS2SMOS/PIOMAS/CMST mainly restricted to the Atlantic Sector and to the month of September. TOPAZ4 shows thinner ice in March and April, especially to the north of the Canadian Arctic Archipelago with a mean bias of -0.30 m when compared to IceBridge. Besides, TOPAZ4 simulates thicker ice in the Beaufort Sea when compared to ULS, with a mean bias of 0.11 m all year round. The benefit from assimilating SIT data in TOPAZ4 is reflected in a 34% improvement in root mean square deviation.
Title: Improving Detectability of Seafloor Deformation From Bottom Pressure Observations Using Numerical Ocean Models
Type: Journal Article
Publication: Frontiers in Earth Science
Author(s): Dobashi, Yoichiro; Inazu, Daisuke
Year: 2021
Formatted Citation: Dobashi, Y. and D. Inazu, 2021: Improving Detectability of Seafloor Deformation From Bottom Pressure Observations Using Numerical Ocean Models. Frontiers in Earth Science, 8, doi:10.3389/feart.2020.598270
Abstract: We investigated ocean bottom pressure (OBP) observation data at six plate subduction zones around the Pacific Ocean. The six regions included the Hikurangi Trough, the Nankai Trough, the Japan Trench, the Aleutian Trench, the Cascadia Subduction Zone, and the Chile Trench. For the sake of improving the detectability of seafloor deformation using OBP observations, we used numerical ocean models to represent realistic oceanic variations, and subtracted them from the observed OBP data. The numerical ocean models included four ocean general circulation models (OGCMs) of HYCOM, GLORYS, ECCO2, and JCOPE2M, and a single-layer ocean model (SOM). The OGCMs are mainly driven by the wind forcing. The SOM is driven by wind and/or atmospheric pressure loading. The modeled OBP was subtracted from the observed OBP data, and root-mean-square (RMS) amplitudes of the residual OBP variations at a period of 3-90 days were evaluated by the respective regions and by the respective numerical ocean models. The OGCMs and SOM driven by wind alone (SOM w ) contributed to 5-27% RMS reduction in the residual OBP. When SOM driven by atmospheric pressure alone (SOM p ) was added to the modeled OBP, residual RMS amplitudes were additionally reduced by 2-15%. This indicates that the atmospheric pressure is necessary to explain substantial amounts of observed OBP variations at the period. The residual RMS amplitudes were 1.0-1.7 hPa when SOM p was added. The RMS reduction was relatively effective as 16-42% at the Hikurangi Trough, the Nankai Trough, and the Japan Trench. The residual RMS amplitudes were relatively small as 1.0-1.1 hPa at the Nankai Trough and the Chile Trench. These results were discussed with previous studies that had identified slow slips using OBP observations. We discussed on further accurate OBP modeling, and on improving detectability of seafloor deformation using OBP observation arrays.
Formatted Citation: Liu, J., L. Baskaran, K. Bowman, D. Schimel, A.A. Bloom, N.C. Parazoo, T. Oda, D. Carroll, D. Menemenlis, J. Joiner, R. Commane, B. Daube, L.V. Gatti, K. McKain, J. Miller, B.B. Stephens, C. Sweeney, and S. Wofsy, 2021: Carbon Monitoring System Flux Net Biosphere Exchange 2020 (CMS-Flux NBE 2020). Earth System Science Data, 13(2), 299-330, doi:10.5194/essd-13-299-2021
Pandey, Lokesh; Dwivedi, Suneet; Martin, Matthew (2021). Short-Term Predictability of the Bay of Bengal Region Using a High-Resolution Indian Ocean Model, Marine Geodesy (1-14), 10.1080/01490419.2021.189427.
Title: Short-Term Predictability of the Bay of Bengal Region Using a High-Resolution Indian Ocean Model
Type: Journal Article
Publication: Marine Geodesy
Author(s): Pandey, Lokesh; Dwivedi, Suneet; Martin, Matthew
Year: 2021
Formatted Citation: Pandey, L., S. Dwivedi, and M. Martin, 2021: Short-Term Predictability of the Bay of Bengal Region Using a High-Resolution Indian Ocean Model. Marine Geodesy, 1-14, doi:10.1080/01490419.2021.189427
Abstract: An ocean circulation model, Nucleus for European Modelling of the Ocean (NEMO version 3.6) is customized to run at high-resolution over a regional domain [30°E-105°E; 20°S-30°N] in the Indian Ocean. It uses horizontal resolution of 1/12° in longitude/latitude and 75 levels in the vertical direction. The model well captures the observed space-time variations of temperature and salinity at the surface and subsurface, and the surface currents and eddy kinetic energy. The short-term spatio-temporal predictability of the Bay of Bengal (BoB) region is quantified using the model currents. The Lagrangian measure of predictability, Finite Time Lyapunov Exponent (FTLE) is compared with the Eulerian measure (Okubo-Weiss parameter). The regions of chaotic stirring are identified in the BoB. The FTLE analysis reveals that the predictability on a biweekly time scale in the BoB is minimum during October-November, and the highest during May to July. The FTLE is shown to serve as a useful tool for planning targeted observations in the BoB region.
Formatted Citation: Ren, S., X. Liang, Q. Sun, H. Yu, L.B. Tremblay, B. Lin, X. Mai, F. Zhao, M. Li, N. Liu, Z. Chen, and Y. Zhang, 2021: A fully coupled Arctic sea-ice-ocean-atmosphere model (ArcIOAM v1.0) based on C-Coupler2: model description and preliminary results. Geoscientific Model Development, 14(2), 1101-1124, doi:10.5194/gmd-14-1101-2021
Min, Chao; Yang, Qinghua; Mu, Longjiang; Kauker, Frank; Ricker, Robert (2021). Ensemble-based estimation of sea-ice volume variations in the Baffin Bay, The Cryosphere, 1 (15), 169-181, 10.5194/tc-15-169-2021.
Formatted Citation: Min, C., Q. Yang, L. Mu, F. Kauker, and R. Ricker, 2021: Ensemble-based estimation of sea-ice volume variations in the Baffin Bay. The Cryosphere, 15(1), 169-181, doi:10.5194/tc-15-169-2021
Team, International Altimetry (2021). Altimetry for the future: Building on 25 years of progress, 25 Years of Progress in Radar Altimetry, https://doi.org/10.1016/j.asr.2021.01.022.
Title: Altimetry for the future: Building on 25 years of progress
Type: Book Section
Publication: 25 Years of Progress in Radar Altimetry
Author(s): Team, International Altimetry
Year: 2021
Formatted Citation: Team, I. A., 2021: Altimetry for the future: Building on 25 years of progress. 25 Years of Progress in Radar Altimetry, doi:https://doi.org/10.1016/j.asr.2021.01.022
Abstract: In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the "Green" Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments' development and satellite missions' evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion.
Wang, Jie; Bai, Xuezhi; Leng, Hengling (2021). Examination of seasonal variation of the equatorial undercurrent termination in the Eastern Pacific diagnosed by ECCO2, Journal of Oceanology and Limnology, 10.1007/s00343-021-0308-6.
Title: Examination of seasonal variation of the equatorial undercurrent termination in the Eastern Pacific diagnosed by ECCO2
Type: Journal Article
Publication: Journal of Oceanology and Limnology
Author(s): Wang, Jie; Bai, Xuezhi; Leng, Hengling
Year: 2021
Formatted Citation: Wang, J., X. Bai, and H. Leng, 2021: Examination of seasonal variation of the equatorial undercurrent termination in the Eastern Pacific diagnosed by ECCO2. Journal of Oceanology and Limnology, doi:10.1007/s00343-021-0308-6
Rossi, Federico; Branch, Andrew; Schodlok, Michael P.; Stanton, Timothy; Fenty, Ian G.; Hook, Joshua Vander; Clark, Evan B. (2021). Stochastic Guidance of Buoyancy Controlled Vehicles under Ice Shelves using Ocean Currents, 2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 8657-8664, 10.1109/IROS51168.2021.9635987.
Title: Stochastic Guidance of Buoyancy Controlled Vehicles under Ice Shelves using Ocean Currents
Type: Conference Proceedings
Publication: 2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)
Author(s): Rossi, Federico; Branch, Andrew; Schodlok, Michael P.; Stanton, Timothy; Fenty, Ian G.; Hook, Joshua Vander; Clark, Evan B.
Year: 2021
Formatted Citation: Rossi, F., A. Branch, M. P. Schodlok, T. Stanton, I. G. Fenty, J. V. Hook, and E. B. Clark, 2021: Stochastic Guidance of Buoyancy Controlled Vehicles under Ice Shelves using Ocean Currents. 2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) IEEE, 8657-8664 pp. doi:10.1109/IROS51168.2021.9635987.
Formatted Citation: Pendleton, S., A. Condron, and J. Donnelly, 2021: The potential of Hudson Valley glacial floods to drive abrupt climate change. Communications Earth & Environment, 2(1), 152, doi:10.1038/s43247-021-00228-1
Abstract: The periodic input of meltwater into the ocean from a retreating Laurentide Ice Sheet is often hypothesized to have weakened the Atlantic meridional overturning circulation (AMOC) and triggered several cold periods during the last deglaciation (21,000 to 8,000 years before present). Here, we use a numerical model to investigate whether the Intra-Allerød Cold Period was triggered by the drainage of Glacial Lake Iroquois, ~13,300 years ago. Performing a large suite of experiments with various combinations of single and successive, short (1 month) and long (1 year) duration flood events, we were unable to find any significant weakening of the AMOC. This result suggests that although the Hudson Valley floods occurred close to the beginning of the Intra-Allerød Cold Period, they were unlikely the sole cause. Our results have implications for re-evaluating the relationship of meltwater flood events (past and future) to periods of climatic cooling, particularly with regards to flood input location, volume, frequency, and duration.
Author(s): Ashley, Kate E.; McKay, Robert; Etourneau, Johan; Jimenez-Espejo, Francisco J.; Condron, Alan; Albot, Anna; Crosta, Xavier; Riesselman, Christina; Seki, Osamu; Massé, Guillaume; Golledge, Nicholas R.; Gasson, Edward; Lowry, Daniel P.; Barrand, Nicholas E.; Johnson, Katelyn; Bertler, Nancy; Escutia, Carlota; Dunbar, Robert; Bendle, James A.
Year: 2021
Formatted Citation: Ashley, K. E. and Coauthors, 2021: Mid-Holocene Antarctic sea-ice increase driven by marine ice sheet retreat. Climate of the Past, 17(1), 1-19, doi:10.5194/cp-17-1-2021
Xi Liang, Chengyan Liu, Lejiang Yu, Martin Losch, Lujun Zhang, Xichen Li, Fu Zhao, and Zhongxiang Tian (2021). Impact of local atmospheric intraseasonal variability on mean sea ice state in the Arctic Ocean, Journal of Climate, 1-52, 10.1175/JCLI-D-21-0376.1.
Title: Impact of local atmospheric intraseasonal variability on mean sea ice state in the Arctic Ocean
Type: Journal Article
Publication: Journal of Climate
Author(s): Xi Liang, Chengyan Liu, Lejiang Yu, Martin Losch, Lujun Zhang, Xichen Li, Fu Zhao, and Zhongxiang Tian
Year: 2021
Formatted Citation: Xi Liang, C. L., 2021: Impact of local atmospheric intraseasonal variability on mean sea ice state in the Arctic Ocean. J. Clim., 1-52, doi:10.1175/JCLI-D-21-0376.1
Abstract: The Arctic atmosphere shows significant variability on intraseasonal timescales of 10-90 days. The intraseasonal variability in the Arctic sea ice is clearly related to that in the Arctic atmosphere. It is well-known that the Arctic mean sea ice state is governed by the local mean atmospheric state. However, the response of the Arctic mean sea ice state to the local atmospheric intraseasonal variability is unclear. The Arctic atmospheric intraseasonal variability exists in both the thermodynamical and dynamical variables. Based on a sea ice-ocean coupled simulation with a quantitative sea ice budget analysis, this study finds that: 1) the intraseasonal atmospheric thermodynamical variability tends to reduce sea ice melting through changing the downward heat flux on the open water area in the marginal sea ice zone, and the intraseasonal atmospheric dynamical variability tends to increase sea ice melting by a combination of modified air-ocean, ice-ocean heat fluxes and sea ice deformation. 2) The intraseasonal atmospheric dynamical variability increases summertime sea ice concentration in the Beaufort Sea and the Greenland Sea but decreases summertime sea ice concentration along the Eurasian continent in the East Siberia-Laptev-Kara Seas, resulting from the joint effects of the modified air-ocean, ice-ocean heat fluxes, the sea ice deformation, as well as the mean sea ice advection due to the changes of sea ice drift. The large spread in sea ice in the CMIP models may be partly attributed to the different model performances in representing the observed atmospheric intraseasonal variability. Reliable modeling of atmospheric intraseasonal variability is an essential condition in correctly projecting future sea ice evolution.
Formatted Citation: Jacques, G., P. Tréguer, and H. Mercier, 2021: Oceans: Evolving Concepts. Wiley, 320 pp. doi:10.1002/9781119818038.
Abstract: Since the HMS Challenger expedition of 1872-1876, our vision of the ocean has changed completely. We now understand that it plays a key role in biodiversity, climate regulation, and mineral and biological resources, and as such, the ocean is a major service provider for humanity. Oceans draws on data from new oceanographic and satellite tools, acquired through international interdisciplinary programs. It describes the processes that control how the ocean functions, on different spatial and temporal scales. After considering the evolution of concepts in physical, chemical and biological oceanography, the book outlines the future of a warmer, acidified, less oxygenated ocean. It shows how a view of the ocean at different scales changes how we understand it. Finally, the book presents the challenges facing the ocean in terms of the exploitation of biological and mineral resources, in the context of sustainable development and the regulation of climate change.
Other URLs: https://onlinelibrary.wiley.com/doi/book/10.1002/9781119818038
Liang, X.; Li, X.; Bi, H.; Losch, M.; Gao, Y.; Zhao, F.; Tian, Z.; Liu, C. (2021). A comparison of factors that led to the extreme sea ice minima in the 21st century in the Arctic Ocean, Journal of Climate, 1-56, 10.1175/JCLI-D-21-0199.1.
Title: A comparison of factors that led to the extreme sea ice minima in the 21st century in the Arctic Ocean
Type: Journal Article
Publication: Journal of Climate
Author(s): Liang, X.; Li, X.; Bi, H.; Losch, M.; Gao, Y.; Zhao, F.; Tian, Z.; Liu, C.
Year: 2021
Formatted Citation: Liang, X., X. Li, H. Bi, M. Losch, Y. Gao, F. Zhao, Z. Tian, and C. Liu, 2021: A comparison of factors that led to the extreme sea ice minima in the 21st century in the Arctic Ocean. J. Clim., 1-56, doi:10.1175/JCLI-D-21-0199.1
Abstract: The extreme Arctic sea ice minima in the 21st century have been attributed to multiple factors, such as anomalous atmospheric circulation, excess solar radiation absorbed by open ocean, and thinning sea ice in a warming world. Most likely it is the combination of these factors that drive the extreme sea ice minima, but it has not been quantified, how the factors rank in setting the conditions for these events. To address this question, the sea ice budget of an Arctic regional sea ice-ocean model forced by atmospheric reanalysis data is analyzed to assess the development of the observed sea ice minima. Results show that the ice area difference in the years 2012, 2019, and 2007 is driven to over 60% by the difference in summertime sea ice area loss due to air-ocean heat flux over open water. Other contributions are small. For the years 2012 and 2020 the situation is different and more complex. The air-ice heat flux causes more sea ice area loss in summer 2020 than in 2012 due to warmer air temperatures, but this difference in sea ice area loss is compensated by reduced advective sea ice loss out of the Arctic Ocean mainly caused by the relaxation of the Arctic Dipole. The difference in open water area in early August leads to different air-ocean heat fluxes, which distinguishes the sea ice minima in 2012 and 2020. Further, sensitivity experiments indicate that both the atmospheric circulation associated with the Arctic Dipole and extreme storms are essential conditions for a new low record of sea ice extent.
Wang, Tianyu; Du, Yan; Wang, Minyang (2021). Overlooked current estimation biases arising from the Lagrangian Argo trajectory derivation method, Journal of Physical Oceanography, 10.1175/JPO-D-20-0287.1.
Title: Overlooked current estimation biases arising from the Lagrangian Argo trajectory derivation method
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Wang, Tianyu; Du, Yan; Wang, Minyang
Year: 2021
Formatted Citation: Wang, T., Y. Du, and M. Wang, 2021: Overlooked current estimation biases arising from the Lagrangian Argo trajectory derivation method. Journal of Physical Oceanography, doi:10.1175/JPO-D-20-0287.1
Abstract: An Argo simulation system is used to provide synthetic Lagrangian trajectories based on the Estimating the Circulation and Climate of the Ocean model, Phase II (ECCO2). In combination with ambient Eulerian velocity at the reference layer (1000 m) from the model, quantitative metrics of the Lagrangian trajectory-derived velocities are computed. The result indicates that the biases induced by the derivation algorithm are strongly linked with ocean dynamics. In low latitudes, Ekman currents and vertically sheared geostrophic currents influence both the magnitude and the direction of the derivation velocity vectors. The maximal shear-induced biases exist near the equator with the amplitudes reaching up to about 1.2 cm s-1. The angles of the shear biases are pronounced in the low latitude oceans, ranging from -8° to 8°. Specifically, the study shows an overlooked bias from the float drifting motions that mainly occurs in the western boundary current and Antarctic circumpolar current (ACC) regions. In these regions, a recently reported horizontal acceleration measured via Lagrangian floats is significantly associated with the strong eddy-jet interactions. The acceleration could induce an overestimation of Eulerian current velocity magnitudes. For the common Argo floats with a 9-day float parking period, the derivation speed biases induced by velocity acceleration would be as large as 3 cm s-1, approximately 12% of the ambient velocity. It might have implications to map the mean mid-depth ocean currents from Argo trajectories, as well as understand the dynamics of eddy-jet interactions in the ocean.
Kumar, Anurag; Bhatla, R. (2021). Modeling the mixed layer depth in Southern Ocean using high resolution regional coupled ocean sea ice model, Modeling Earth Systems and Environment, 10.1007/s40808-021-01321-2.
Title: Modeling the mixed layer depth in Southern Ocean using high resolution regional coupled ocean sea ice model
Type: Journal Article
Publication: Modeling Earth Systems and Environment
Author(s): Kumar, Anurag; Bhatla, R.
Year: 2021
Formatted Citation: Kumar, A., and R. Bhatla, 2021: Modeling the mixed layer depth in Southern Ocean using high resolution regional coupled ocean sea ice model. Modeling Earth Systems and Environment, doi:10.1007/s40808-021-01321-2
Title: Global drivers of eukaryotic plankton biogeography in the sunlit ocean
Type: Journal Article
Publication: Science
Author(s): Sommeria-Klein, Guilhem; Watteaux, Romain; Ibarbalz, Federico M.; Pierella Karlusich, Juan José; Iudicone, Daniele; Bowler, Chris; Morlon, Hélène
Year: 2021
Formatted Citation: Sommeria-Klein, G., R. Watteaux, F. M. Ibarbalz, J. J. Pierella Karlusich, D. Iudicone, C. Bowler, and H. Morlon, 2021: Global drivers of eukaryotic plankton biogeography in the sunlit ocean. Science, 374(6567), 594-599, doi:10.1126/science.abb3717
Love, Ryan; Andres, Heather J.; Condron, Alan; Tarasov, Lev (2021). Freshwater routing in eddy-permitting simulations of the last deglacial: the impact of realistic freshwater discharge, Climate of the Past, 6 (17), 2327-2341, 10.5194/cp-17-2327-2021.
Title: Freshwater routing in eddy-permitting simulations of the last deglacial: the impact of realistic freshwater discharge
Type: Journal Article
Publication: Climate of the Past
Author(s): Love, Ryan; Andres, Heather J.; Condron, Alan; Tarasov, Lev
Year: 2021
Formatted Citation: Love, R., H. J. Andres, A. Condron, and L. Tarasov, 2021: Freshwater routing in eddy-permitting simulations of the last deglacial: the impact of realistic freshwater discharge. Climate of the Past, 17(6), 2327-2341, doi:10.5194/cp-17-2327-2021
Wickramage, C. H.; Wang, Weiqiang; Arulananthan, K.; Jayathilake, Ruchira (2021). Dynamics of counter wind current along the south Sri Lanka coast during the Southwest Monsoon, Ocean Dynamics, 10.1007/s10236-021-01477-6.
Title: Dynamics of counter wind current along the south Sri Lanka coast during the Southwest Monsoon
Type: Journal Article
Publication: Ocean Dynamics
Author(s): Wickramage, C. H.; Wang, Weiqiang; Arulananthan, K.; Jayathilake, Ruchira
Year: 2021
Formatted Citation: Wickramage, C.H., W. Wang, K. Arulananthan, and R. Jayathilake, 2021: Dynamics of counter wind current along the south Sri Lanka coast during the Southwest Monsoon, Ocean Dynamics, doi: 10.1007/s10236-021-01477-6
Abstract: Shipboard velocity profiles collected in July 2018 are used to study coastal current in the south of Sri Lanka during the summer monsoon. The observations reveal that there is a narrow (~50 km wide) westward coastal current against the summer monsoon, separated the eastward southwest monsoon current (SMC) from the island of Sri Lanka. However, the climatological south Sri Lanka coastal current (SSLCC) is eastward following the direction of the SMC. The deviations between the observations and climatology of the SSLCC suggest its significant interannual variability. The dynamics of the westward SSLCC and its impact factors are thus focused on in this study. The results indicate that two main processes are responsible. First, the boreal summer intraseasonal oscillation (BSISO) plays an important role in the presence of westward SSLCC. The BSISO signal intensifies the wind strength east and south of Sri Lanka, reinforces the east India coastal current (EICC), and bends the SMC favoring occurrence of the westward SSLCC. Second, the upwelling Rossby wave signal propagates to Sri Lanka but stops at 82°E, which favors the Sri Lanka Dome developing. As the western flank of the SLD, the strengthened EICC flows southward and turns to west resulting in the westward SSLCC. Accordingly, the energy conversions by baroclinic and barotropic instability between mean flow and eddy are analyzed for both the westward and eastward SSLCC.
Author(s): Dimitris Menemenlis; Horace G Mitchell; Christopher N Hill; Borner, Katy
Year: 2021
Formatted Citation: Menemenlis, D., H.G. Mitchell, C.N. Hill, and K. Borner, 2021: Perpetually Moving Ocean, Atlas of Forecasts: Modeling and Mapping Desirable Futures, MIT Press, 126, isbn: 9780262045957
Abstract: NASA Views Our Perpetually Moving Ocean By Dimitris Menemenlis, Horace G. Mitchell, Christopher N. Hill, and Gregory W. Shirah Greenvelt, Maryland, 2011. Courtesy of the Scientific Visualization Studio at NASA's Goddard Space Flight Center. This scientific visualization is the result of a collaboration between MIT and NASA's Jet Propulsion Laboratory. Using advanced mathematical tools, observational data from ECCO (Estimating the Circulation and Climate of the Ocean) is combined with the MIT numerical ocean model to obtain realistic descriptions of how ocean circulation evolves over time. These circulation estimates, made possible by NASA Advanced Supercomputing resources at the Ames Research Center, are among the largest computations of their kind ever undertaken. They are used to quantify the ocean's role in the global carbon cycle; to understand the recent evolution of the polar oceans; to monitor time-evolving heat, water.
Formatted Citation: Chen, X., B. Qiu, S. Chen, and Y. Qi, 2021: Period-Lengthening of the Mindanao Current Variability From the Long-Term Tide Gauge Sea Level Measurements, Journal of Geophysical Research: Oceans, 126(8), doi: 10.1029/2020JC016932
Abstract: Long-term tide gauge sea level data from 1969 to 2014 at Davao (7.08°N, 125.63°E) and Malakal (7. 33°N, 134.46°E) are analyzed to examine the decadal frequency modulations embedded in the Mindanao Current (MC) variability. The MC variability inferred from the Davao–Malakal sea level was predominantly biennial in the 1970s. This prevailing period switched to interannual in the 1980s and lengthened to decadal during the last two decades. With the aid of the basin-scale sea level information from satellite altimeter measurements, it is found that the sea level-inferred MC variability represents the coherent changes of the wind-driven tropical gyre in the western North Pacific. An investigation into the long-term wind stress curl data reveals that its prevailing period underwent similar biennial-interannual-decadal transitions in the western tropical Pacific, implying the forced nature of the period-lengthening of the MC variability during the past half-a-century. While the sign of the MC variability is largely determined by the Malakal sea level signals on the interannual and decadal time scales, the Davao sea level change becomes important when the time scale extends to multi-decades.
Pefanis, Vasileios (2021). Loading of coloured dissolved organic matter in the Arctic Mediterranean Sea and its effects on the ocean heat budget, University of Bremen.
Title: Loading of coloured dissolved organic matter in the Arctic Mediterranean Sea and its effects on the ocean heat budget
Type: Thesis
Publication: University of Bremen
Author(s): Pefanis, Vasileios
Year: 2021
Formatted Citation: Pefanis, V., 2020: Loading of coloured dissolved organic matter in the Arctic Mediterranean Sea and its effects on the ocean heat budget, University of Bremen
Abstract: Currently, the most rapid increase in near-surface air temperature takes place inthe Arctic, accompanied by a decline in sea ice cover. Consequently, the underwater shortwave radiation, and thus, the type and amount of phytoplankton are changing. In this context, the thawing permafrost, accompanied by increased precipitation and freshwater discharge, is expected to result in higher loads of coloured dissolved organic matter (CDOM) and total suspended matter (TSM) entering the Arctic Ocean. The amount of these optically active water constituents determines how much light is absorbed in the surface waters and how much can reach greater depths, affecting the vertical distribution of heat. In this thesis, I first examine the potential of CDOM and TSM in enhancing the radiative heating and sea ice melting in the shelf waters of the Laptev Sea, an area heavily influenced by one of the largest river systems in the Arctic region. By using in situ observations, I simulate the in-water radiative heating utilizing coupled atmosphere-ocean radiative transfer modelling (RTM). The results indicate that CDOM and TSM highly affect the energy budget of the Laptev Sea shelf waters, absorbing most of the solar energy in the first 2 meters of the water column. The increased absorbed energy leads to higher sea ice melt rates and changes in the heat exchange with the atmosphere. By using satellite remote sensing and RTM, I quantify the spatial distribution of radiative heating in the Laptev Sea for a typical summer day. The spatial patterns of radiative heating closely follow the distribution of the optically active water constituents, with the highest energy absorption occurring over river-influenced waters. As a next step, I upscale the previous one-dimensional and regional study by means of general circulation modelling for the entire Arctic Mediterranean Sea. By operating an ocean biogeochemical model coupled to a general circulation model with sea ice vi (Darwin-MITgcm), the effect of phytoplankton and CDOM is incorporated into the in-water shortwave radiation penetration scheme. Accounting for their radiative effect increases the sea surface temperature (SST) in summer, decreases the sea ice concentration, and induces more heat loss to the atmosphere, primarily through sensible and latent heat flux. In some parts of the Eastern Arctic, the sea ice season is reduced by up to one month. CDOM drives 48% of the summertime changes in SST, suggesting that an increase in its concentration will amplify the observed Arctic surface warming. Additionally, the CDOM effect alters the vertical diffusion, advection, and non-local vertical mixing of heat. The shortwave heating and vertical diffusion terms account for a large part of the Arctic-wide changes in the heat budget throughout the year. On the contrary, in the Atlantic sector, differences in the subsurface heating can be largely determined by advective and non-local mixing processes in spring and winter. In the Norwegian Sea, the subsurface wintertime indirect dynamical effect is 2.7 times larger than the effect of shortwave heating. These results underline the potential of indirect changes in advective and mixing processes in intensifying or dumping the direct effect of CDOM at the subsurface. The changes induced by CDOM feed back on phytoplankton and CDOM itself, leading to higher annual mean surface concentrations for both of them. On the contrary, phytoplankton reduces at the subsurface resulting in a 16.6% overall biomass decrease in the upper 100 m. The areas where light limits phytoplankton growth, expand at the expense of nutrient limitation. In spring, reduced light availability causes a phytoplankton bloom delay and an increase in nutrient concentrations. However, in summer the excess of nutrients together with the light limitation confine phytoplankton growth in a few tens of meters from the ocean surface leading to an intensification and delay of the end of the bloom, especially at the Barents Sea. These findings indicate that a future increase of CDOM will ignite a secondary positive feedback mechanism on the Arctic's surface warming, through increased phytoplankton and CDOM light absorption close to the surface.
Williams, Timothy; Korosov, Anton; Rampal, Pierre; Ólason, Einar (2021). Presentation and evaluation of the Arctic sea ice forecasting system neXtSIM-F, The Cryosphere, 7 (15), 3207-3227, 10.5194/tc-15-3207-2021.
Title: Presentation and evaluation of the Arctic sea ice forecasting system neXtSIM-F
Type: Journal Article
Publication: The Cryosphere
Author(s): Williams, Timothy; Korosov, Anton; Rampal, Pierre; Ólason, Einar
Year: 2021
Formatted Citation: Williams, T., A. Korosov, P. Rampal, and E. Ólason, 2021: Presentation and evaluation of the Arctic sea ice forecasting system neXtSIM-F, The Cryosphere, 15(7), 3207-3227, doi: 10.5194/tc-15-3207-2021
Abstract: The neXtSIM-F (neXtSIM forecast) forecasting system consists of a stand-alone sea ice model, neXtSIM (neXt-generation Sea Ice Model), forced by the TOPAZ ocean forecast and the ECMWF atmospheric forecast, combined with daily data assimilation of sea ice concentration. It uses the novel brittle Bingham–Maxwell (BBM) sea ice rheology, making it the first forecast based on a continuum model not to use the viscous–plastic (VP) rheology. It was tested in the Arctic for the time period November 2018-June 2020 and was found to perform well, although there are some shortcomings. Despite drift not being assimilated in our system, the sea ice drift is good throughout the year, being relatively unbiased, even for longer lead times like 5 d. The RMSE in speed and the total RMSE are also good for the first 3 or so days, although they both increase steadily with lead time. The thickness distribution is relatively good, although there are some regions that experience excessive thickening with negative implications for the summertime sea ice extent, particularly in the Greenland Sea. The neXtSIM-F forecasting system assimilates OSI SAF sea ice concentration products (both SSMIS and AMSR2) by modifying the initial conditions daily and adding a compensating heat flux to prevent removed ice growing back too quickly. The assimilation greatly improves the sea ice extent for the forecast duration.
Formatted Citation: Kotabova, E., R. Malych, K. Pierella, J. Juan, E. Kazamia, M. Eichner, J. Mach, E. Lesuisse, C. Bowler, O. Prášil, and R. Sutak, 2021: Complex Response of the Chlorarachniophyte Bigelowiella natans to Iron Availability, mSystems, 6(1), doi: 10.1128/mSystems.00738-20
Abstract: Despite low iron availability in the ocean, marine phytoplankton require considerable amounts of iron for their growth and proliferation. While there is a constantly growing knowledge of iron uptake and its role in the cellular processes of the most abundant marine photosynthetic groups, there are still largely overlooked branches of the eukaryotic tree of life, such as the chlorarachniophytes.
Other URLs: https://msystems.asm.org/content/6/1/e00738-20
Condron, Alan; Hill, Jenna C. (2021). Timing of iceberg scours and massive ice-rafting events in the subtropical North Atlantic, Nature Communications, 3668 (12), 10.1038/s41467-021-23924-0.
Title: Timing of iceberg scours and massive ice-rafting events in the subtropical North Atlantic
Type: Journal Article
Publication: Nature Communications
Author(s): Condron, Alan; Hill, Jenna C.
Year: 2021
Formatted Citation: Condron, A. and J.C. Hill, 2021: Timing of iceberg scours and massive ice-rafting events in the subtropical North Atlantic, Nature Communications, 12(1), 3668, doi: 10.1038/s41467-021-23924-0
Abstract: High resolution seafloor mapping shows extraordinary evidence that massive (>300 m thick) icebergs once drifted >5,000 km south along the eastern United States, with >700 iceberg scours now identified south of Cape Hatteras. Here we report on sediment cores collected from several buried scours that show multiple plow marks align with Heinrich Event 3 (H3), ~31,000 years ago. Numerical glacial iceberg simulations indicate that the transport of icebergs to these sites occurs during massive, but short-lived, periods of elevated meltwater discharge. Transport of icebergs to the subtropics, away from deep water formation sites, may explain why H3 was associated with only a modest increase in ice-rafting across the subpolar North Atlantic, and implies a complex relationship between freshwater forcing and climate change. Stratigraphy from subbottom data across the scour marks shows there are additional features that are both older and younger, and may align with other periods of elevated meltwater discharge.
Title: Intercomparison of Arctic sea ice simulation in ROMS-CICE and ROMS-Budgell
Type: Journal Article
Publication: Polar Science
Author(s): Kumar, Rajesh; Li, Junde; Hedstrom, Kate; Babanin, Alexander V.; Holland, David M.; Heil, Petra; Tang, Youmin
Year: 2021
Formatted Citation: Kumar, R., J. Li, K, Hedstrom, A.V. Babanin, D.M. Holland, P. Heil, and Y. Tang, 2021: Intercomparison of Arctic sea ice simulation in ROMS-CICE and ROMS-Budgell, Polar Science, 100716, doi: 10.1016/j.polar.2021.100716
Abstract: Accurate representation of the complex ocean-sea ice interaction is still an ongoing effort. In this study, we have coupled the Community Ice Code (CICE) model and Regional Ocean Modeling System (ROMS) to develop a high-resolution regional coupled ocean-sea ice model for polar regions. This setup allows us to investigate the interaction between ocean and sea ice in detail. The Coupled-Ocean-Atmosphere-Wave-Sediment-Transport (COAWST) modeling system is the core of this coupled model. Currently, the ROMS model in COAWST uses the Budgell sea ice model, embedded as a sub-module in it but introducing a more comprehensive sea ice model (CICE) may provide a better treatment of sea ice. Here, we present our preliminary results based on the coupled ROMS-CICE and ROMS-Budgell simulation over the Arctic Ocean. Our results show that both CICE and Budgell models perform better in simulating sea ice concentration during winter than during summer. Compared to the satellite observations, sea ice concentrations from the CICE model in most subregions have higher correlations and smaller centered root mean square errors, showing higher simulation skills. The sea ice thickness biases are larger in the Budgell model in the early months of the year, whereas in the CICE model they are larger after October. Both CICE and Budgell models overestimate the sea ice extent and sea ice volume in summer, and their performances differ in the subregions.
Formatted Citation: Wu, Y., Z. Wang, C. Liu, and L. Yan, 2021: Energetics of Eddy-Mean Flow Interactions in the Amery Ice Shelf Cavity, Frontiers in Marine Science, 8, doi: 10.3389/fmars.2021.638741
Abstract: Previous studies demonstrated that eddy processes play an important role in ice shelf basal melting and the water mass properties of ice shelf cavities. However, the eddy energy generation and dissipation mechanisms in ice shelf cavities have not been studied systematically. The dynamic processes of the ocean circulation in the Amery Ice Shelf cavity are studied quantitatively through a Lorenz energy cycle approach for the first time by using the outputs of a high-resolution coupled regional ocean-sea ice-ice shelf model. Over the entire sub-ice-shelf cavity, mean available potential energy (MAPE) is the largest energy reservoir (112 TJ), followed by the mean kinetic energy (MKE, 70 TJ) and eddy available potential energy (EAPE, 10 TJ). The eddy kinetic energy (EKE) is the smallest pool (5.5 TJ), which is roughly 8% of the MKE, indicating significantly suppressed eddy activities by the drag stresses at ice shelf base and bottom topography. The total generation rate of available potential energy is about 1.0 GW, almost all of which is generated by basal melting and seawater refreezing, i.e., the so-called "ice pump." The energy generated by ice pump is mainly dissipated by the ocean-ice shelf and ocean-bottom drag stresses, amounting to 0.3 GW and 0.2 GW, respectively. The EKE is generated through two pathways: the barotropic pathway MAPE→MKE→EKE (0.03 GW) and the baroclinic pathway MAPE→EAPE→EKE (0.2 GW). In addition to directly supplying the EAPE through baroclinic pathway (0.2 GW), MAPE also provides 0.5 GW of power to MKE to facilitate the barotropic pathway.
Title: Water Depth Dependence of Long-Range Correlation in Nontidal Variations in Seafloor Pressure
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Inoue, Tomohiro; Ito, Yoshihiro; Wallace, Laura M.; Yoshikawa, Yutaka; Inazu, Daisuke; Garcia, Emmanuel Soliman M.; Muramoto, Tomoya; Webb, Spahr C.; Ohta, Kazuaki; Suzuki, Syuichi; Hino, Ryota
Year: 2021
Formatted Citation: Inoue, T. and Coauthors, 2021: Water Depth Dependence of Long-Range Correlation in Nontidal Variations in Seafloor Pressure. Geophys. Res. Lett., 48(8), doi:10.1029/2020GL092173
Leng, Hengling; Spall, Michael A.; Pickart, Robert S.; Lin, Peigen; Bai, Xuezhi (2021). Origin and Fate of the Chukchi Slope Current Using a Numerical Model and In-situ Data, Journal of Geophysical Research: Oceans, 10.1029/2021JC017291.
Title: Origin and Fate of the Chukchi Slope Current Using a Numerical Model and In-situ Data
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Leng, Hengling; Spall, Michael A.; Pickart, Robert S.; Lin, Peigen; Bai, Xuezhi
Year: 2021
Formatted Citation: Leng, H., M. A. Spall, R. S. Pickart, P. Lin, and X. Bai, 2021: Origin and Fate of the Chukchi Slope Current Using a Numerical Model and In-situ Data. J. Geophys. Res. Ocean., doi:10.1029/2021JC017291
Li, Mingting; Yuan, Dongliang; Gordon, Arnold L.; Gruenburg, Laura K.; Li, Xiang; Li, Rui; Yin, Xueli; Yang, Ya; Corvianatie, Corry; Wei, Jun; Yang, Song (2021). A Strong Sub-Thermocline Intrusion of the North Equatorial Subsurface Current Into the Makassar Strait in 2016-2017, Geophysical Research Letters, 8 (48), 10.1029/2021GL092505.
Title: A Strong Sub-Thermocline Intrusion of the North Equatorial Subsurface Current Into the Makassar Strait in 2016-2017
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Li, Mingting; Yuan, Dongliang; Gordon, Arnold L.; Gruenburg, Laura K.; Li, Xiang; Li, Rui; Yin, Xueli; Yang, Ya; Corvianatie, Corry; Wei, Jun; Yang, Song
Year: 2021
Formatted Citation: Li, M. and Coauthors, 2021: A Strong Sub-Thermocline Intrusion of the North Equatorial Subsurface Current Into the Makassar Strait in 2016-2017. Geophys. Res. Lett., 48(8), doi:10.1029/2021GL092505
Wu, Yang; Wang, Zhaomin; Liu, Chengyan (2021). Impacts of Changed Ice-Ocean Stress on the North Atlantic Ocean: Role of Ocean Surface Currents, Frontiers in Marine Science (8), 10.3389/fmars.2021.628892.
Title: Impacts of Changed Ice-Ocean Stress on the North Atlantic Ocean: Role of Ocean Surface Currents
Type: Journal Article
Publication: Frontiers in Marine Science
Author(s): Wu, Yang; Wang, Zhaomin; Liu, Chengyan
Year: 2021
Formatted Citation: Wu, Y., Z. Wang, and C. Liu, 2021: Impacts of Changed Ice-Ocean Stress on the North Atlantic Ocean: Role of Ocean Surface Currents. Frontiers in Marine Science, 8, doi:10.3389/fmars.2021.628892
Abstract: The importance of considering ocean surface currents in ice-ocean stress calculation in the North Atlantic Ocean and Arctic sea ice is investigated for the first time using a global coupled ocean-sea ice model. Considering ocean surface currents in ice-ocean stress calculation weakens the ocean surface stress and Ekman pumping by about 7.7 and 15% over the North Atlantic Ocean, respectively. It also significantly reduces the mechanical energy input to ageostrophic and geostrophic currents, and weakens the mean and eddy kinetic energy by reducing the energy conversion rates of baroclinic and barotropic pathways. Furthermore, the strength of the Atlantic Meridional Overturning Circulation (AMOC), the Nordic Seas MOC, and the North Atlantic subpolar gyre are found to be reduced considerably (by 14.3, 31.0, and 18.1%, respectively). The weakened AMOC leads to a 0.12 PW reduction in maximum northward ocean heat transport, resulting in a reduced surface heat loss and lower sea surface temperature over the North Atlantic Ocean. This reduction also leads to a shrink in sea ice extent and an attenuation of sea ice thickness. These findings highlight the importance of properly considering both the geostrophic and ageostrophic components of ocean surface currents in ice-ocean stress calculation on ocean circulation and climate studies.
Narvekar, Jayu; Roy Chowdhury, Riyanka; Gaonkar, Diksha; Kumar, P. K. Dinesh; Prasanna Kumar, S. (2021). Observational evidence of stratification control of upwelling and pelagic fishery in the eastern Arabian Sea, Scientific Reports, 1 (11), 7293, 10.1038/s41598-021-86594-4.
Title: Observational evidence of stratification control of upwelling and pelagic fishery in the eastern Arabian Sea
Type: Journal Article
Publication: Scientific Reports
Author(s): Narvekar, Jayu; Roy Chowdhury, Riyanka; Gaonkar, Diksha; Kumar, P. K. Dinesh; Prasanna Kumar, S.
Year: 2021
Formatted Citation: Narvekar, J., R. Roy Chowdhury, D. Gaonkar, P. K. D. Kumar, and S. Prasanna Kumar, 2021: Observational evidence of stratification control of upwelling and pelagic fishery in the eastern Arabian Sea. Scientific Reports, 11(1), 7293, doi:10.1038/s41598-021-86594-4
Abstract: Upwelling is a physical phenomenon that occurs globally along the eastern boundary of the ocean and supports pelagic fishery which is an important source of protein for the coastal population. Though upwelling and associated small pelagic fishery along the eastern Arabian Sea (EAS) is known to exist at least for the past six decades, our understanding of the factors controlling them are still elusive. Based on observation and data analysis we hypothesize that upwelling in the EAS during 2017 was modulated by freshwater-induced stratification. To validate this hypothesis, we examined 17 years of data from 2001 and show that inter-annual variability of freshwater influx indeed controls the upwelling in the EAS through stratification, a mechanism hitherto unexplored. The upper ocean stratification in turn is regulated by the fresh water influx through a combination of precipitation and river runoff. We further show that the oil sardine which is one of the dominant fish of the small pelagic fishery of the EAS varied inversely with stratification. Our study for the first time underscored the role of freshwater influx in regulating the coastal upwelling and upper ocean stratification controlling the regional pelagic fishery of the EAS.
Feng, Yang; Menemenlis, Dimitris; Xue, Huijie; Zhang, Hong; Carroll, Dustin; Du, Yan; Wu, Hui (2021). Improved representation of river runoff in Estimating the Circulation and Climate of the Ocean Version 4 (ECCOv4) simulations: implementation, evaluation, and impacts to coastal plume regions, Geoscientific Model Development, 3 (14), 1801-1819, 10.5194/gmd-14-1801-2021.
Title: Improved representation of river runoff in Estimating the Circulation and Climate of the Ocean Version 4 (ECCOv4) simulations: implementation, evaluation, and impacts to coastal plume regions
Formatted Citation: Feng, Y., D. Menemenlis, H. Xue, H. Zhang, D. Carroll, Y. Du, and H. Wu, 2021: Improved representation of river runoff in Estimating the Circulation and Climate of the Ocean Version 4 (ECCOv4) simulations: implementation, evaluation, and impacts to coastal plume regions. Geoscientific Model Development, 14(3), 1801-1819, doi:10.5194/gmd-14-1801-2021
Formatted Citation: Li, J., A. V. Babanin, Q. Liu, J. J. Voermans, P. Heil, and Y. Tang, 2021: Effects of Wave-Induced Sea Ice Break-Up and Mixing in a High-Resolution Coupled Ice-Ocean Model. Journal of Marine Science and Engineering, 9(4), 365, doi:10.3390/jmse9040365
Abstract: Arctic sea ice plays a vital role in modulating the global climate. In the most recent decades, the rapid decline of the Arctic summer sea ice cover has exposed increasing areas of ice-free ocean, with sufficient fetch for waves to develop. This has highlighted the complex and not well-understood nature of wave-ice interactions, requiring modeling effort. Here, we introduce two independent parameterizations in a high-resolution coupled ice-ocean model to investigate the effects of wave-induced sea ice break-up (through albedo change) and mixing on the Arctic sea ice simulation. Our results show that wave-induced sea ice break-up leads to increases in sea ice concentration and thickness in the Bering Sea, the Baffin Sea and the Barents Sea during the ice growth season, but accelerates the sea ice melt in the Chukchi Sea and the East Siberian Sea in summer. Further, wave-induced mixing can decelerate the sea ice formation in winter and the sea ice melt in summer by exchanging the heat fluxes between the surface and subsurface layer. As our baseline model underestimates sea ice cover in winter and produces more sea ice in summer, wave-induced sea ice break-up plays a positive role in improving the sea ice simulation. This study provides two independent parameterizations to directly include the wave effects into the sea ice models, with important implications for the future sea ice model development.
Li, Qiang; Zhou, Lei; Xie, Lingling (2021). Seasonal and Interannual Variability of EAPE in the South China Sea Derived from ECCO2 Data from 1997 to 2019, Water, 7 (13), 926, 10.3390/w13070926.
Title: Seasonal and Interannual Variability of EAPE in the South China Sea Derived from ECCO2 Data from 1997 to 2019
Type: Journal Article
Publication: Water
Author(s): Li, Qiang; Zhou, Lei; Xie, Lingling
Year: 2021
Formatted Citation: Li, Q., L. Zhou, and L. Xie, 2021: Seasonal and Interannual Variability of EAPE in the South China Sea Derived from ECCO2 Data from 1997 to 2019. Water, 13(7), 926, doi:10.3390/w13070926
Abstract: Using Estimating the Circulation and Climate of the Ocean (phase 2, ECCO2) reanalysis products from 1997 to 2019, this study analyzes the spatiotemporal features of the eddy available gravitational potential energy (EAPE) in the South China Sea (SCS). The results indicate that the EAPE accounts for 64% of the total APE in the SCS with the climatological mean. The 2D EAPE distribution images manifest show high-value regions which are generally consistent with the eddy distributions. One region is located around 21° N and west of the Luzon Strait, the second around 17° N and near Luzon Island, and the third off the Vietnam coast. In the region around 21° N and 17° N, both the seasonal variability and the interannual variability associated with the El Niño-Southern Oscillation (ENSO) are significant. Off the Vietnam coast, the EAPE is closely associated with coastal processes which heavily depend on the seasonal monsoon, the El Nino/La Nina events, and the Indian Ocean Dipole (IOD). The results provide new insights into SCS dynamics from the point of view of ocean energy sources.
Stanley, Geoffrey J.; McDougall, Trevor J.; Barker, Paul M. (2021). Algorithmic Improvements to Finding Approximately Neutral Surfaces, Journal of Advances in Modeling Earth Systems, 5 (13), 10.1029/2020MS002436.
Title: Algorithmic Improvements to Finding Approximately Neutral Surfaces
Type: Journal Article
Publication: Journal of Advances in Modeling Earth Systems
Author(s): Stanley, Geoffrey J.; McDougall, Trevor J.; Barker, Paul M.
Year: 2021
Formatted Citation: Stanley, G. J., T. J. McDougall, and P. M. Barker, 2021: Algorithmic Improvements to Finding Approximately Neutral Surfaces. Journal of Advances in Modeling Earth Systems, 13(5), doi:10.1029/2020MS002436
Kersalé, M.; Meinen, C. S.; Perez, R. C.; Piola, A. R.; Speich, S.; Campos, E. J. D.; Garzoli, S. L.; Ansorge, I.; Volkov, D. L.; Le Hénaff, M.; Dong, S.; Lamont, T.; Sato, O. T.; van den Berg, M. (2021). Multi-Year Estimates of Daily Heat Transport by the Atlantic Meridional Overturning Circulation at 34.5°S, Journal of Geophysical Research: Oceans, 5 (126), 10.1029/2020JC016947.
Title: Multi-Year Estimates of Daily Heat Transport by the Atlantic Meridional Overturning Circulation at 34.5°S
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Kersalé, M.; Meinen, C. S.; Perez, R. C.; Piola, A. R.; Speich, S.; Campos, E. J. D.; Garzoli, S. L.; Ansorge, I.; Volkov, D. L.; Le Hénaff, M.; Dong, S.; Lamont, T.; Sato, O. T.; van den Berg, M.
Year: 2021
Formatted Citation: Kersalé, M. and Coauthors, 2021: Multi-Year Estimates of Daily Heat Transport by the Atlantic Meridional Overturning Circulation at 34.5°S. J. Geophys. Res. Ocean., 126(5), doi:10.1029/2020JC016947
Title: Ocean forcing drives glacier retreat in Greenland
Type: Journal Article
Publication: Science Advances
Author(s): Wood, Michael; Rignot, Eric; Fenty, Ian; An, Lu; Bjørk, Anders; van den Broeke, Michiel; Cai, Cilan; Kane, Emily; Menemenlis, Dimitris; Millan, Romain; Morlighem, Mathieu; Mouginot, Jeremie; Noël, Brice; Scheuchl, Bernd; Velicogna, Isabella; Willis, Josh K.; Zhang, Hong
Year: 2021
Formatted Citation: Wood, M. and Coauthors, 2021: Ocean forcing drives glacier retreat in Greenland. Science Advances, 7(1), eaba7282, doi:10.1126/sciadv.aba7282
Abstract: The retreat and acceleration of Greenland glaciers since the mid-1990s have been attributed to the enhanced intrusion of warm Atlantic Waters (AW) into fjords, but this assertion has not been quantitatively tested on a Greenland-wide basis or included in models. Here, we investigate how AW influenced retreat at 226 marine-terminating glaciers using ocean modeling, remote sensing, and in situ observations. We identify 74 glaciers in deep fjords with AW controlling 49% of the mass loss that retreated when warming increased undercutting by 48%. Conversely, 27 glaciers calving on shallow ridges and 24 in cold, shallow waters retreated little, contributing 15% of the loss, while 10 glaciers retreated substantially following the collapse of several ice shelves. The retreat mechanisms remain undiagnosed at 87 glaciers without ocean and bathymetry data, which controlled 19% of the loss. Ice sheet projections that exclude ocean-induced undercutting may underestimate mass loss by at least a factor of 2.
Formatted Citation: Zheng, F., Y. Sun, Q. Yang, and L. Mu, 2021: Evaluation of Arctic Sea-ice Cover and Thickness Simulated by MITgcm. Advances in Atmospheric Sciences, 38(1), 29-48, doi:10.1007/s00376-020-9223-6
An, Lu; Rignot, Eric; Wood, Michael; Willis, Josh K.; Mouginot, Jérémie; Khan, Shfaqat A. (2021). Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland, Proceedings of the National Academy of Sciences, 2 (118), e2015483118, 10.1073/pnas.2015483118.
Title: Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland
Type: Journal Article
Publication: Proceedings of the National Academy of Sciences
Author(s): An, Lu; Rignot, Eric; Wood, Michael; Willis, Josh K.; Mouginot, Jérémie; Khan, Shfaqat A.
Year: 2021
Formatted Citation: An, L., E. Rignot, M. Wood, J. K. Willis, J. Mouginot, and S. A. Khan, 2021: Ocean melting of the Zachariae Isstrøm and Nioghalvfjerdsfjorden glaciers, northeast Greenland. Proceedings of the National Academy of Sciences, 118(2), e2015483118, doi:10.1073/pnas.2015483118
Abstract: Zachariae Isstrøm (ZI) and Nioghalvfjerdsfjorden (79N) are marine-terminating glaciers in northeast Greenland that hold an ice volume equivalent to a 1.1-m global sea level rise. ZI lost its floating ice shelf, sped up, retreated at 650 m/y, and experienced a 5-gigaton/y mass loss. Glacier 79N has been more stable despite its exposure to the same climate forcing. We analyze the impact of ocean thermal forcing on the glaciers. A three-dimensional inversion of airborne gravity data reveals an 800-m-deep, broad channel that allows subsurface, warm, Atlantic Intermediate Water (AIW) (+1.25°C) to reach the front of ZI via two sills at 350-m depth. Subsurface ocean temperature in that channel has warmed by 1.3 ± 0.5°C since 1979. Using an ocean model, we calculate a rate of ice removal at the grounding line by the ocean that increased from 108 m/y to 185 m/y in 1979-2019. Observed ice thinning caused a retreat of its flotation line to increase from 105 m/y to 217 m/y, for a combined grounding line retreat of 13 km in 41 y that matches independent observations within 14%. In contrast, the limited access of AIW to 79N via a narrower passage yields lower grounded ice removal (53 m/y to 99 m/y) and thinning-induced retreat (27 m/y to 50 m/y) for a combined retreat of 4.4 km, also within 12% of observations. Ocean-induced removal of ice at the grounding line, modulated by bathymetric barriers, is therefore a main driver of ice sheet retreat, but it is not incorporated in most ice sheet models.
Li, Hongjie; Xu, Yongsheng (2021). Barotropic and baroclinic inverse kinetic energy cascade in the Antarctic Circumpolar Current, Journal of Physical Oceanography, 10.1175/JPO-D-20-0053.1.
Title: Barotropic and baroclinic inverse kinetic energy cascade in the Antarctic Circumpolar Current
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Li, Hongjie; Xu, Yongsheng
Year: 2021
Formatted Citation: Li, H., and Y. Xu, 2021: Barotropic and baroclinic inverse kinetic energy cascade in the Antarctic Circumpolar Current. Journal of Physical Oceanography, doi:10.1175/JPO-D-20-0053.1
Abstract: Stratified geostrophic turbulence theory predicts an inverse energy cascade for the barotropic (BT) mode. Satellite altimetry has revealed a net inverse cascade in the baroclinic (BC) mode. Here the spatial variabilities of BT and BC kinetic energy fluxes in the Antarctic Circumpolar Current (ACC) were investigated using ECCO2 data, which synthesizes satellite data and in situ measurements with an eddy-permitting general circulation models containing realistic bathymetry and wind forcing. The BT and BC inverse kinetic energy cascades both reveal complex spatial variations that could not be explained fully by classical arguments. For example, the BC injection scales match better with most unstable scales than with the first-mode deformation scales, but the opposite is true for the BT mode. In addition, the BT and BC arrest scales do not follow the Rhines scale well in term of spatial variation, but show better consistency with their own energy-containing scales. The reverse cascade of the BT and BC modes was found related to their EKE, and better correlation was found between the BT inverse cascade and barotropization. Speculations of the findings were proposed. however, further observations and modeling experiments are needed to test these interpretations. Spectral flux anisotropy exhibits a feature associated with oceanic jets that is consistent with classical expectations. Specifically, the spectral flux along the along-stream direction remains negative at scales up to that of the studied domain (~2000km), while that in the perpendicular direction becomes positive close to the scale of the width of a typical jet.
Ganesan, A. L.; Manizza, M.; Morgan, E. J.; Harth, C. M.; Kozlova, E.; Lueker, T.; Manning, A. J.; Lunt, M. F.; Mühle, J.; Lavric, J. V.; Heimann, M.; Weiss, R. F.; Rigby, M. (2020). Marine Nitrous Oxide Emissions From Three Eastern Boundary Upwelling Systems Inferred From Atmospheric Observations, Geophysical Research Letters, 14 (47), 10.1029/2020GL087822.
Title: Marine Nitrous Oxide Emissions From Three Eastern Boundary Upwelling Systems Inferred From Atmospheric Observations
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Ganesan, A. L.; Manizza, M.; Morgan, E. J.; Harth, C. M.; Kozlova, E.; Lueker, T.; Manning, A. J.; Lunt, M. F.; Mühle, J.; Lavric, J. V.; Heimann, M.; Weiss, R. F.; Rigby, M.
Year: 2020
Formatted Citation: Ganesan, A. L. and Coauthors, 2020: Marine Nitrous Oxide Emissions From Three Eastern Boundary Upwelling Systems Inferred From Atmospheric Observations. Geophys. Res. Lett., 47(14), doi:10.1029/2020GL087822
Cherniavskaia, E. A.; Timokhov, L. A.; Karpiy, V. Y.; Malinovskiy, S. Y. (2020). Interannual variability of parameters of the Arctic Ocean surface layer and halocline, Arctic and Antarctic Research, 4 (66), 404-426, 10.30758/0555-2648-2020-66-4-404-426.
Title: Interannual variability of parameters of the Arctic Ocean surface layer and halocline
Type: Journal Article
Publication: Arctic and Antarctic Research
Author(s): Cherniavskaia, E. A.; Timokhov, L. A.; Karpiy, V. Y.; Malinovskiy, S. Y.
Year: 2020
Formatted Citation: Cherniavskaia, E. A., L. A. Timokhov, V. Y. Karpiy, and S. Y. Malinovskiy, 2020: Interannual variability of parameters of the Arctic Ocean surface layer and halocline. Arctic and Antarctic Research, 66(4), 404-426, doi:10.30758/0555-2648-2020-66-4-404-426
Sierro, Francisco J.; Hodell, David A.; Andersen, Nils; Azibeiro, Lucia A.; Jimenez-Espejo, Francisco J.; Bahr, André; Flores, Jose Abel; Ausin, Blanca; Rogerson, Mike; Lozano-Luz, Rocio; Lebreiro, Susana M.; Hernandez-Molina, Francisco Javier (2020). Mediterranean Overflow Over the Last 250 kyr: Freshwater Forcing From the Tropics to the Ice Sheets, Paleoceanography and Paleoclimatology, 9 (35), 10.1029/2020PA003931.
Title: Mediterranean Overflow Over the Last 250 kyr: Freshwater Forcing From the Tropics to the Ice Sheets
Type: Journal Article
Publication: Paleoceanography and Paleoclimatology
Author(s): Sierro, Francisco J.; Hodell, David A.; Andersen, Nils; Azibeiro, Lucia A.; Jimenez-Espejo, Francisco J.; Bahr, André; Flores, Jose Abel; Ausin, Blanca; Rogerson, Mike; Lozano-Luz, Rocio; Lebreiro, Susana M.; Hernandez-Molina, Francisco Javier
Year: 2020
Formatted Citation: Sierro, F. J. and Coauthors, 2020: Mediterranean Overflow Over the Last 250 kyr: Freshwater Forcing From the Tropics to the Ice Sheets. Paleoceanography and Paleoclimatology, 35(9), doi:10.1029/2020PA003931
Condron, Alan; Joyce, Anthony J.; Bradley, Raymond S. (2020). Arctic sea ice export as a driver of deglacial climate, Geology, 4 (48), 395-399, 10.1130/G47016.1.
Title: Arctic sea ice export as a driver of deglacial climate
Type: Journal Article
Publication: Geology
Author(s): Condron, Alan; Joyce, Anthony J.; Bradley, Raymond S.
Year: 2020
Formatted Citation: Condron, A., A.J. Joyce, and R.S. Bradley, 2020: Arctic sea ice export as a driver of deglacial climate. Geology, 48(4), 395-399, doi:10.1130/G47016.1
Abstract: A widespread theory in paleoclimatology suggests that changes in freshwater discharge to the Nordic (Greenland, Norwegian, and Icelandic) Seas from ice sheets and proglacial lakes over North America played a role in triggering episodes of abrupt climate change during deglaciation (21-8 ka) by slowing the strength of the Atlantic Meridional Overturning circulation (AMOC). Yet, proving this link has been problematic, as climate models are unable to produce centennial-to-millennial-length reductions in overturning from short-lived outburst floods, while periods of iceberg discharge during Heinrich Event 1 (ca. 16 ka) may have occurred after the climate had already begun to cool. Here, results from a series of numerical model experiments are presented to show that prior to deglaciation, sea ice could have become tens of meters thick over large parts of the Arctic Basin, forming an enormous reservoir of freshwater independent from terrestrial sources. Our model then shows that deglacial sea-level rise, changes in atmospheric circulation, and terrestrial outburst floods caused this ice to be exported through Fram Strait, where its subsequent melt freshened the Nordic Seas enough to weaken the AMOC. Given that both the volume of ice stored in the Arctic Basin and the magnitude of the simulated export events exceed estimates of the volumes and fluxes of meltwater periodically discharged from proglacial Lake Agassiz, our results show that non-terrestrial freshwater sources played an important role in causing past abrupt climate change.
Formatted Citation: Shan, X., Z. Jing, B. Sun, and L. Wu, 2020: Impacts of ocean current-atmosphere interactions on mesoscale eddy energetics in the Kuroshio extension region. Geoscience Letters, 7(1), 3, doi:10.1186/s40562-020-00152-w
Nagai, T.; Hibiya, T. (2020). Combined Effects of Tidal Mixing in Narrow Straits and the Ekman Transport on the Sea Surface Temperature Cooling in the Southern Indonesian Seas, Journal of Geophysical Research: Oceans, 11 (125), 10.1029/2020JC016314.
Title: Combined Effects of Tidal Mixing in Narrow Straits and the Ekman Transport on the Sea Surface Temperature Cooling in the Southern Indonesian Seas
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Nagai, T.; Hibiya, T.
Year: 2020
Formatted Citation: Nagai, T. and T. Hibiya, 2020: Combined Effects of Tidal Mixing in Narrow Straits and the Ekman Transport on the Sea Surface Temperature Cooling in the Southern Indonesian Seas. Journal of Geophysical Research: Oceans, 125(11), doi:10.1029/2020JC016314
Formatted Citation: Petäjä, Tuukka, E-M. Duplissy, K. Tabakova, J. Schmale, B. Altstädter, G. Ancellet, M. Arshinov, Y. Balin, U. Baltensperger, J. Bange, A. Beamish, B. Belan, A. Berchet, R. Bossi, W. R.L. Cairns, R. Ebinghaus, I. El Haddad, B. Ferreira-Araujo, A. Franck, L. Huang, A. Hyvärinen, A. Humbert, A-C. Kalogridis, P. Konstantinov, A. Lampert, M. MacLeod, O. Magand, A. Mahura, L. Marelle, V. Masloboev, D. Moisseev, V. Moschos, N. Neckel, T. Onishi, S. Osterwalder, A. Ovaska, P. Paasonen, M. Panchenko, F. Pankratov, J.B. Pernov, A. Platis, O. Popovicheva, J-C. Raut, A. Riandet, T. Sachs, R. Salvatori, R. Salzano, L. Schröder, M. Schön, V. Shevchenko, H. Skov, J.E. Sonke, A. Spolaor, V.K. Stathopoulos, M. Strahlendorff, J.L. Thomas, V. Vitale, S. Vratolis, C. Barbante, S. Chabrillat, A. Dommergue, K. Eleftheriadis, J. Heilimo, K.S. Law, A. Massling, S.M. Noe, J-D. Paris, A.S.H. Prévôt, I. Riipinen, B. Wehner, Z. Xie, and H.K. Lappalainen, 2020: Overview: Integrative and Comprehensive Understanding on Polar Environments (iCUPE)-concept and initial results. Atmospheric Chemistry and Physics, 20(14), 8551-8592, doi:10.5194/acp-20-8551-2020
Zemskova, Varvara E.; White, Brian L.; Scotti, Alberto (2020). Energetics of a Rotating Wind-forced Horizontal Convection Model of a Reentrant Channel, Journal of Physical Oceanography, 10.1175/JPO-D-19-0169.1.
Title: Energetics of a Rotating Wind-forced Horizontal Convection Model of a Reentrant Channel
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Zemskova, Varvara E.; White, Brian L.; Scotti, Alberto
Year: 2020
Formatted Citation: Zemskova, V.E., B.L. White, and A. Scotti, 2020: Energetics of a Rotating Wind-forced Horizontal Convection Model of a Reentrant Channel. Journal of Physical Oceanography, doi:10.1175/JPO-D-19-0169.1
Abstract: We present numerical results for an idealized rotating, buoyancy- and windforced channel as a simple model for the Southern Ocean branch of the Meridional Overturning Circulation (MOC). Differential buoyancy forcing is applied along the top horizontal surface, with surface cooling at one end (to represent the pole) and surface warming at the other (to represent the equatorial region) and a zonally re-entrant channel to represent the Antarctic Circumpolar Current (ACC). Zonally-uniform surface wind forcing is applied with a similar pattern to the westerlies and easterlies with varying magnitude relative to the buoyancy forcing. The problem is solved numerically using a 3D DNS model based on a finite-volume solver for the Boussinesq Navier-Stokes equations with rotation. The overall dynamics, including large-scale overturning, baroclinic eddying, turbulent mixing, and resulting energy cascades are studied by calculating terms in the energy budget using the local Available Potential Energy framework. The basic physics of the overturning in the Southern Ocean are investigated at multiple scales and the output from the fully-resolved DNS simulations is compared with the results from previous studies of the global (ECCO2) and Southern Ocean eddy-permitting state estimates. We find that both the magnitude and shape of the zonal wind stress profile are important to the spatial pattern of the overturning circulation. However, the available potential energy budget and the diapycnal mixing are not significantly affected by the surface wind stress and are primarily set by the buoyancy forcing at the surface.
Praetorius, Summer K.; Condron, Alan; Mix, Alan C.; Walczak, Maureen H.; McKay, Jennifer L.; Du, Jianghui (2020). The role of Northeast Pacific meltwater events in deglacial climate change, Science Advances, 9 (6), 10.1126/sciadv.aay2915.
Title: The role of Northeast Pacific meltwater events in deglacial climate change
Type: Journal Article
Publication: Science Advances
Author(s): Praetorius, Summer K.; Condron, Alan; Mix, Alan C.; Walczak, Maureen H.; McKay, Jennifer L.; Du, Jianghui
Year: 2020
Formatted Citation: Praetorius, S. K., A. Condron, A. C. Mix, M. H. Walczak, J. L. McKay, and J. Du, 2020: The role of Northeast Pacific meltwater events in deglacial climate change. Science Advances, 6(9), doi:10.1126/sciadv.aay2915
Formatted Citation: Rosat, S., N. Gillet, J-P. Boy, A. Couhert, A., and M. Dumberry, 2020: Interannual variations of degree 2 from geodetic observations and surface processes, Geophysical Journal International, doi: 10.1093/gji/ggaa590
Abstract: Geodetic observations from space continuously record surface deformation and global mass redistribution with an increasing accuracy. In parallel, surficial processes (oceanic, atmospheric, and hydrological loading) are more and more precisely modeled.We propose a confrontation of the geodetic Global Positioning System (GPS) and gravity-field satellite laser ranging (SLR) observations at decadal and interannual time scales, in terms of resolution, correlation and comparison with surficial loading models. We focus on the largest global scale signals of degree 2. At interannual periods, surface deformations retrieved from GPS time-series do not exceed 0.8 mm. Our analysis does not reveal the presence of a dominant signal at a specific period, except perhaps for a signal of approximately 3 yr likely connected to the loading response to El Niño / Southern Oscillations. Contrary to the results of previous studies, we do not find in GPS time-series a clear 6-yr oscillation associated with a degree-2 order-2 pattern. Interannual variations in the degree-2 Stokes coefficients of the gravity field do not exceed 2 × 10-11. We do not detect a dominant gravity signal at one specific period but instead a broad spectrum of frequencies. The comparison between the degree 2 deformations built from GPS time-series with a prediction from SLR derived gravity variations reveals some correlations, though their differences remain important. This highlights the present day limitations of these techniques in their ability to characterize global scale interannual variations. Hydrological loading models show some correlations with both GPS and SLR signals, but we cannot firmly establish that continental hydrology is dominantly responsible for the observed variations. Given the current limits in the resolution of both gravity and surface deformation and in the modelling of surface processes, we conclude that it will be a challenge to retrieve a geodetic signal of sub-decadal period originating in the Earth's core.
Travis, Seth (2020). Mesoscale Eddy Activity in the South Pacific Subtropical Counter-current: Decadal Variability and Bio-physical Connections, University of Hawai'i at Manoa, 147.
Title: Mesoscale Eddy Activity in the South Pacific Subtropical Counter-current: Decadal Variability and Bio-physical Connections
Type: Thesis
Publication: University of Hawai'i at Manoa
Author(s): Travis, Seth
Year: 2020
Formatted Citation: Travis, S., 2020: Mesoscale Eddy Activity in the South Pacific Subtropical Counter-current: Decadal Variability and Bio-physical Connections, University of Hawai'i at Manoa
Abstract: Mesoscale eddies are important contributors to ocean circulation, and are ubiquitous throughout the world's oceans. They are capable of transporting heat, salinity, nutrients, and phytoplankton, and are important in the transfer of energy between different scales. In the South Pacific the Subtropical Counter-current is a region of heightened eddy activity which has been little studied. The South Pacific Subtropical Counter-current (STCC) is an eastward flowing current which overlays the westward South Equatorial Current (SEC). This vertically sheared STCC-SEC system is subject to baroclinic instabilities, which gives rise to mesoscale eddies. Decadal variability of eddy activity in the western, subtropical South Pacific is examined using the past two decades of satellite altimetry data. By using ocean reanalysis data, low-frequency variations in the state of the ocean in this region are investigated. It is found that the low-frequency changes in shear and stratification simultaneously work to modulate the strength of baroclinic instabilities. These changes in the strength of the instabilities consequently affect the observed eddy activity. Using a linearization of the baroclinic growth rate, the contribution to the variability from the changes in shearing is found to be roughly twice as large as those from changes in stratification. Additionally, changes in the temperature and salinity fields are both found to have significant impacts on the low-frequency variability of shearing and stratification, for which salinity changes are responsible for 50-75% of the variability as caused by temperature changes. However, the changes in all these parameters do not occur concurrently, and can alternately work to negate or augment each other. By furthering the investigation of this system to look at the driving mechanisms leading to changes in the shear and stratification, larger drivers of overall eddy activity can be identified. The Estimating the Circulation and Climate of the Ocean, phase II (ECCO2) ocean state model is used to perform budget analyses to identify to most important mechanisms altering the temperature and salinity fields in the STCC, and subsequently, the shear and stratification. These budgets can then be related back to the linearized baroclinic growth rate to look at the impact of individual drivers on eddy activity. Variability in advective flux convergence is found to be the most consequential driver, for both shear and stratification, while direct atmospheric surface forcing through net heat flux and moisture fluxes are of approximately equal importance. Atmospheric forcings are additionally found to be related to the Interdecadal Pacific Oscillation through changes in the location and strength of the South Pacific Convergence Zone. Mesoscale eddies have been shown to have significant effects on biogeochemical cycles, as observed in local levels of near-surface chlorophyll. In the South Pacific Subtropical Counter-current, however, an inconsistent chlorophyll anomaly response and a low correlation to the presence of eddies challenges simple explanation of the mechanisms at play. Using Glob-Colour ocean color data and Aviso altimetry data, an investigation of the area found that a seasonal reversal occurs in the character of the chlorophyll anomaly within eddies (reversal from positive to negative, and vice versa). The cause of this reversal is inferred to be a seasonally-changing limiting factor within the region. Argo float profiles co-located inside and outside of eddies are used to show the coincidence of chlorophyll anomalies with seasonally changing mixed layer depths and the ability of the eddies to access deep nutrient pools. Observations of other mechanisms, such as eddy stirring or eddy-Ekman pumping, are found to be seasonally less important than the mixed layer depth change induced nutrient flux. Additionally, metrics are developed to globally identify oceanic regions in which such seasonal reversals in chlorophyll anomalies could occur.
Stephanie Dutkiewicz, Mark Baird, Stefano Ciavatta, Stephanie Henson, AnnaHickman, Cecile Rousseaux and Charles Stock (2020). Synergy between Ocean Colour and Biogeochemical/ Ecosystem Models.
Title: Synergy between Ocean Colour and Biogeochemical/ Ecosystem Models
Type: Report
Publication:
Author(s): Stephanie Dutkiewicz, Mark Baird, Stefano Ciavatta, Stephanie Henson, AnnaHickman, Cecile Rousseaux and Charles Stock
Year: 2020
Formatted Citation: Stephanie Dutkiewicz, M. B., 2020: Synergy between Ocean Colour and Biogeochemical/ Ecosystem Models.., 184pp pp. doi:http://dx.doi.org/10.25607/OBP-711.
Liang Xi , Zhao Fu, Li Chunhua, Zhang Lin, Li Bingrui (2020). Evaluation of ArcIOPS sea ice forecasting products during the ninth CHINARE-Arctic in summer 2018, Advances in Polar Science, 1 (31), 14-25, dx.doi.org/10.13679/j.advps.2019.0019.
Pefanis, Vasileios; Losa, Svetlana N.; Losch, Martin; Janout, Markus A.; Bracher, Astrid (2020). Amplified Arctic Surface Warming and Sea Ice Loss Due to Phytoplankton and Colored Dissolved Material, Geophysical Research Letters, 21 (47), 10.1029/2020GL088795.
Title: Amplified Arctic Surface Warming and Sea Ice Loss Due to Phytoplankton and Colored Dissolved Material
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Pefanis, Vasileios; Losa, Svetlana N.; Losch, Martin; Janout, Markus A.; Bracher, Astrid
Year: 2020
Formatted Citation: Pefanis, V., S. N. Losa, M. Losch, M. A. Janout, and A. Bracher, 2020: Amplified Arctic Surface Warming and Sea Ice Loss Due to Phytoplankton and Colored Dissolved Material. Geophys. Res. Lett., 47(21), doi:10.1029/2020GL088795
Liu, Junjie; Wennberg, Paul O.; Parazoo, Nicholas C.; Yin, Yi; Frankenberg, Christian (2020). Observational Constraints on the Response of High-Latitude Northern Forests to Warming, AGU Advances, 4 (1), 10.1029/2020AV000228.
Title: Observational Constraints on the Response of High-Latitude Northern Forests to Warming
Type: Journal Article
Publication: AGU Advances
Author(s): Liu, Junjie; Wennberg, Paul O.; Parazoo, Nicholas C.; Yin, Yi; Frankenberg, Christian
Year: 2020
Formatted Citation: Liu, J., P. O. Wennberg, N. C. Parazoo, Y. Yin, and C. Frankenberg, 2020: Observational Constraints on the Response of High-Latitude Northern Forests to Warming. AGU Advances, 1(4), doi:10.1029/2020AV000228
England, Mark R.; Wagner, Till J. W.; Eisenman, Ian (2020). Modeling the breakup of tabular icebergs, Science Advances, 51 (6), eabd1273, 10.1126/sciadv.abd1273.
Author(s): England, Mark R.; Wagner, Till J. W.; Eisenman, Ian
Year: 2020
Formatted Citation: England, M. R., T. J. W. Wagner, and I. Eisenman, 2020: Modeling the breakup of tabular icebergs. Science Advances, 6(51), eabd1273, doi:10.1126/sciadv.abd1273
Abstract: Nearly half of the freshwater flux from the Antarctic Ice Sheet into the Southern Ocean occurs in the form of large tabular icebergs that calve off the continent's ice shelves. However, because of difficulties in adequately simulating their breakup, large Antarctic icebergs to date have either not been represented in models or represented but with no breakup scheme such that they consistently survive too long and travel too far compared with observations. Here, we introduce a representation of iceberg fracturing using a breakup scheme based on the "footloose mechanism." We optimize the parameters of this breakup scheme by forcing the iceberg model with an ocean state estimate and comparing the modeled iceberg trajectories and areas with the Antarctic Iceberg Tracking Database. We show that including large icebergs and a representation of their breakup substantially affects the iceberg meltwater distribution, with implications for the circulation and stratification of the Southern Ocean.
Fayman, P. A.; Prants, S. V.; Budyansky, M. V.; Uleysky, M. Yu. (2020). New Circulation Features in the Okhotsk Sea from a Numerical Model, Izvestiya, Atmospheric and Oceanic Physics, 6 (56), 618-631, 10.1134/S0001433820060043.
Title: New Circulation Features in the Okhotsk Sea from a Numerical Model
Type: Journal Article
Publication: Izvestiya, Atmospheric and Oceanic Physics
Author(s): Fayman, P. A.; Prants, S. V.; Budyansky, M. V.; Uleysky, M. Yu.
Year: 2020
Formatted Citation: Fayman, P. A., S. V. Prants, M. V. Budyansky, and M. Y. Uleysky, 2020: New Circulation Features in the Okhotsk Sea from a Numerical Model. Izvestiya, Atmospheric and Oceanic Physics, 56(6), 618-631, doi:10.1134/S0001433820060043
Formatted Citation: Wu, Y., Z. Wang, C. Liu, and X. Lin, 2020: Impacts of High-Frequency Atmospheric Forcing on Southern Ocean Circulation and Antarctic Sea Ice. Advances in Atmospheric Sciences, 37(5), 515-531, doi:10.1007/s00376-020-9203-x
Hu, Shijian; Sprintall, Janet; Guan, Cong; McPhaden, Michael J.; Wang, Fan; Hu, Dunxin; Cai, Wenju (2020). Deep-reaching acceleration of global mean ocean circulation over the past two decades, Science Advances, 6 (6), eaax7727, 10.1126/sciadv.aax7727.
Formatted Citation: Hu, S., J. Sprintall, C. Guan, M. J. McPhaden, F. Wang, D. Hu, and W. Cai, 2020: Deep-reaching acceleration of global mean ocean circulation over the past two decades. Science Advances, 6(6), eaax7727, doi:10.1126/sciadv.aax7727
Abstract: Ocean circulation redistributes Earth's energy and water masses and influences global climate. Under historical greenhouse warming, regional ocean currents show diverse tendencies, but whether there is an emerging trend of the global mean ocean circulation system is not yet clear. Here, we show a statistically significant increasing trend in the globally integrated oceanic kinetic energy since the early 1990s, indicating a substantial acceleration of global mean ocean circulation. The increasing trend in kinetic energy is particularly prominent in the global tropical oceans, reaching depths of thousands of meters. The deep-reaching acceleration of the ocean circulation is mainly induced by a planetary intensification of surface winds since the early 1990s. Although possibly influenced by wind changes associated with the onset of a negative Pacific decadal oscillation since the late 1990s, the recent acceleration is far larger than that associated with natural variability, suggesting that it is principally part of a long-term trend.
Koldunov, A. V.; Belonenko, T. V. (2020). Hydrodynamic Modeling of Vertical Velocities in the Lofoten Vortex, Izvestiya, Atmospheric and Oceanic Physics, 5 (56), 502-511, 10.1134/S0001433820040040.
Title: Hydrodynamic Modeling of Vertical Velocities in the Lofoten Vortex
Type: Journal Article
Publication: Izvestiya, Atmospheric and Oceanic Physics
Author(s): Koldunov, A. V.; Belonenko, T. V.
Year: 2020
Formatted Citation: Koldunov, A. V., and T. V. Belonenko, 2020: Hydrodynamic Modeling of Vertical Velocities in the Lofoten Vortex. Izvestiya, Atmospheric and Oceanic Physics, 56(5), 502-511, doi:10.1134/S0001433820040040
Title: Comparing Arctic Sea Ice Model Simulations to Satellite Observations by Multiscale Directional Analysis of Linear Kinematic Features
Type: Journal Article
Publication: Monthly Weather Review
Author(s): Mohammadi-Aragh, Mahdi; Losch, Martin; Goessling, Helge F.
Year: 2020
Formatted Citation: Mohammadi-Aragh, M., M. Losch, and H. F. Goessling, 2020: Comparing Arctic Sea Ice Model Simulations to Satellite Observations by Multiscale Directional Analysis of Linear Kinematic Features. Monthly Weather Review, 148(8), 3287-3303, doi:10.1175/MWR-D-19-0359.1
Abstract: Sea ice models have become essential components of weather, climate, and ocean models. A realistic representation of sea ice affects the reliability of process representation, environmental forecast, and climate projections. Realistic simulations of sea ice kinematics require the consideration of both large-scale and finescale geomorphological structures such as linear kinematic features (LKF). We propose a multiscale directional analysis (MDA) that diagnoses the spatial characteristics of LKFs. The MDA is different from previous analyses in that it (i) does not detect LKFs as objects, (ii) takes into account the width of LKFs, and (iii) estimates scale-dependent orientation and intersection angles. The MDA is applied to pairs of deformation fields derived from satellite remote sensing data and from a numerical model simulation with a horizontal grid spacing of ~4.5 km. The orientation and intersection angles of LKFs agree with the observations and confirm the visual impression that the intersection angles tend to be smaller in the satellite data compared to the model data. The MDA distributions can be used to compare satellite data and numerical model fields using conventional metrics such as a Euclidean distance, the Bhattacharyya coefficient, or the Earth mover's distance. The latter is found to be the most meaningful metric to compare distributions of LKF orientations and intersection angles. The MDA proposed here provides a tool to diagnose if modified sea ice rheologies lead to more realistic simulations of LKFs.
Gao, Guandong; Marin, Maxime; Feng, Ming; Yin, Baoshu; Yang, Dezhou; Feng, Xingru; Ding, Yang; Song, Dehai (2020). Drivers of marine heatwaves in the East China Sea and the South Yellow Sea in three consecutive summers during 2016-2018, Journal of Geophysical Research: Oceans, 10.1029/2020JC016518.
Formatted Citation: Gao, G., M. Marin, M. Feng, B. Yin, D. Yang, X. Feng, Y. Ding, and D. Song, 2020: Drivers of marine heatwaves in the East China Sea and the South Yellow Sea in three consecutive summers during 2016-2018. J. Geophys. Res. Ocean., doi:10.1029/2020JC016518
Lang, Yandong; Stanley, Geoffrey J.; McDougall, Trevor J.; Barker, Paul M. (2020). A pressure-invariant Neutral Density variable for the World’s Oceans, Journal of Physical Oceanography, 1-58, 10.1175/JPO-D-19-0321.1.
Title: A pressure-invariant Neutral Density variable for the World’s Oceans
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Lang, Yandong; Stanley, Geoffrey J.; McDougall, Trevor J.; Barker, Paul M.
Year: 2020
Formatted Citation: Lang, Y., G. J. Stanley, T. J. McDougall, and P. M. Barker, 2020: A pressure-invariant Neutral Density variable for the World's Oceans. Journal of Physical Oceanography, 1-58, doi:10.1175/JPO-D-19-0321.1
Abstract: We present a new method to calculate the neutral density of an arbitrary water parcel. Using this method the value of neutral density depends only on the parcel's salinity, temperature, latitude, and longitude, and is independent of the pressure (or depth) of the parcel, and is therefore independent of heave in observations or high-resolution models. In this method we move the parcel adiabatically and isentropically like a Submesoscale Coherent Vortex (SCV), to its level of neutral buoyancy on four nearby water columns of a climatological atlas. The parcel's neutral density γSCV is interpolated from pre-labelled neutral density values at these four reference locations in the climatological atlas. This method is similar to the neutral density variable, γn, of Jackett and McDougall: their discretization of the neutral relationship equated the potential density of two parcels referenced to their average pressure, whereas our discretization equates the parcels' potential density referenced to the pressure of the climatological parcel. We calculate the numerical differences between γSCV and γn and we find similar variations of γn and γSCVon the ω-surfaces of Klocker, McDougall and Jackett. We also find that isosurfaces of γn and γSCV deviate from the neutral tangent plane by similar amounts. We compare the material derivative of γSCV with that of γn, finding their total material derivatives are of a similar magnitude.
Li; Huang; Chen; Dam; Fok; Zhao; Wu; Wang (2020). Quantitative Evaluation of Environmental Loading Induced Displacement Products for Correcting GNSS Time Series in CMONOC, Remote Sensing, 4 (12), 594, 10.3390/rs12040594.
Title: Quantitative Evaluation of Environmental Loading Induced Displacement Products for Correcting GNSS Time Series in CMONOC
Type: Journal Article
Publication: Remote Sensing
Author(s): Li; Huang; Chen; Dam; Fok; Zhao; Wu; Wang
Year: 2020
Formatted Citation: Li, Huang, Chen, Dam, Fok, Zhao, Wu, and Wang, 2020: Quantitative Evaluation of Environmental Loading Induced Displacement Products for Correcting GNSS Time Series in CMONOC. Remote Sensing, 12(4), 594, doi:10.3390/rs12040594
Abstract: Mass redistribution within the Earth system deforms the surface elastically. Loading theory allows us to predict loading induced displacement anywhere on the Earth's surface using environmental loading models, e.g., Global Land Data Assimilation System. In addition, different publicly available loading products are available. However, there are differences among those products and the differences among the combinations of loading models cannot be ignored when precisions of better than 1 cm are required. Many scholars have applied these loading corrections to Global Navigation Satellite System (GNSS) time series from mainland China without considering or discussing the differences between the available models. Evaluating the effects of different loading products over this region is of paramount importance for accurately removing the loading signal. In this study, we investigate the performance of these different publicly available loading products on the scatter of GNSS time series from the Crustal Movement Observation Network of China. We concentrate on five different continental water storage loading models, six different non-tidal atmospheric loading models, and five different non-tidal oceanic loading models. We also investigate all the different combinations of loading products. The results show that the difference in RMS reduction can reach 20% in the vertical component depending on the loading correction applied. We then discuss the performance of different loading combinations and their effects on the noise characteristics of GNSS height time series and horizontal velocities. The results show that the loading products from NASA may be the best choice for corrections in mainland China. This conclusion could serve as an important reference for loading products users in this region.
Wang, Haodi; Chen, Shiyao; Wang, Ning; Yu, Peilong; Yang, Xiao; Wang, Yang; Zhang, Yongchui (2020). Evaluation of multi-model current data in the East/Japan Sea, 2020 IEEE 3rd International Conference on Information Communication and Signal Processing (ICICSP), 486-491, 10.1109/ICICSP50920.2020.9232090.
Formatted Citation: Wang, H., S. Chen, N. Wang, P. Yu, X. Yang, Y. Wang, and Y. Zhang, 2020: Evaluation of multi-model current data in the East/Japan Sea. 2020 IEEE 3rd International Conference on Information Communication and Signal Processing (ICICSP) IEEE, 486-491 pp. doi:10.1109/ICICSP50920.2020.9232090.
Chaudhuri, Anya; Shankar, D; Aparna, S G; Amol, P; Fernando, V; Kankonkar, A; Michael, G S; Satelkar, N P; Khalap, S T; Tari, A P; Gaonkar, M G; Ghatkar, S; Khedekar, R R (2020). Observed variability of the West India Coastal Current on the continental slope from 2009-2018, Journal of Earth System Science, 1 (129), 57, 10.1007/s12040-019-1322-3.
Title: Observed variability of the West India Coastal Current on the continental slope from 2009-2018
Type: Journal Article
Publication: Journal of Earth System Science
Author(s): Chaudhuri, Anya; Shankar, D; Aparna, S G; Amol, P; Fernando, V; Kankonkar, A; Michael, G S; Satelkar, N P; Khalap, S T; Tari, A P; Gaonkar, M G; Ghatkar, S; Khedekar, R R
Year: 2020
Formatted Citation: Chaudhuri, A. and Coauthors, 2020: Observed variability of the West India Coastal Current on the continental slope from 2009-2018. Journal of Earth System Science, 129(1), 57, doi:10.1007/s12040-019-1322-3
Jiang, Huichang; Yu, Liu; Xu, Hongzhou; Vetter, Philip A. (2020). Evaluation of Global Ocean Models on Simulating the Deep Western Boundary Current in the Pacific, Atmosphere-Ocean, 1-12, 10.1080/07055900.2020.1789547.
Title: Evaluation of Global Ocean Models on Simulating the Deep Western Boundary Current in the Pacific
Type: Journal Article
Publication: Atmosphere-Ocean
Author(s): Jiang, Huichang; Yu, Liu; Xu, Hongzhou; Vetter, Philip A.
Year: 2020
Formatted Citation: Jiang, H., L. Yu, H. Xu, and P. A. Vetter, 2020: Evaluation of Global Ocean Models on Simulating the Deep Western Boundary Current in the Pacific. Atmosphere-Ocean, 1-12, doi:10.1080/07055900.2020.1789547
Anandh, Thanka Swamy; Das, Bijan Kumar; Kuttippurath, J.; Chakraborty, Arun (2020). A coupled model analyses on the interaction between oceanic eddies and tropical cyclones over the Bay of Bengal, Ocean Dynamics, 3 (70), 327-337, 10.1007/s10236-019-01330-x.
Formatted Citation: Anandh, T. S., B. K. Das, J. Kuttippurath, and A. Chakraborty, 2020: A coupled model analyses on the interaction between oceanic eddies and tropical cyclones over the Bay of Bengal. Ocean Dynamics, 70(3), 327-337, doi:10.1007/s10236-019-01330-x
Guan, Cong; Wang, Fan; Hu, Shijian (2020). The role of oceanic feedbacks in the 2014-2016 El Niño events as derived from ocean reanalysis data, Journal of Oceanology and Limnology, 5 (38), 1394-1407, 10.1007/s00343-020-0038-1.
Title: The role of oceanic feedbacks in the 2014-2016 El Niño events as derived from ocean reanalysis data
Type: Journal Article
Publication: Journal of Oceanology and Limnology
Author(s): Guan, Cong; Wang, Fan; Hu, Shijian
Year: 2020
Formatted Citation: Guan, C., F. Wang, and S. Hu, 2020: The role of oceanic feedbacks in the 2014-2016 El Niño events as derived from ocean reanalysis data. Journal of Oceanology and Limnology, 38(5), 1394-1407, doi:10.1007/s00343-020-0038-1
Wang, Linsong; Chen, Chao; Ma, Xian; Fu, Zhengyan; Zheng, Yuhao; Peng, Zhenran (2020). Evaluation of GRACE mascon solutions using in-situ geodetic data: The case of hydrologic-induced crust displacement in the Yangtze River Basin, Science of The Total Environment (707), 135606, 10.1016/j.scitotenv.2019.135606.
Formatted Citation: Wang, L., C. Chen, X. Ma, Z. Fu, Y. Zheng, and Z. Peng, 2020: Evaluation of GRACE mascon solutions using in-situ geodetic data: The case of hydrologic-induced crust displacement in the Yangtze River Basin. Science of The Total Environment, 707, 135606, doi:10.1016/j.scitotenv.2019.135606
Wang, Tianyu; Gille, Sarah T.; Mazloff, Matthew R.; Zilberman, Nathalie V.; Du, Yan (2020). Eddy-induced acceleration of Argo floats, Journal of Geophysical Research: Oceans, 10.1029/2019JC016042.
Publication: Journal of Geophysical Research: Oceans
Author(s): Wang, Tianyu; Gille, Sarah T.; Mazloff, Matthew R.; Zilberman, Nathalie V.; Du, Yan
Year: 2020
Formatted Citation: Wang, T., S. T. Gille, M. R. Mazloff, N. V. Zilberman, and Y. Du, 2020: Eddy-induced acceleration of Argo floats. J. Geophys. Res. Ocean., doi:10.1029/2019JC016042
Carroll, D.; Menemenlis, D.; Adkins, J. F.; Bowman, K. W.; Brix, H.; Dutkiewicz, Stephanie; Fenty, I.; Gierach, M. M.; Hill, C.; Jahn, O.; Landschützer, P.; Lauderdale, J. M.; Liu, J.; Manizza, M.; Naviaux, J. D.; Rödenbeck, C.; Schimel, D. S.; Van der Stocken, T.; Zhang, H. (2020). The ECCO-Darwin Data-assimilative Global Ocean Biogeochemistry Model: Estimates of Seasonal to Multi-decadal Surface Ocean pCO 2 and Air-sea CO 2 Flux, Journal of Advances in Modeling Earth Systems, 10.1029/2019MS001888.
Title: The ECCO-Darwin Data-assimilative Global Ocean Biogeochemistry Model: Estimates of Seasonal to Multi-decadal Surface Ocean pCO 2 and Air-sea CO 2 Flux
Type: Journal Article
Publication: Journal of Advances in Modeling Earth Systems
Author(s): Carroll, D.; Menemenlis, D.; Adkins, J. F.; Bowman, K. W.; Brix, H.; Dutkiewicz, Stephanie; Fenty, I.; Gierach, M. M.; Hill, C.; Jahn, O.; Landschützer, P.; Lauderdale, J. M.; Liu, J.; Manizza, M.; Naviaux, J. D.; Rödenbeck, C.; Schimel, D. S.; Van der Stocken, T.; Zhang, H.
Year: 2020
Formatted Citation: Carroll, D. and Coauthors, 2020: The ECCO-Darwin Data-assimilative Global Ocean Biogeochemistry Model: Estimates of Seasonal to Multi-decadal Surface Ocean pCO 2 and Air-sea CO 2 Flux. Journal of Advances in Modeling Earth Systems, doi:10.1029/2019MS001888
Nguyen, An T.; Woodgate, Rebecca A.; Heimbach, Patrick (2020). Elucidating large-scale atmospheric controls on Bering Strait throughflow variability using a data-constrained ocean model and its adjoint, Journal of Geophysical Research: Oceans, 10.1029/2020JC016213.
Title: Elucidating large-scale atmospheric controls on Bering Strait throughflow variability using a data-constrained ocean model and its adjoint
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Nguyen, An T.; Woodgate, Rebecca A.; Heimbach, Patrick
Year: 2020
Formatted Citation: Nguyen, A. T., R. A. Woodgate, and P. Heimbach, 2020: Elucidating large-scale atmospheric controls on Bering Strait throughflow variability using a data-constrained ocean model and its adjoint. J. Geophys. Res. Ocean., doi:10.1029/2020JC016213
Klos, Anna; Bogusz, Janusz; Bos, Machiel S.; Gruszczynska, Marta (2020). Modelling the GNSS Time Series: Different Approaches to Extract Seasonal Signals.
Title: Modelling the GNSS Time Series: Different Approaches to Extract Seasonal Signals
Type: Book Section
Publication:
Author(s): Klos, Anna; Bogusz, Janusz; Bos, Machiel S.; Gruszczynska, Marta
Year: 2020
Formatted Citation: Klos, A., J. Bogusz, M. S. Bos, and M. Gruszczynska, 2020: Modelling the GNSS Time Series: Different Approaches to Extract Seasonal Signals., 211-237, doi:10.1007/978-3-030-21718-1_7
Wang, Minyang; Xie, Shang-Ping; Shen, Samuel S. P.; Du, Yan (2020). Rossby and Yanai Modes of Tropical Instability Waves in the Equatorial Pacific Ocean and a Diagnostic Model for Surface Currents, Journal of Physical Oceanography, 10 (50), 3009-3024, 10.1175/JPO-D-20-0063.1.
Title: Rossby and Yanai Modes of Tropical Instability Waves in the Equatorial Pacific Ocean and a Diagnostic Model for Surface Currents
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Wang, Minyang; Xie, Shang-Ping; Shen, Samuel S. P.; Du, Yan
Year: 2020
Formatted Citation: Wang, M., S. Xie, S. S. P. Shen, and Y. Du, 2020: Rossby and Yanai Modes of Tropical Instability Waves in the Equatorial Pacific Ocean and a Diagnostic Model for Surface Currents. Journal of Physical Oceanography, 50(10), 3009-3024, doi:10.1175/JPO-D-20-0063.1
Abstract: Mesoscale activities over the equatorial Pacific Ocean are dominated by the Rossby and Yanai modes of tropical instability waves (TIWs). The TIW-induced surface velocity has not been accurately estimated in previous diagnostic models, especially for the meridional component across the equator. This study develops a diagnostic model that retains the acceleration terms to estimate the TIW surface velocity from the satellite-observed sea surface height. Validated against moored observations, the velocity across the equator is accurately estimated for the first time, much improved from existing products. The results identify the Rossby- and Yanai-mode TIWs as the northwest-southeastward (NW-SE) velocity oscillations north of the equator and the northeast-southwestward (NE-SW) velocity oscillations on the equator, respectively. Barotropic instability is the dominant energy source of the two TIW modes. The NE-SW velocity oscillation of the Yanai mode is associated with the counterclockwise shear of the South Equatorial Current on the equator. The two TIW modes induce different sea surface temperature patterns and vertical motions. Accurate estimates of TIW velocity are important for studying equatorial ocean dynamics and climate variability in the tropical Pacific Ocean.
Wu, Shuguang; Nie, Guigen; Meng, Xiaolin; Liu, Jingnan; He, Yuefan; Xue, Changhu; Li, Haiyang (2020). Comparative Analysis of the Effect of the Loading Series from GFZ and EOST on Long-Term GPS Height Time Series, Remote Sensing, 17 (12), 2822, 10.3390/rs12172822.
Formatted Citation: Wu, S., G. Nie, X. Meng, J. Liu, Y. He, C. Xue, and H. Li, 2020: Comparative Analysis of the Effect of the Loading Series from GFZ and EOST on Long-Term GPS Height Time Series. Remote Sensing, 12(17), 2822, doi:10.3390/rs12172822
Abstract: In order to investigate the effect of different loading models on the nonlinear variations in Global Positioning System (GPS) height time series, the characteristics of annual signals (amplitude and phase) of GPS time series, loading series from Deutsche GeoForschungsZentrum, Germany (GFZ) and School and Observatory of Earth Sciences, France (EOST) at 633 global GPS stations are processed and analyzed. The change characteristics of the root mean square (RMS) reduction rate, annual amplitude and phase of GPS time series after environmental loading corrections (ELCs) are then detected. Results show that ELCs have a positive effect on the reduction in the nonlinear deformation contained in most GPS stations around the world. RMS reduction rates are positive at 82.6% stations after GFZ correction and 87.4% after EOST correction, and the average reduction rates of all stations are 10.6% and 15.4%, respectively. As for the environmental loading series from GFZ and EOST, their average annual amplitudes are 2.7 and 3.1 mm, which explains ~40% annual amplitude of GPS height time series (7.2 mm). Further analysis of some specific stations indicates that the annual phase difference between GPS height time series and the environmental loading series is an important reason that affects the reduction rates of the RMS and annual amplitude. The linear relationship between the annual phase difference and the annual amplitude reduction rate is significant. The linear fitting results show that when there is no annual phase difference between GPS and loading series, the reduction rates of the RMS and annual amplitude will increase to the maximum of 15.6% and 41.6% for GFZ, and 22.0% and 46.6% for EOST.
Byrne, B.; Liu, J.; Lee, M.; Baker, I.; Bowman, K. W.; Deutscher, N. M.; Feist, D. G.; Griffith, D. W. T.; Iraci, L. T.; Kiel, M.; Kimball, J. S.; Miller, C. E.; Morino, I.; Parazoo, N. C.; Petri, C.; Roehl, C. M.; Sha, M. K.; Strong, K.; Velazco, V. A.; Wennberg, P. O.; Wunch, D. (2020). Improved Constraints on Northern Extratropical CO 2 Fluxes Obtained by Combining Surface-Based and Space-Based Atmospheric CO 2 Measurements, Journal of Geophysical Research: Atmospheres, 15 (125), 10.1029/2019JD032029.
Title: Improved Constraints on Northern Extratropical CO 2 Fluxes Obtained by Combining Surface-Based and Space-Based Atmospheric CO 2 Measurements
Type: Journal Article
Publication: Journal of Geophysical Research: Atmospheres
Author(s): Byrne, B.; Liu, J.; Lee, M.; Baker, I.; Bowman, K. W.; Deutscher, N. M.; Feist, D. G.; Griffith, D. W. T.; Iraci, L. T.; Kiel, M.; Kimball, J. S.; Miller, C. E.; Morino, I.; Parazoo, N. C.; Petri, C.; Roehl, C. M.; Sha, M. K.; Strong, K.; Velazco, V. A.; Wennberg, P. O.; Wunch, D.
Year: 2020
Formatted Citation: Byrne, B. and Coauthors, 2020: Improved Constraints on Northern Extratropical CO 2 Fluxes Obtained by Combining Surface-Based and Space-Based Atmospheric CO 2 Measurements. Journal of Geophysical Research: Atmospheres, 125(15), doi:10.1029/2019JD032029
Butler, Martha P.; Lauvaux, Thomas; Feng, Sha; Liu, Junjie; Bowman, Kevin W.; Davis, Kenneth J. (2020). Atmospheric Simulations of Total Column CO2 Mole Fractions from Global to Mesoscale within the Carbon Monitoring System Flux Inversion Framework, Atmosphere, 8 (11), 787, 10.3390/atmos11080787.
Title: Atmospheric Simulations of Total Column CO2 Mole Fractions from Global to Mesoscale within the Carbon Monitoring System Flux Inversion Framework
Type: Journal Article
Publication: Atmosphere
Author(s): Butler, Martha P.; Lauvaux, Thomas; Feng, Sha; Liu, Junjie; Bowman, Kevin W.; Davis, Kenneth J.
Year: 2020
Formatted Citation: Butler, M. P., T. Lauvaux, S. Feng, J. Liu, K. W. Bowman, and K. J. Davis, 2020: Atmospheric Simulations of Total Column CO2 Mole Fractions from Global to Mesoscale within the Carbon Monitoring System Flux Inversion Framework. Atmosphere, 11(8), 787, doi:10.3390/atmos11080787
Abstract: Quantifying the uncertainty of inversion-derived CO2 surface fluxes and attributing the uncertainty to errors in either flux or atmospheric transport simulations continue to be challenges in the characterization of surface sources and sinks of carbon dioxide (CO2). Despite recent studies inferring fluxes while using higher-resolution modeling systems, the utility of regional-scale models remains unclear when compared to existing coarse-resolution global systems. Here, we present an off-line coupling of the mesoscale Weather Research and Forecasting (WRF) model to optimized biogenic CO2 fluxes and mole fractions from the global Carbon Monitoring System inversion system (CMS-Flux). The coupling framework consists of methods to constrain the mass of CO2 introduced into WRF, effectively nesting our regional domain covering most of North America (except the northern half of Canada) within the CMS global model. We test the coupling by simulating Greenhouse gases Observing SATellite (GOSAT) column-averaged dry-air mole fractions (XCO2) over North America for 2010. We find mean model-model differences in summer of ∼0.12 ppm, significantly lower than the original coupling scheme (from 0.5 to 1.5 ppm, depending on the boundary). While 85% of the XCO2 values are due to long-range transport from outside our North American domain, most of the model-model differences appear to be due to transport differences in the fraction of the troposphere below 850 hPa. Satellite data from GOSAT and tower and aircraft data are used to show that vertical transport above the Planetary Boundary Layer is responsible for significant model-model differences in the horizontal distribution of column XCO2 across North America.
Formatted Citation: Androsov, A., O. Boebel, J. Schröter, S. Danilov, A. Macrander, and I. Ivanciu, 2020: Ocean Bottom Pressure Variability: Can It Be Reliably Modeled? J. Geophys. Res. Ocean., 125(3), doi:10.1029/2019JC015469
Anandh, T. S; Das, Bijan Kumar; Kuttippurath, J.; Chakraborty, Arun (2020). A Comparative Analysis of the Bay of Bengal Ocean State Using Standalone and Coupled Numerical Models, Asia-Pacific Journal of Atmospheric Sciences, 10.1007/s13143-020-00197-z.
Formatted Citation: Anandh, T. S., B. K. Das, J. Kuttippurath, and A. Chakraborty, 2020: A Comparative Analysis of the Bay of Bengal Ocean State Using Standalone and Coupled Numerical Models. Asia-Pacific Journal of Atmospheric Sciences, doi:10.1007/s13143-020-00197-z
Shi, Hongkai; He, Xiufeng; Wu, Yihao; Huang, Jia (2020). The parameterization of mean dynamic topography based on the Lagrange basis functions, Advances in Space Research, 10.1016/j.asr.2020.07.042.
Formatted Citation: Shi, H., X. He, Y. Wu, and J. Huang, 2020: The parameterization of mean dynamic topography based on the Lagrange basis functions. Advances in Space Research, doi:10.1016/j.asr.2020.07.042
Title: Mass balance of the Greenland Ice Sheet from 1992 to 2018
Type: Journal Article
Publication: Nature
Author(s): Team, The IMBIE
Year: 2020
Formatted Citation: Team, T. I., 2020: Mass balance of the Greenland Ice Sheet from 1992 to 2018. Nature, 579(7798), 233-239, doi:10.1038/s41586-019-1855-2
Wang, Yingying; Luo, Yiyong (2020). Variability of spice injection in the upper ocean of the southeastern Pacific during 1992-2016, Climate Dynamics, 5-6 (54), 3185-3200, 10.1007/s00382-020-05164-y.
Title: Variability of spice injection in the upper ocean of the southeastern Pacific during 1992-2016
Type: Journal Article
Publication: Climate Dynamics
Author(s): Wang, Yingying; Luo, Yiyong
Year: 2020
Formatted Citation: Wang, Y., and Y. Luo, 2020: Variability of spice injection in the upper ocean of the southeastern Pacific during 1992-2016. Climate Dynamics, 54(5-6), 3185-3200, doi:10.1007/s00382-020-05164-y
Xing, Qinwang; Yu, Huaming; Yu, Haiqing; Sun, Peng; Liu, Yang; Ye, Zhenjiang; Li, Jianchao; Tian, Yongjun (2020). A comprehensive model-based index for identification of larval retention areas: A case study for Japanese anchovy Engraulis japonicus in the Yellow Sea, Ecological Indicators (116), 106479, 10.1016/j.ecolind.2020.106479.
Title: A comprehensive model-based index for identification of larval retention areas: A case study for Japanese anchovy Engraulis japonicus in the Yellow Sea
Formatted Citation: Xing, Q., H. Yu, H. Yu, P. Sun, Y. Liu, Z. Ye, J. Li, and Y. Tian, 2020: A comprehensive model-based index for identification of larval retention areas: A case study for Japanese anchovy Engraulis japonicus in the Yellow Sea. Ecological Indicators, 116, 106479, doi:10.1016/j.ecolind.2020.106479
Johns, Elizabeth M.; Lumpkin, Rick; Putman, Nathan F.; Smith, Ryan H.; Muller-Karger, Frank E.; T. Rueda-Roa, Digna; Hu, Chuanmin; Wang, Mengqiu; Brooks, Maureen T.; Gramer, Lewis J.; Werner, Francisco E. (2020). The establishment of a pelagic Sargassum population in the tropical Atlantic: Biological consequences of a basin-scale long distance dispersal event, Progress in Oceanography (182), 102269, 10.1016/j.pocean.2020.102269.
Title: The establishment of a pelagic Sargassum population in the tropical Atlantic: Biological consequences of a basin-scale long distance dispersal event
Type: Journal Article
Publication: Progress in Oceanography
Author(s): Johns, Elizabeth M.; Lumpkin, Rick; Putman, Nathan F.; Smith, Ryan H.; Muller-Karger, Frank E.; T. Rueda-Roa, Digna; Hu, Chuanmin; Wang, Mengqiu; Brooks, Maureen T.; Gramer, Lewis J.; Werner, Francisco E.
Year: 2020
Formatted Citation: Johns, E. M. and Coauthors, 2020: The establishment of a pelagic Sargassum population in the tropical Atlantic: Biological consequences of a basin-scale long distance dispersal event. Progress in Oceanography, 182, 102269, doi:10.1016/j.pocean.2020.102269
Yu, Xi; Hsieh, M. Ani; Wei, Cong; Tanner, Hebert G. (2019). Synchronous Rendezvous for Networks of Marine Robots in Large Scale Ocean Monitoring, Frontiers in Robotics and AI (6), 10.3389/frobt.2019.00076.
Title: Synchronous Rendezvous for Networks of Marine Robots in Large Scale Ocean Monitoring
Type: Journal Article
Publication: Frontiers in Robotics and AI
Author(s): Yu, Xi; Hsieh, M. Ani; Wei, Cong; Tanner, Hebert G.
Year: 2019
Formatted Citation: Yu, X., M. A. Hsieh, C. Wei, and H. G. Tanner, 2019: Synchronous Rendezvous for Networks of Marine Robots in Large Scale Ocean Monitoring. Frontiers in Robotics and AI, 6, doi:10.3389/frobt.2019.00076
Min, Chao; Mu, Longjiang; Yang, Qinghua; Ricker, Robert; Shi, Qian; Han, Bo; Wu, Renhao; Liu, Jiping (2019). Sea ice export through the Fram Strait derived from a combined model and satellite data set, The Cryosphere, 12 (13), 3209-3224, 10.5194/tc-13-3209-2019.
Formatted Citation: Min, C., L. Mu, Q. Yang, R. Ricker, Q. Shi, B. Han, R. Wu, and J. Liu, 2019: Sea ice export through the Fram Strait derived from a combined model and satellite data set. The Cryosphere, 13(12), 3209-3224, doi:10.5194/tc-13-3209-2019
Title: Modelling the dynamics of the Antarctic Slope Front
Type: Thesis
Publication: University of Tasmania
Author(s): Huneke, Wilma Gertrud Charlotte
Year: 2019
Formatted Citation: Huneke, W.G.C., 2019: Modelling the dynamics of the Antarctic Slope Front, University of Tasmania
Abstract: This thesis investigates the dynamics of the Antarctic Slope Front (ASF),which controls heat exchange across the Antarctic continental slope. The motivation comes from the need to advance the understanding of oceanic heat supply to the Antarctic ice shelf cavities which impacts the stability of the Antarctic Ice Sheet. To address this question, the ocean dynamics at the Antarctic continental shelf break system is explored using the Regional Ocean Modeling System (ROMS) which has been adapted for ocean/ice shelf interactions. The ASF is examined in two different model configurations, in an idealised channel domain and in a realistic circumpolar domain, with a focus on the sensitivity to surface forcing to understand how the ASF may change in a future climate. Firstly, an idealised model configuration of the Antarctic continental shelf break system in a zonally-symmetric periodic domain is developed. An intrinsic variability of the ASF that is driven by a deep bottom mixed layer is discussed in the case of a relatively fresh continental shelf. Secondly, the role of surface buoyancy forcing and wind for the strength and shape of the ASF is investigated by analysing sensitivity experiments using the idealised domain. Different frontal regimes and their thresholds are determined on the basis of the relative ratio between buoyancy forcing to mechanical forcing. Thirdly, perturbation experiments with artificially increased basal fresh-water are performed in a realistic circumpolar domain. This work is motivated by the projected increase in freshwater supply to the ocean due to basal melting in a warmer climate. The response to the additional freshwater in the perturbed simulations is overall non-local. Findings between the idealised and realistic model agree in that the transport along the Antarctic continental slope increases for fresher continental shelves.
Chatterjee, Abhisek; Kumar, B. Praveen; Prakash, Satya; Singh, Prerna (2019). Annihilation of the Somali upwelling system during summer monsoon, Scientific Reports, 1 (9), 7598, 10.1038/s41598-019-44099-1.
Title: Annihilation of the Somali upwelling system during summer monsoon
Type: Journal Article
Publication: Scientific Reports
Author(s): Chatterjee, Abhisek; Kumar, B. Praveen; Prakash, Satya; Singh, Prerna
Year: 2019
Formatted Citation: Chatterjee, A., B.P. Kumar; S. Prakash, and P. Singh, 2019: Annihilation of the Somali upwelling system during summer monsoon, Scientific Reports, 9(1), 7598, doi: 10.1038/s41598-019-44099-1
Abstract: Somali upwelling system during northern summer is believed to be the largest upwelling region in the Indian Ocean and has motivated some of the early studies on the Indian Ocean. Here we present results from observations and ocean model to show that the upwelling along the Somali coast is limited to the early phase of the summer monsoon and later primarily limited to the eddy dominated flows in the northern and some extent in the southern part of the coast. Major part of the Somali coast (~60% of the entire coastal length) shows prominent downwelling features driven by offshore negative windstress curl and subsurface entrainment mixing. Further, we show that the surface cooling of coastal waters are dominantly driven by subsurface entrainment and surface heat fluxes. These findings not only augment the existing knowledge of the Somali upwelling system, but also have serious implications on the regional climate. Most importantly, our analysis underscores the use of alongshore winds only to project future (climate driven) changes in the upwelling intensity along this coast.
Xiang, Yunfei; Yue, Jianping; Cong, Kanglin; Xing, Yin; Cai, Dongjian (2019). Characterizing the Seasonal Hydrological Loading Over the Asian Continent Using GPS, GRACE, and Hydrological Model, Pure and Applied Geophysics, 11 (176), 5051-5068, 10.1007/s00024-019-02251-y.
Formatted Citation: Xiang, Y., J. Yue, K. Cong, Y. Xing, and D. Cai, 2019: Characterizing the Seasonal Hydrological Loading Over the Asian Continent Using GPS, GRACE, and Hydrological Model, Pure and Applied Geophysics, 176 (11), 5051-5068, doi: 10.1007/s00024-019-02251-y
Abstract: Based on combined data of the Global Positioning System (GPS), Global Land Data Assimilation System (GLDAS), and Gravity Recovery and Climate Experiment (GRACE), the seasonal hydrological loading over the Asian continent is characterized in this study. The hydrological loading effects over the Asian continent display strong latitude dependence. The significant hydrological loading effects appear at the GPS stations situated in the coastal areas, some regions near large rivers and lakes, and high-latitude areas in Russia, as evidenced by the fact that a large root mean square (RMS) and high percentage of the variance related to the annual signal modeled by singular spectrum analysis (SSA) for each measurement are cumulated at the stations located in these regions. In contrast, the hydrological loading effects are not pronounced in mid-latitude areas of the Asian continent (e.g., Central Asia, northern and plateau regions of China), which is due to the high topographical variability and scarce water resources in these regions. Then, the cross wavelet transform (XWT) is used to quantify the consistency between different data sets. For the data sets of GPS/GLDAS, the XWT-based semblance for 64% of the stations reaches above 0.8, while it reaches above 0.8 for 48% for the data sets of GPS/GRACE, indicating that the data sets of GPS/GLDAS present better consistency. In addition, we also discuss the effects of hydrological loading on GPS observations from the RMS value, noise characteristic, and velocity uncertainty. After applying the hydrological loading correction, the RMS values of almost all GPS observations are reduced with different amplitudes, implying that the hydrological loading correction can reduce the RMS values of most GPS observations in the Asian continent. Meanwhile, the variations of noise and velocity uncertainty suggest that hydrological loading has changed the noise characteristic of almost all GPS observations, and thus lead to the overestimation of velocity uncertainty.
Yurganov, Leonid; Muller-Karger, Frank; Leifer, Ira (2019). Methane increase over the Barents and Kara seas after the autumn pycnocline breakdown: satellite observations, Advances in Polar Science, 4 (30), 382-390, 10.13679/j.advps.2019.0024.
Title: Methane increase over the Barents and Kara seas after the autumn pycnocline breakdown: satellite observations
Type: Journal Article
Publication: Advances in Polar Science
Author(s): Yurganov, Leonid; Muller-Karger, Frank; Leifer, Ira
Year: 2019
Formatted Citation: Yurganov, L., F. Muller-Karger, and I. Leifer, 2019: Methane increase over the Barents and Kara seas after the autumn pycnocline breakdown: satellite observations. Advances in Polar Science, 30(4), 382-390, doi:10.13679/j.advps.2019.0024
Ott, Lesley; Pawson, Steven; Collatz, Jim; Watson, Gregg; Menemenlis, Dimitris; Brix, Holger; Rousseaux, Cecile; Bowman, Kevin; Liu, Junjie; Eldering, Annmarie; Gunson, Michael; Kawa, Stephan R. (2019). Quantifying the observability of CO2 flux uncertainty in atmospheric CO2 records using products from NASA’s Carbon Monitoring Flux Pilot Project.
Title: Quantifying the observability of CO2 flux uncertainty in atmospheric CO2 records using products from NASA’s Carbon Monitoring Flux Pilot Project
Type: Report
Publication:
Author(s): Ott, Lesley; Pawson, Steven; Collatz, Jim; Watson, Gregg; Menemenlis, Dimitris; Brix, Holger; Rousseaux, Cecile; Bowman, Kevin; Liu, Junjie; Eldering, Annmarie; Gunson, Michael; Kawa, Stephan R.
Year: 2019
Formatted Citation: Ott, L. and Coauthors, 2019: Quantifying the observability of CO2 flux uncertainty in atmospheric CO2 records using products from NASA's Carbon Monitoring Flux Pilot Project., Greenbelt, MD, 21 pp. https://ntrs.nasa.gov/search.jsp?R=20150001279.
Abstract: NASAs Carbon Monitoring System (CMS) Flux Pilot Project (FPP) was designed to better understand contemporary carbon fluxes by bringing together state-of-the art models with remote sensing datasets. Here we report on simulations using NASAs Goddard Earth Observing System Model, version 5 (GEOS-5) which was used to evaluate the consistency of two different sets of observationally constrained land and ocean fluxes with atmospheric CO2 records. Despite the strong data constraint, the average difference in annual terrestrial biosphere flux between the two land (NASA Ames CASA and CASA-GFED) models is 1.7 Pg C for 2009-2010. Ocean models (NOBM and ECCO2-Darwin) differ by 35 in their global estimates of carbon flux with particularly strong disagreement in high latitudes. Based upon combinations of terrestrial and ocean fluxes, GEOS-5 reasonably simulated the seasonal cycle observed at northern hemisphere surface sites and by the Greenhouse gases Observing SATellite (GOSAT) while the model struggled to simulate the seasonal cycle at southern hemisphere surface locations. Though GEOS-5 was able to reasonably reproduce the patterns of XCO2 observed by GOSAT, it struggled to reproduce these aspects of AIRS observations. Despite large differences between land and ocean flux estimates, resulting differences in atmospheric mixing ratio were small, typically less than 5 ppmv at the surface and 3 ppmv in the XCO2 column. A statistical analysis based on the variability of observations shows that flux differences of these magnitudes are difficult to distinguish from natural variability, regardless of measurement platform.
Klos, Anna; Gruszczynska, Marta; Bos, Machiel Simon; Boy, Jean-paul; Bogusz, Janusz (2019). Estimates of Vertical Velocity Errors for IGS ITRF2014 Stations by Applying the Improved Singular Spectrum Analysis Method and Environmental Loading Models, Geodynamics and Earth Tides Observations from Global to Micro Scale, 229-246, 10.1007/978-3-319-96277-1_18.
Title: Estimates of Vertical Velocity Errors for IGS ITRF2014 Stations by Applying the Improved Singular Spectrum Analysis Method and Environmental Loading Models
Type: Book Section
Publication: Geodynamics and Earth Tides Observations from Global to Micro Scale
Formatted Citation: Klos, A., M. Gruszczynska, M. S. Bos, J. Boy, and J. Bogusz, 2019: Estimates of Vertical Velocity Errors for IGS ITRF2014 Stations by Applying the Improved Singular Spectrum Analysis Method and Environmental Loading Models. Geodynamics and Earth Tides Observations from Global to Micro Scale, Springer, 229-246, doi:10.1007/978-3-319-96277-1_18
Other URLs: http://link.springer.com/10.1007/978-3-319-96277-1_18
Hutter, Nils; Zampieri, Lorenzo; Losch, Martin (2019). Leads and ridges in Arctic sea ice from RGPS data and a new tracking algorithm, The Cryosphere, 2 (13), 627-645, 10.5194/tc-13-627-2019.
Title: Leads and ridges in Arctic sea ice from RGPS data and a new tracking algorithm
Type: Journal Article
Publication: The Cryosphere
Author(s): Hutter, Nils; Zampieri, Lorenzo; Losch, Martin
Year: 2019
Formatted Citation: Hutter, N., L. Zampieri, and M. Losch, 2019: Leads and ridges in Arctic sea ice from RGPS data and a new tracking algorithm. Cryosph., 13(2), 627-645, doi:10.5194/tc-13-627-2019
Other URLs: https://doi.org/10.5194/tc-13-627-2019%0A, https://www.the-cryosphere.net/13/627/2019/
Lebehot, Alice D.; Halloran, Paul R.; Watson, Andrew J.; McNeall, Doug; Ford, David A.; Landschützer, Peter; Lauvset, Siv K.; Schuster, Ute (2019). Reconciling Observation and Model Trends in North Atlantic Surface CO 2, Global Biogeochemical Cycles, 10 (33), 1204-1222, 10.1029/2019GB006186.
Title: Reconciling Observation and Model Trends in North Atlantic Surface CO 2
Type: Journal Article
Publication: Global Biogeochemical Cycles
Author(s): Lebehot, Alice D.; Halloran, Paul R.; Watson, Andrew J.; McNeall, Doug; Ford, David A.; Landschützer, Peter; Lauvset, Siv K.; Schuster, Ute
Year: 2019
Formatted Citation: Lebehot, A. D., P. R. Halloran, A. J. Watson, D. McNeall, D. A. Ford, P. Landschützer, S. K. Lauvset, and U. Schuster, 2019: Reconciling Observation and Model Trends in North Atlantic Surface CO 2. Global Biogeochemical Cycles, 33(10), 1204-1222, doi:10.1029/2019GB006186
Zhang, Y.; Guan, Y. P. (2019). Striations in Marginal Seas and the Mediterranean Sea, Geophysical Research Letters, 5 (46), https://doi.org/10.1029/2018GL081050.
Title: Striations in Marginal Seas and the Mediterranean Sea
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Zhang, Y.; Guan, Y. P.
Year: 2019
Formatted Citation: Zhang, Y., and Y. P. Guan, 2019: Striations in Marginal Seas and the Mediterranean Sea. Geophys. Res. Lett., 46(5), doi:https://doi.org/10.1029/2018GL081050
Ridenour, Natasha A.; Hu, Xianmin; Sydor, Kevin; Myers, Paul G.; Barber, David G. (2019). Revisiting the Circulation of Hudson Bay: Evidence for a Seasonal Pattern, Geophysical Research Letters, 7 (46), 3891-3899, 10.1029/2019GL082344.
Title: Revisiting the Circulation of Hudson Bay: Evidence for a Seasonal Pattern
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Ridenour, Natasha A.; Hu, Xianmin; Sydor, Kevin; Myers, Paul G.; Barber, David G.
Year: 2019
Formatted Citation: Ridenour, N. A., X. Hu, K. Sydor, P. G. Myers, and D. G. Barber, 2019: Revisiting the Circulation of Hudson Bay: Evidence for a Seasonal Pattern. Geophys. Res. Lett., 46(7), 3891-3899, doi:10.1029/2019GL082344
Abstract: The Hudson Bay Complex (HBC) is the outlet for many Canadian rivers, receiving roughly 900 km3/year of river runoff. Historically, studies found a consistent cyclonic flow year-round in Hudson Bay, due to the geostrophic boundary current induced by river discharge and cyclonic wind forcing that was supported by available observations at that time. Using a high resolution ocean general circulation model, we show that, in summer, the mean circulation is not cyclonic, but consists of multiple small cyclonic and anticyclonic features, with the mean flow directed through the center of the bay. Absolute Dynamic Topography (ADT) and velocity observations also show this seasonal flow pattern. We find that this summer circulation is driven by geostrophic currents, generated by steric height gradients which are induced by increased river discharge during the spring freshet, and reinforced by anticyclonic seasonal wind patterns.
Formatted Citation: Mu, L., X. Liang, Q. Yang, J. Liu, and F. Zheng, 2019: Arctic Ice Ocean Prediction System: evaluating sea-ice forecasts during Xuelong 's first trans-Arctic Passage in summer 2017. Journal of Glaciology, 65(253), 813-821, doi:10.1017/jog.2019.55
Abstract: In an effort to improve the reliability of Arctic sea-ice predictions, an ensemble-based Arctic Ice Ocean Prediction System (ArcIOPS) has been developed to meet operational demands. The system is based on a regional Arctic configuration of the Massachusetts Institute of Technology general circulation model. A localized error subspace transform ensemble Kalman filter is used to assimilate the weekly merged CryoSat-2 and Soil Moisture and Ocean Salinity sea-ice thickness data together with the daily Advanced Microwave Scanning Radiometer 2 (AMSR2) sea-ice concentration data. The weather forecasts from the Global Forecast System of the National Centers for Environmental Prediction drive the sea ice-ocean coupled model. The ensemble mean sea-ice forecasts were used to facilitate the Chinese National Arctic Research Expedition in summer 2017. The forecasted sea-ice concentration is evaluated against AMSR2 and Special Sensor Microwave Imager/Sounder sea-ice concentration data. The forecasted sea-ice thickness is compared to the in-situ observations and the Pan-Arctic Ice-Ocean Modeling and Assimilation System. These comparisons show the promising potential of ArcIOPS for operational Arctic sea-ice forecasts. Nevertheless, the forecast bias in the Beaufort Sea calls for a delicate parameter calibration and a better design of the assimilation system.
Formatted Citation: Caputi, L. and Coauthors, 2019: Community-Level Responses to Iron Availability in Open Ocean Plankton Ecosystems. Global Biogeochemical Cycles, doi:10.1029/2018GB006022
Abstract: Predicting responses of plankton to variations in essential nutrients is hampered by limited in situ measurements, a poor understanding of community composition, and the lack of reference gene catalogs for key taxa. Iron is a key driver of plankton dynamics and, therefore, of global biogeochemical cycles and climate. To assess the impact of iron availability on plankton communities, we explored the comprehensive bio-oceanographic and bio-omics data sets from Tara Oceans in the context of the iron products from two state-of-the-art global scale biogeochemical models. We obtained novel information about adaptation and acclimation toward iron in a range of phytoplankton, including picocyanobacteria and diatoms, and identified whole subcommunities covarying with iron. Many of the observed global patterns were recapitulated in the Marquesas archipelago, where frequent plankton blooms are believed to be caused by natural iron fertilization, although they are not captured in large-scale biogeochemical models. This work provides a proof of concept that integrative analyses, spanning from genes to ecosystems and viruses to zooplankton, can disentangle the complexity of plankton communities and can lead to more accurate formulations of resource bioavailability in biogeochemical models, thus improving our understanding of plankton resilience in a changing environment.
Keywords: iron response, meta-omics, species networks, system biology
Fu, Yao; Wang, Chunzai; Brandt, Peter; Greatbatch, Richard J. (2019). Interannual Variability of Antarctic Intermediate Water in the Tropical North Atlantic, Journal of Geophysical Research: Oceans, 6 (124), 4044-4057, 10.1029/2018JC014878.
Title: Interannual Variability of Antarctic Intermediate Water in the Tropical North Atlantic
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Fu, Yao; Wang, Chunzai; Brandt, Peter; Greatbatch, Richard J.
Year: 2019
Formatted Citation: Fu, Y., C. Wang, P. Brandt, and R. J. Greatbatch, 2019: Interannual Variability of Antarctic Intermediate Water in the Tropical North Atlantic. J. Geophys. Res. Ocean., 124(6), 4044-4057, doi:10.1029/2018JC014878
Title: Arctic Ocean Freshwater Dynamics: Transient Response to Increasing River Runoff and Precipitation
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Brown, Nicola Jane; Nilsson, Johan; Pemberton, Per
Year: 2019
Formatted Citation: Brown, N. J., J. Nilsson, and P. Pemberton, 2019: Arctic Ocean Freshwater Dynamics: Transient Response to Increasing River Runoff and Precipitation. J. Geophys. Res. Ocean., 124(7), 5205-5219, doi:10.1029/2018JC014923
Formatted Citation: Liang, X., M. Losch, L. Nerger, L. Mu, Q. Yang, and C. Liu, 2019: Using Sea Surface Temperature Observations to Constrain Upper Ocean Properties in an Arctic Sea Ice-Ocean Data Assimilation System. J. Geophys. Res. Ocean., 124(7), 4727-4743, doi:10.1029/2019JC015073
Mikolaj, M.; Reich, M.; Güntner, A. (2019). Resolving Geophysical Signals by Terrestrial Gravimetry: A Time Domain Assessment of the Correction-Induced Uncertainty, Journal of Geophysical Research: Solid Earth, 10.1029/2018JB016682.
Title: Resolving Geophysical Signals by Terrestrial Gravimetry: A Time Domain Assessment of the Correction-Induced Uncertainty
Type: Journal Article
Publication: Journal of Geophysical Research: Solid Earth
Author(s): Mikolaj, M.; Reich, M.; Güntner, A.
Year: 2019
Formatted Citation: Mikolaj, M., M. Reich, and A. Güntner, 2019: Resolving Geophysical Signals by Terrestrial Gravimetry: A Time Domain Assessment of the Correction-Induced Uncertainty. Journal of Geophysical Research: Solid Earth, doi:10.1029/2018JB016682
Abstract: Terrestrial gravimetry is increasingly used to monitor mass transport processes in geophysics boosted by the ongoing technological development of instruments. Resolving a particular phenomenon of interest, however, requires a set of gravity corrections of which the uncertainties have not been addressed up to now. In this study, we quantify the time domain uncertainty of tide, global atmospheric, large-scale hydrological, and non-tidal ocean loading corrections. The uncertainty is assessed by comparing the majority of available global models for a suite of sites worldwide . The average uncertainty expressed as root-mean-square error equals 5.1 nm/s2, discounting local hydrology or air pressure. The correction-induced uncertainty of gravity changes over various time periods of interest ranges from 0.6 nm/s2 for hours up to a maximum of 6.7 nm/s2 for six months. The corrections are shown to be significant and should be applied for most geophysical applications of terrestrial gravimetry. From a statistical point of view however, resolving subtle gravity effects in the order of few nm/s2 is challenged by the uncertainty of the corrections. Many scientist are exploring ways to benefit from gravity measurements in fields of high societal relevance such as monitoring of volcanoes or measuring the amount of water in underground. Any application of such new methods, however, requires careful preparation of the gravity measurements. The intention of the preparation process is to ensure that the measurements do not contain information about processes which are not of interest. For that reason, the influence of atmosphere, ocean, tides and hydrology needs to be reduced from the gravity. In this study, we investigate how this reduction process influences the quality of the measurement. We found that the precision degrades especially owing to the hydrology. The ocean plays an important role at sites close to the coast and the atmosphere at sites located in mountains. The overall errors of the reductions may complicate a reliable use of gravity measurements in certain studies focusing on very small signals. Nevertheless, the precision of gravity reductions alone does not obstruct a meaningful use of gravity measurements in most research fields. Details specifying the reduction precision are provided in this study allowing scientist dealing with gravity measurements to decide if their signal of interest can be reliably resolved. Global-scale uncertainty assessment of tidal, oceanic, large-scale hydrological and atmospheric corrections for terrestrial gravimetry Resolving subtle gravity signals in the order of few nm/s2 is challenged by the statistical uncertainty of correction models Uncertainty computed for selected periods varies significantly with latitude and altitude of the gravi
Formatted Citation: Storto, A. and Coauthors, 2019: Ocean Reanalyses: Recent Advances and Unsolved Challenges. Frontiers in Marine Science, 6, doi:10.3389/fmars.2019.00418
Doddridge, Edward W.; Meneghello, Gianluca; Marshall, John; Scott, Jeffery; Lique, Camille (2019). A Three-way Balance in The Beaufort Gyre: The Ice-Ocean Governor, Wind Stress, and Eddy Diffusivity, Journal of Geophysical Research: Oceans, 10.1029/2018JC014897.
Formatted Citation: Doddridge, E. W., G. Meneghello, J. Marshall, J. Scott, and C. Lique, 2019: A Three-way Balance in The Beaufort Gyre: The Ice-Ocean Governor, Wind Stress, and Eddy Diffusivity. J. Geophys. Res. Ocean., doi:10.1029/2018JC014897
Abstract: The Beaufort Gyre (BG) is a large anticyclonic circulation in the Arctic Ocean. Its strength is directly related to the halocline depth, and therefore also to the storage of freshwater. It has recently been proposed that the equilibrium state of the BG is set by the Ice-Ocean Governor, a negative feedback between surface currents and ice-ocean stress, rather than a balance between lateral mesoscale eddy fluxes and surface Ekman pumping. However, mesoscale eddies are present in the Arctic Ocean; it is therefore important to extend the Ice-Ocean Governor theory to include lateral fluxes due to mesoscale eddies. Here, a non-linear ordinary differential equation is derived that represents the effects of wind stress, the Ice-Ocean Governor, and eddy fluxes. Equilibrium and time-varying solutions to this three-way balance equation are obtained and shown to closely match the output from a hierarchy of numerical simulations, indicating that the analytical model represents the processes controlling BG equilibration. The equilibration timescale derived from this three-way balance is faster than the eddy equilibration timescale and slower than the Ice-Ocean Governor equilibration timescales for most values of eddy diffusivity. The sensitivity of the BG equilibrium depth to changes in eddy diffusivity and the presence of the Ice-Ocean Governor is also explored. These results show that predicting the response of the BG to changing surface forcing and sea ice conditions requires faithfully capturing the three-way balance between the Ice-Ocean Governor, wind stress, and eddy fluxes.
Formatted Citation: Wang, Z., J. Turner, Y. Wu, and C. Liu, 2019: Rapid Decline of Total Antarctic Sea Ice Extent during 2014-16 Controlled by Wind-Driven Sea Ice Drift. J. Clim., 32(17), 5381-5395, doi:10.1175/JCLI-D-18-0635.1
Abstract: Between 2014 and 2016 the annual mean total extent of Antarctic sea ice decreased by a record, unprecedented amount of 1.6 × 10 6 km 2 , the largest in a record starting in the late 1970s. The mechanisms behind such a rapid decrease remain unknown. Using the outputs of a high-resolution, global ocean-sea ice model we show that the change was predominantly a result of record atmospheric low pressure systems over sectors of the Southern Ocean in 2016, with the associated winds inducing strong sea ice drift. Regions of large positive and negative sea ice extent anomaly were generated by both thermal and dynamic effects of the wind anomalies. Although the strong wind forcing also generated the warmest ocean surface state from April to December 2016, we show that enhanced northward sea ice drift and hence increased melting at lower latitudes driven by strong winds made the dominant contribution to the large decrease in total Antarctic sea ice extent between 2014 and 2016.
LIANG, QI; ZHOU, CHUNXIA; HOWAT, IAN M.; JEONG, SEONGSU; LIU, RUIXI; CHEN, YIMING (2019). Ice flow variations at Polar Record Glacier, East Antarctica, Journal of Glaciology (65).
Title: Ice flow variations at Polar Record Glacier, East Antarctica
Type: Journal Article
Publication: Journal of Glaciology
Author(s): LIANG, QI; ZHOU, CHUNXIA; HOWAT, IAN M.; JEONG, SEONGSU; LIU, RUIXI; CHEN, YIMING
Year: 2019
Formatted Citation: LIANG, Q., C. ZHOU, I. M. HOWAT, S. JEONG, R. LIU, and Y. CHEN, 2019: Ice flow variations at Polar Record Glacier, East Antarctica. Journal of Glaciology, 65, https://doi.org/10.1017/jog.2019.6%0A
O'Callaghan, B.; Chabchoub, A.; Waseda, T. (2019). Marine current energy in Eastern Australia: Evolution of currents and mesoscale anticyclonic eddies, Advances in Renewable Energies Offshore, 31-38.
Title: Marine current energy in Eastern Australia: Evolution of currents and mesoscale anticyclonic eddies
Type: Book Section
Publication: Advances in Renewable Energies Offshore
Author(s): O'Callaghan, B.; Chabchoub, A.; Waseda, T.
Year: 2019
Formatted Citation: O'Callaghan, B., A. Chabchoub, and T. Waseda, 2019: Marine current energy in Eastern Australia: Evolution of currents and mesoscale anticyclonic eddies. Advances in Renewable Energies Offshore, Taylor & Francis Group, 31-38, https://books.google.com/books?hl=en&lr=&id=YMp6DwAAQBAJ&oi=fnd&pg=PA31&dq=ecco2+menemenlis&ots=78V-4WfRD_&sig=N36qJ6EV-2lXg6fmpv_loylDAbo#v=twopage&q=ecco2 menemenlis&f=true
Formatted Citation: Qiu, B., S. Chen, B. Powell, P. Colin, D. Rudnick, and M. Schönau, 2019: Nonlinear Short-Term Upper Ocean Circulation Variability in the Tropical Western Pacific. Oceanography, 32(4), 22-31, doi:10.5670/oceanog.2019.408
Yang, Haiyuan; Chang, Ping; Qiu, Bo; Zhang, Qiuying; Wu, Lixin; Chen, Zhaohui; Wang, Hong (2019). Mesoscale Air-Sea Interaction and Its Role in Eddy Energy Dissipation in the Kuroshio Extension, Journal of Climate, 24 (32), 8659-8676, 10.1175/JCLI-D-19-0155.1.
Formatted Citation: Yang, H., P. Chang, B. Qiu, Q. Zhang, L. Wu, Z. Chen, and H. Wang, 2019: Mesoscale Air-Sea Interaction and Its Role in Eddy Energy Dissipation in the Kuroshio Extension. J. Clim., 32(24), 8659-8676, doi:10.1175/JCLI-D-19-0155.1
Abstract: Using the high-resolution Community Earth System Model (CESM) output, this study investigates air-sea interaction and its role in eddy energy dissipation in the Kuroshio Extension (KE) region. Based on an eddy energetics analysis, it is found that the baroclinic pathway associated with temperature variability is the main eddy energy source in this region. Both the air-sea heat flux and wind stress act as eddy killers that remove energy from oceanic eddies. Heat exchange between atmosphere and oceanic eddies dominates the dissipation of eddy temperature variance within the surface layer and accounts for 36% of the total dissipation in the upper 350-m layer. Compared to the heat exchange, the role of wind power in damping the eddy kinetic energy (EKE) is relatively small. Only 18% of EKE dissipation in the upper 350 m is attributed to eddy wind power. Misrepresentation of the damping role of mesoscale ocean-atmosphere interaction can result in an incorrect vertical structure of eddy energy dissipation, leading to an erroneous representation of vertical mixing in the interior ocean.
Volkov, Denis L.; Lee, Sang-Ki; Domingues, Ricardo; Zhang, Hong; Goes, Marlos (2019). Interannual Sea Level Variability Along the Southeastern Seaboard of the United States in Relation to the Gyre-Scale Heat Divergence in the North Atlantic, Geophysical Research Letters, 13 (46), 7481-7490, 10.1029/2019GL083596.
Title: Interannual Sea Level Variability Along the Southeastern Seaboard of the United States in Relation to the Gyre-Scale Heat Divergence in the North Atlantic
Formatted Citation: Volkov, D. L., S. Lee, R. Domingues, H. Zhang, and M. Goes, 2019: Interannual Sea Level Variability Along the Southeastern Seaboard of the United States in Relation to the Gyre-Scale Heat Divergence in the North Atlantic. Geophys. Res. Lett., 46(13), 7481-7490, doi:10.1029/2019GL083596
Guo, Haihong; Chen, Zhaohui; Yang, Haiyuan (2019). Poleward Shift of the Pacific North Equatorial Current Bifurcation, Journal of Geophysical Research: Oceans, 7 (124), 4557-4571, 10.1029/2019JC015019.
Formatted Citation: Guo, H., Z. Chen, and H. Yang, 2019: Poleward Shift of the Pacific North Equatorial Current Bifurcation. J. Geophys. Res. Ocean., 124(7), 4557-4571, doi:10.1029/2019JC015019
Amin, Hadi; Sjöberg, Lars E.; Bagherbandi, Mohammad (2019). A global vertical datum defined by the conventional geoid potential and the Earth ellipsoid parameters, Journal of Geodesy, 10 (93), 1943-1961, 10.1007/s00190-019-01293-3.
Title: A global vertical datum defined by the conventional geoid potential and the Earth ellipsoid parameters
Type: Journal Article
Publication: Journal of Geodesy
Author(s): Amin, Hadi; Sjöberg, Lars E.; Bagherbandi, Mohammad
Year: 2019
Formatted Citation: Amin, H., L. E. Sjöberg, and M. Bagherbandi, 2019: A global vertical datum defined by the conventional geoid potential and the Earth ellipsoid parameters. Journal of Geodesy, 93(10), 1943-1961, doi:10.1007/s00190-019-01293-3
Abstract: The geoid, according to the classical Gauss-Listing definition, is, among infinite equipotential surfaces of the Earth's gravity field, the equipotential surface that in a least squares sense best fits the undisturbed mean sea level. This equipotential surface, except for its zero-degree harmonic, can be characterized using the Earth's global gravity models (GGM). Although, nowadays, satellite altimetry technique provides the absolute geoid height over oceans that can be used to calibrate the unknown zero-degree harmonic of the gravimetric geoid models, this technique cannot be utilized to estimate the geometric parameters of the mean Earth ellipsoid (MEE). The main objective of this study is to perform a joint estimation of W0, which defines the zero datum of vertical coordinates, and the MEE parameters relying on a new approach and on the newest gravity field, mean sea surface and mean dynamic topography models. As our approach utilizes both satellite altimetry observations and a GGM model, we consider different aspects of the input data to evaluate the sensitivity of our estimations to the input data. Unlike previous studies, our results show that it is not sufficient to use only the satellite-component of a quasi-stationary GGM to estimate W0. In addition, our results confirm a high sensitivity of the applied approach to the altimetry-based geoid heights, i.e., mean sea surface and mean dynamic topography models. Moreover, as W0 should be considered a quasi-stationary parameter, we quantify the effect of time-dependent Earth's gravity field changes as well as the time-dependent sea level changes on the estimation of W0. Our computations resulted in the geoid potential W0 = 62636848.102 ± 0.004 m2 s−2 and the semi-major and minor axes of the MEE, a = 6378137.678 ± 0.0003 m and b = 6356752.964 ± 0.0005 m, which are 0.678 and 0.650 m larger than those axes of GRS80 reference ellipsoid, respectively. Moreover, a new estimation for the geocentric gravitational constant was obtained as GM = (398600460.55 ± 0.03) × 106 m3 s−2.
Keywords: Geodetic reference system, Geoid potential W0, Global vertical datum, Mean Earth ellipsoid, Reference ellipsoid
Kuhn, A. M.; Dutkiewicz, Stephanie; Jahn, O.; Clayton, S.; Rynearson, T. A.; Mazloff, M. R.; Barton, A. D. (2019). Temporal and Spatial Scales of Correlation in Marine Phytoplankton Communities, Journal of Geophysical Research: Oceans, 12 (124), 9417-9438, 10.1029/2019JC015331.
Title: Temporal and Spatial Scales of Correlation in Marine Phytoplankton Communities
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Kuhn, A. M.; Dutkiewicz, Stephanie; Jahn, O.; Clayton, S.; Rynearson, T. A.; Mazloff, M. R.; Barton, A. D.
Year: 2019
Formatted Citation: Kuhn, A. M., S. Dutkiewicz, O. Jahn, S. Clayton, T. A. Rynearson, M. R. Mazloff, and A. D. Barton, 2019: Temporal and Spatial Scales of Correlation in Marine Phytoplankton Communities. J. Geophys. Res. Ocean., 124(12), 9417-9438, doi:10.1029/2019JC015331
Formatted Citation: Yang, Q., L. Mu, X. Wu, J. Liu, F. Zheng, J. Zhang, and C. Li, 2019: Improving Arctic sea ice seasonal outlook by ensemble prediction using an ice-ocean model. Atmospheric Research, 227, 14-23, doi:10.1016/j.atmosres.2019.04.021
Other URLs: https://linkinghub.elsevier.com/retrieve/pii/S0169809518314406
Denvil-Sommer, Anna; Gehlen, Marion; Vrac, Mathieu; Mejia, Carlos (2019). LSCE-FFNN-v1: a two-step neural network model for the reconstruction of surface ocean p CO 2 over the global ocean, Geoscientific Model Development, 5 (12), 2091-2105, 10.5194/gmd-12-2091-2019.
Title: LSCE-FFNN-v1: a two-step neural network model for the reconstruction of surface ocean p CO 2 over the global ocean
Type: Journal Article
Publication: Geoscientific Model Development
Author(s): Denvil-Sommer, Anna; Gehlen, Marion; Vrac, Mathieu; Mejia, Carlos
Year: 2019
Formatted Citation: Denvil-Sommer, A., M. Gehlen, M. Vrac, and C. Mejia, 2019: LSCE-FFNN-v1: a two-step neural network model for the reconstruction of surface ocean p CO 2 over the global ocean. Geoscientific Model Development, 12(5), 2091-2105, doi:10.5194/gmd-12-2091-2019
Title: Polar climate system modeling in China: Recent progress and future challenges
Type: Journal Article
Publication: Science China Earth Sciences
Author(s): WANG, Zhaomin; CHEN, Dake
Year: 2019
Formatted Citation: WANG, Z., and D. CHEN, 2019: Polar climate system modeling in China: Recent progress and future challenges. Science China Earth Sciences, doi:https://doi.org/10.1007/s11430-018-9355-2
Wei, Jianfen; Zhang, Xiangdong; Wang, Zhaomin (2019). Reexamination of Fram Strait sea ice export and its role in recently accelerated Arctic sea ice retreat, Climate Dynamics, 10.1007/s00382-019-04741-0.
Formatted Citation: Wei, J., X. Zhang, and Z. Wang, 2019: Reexamination of Fram Strait sea ice export and its role in recently accelerated Arctic sea ice retreat. Climate Dynamics, doi:10.1007/s00382-019-04741-0
Abstract:
Keywords: Fram Strait, MITgcm-ECCO2, Regime shift, Sea ice export
Title: Observing System Evaluation Based on Ocean Data Assimilation and Prediction Systems: On-Going Challenges and a Future Vision for Designing and Supporting Ocean Observational Networks
Formatted Citation: Fujii, Y. and Coauthors, 2019: Observing System Evaluation Based on Ocean Data Assimilation and Prediction Systems: On-Going Challenges and a Future Vision for Designing and Supporting Ocean Observational Networks. Frontiers in Marine Science, 6, doi:10.3389/fmars.2019.00417
Gruszczynska, Marta; Rosat, Severine; Klos, Anna; Gruszczynski, Maciej; Bogusz, Janusz (2019). Multichannel Singular Spectrum Analysis in the Estimates of Common Environmental Effects Affecting GPS Observations, Geodynamics and Earth Tides Observations from Global to Micro Scale, 211-228, 10.1007/978-3-319-96277-1_17.
Formatted Citation: Gruszczynska, M., S. Rosat, A. Klos, M. Gruszczynski, and J. Bogusz, 2019: Multichannel Singular Spectrum Analysis in the Estimates of Common Environmental Effects Affecting GPS Observations. Geodynamics and Earth Tides Observations from Global to Micro Scale, Springer, 211-228, doi:10.1007/978-3-319-96277-1_17
Other URLs: http://link.springer.com/10.1007/978-3-319-96277-1_17
Yang, Shengmu; Xing, Jiuxing; Sheng, Jinyu; Chen, Shengli; Chen, Daoyi (2019). A process study of interactions between a warm eddy and the Kuroshio Current in Luzon Strait: The fate of eddies, Journal of Marine Systems, 10.1016/j.jmarsys.2019.02.009.
Formatted Citation: Yang, S., J. Xing, J. Sheng, S. Chen, and D. Chen, 2019: A process study of interactions between a warm eddy and the Kuroshio Current in Luzon Strait: The fate of eddies. Journal of Marine Systems, doi:10.1016/j.jmarsys.2019.02.009
Abstract: Satellite observations reveal many mesoscale eddies in the West Pacific Ocean (WPO) that propagate westwards and eventually interact with the Kuroshio Current. Examination of global ocean and sea ice reanalysis data in years 2008-2015 suggests trajectories of these mesoscale eddies over the Kuroshio zone can be categorized into three different patterns: ~63% of mesoscale eddies dissipating during the eddy-current interaction, ~33% moving to the north along the Kuroshio and only ~4% passing through the Kuroshio and Luzon Strait (LS) to enter to the South China Sea (SCS). A three-dimensional ocean circulation model based on the MIT General Circulation Model (MITgcm) is used to study the evolution of a westward propagating mesoscale eddy during the eddy-current interaction. Thirteen numerical experiments are conducted with the circulation model driven by currents specified at the southern and northern open boundaries to represent the influence of the Kuroshio. A mesoscale eddy is initialized to the east of the Kuroshio and the model is integrated for 70 days in each experiment. Model results suggest that the northward-flowing Kuroshio Current and the seamount topography within LS form a barrier for the westward propagating eddies to enter the South China Sea (SCS). Non-linear interactions between the Kuroshio Current, local topography and westward propagating mesoscale eddies can generate localized eddies in LS which could be shed into the SCS. Furthermore, the eddy-current interaction is found to be one of mechanisms for generating a multi-eddy structure in LS region.
Keywords: Eddy-current interaction, Luzon Strait, Mesoscale eddies, Numerical model, Process study, The Kuroshio Current
Tang, Yi; Stewart, Gillian (2019). The 210Po/210Pb method to calculate particle export: Lessons learned from the results of three GEOTRACES transects, Marine Chemistry (217), 103692, 10.1016/j.marchem.2019.103692.
Title: The 210Po/210Pb method to calculate particle export: Lessons learned from the results of three GEOTRACES transects
Type: Journal Article
Publication: Marine Chemistry
Author(s): Tang, Yi; Stewart, Gillian
Year: 2019
Formatted Citation: Tang, Y., and G. Stewart, 2019: The 210Po/210Pb method to calculate particle export: Lessons learned from the results of three GEOTRACES transects. Marine Chemistry, 217, 103692, doi:10.1016/j.marchem.2019.103692
Yang, Yang; Liang, X. San (2019). The intrinsic nonlinear multiscale interactions among the mean flow, low frequency variability and mesoscale eddies in the Kuroshio region, Science China Earth Sciences, 10.1007/s11430-018-9289-4.
Title: The intrinsic nonlinear multiscale interactions among the mean flow, low frequency variability and mesoscale eddies in the Kuroshio region
Type: Journal Article
Publication: Science China Earth Sciences
Author(s): Yang, Yang; Liang, X. San
Year: 2019
Formatted Citation: Yang, Y., and X. S. Liang, 2019: The intrinsic nonlinear multiscale interactions among the mean flow, low frequency variability and mesoscale eddies in the Kuroshio region. Science China Earth Sciences, doi:10.1007/s11430-018-9289-4
Manizza, Manfredi; Menemenlis, Dimitris; Zhang, Hong; Miller, Charles E. (2019). Modeling the Recent Changes in the Arctic Ocean CO 2 Sink (2006-2013), Global Biogeochemical Cycles, 10.1029/2018GB006070.
Title: Modeling the Recent Changes in the Arctic Ocean CO 2 Sink (2006-2013)
Type: Journal Article
Publication: Global Biogeochemical Cycles
Author(s): Manizza, Manfredi; Menemenlis, Dimitris; Zhang, Hong; Miller, Charles E.
Year: 2019
Formatted Citation: Manizza, M., D. Menemenlis, H. Zhang, and C. E. Miller, 2019: Modeling the Recent Changes in the Arctic Ocean CO 2 Sink (2006-2013). Global Biogeochemical Cycles, doi:10.1029/2018GB006070
Title: The export flux of particulate organic carbon derived from 210 Po/ 210 Pb disequilibria along the North Atlantic GEOTRACES GA01 transect: GEOVIDE cruise
Formatted Citation: Tang, Y., N. Lemaitre, M. Castrillejo, M. Roca-Martí, P. Masqué, and G. Stewart, 2019: The export flux of particulate organic carbon derived from 210 Po/ 210 Pb disequilibria along the North Atlantic GEOTRACES GA01 transect: GEOVIDE cruise. Biogeosciences, doi:10.5194/bg-16-309-2019
Abstract: The disequilibrium between 210Po activity and 210Pb activity in seawater samples was determined along the GEOTRACES GA01 transect in the North Atlantic during the GEOVIDE cruise (May-June 2014). A steady-state model was used to quantify vertical export of particulate 210Po. Vertical advection was incorporated into one version of the model using time-averaged vertical velocity, which had substantial variance. This resulted in large uncertainties for the 210Po export flux in this model, suggesting that those calculations of 210Po export fluxes should be used with great care. Despite the large uncertainties, there is no question that the deficits of 210Po in the Iberian Basin and at the Greenland Shelf have been strongly affected by vertical advection. Using the export flux of 210Po and the particulate organic carbon (POC) to 210Po ratio of total (>1µm) particles, we determined the POC export fluxes along the transect. Both the magnitude and efficiency of the estimated POC export flux from the surface ocean varied spatially within our study region. Export fluxes of POC ranged from negligible to 10mmolCm−2d−1, with enhanced POC export in the Labrador Sea. The cruise track was characterized by overall low POC export relative to net primary production (export efficiency <1%-15%), but relatively high export efficiencies were seen in the basins where diatoms dominated the phytoplankton community. The particularly low export efficiencies in the Iberian Basin, on the other hand, were explained by the dominance of smaller phytoplankton, such as cyanobacteria or coccolithophores. POC fluxes estimated from the 210Po∕210Pb and 234Th∕238U disequilibria agreed within a factor of 3 along the transect, with higher POC estimates generally derived from 234Th. The differences were attributed to integration timescales and the history of bloom events.
Title: Hydrometeorological and gravity signals at the Argentine-German Geodetic Observatory (AGGO) in La Plata
Type: Journal Article
Publication: Earth System Science Data
Author(s): Mikolaj, Michal; Güntner, Andreas; Brunini, Claudio; Wziontek, Hartmut; Gende, Mauricio; Schröder, Stephan; Cassino, Augusto M.; Pasquaré, Alfredo; Reich, Marvin; Hartmann, Anne; Oreiro, Fernando A.; Pendiuk, Jonathan; Guarracino, Luis; Antokoletz, Ezequiel D.
Year: 2019
Formatted Citation: Mikolaj, M. and Coauthors, 2019: Hydrometeorological and gravity signals at the Argentine-German Geodetic Observatory (AGGO) in La Plata. Earth System Science Data, 11(4), 1501-1513, doi:10.5194/essd-11-1501-2019
Abstract: The Argentine-German Geodetic Observatory (AGGO) is one of the very few sites in the Southern Hemisphere equipped with comprehensive cutting-edge geodetic instrumentation. The employed observation techniques are used for a wide range of geophysical applications. The data set provides gravity time series and selected gravity models together with the hydrometeorological monitoring data of the observatory. These parameters are of great interest to the scientific community, e.g. for achieving accurate realization of terrestrial and celestial reference frames. Moreover, the availability of the hydrometeorological products is beneficial to inhabitants of the region as they allow for monitoring of environmental changes and natural hazards including extreme events. The hydrological data set is composed of time series of groundwater level, modelled and observed soil moisture content, soil temperature, and physical soil properties and aquifer properties. The meteorological time series include air temperature, humidity, pressure, wind speed, solar radiation, precipitation, and derived reference evapotranspiration. These data products are extended by gravity models of hydrological, oceanic, La Plata estuary, and atmospheric effects. The quality of the provided meteorological time series is tested via comparison to the two closest WMO (World Meteorological Organization) sites where data are available only in an inferior temporal resolution. The hydrological series are validated by comparing the respective forward-modelled gravity effects to independent gravity observations reduced up to a signal corresponding to local water storage variation. Most of the time series cover the time span between April 2016 and November 2018 with either no or only few missing data points. The data set is available at https://doi.org/10.5880/GFZ.5.4.2018.001 (Mikolaj et al., 2018).
Jyoti, J.; Swapna, P.; Krishnan, R.; Naidu, C. V. (2019). Pacific modulation of accelerated south Indian Ocean sea level rise during the early 21st Century, Climate Dynamics, https://doi.org/10.1007/s00382-019-04795-0.
Title: Pacific modulation of accelerated south Indian Ocean sea level rise during the early 21st Century
Type: Journal Article
Publication: Climate Dynamics
Author(s): Jyoti, J.; Swapna, P.; Krishnan, R.; Naidu, C. V.
Year: 2019
Formatted Citation: Jyoti, J., P. Swapna, R. Krishnan, and C. V. Naidu, 2019: Pacific modulation of accelerated south Indian Ocean sea level rise during the early 21st Century. Climate Dynamics, doi:https://doi.org/10.1007/s00382-019-04795-0
Formatted Citation: Ibarbalz, F. M. and Coauthors, 2019: Global Trends in Marine Plankton Diversity across Kingdoms of Life. Cell, 179(5), 1084-1097.e21, doi:10.1016/j.cell.2019.10.008
Howe, Bruce M.; Miksis-Olds, Jennifer; Rehm, Eric; Sagen, Hanne; Worcester, Peter F.; Haralabus, Georgios (2019). Observing the Oceans Acoustically, Frontiers in Marine Science (6), 10.3389/fmars.2019.00426.
Author(s): Howe, Bruce M.; Miksis-Olds, Jennifer; Rehm, Eric; Sagen, Hanne; Worcester, Peter F.; Haralabus, Georgios
Year: 2019
Formatted Citation: Howe, B. M., J. Miksis-Olds, E. Rehm, H. Sagen, P. F. Worcester, and G. Haralabus, 2019: Observing the Oceans Acoustically. Frontiers in Marine Science, 6, doi:10.3389/fmars.2019.00426
Siegfried, Lydia; Schmidt, Martin; Mohrholz, Volker; Pogrzeba, Hans; Nardini, Pascal; Böttinger, Michael; Scheuermann, Gerik (2019). The tropical-subtropical coupling in the Southeast Atlantic from the perspective of the northern Benguela upwelling system, PLoS ONE, 10.1371/journal.pone.0210083.
Formatted Citation: Siegfried, L., M. Schmidt, V. Mohrholz, H. Pogrzeba, Nardini, P., M. Böttinger, and G. Scheuermann, 2019: The tropical-subtropical coupling in the Southeast Atlantic from the perspective of the northern Benguela upwelling system. PLoS ONE, doi:10.1371/journal.pone.0210083
Ding, Yang; Bao, Xianwen; Yao, Zhigang; Bi, Congcong; Wan, Kai; Bao, Min; Jiang, Zhipeng; Song, Jun; Gao, Jia (2019). Observational and model studies of synoptic current fluctuations in the Bohai Strait on the Chinese continental shelf, Ocean Dynamics, 10.1007/s10236-019-01247-5.
Formatted Citation: Ding, Y. and Coauthors, 2019: Observational and model studies of synoptic current fluctuations in the Bohai Strait on the Chinese continental shelf. Ocean Dynamics, doi:10.1007/s10236-019-01247-5
Springer, Anne; Karegar, Makan A.; Kusche, Jürgen; Keune, Jessica; Kurtz, Wolfgang; Kollet, Stefan (2019). Evidence of daily hydrological loading in GPS time series over Europe, Journal of Geodesy, 10 (93), 2145-2153, 10.1007/s00190-019-01295-1.
Formatted Citation: Springer, A., M. A. Karegar, J. Kusche, J. Keune, W. Kurtz, and S. Kollet, 2019: Evidence of daily hydrological loading in GPS time series over Europe. Journal of Geodesy, 93(10), 2145-2153, doi:10.1007/s00190-019-01295-1
Heimbach, Patrick; Fukumori, Ichiro; Hill, Christopher N.; Ponte, Rui M.; Stammer, Detlef; Wunsch, Carl; Campin, Jean-Michel; Cornuelle, Bruce; Fenty, Ian; Forget, Gaël; Köhl, Armin; Mazloff, Matthew; Menemenlis, Dimitris; Nguyen, An T.; Piecuch, Christopher; Trossman, David; Verdy, Ariane; Wang, Ou; Zhang, Hong (2019). Putting It All Together: Adding Value to the Global Ocean and Climate Observing Systems With Complete Self-Consistent Ocean State and Parameter Estimates, Frontiers in Marine Science (6), 55, 10.3389/fmars.2019.00055.
Title: Putting It All Together: Adding Value to the Global Ocean and Climate Observing Systems With Complete Self-Consistent Ocean State and Parameter Estimates
Type: Journal Article
Publication: Frontiers in Marine Science
Author(s): Heimbach, Patrick; Fukumori, Ichiro; Hill, Christopher N.; Ponte, Rui M.; Stammer, Detlef; Wunsch, Carl; Campin, Jean-Michel; Cornuelle, Bruce; Fenty, Ian; Forget, Gaël; Köhl, Armin; Mazloff, Matthew; Menemenlis, Dimitris; Nguyen, An T.; Piecuch, Christopher; Trossman, David; Verdy, Ariane; Wang, Ou; Zhang, Hong
Year: 2019
Formatted Citation: Heimbach, P. and Coauthors, 2019: Putting It All Together: Adding Value to the Global Ocean and Climate Observing Systems With Complete Self-Consistent Ocean State and Parameter Estimates. Frontiers in Marine Science, 6, 55, doi:10.3389/fmars.2019.00055
Abstract: In 1999, the consortium for Estimating the Circulation and Climate of the Ocean (ECCO) set out to synthesize the hydrographic data collected by the World Ocean Circulation Experiment (WOCE) and satellite sea surface height measurements into a complete and coherent description of the ocean afforded by an ocean general circulation model. Twenty years later, the versatility of ECCO's estimation framework enables production of global and regional ocean and sea-ice state estimates that incorporate not only the initial suite of data and its successors, but nearly all data streams available today. New observations include measurements from Argo floats, marine mammal-based hydrography, satellite retrievals of ocean bottom pressure and sea surface salinity, and ice-tethered profiler data in polar regions. The framework also produces improved estimates of uncertain inputs, including initial conditions, surface atmospheric state variables, and mixing parameters. The freely available state estimates and related efforts are property-conserving, allowing closed budget calculations that are a requisite to detect, quantify, and understand the evolution of climate-relevant signals as mandated by the Coupled Model Intercomparison Project Phase 6 (CMIP6) protocol. The solutions can be reproduced by users through provision of the underlying modeling and assimilation machinery. Regional efforts have spun off that offer increased spatial resolution to better resolve relevant processes. Emerging foci of ECCO are on global sea level change, in particular contributions from polar ice sheets, and the increased use of biogeochemical and ecosystem data to constrain global cycles of carbon, nitrogen and oxygen. Challenges in the coming decade include provision of uncertainties, informing observing system design, globally increased resolution, and moving toward coupled Earth system estimation with consistent momentum, heat and freshwater fluxes between the ocean, atmosphere, cryosphere and land.
Keywords: Adjoint method, ECCO, Ocean circulation and climate, coupled Earth system data assimilation, global ocean inverse modeling, ocean observations, optimal state and parameter estimation
Flemming, Burghard W.; Kudrass, Hermann-Rudolf (2018). Large dunes on the outer shelf off the Zambezi Delta, Mozambique: evidence for the existence of a Mozambique Current, Geo-Marine Letters, 1 (38), 95-106, 10.1007/s00367-017-0515-5.
Formatted Citation: Flemming, B. W., and H. Kudrass, 2018: Large dunes on the outer shelf off the Zambezi Delta, Mozambique: evidence for the existence of a Mozambique Current. Geo-Marine Letters, 38(1), 95-106, doi:10.1007/s00367-017-0515-5
Sonke, Jeroen E.; Teisserenc, Roman; Heimbürger-Boavida, Lars-Eric; Petrova, Mariia V.; Marusczak, Nicolas; Le Dantec, Theo; Chupakov, Artem V.; Li, Chuxian; Thackray, Colin P.; Sunderland, Elsie M.; Tananaev, Nikita; Pokrovsky, Oleg S. (2018). Eurasian river spring flood observations support net Arctic Ocean mercury export to the atmosphere and Atlantic Ocean, Proceedings of the National Academy of Sciences, 50 (115), E11586-E11594, 10.1073/pnas.1811957115.
Title: Eurasian river spring flood observations support net Arctic Ocean mercury export to the atmosphere and Atlantic Ocean
Type: Journal Article
Publication: Proceedings of the National Academy of Sciences
Author(s): Sonke, Jeroen E.; Teisserenc, Roman; Heimbürger-Boavida, Lars-Eric; Petrova, Mariia V.; Marusczak, Nicolas; Le Dantec, Theo; Chupakov, Artem V.; Li, Chuxian; Thackray, Colin P.; Sunderland, Elsie M.; Tananaev, Nikita; Pokrovsky, Oleg S.
Year: 2018
Formatted Citation: Sonke, J.E., R. Teisserenc, L-E. Heimbürger-Boavida, M.V. Petrova, N. Marusczak, T. Le Dantec, A.V. Chupakov, C. Li, C.P. Thackray, E.M. Sunderland, N. Tananaev, and O.S. Pokrovsky, 2018: Eurasian river spring flood observations support net Arctic Ocean mercury export to the atmosphere and Atlantic Ocean. Proceedings of the National Academy of Sciences, 115(50), E11586-E11594, doi:10.1073/pnas.1811957115
Abstract: Midlatitude anthropogenic mercury (Hg) emissions and discharge reach the Arctic Ocean (AO) by atmospheric and oceanic transport. Recent studies suggest that Arctic river Hg inputs have been a potentially overlooked source of Hg to the AO. Observations on Hg in Eurasian rivers, which represent 80% of freshwater inputs to the AO, are quasi-inexistent, however, putting firm understanding of the Arctic Hg cycle on hold. Here, we present comprehensive seasonal observations on dissolved Hg (DHg) and particulate Hg (PHg) concentrations and fluxes for two large Eurasian rivers, the Yenisei and the Severnaya Dvina. We find large DHg and PHg fluxes during the spring flood, followed by a second pulse during the fall flood. We observe well-defined water vs. Hg runoff relationships for Eurasian and North American Hg fluxes to the AO and for Canadian Hg fluxes into the larger Hudson Bay area. Extrapolation to pan-Arctic rivers and watersheds gives a total Hg river flux to the AO of 44 ± 4 Mg per year (1σ), in agreement with the recent model-based estimates of 16 to 46 Mg per year and Hg/dissolved organic carbon (DOC) observation-based estimate of 50 Mg per year. The river Hg budget, together with recent observations on tundra Hg uptake and AO Hg dynamics, provide a consistent view of the Arctic Hg cycle in which continental ecosystems traffic anthropogenic Hg emissions to the AO via rivers, and the AO exports Hg to the atmosphere, to the Atlantic Ocean, and to AO marine sediments.
Formatted Citation: Tréguer, P. and Coauthors, 2018: Influence of diatom diversity on the ocean biological carbon pump. Nature Geoscience, 11(1), 27-37, doi:10.1038/s41561-017-0028-x
Cole, Sylvia T. (2018). Investigating Small-Scale Processes from an Abundance of Autonomous Observations, ALPS II: Autonomous and Lagrangian Platforms and Sensors, 25-27.
Title: Investigating Small-Scale Processes from an Abundance of Autonomous Observations
Type: Conference Proceedings
Publication: ALPS II: Autonomous and Lagrangian Platforms and Sensors
Author(s): Cole, Sylvia T.
Year: 2018
Formatted Citation: Cole, S. T., 2018: Investigating Small-Scale Processes from an Abundance of Autonomous Observations. ALPS II: Autonomous and Lagrangian Platforms and Sensors, D. C. D Rudnick, Eds., La Jolla, California,, 25-27 pp.
Abstract: Small-scale processes, those with spatial and/or temporal scales less than a few hundred kilometers and a few weeks, vary on global and decadal scales. Such large-scale variations in small- scale processes have been difficult to observe. Within the last decade, global and regional-scale autonomous observations have begun to fill this observational gap. The specific processes that can be investigated from autonomous platforms are deter- mined by the minimum scale in space and time sampled by each platform. Recent examples are highlighted, and the future potential is discussed.
Srinivas, G.; Chowdary, Jasti S.; Gnanaseelan, C.; Prasad, K.V.S.R.; Karmakar, Ananya; Parekh, Anant (2018). Association between mean and interannual equatorial Indian Ocean subsurface temperature bias in a coupled model, Climate Dynamics, 5-6 (50), 1659-1673, 10.1007/s00382-017-3713-y.
Formatted Citation: Srinivas, G., J.S. Chowdary, C. Gnanaseelan, K.V.S.R Prasad, A. Karmakar, and A. Parekh, 2018: Association between mean and interannual equatorial Indian Ocean subsurface temperature bias in a coupled model, Climate Dynamics, 50(5-6), 1659-1673, doi: 10.1007/s00382-017-3713-y
Abstract: In the present study the association between mean and interannual subsurface temperature bias over the equatorial Indian Ocean (EIO) is investigated during boreal summer (June through September; JJAS) in the National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFSv2) hindcast. Anomalously high subsurface warm bias (greater than 3°C) over the eastern EIO (EEIO) region is noted in CFSv2 during summer, which is higher compared to other parts of the tropical Indian Ocean. Prominent eastward current bias in the upper 100 m over the EIO region induced by anomalous westerly winds is primarily responsible for subsurface temperature bias. The eastward currents transport warm water to the EEIO and is pushed down to subsurface due to downwelling. Thus biases in both horizontal and vertical currents over the EIO region support subsurface warm bias. The evolution of systematic subsurface warm bias in the model shows strong interannual variability. These maximum subsurface warming episodes over the EEIO are mainly associated with La Niña like forcing. Strong convergence of low level winds over the EEIO and Maritime continent enhanced the westerly wind bias over the EIO during maximum warming years. This low level convergence of wind is induced by the bias in the gradient in the mean sea level pressure with positive bias over western EIO and negative bias over EEIO and parts of western Pacific. Consequently, changes in the atmospheric circulation associated with La Niña like conditions affected the ocean dynamics by modulating the current bias thereby enhancing the subsurface warm bias over the EEIO. It is identified that EEIO subsurface warming is stronger when La Niña co-occurred with negative Indian Ocean Dipole events as compared to La Niña only years in the model. Ocean general circulation model (OGCM) experiments forced with CFSv2 winds clearly support our hypothesis that ocean dynamics influenced by westerly winds bias is primarily responsible for the strong subsurface warm bias over the EEIO. This study advocates the importance of understanding the ability of the models in representing the large scale air-sea interactions over the tropics and their impact on ocean biases for better monsoon forecast.
Morlighem, Mathieu; Wood, Michael; Seroussi, Hélène; Choi, Youngmin; Rignot, Eric (2018). Modeling the response of Northwest Greenland to enhanced ocean thermal forcing and subglacial discharge, The Cryosphere Discussions, 1-18, 10.5194/tc-2018-214.
Formatted Citation: Morlighem, M., M. Wood, H. Seroussi, Y. Choi, and E. Rignot, 2018: Modeling the response of Northwest Greenland to enhanced ocean thermal forcing and subglacial discharge. The Cryosphere Discussions, 1-18, doi:10.5194/tc-2018-214
Abstract: Calving front dynamics is an important control on Greenland's ice mass balance. Ice front retreat of marine-terminating glaciers may, for example, lead to a loss in resistive stress, which ultimately results in glacier acceleration and thinning. Over the past decade, it has been suggested that such retreats may be triggered by warm and salty Atlantic water, which is typically found at a depth below 200–300m. An increase in subglacial water discharge at glacier ice fronts due to enhanced surface runoff may also be responsible for an intensification of undercutting and calving. An increase in ocean thermal forcing or subglacial discharge therefore has the potential to destabilize marine terminating glaciers along the coast of Greenland. It remains unclear which glaciers are currently stable but may retreat in the future, and how far inland and how fast they will retreat. Here, we quantify the sensitivity and vulnerability of marine-terminating glaciers along the Northwest coast of Greenland (from 72.5º to 76ºN) to the ocean forcing and subglacial discharge using the Ice Sheet System Model (ISSM). We rely on the undercutting parameterization based on ocean thermal forcing and subglacial discharge, and use ocean temperature and salinity from high-resolution ECCO2 (Estimating the Circulation & Climate of the Ocean, Phase II) simulations at the fjords mouth to constrain the ocean thermal forcing. The ice flow model includes a calving law based on a tensile Von Mises criterion. While these parameterizations remain approximations and do not include all the physical processes at play, they have been shown to provide reliable estimates of undercutting and calving rates, respectively, on a number of glaciers along the coast of Greenland. We find that some glaciers, such as Dietrichson Gletscher or Alison Gletscher, are sensitive to small increases in ocean thermal forcing, while others, such as Illullip Sermia or Cornell Gletscher, are remarkably stable and remain stable, even in a 3-degree ocean warming scenario. Under the most intense experiment, we find that Hayes Gletscher retreats by more than 50km inland into a deep trough and its velocity increases by a factor of 10 over only 15 years. The model confirms that ice-ocean interactions can trigger extensive and rapid glacier retreat, but the bed controls the rate and magnitude of the retreat. Under current oceanic and atmospheric condition, we find that this sector alone will contribute more than 1cm to sea level, and up to 3cm under the most extreme scenario.
Cole, Sylvia T. (2018). Investigating small-scale processes from an abundance of autonomous observations, ALPS II - Autonomous Lagrangian Platforms and Sensors. A Report of the ALPS II Workshop, 25-27.
Title: Investigating small-scale processes from an abundance of autonomous observations
Type: Report
Publication: ALPS II - Autonomous Lagrangian Platforms and Sensors. A Report of the ALPS II Workshop
Author(s): Cole, Sylvia T.
Year: 2018
Formatted Citation: Cole, S. T., 2018: Investigating small-scale processes from an abundance of autonomous observations. ALPS II - Autonomous Lagrangian Platforms and Sensors. A Report of the ALPS II Workshop, La Jolla, CA, 25-27 pp.
Abstract: Small-scale processes, those with spatial and/or temporal scales less than a few hundred kilometers and a few weeks, vary on global and decadal scales. Such large-scale variations in small- scale processes have been difficult to observe. Within the last decade, global and regional-scale autonomous observations have begun to fill this observational gap. The specific processes that can be investigated from autonomous platforms are deter- mined by the minimum scale in space and time sampled by each platform. Recent examples are highlighted, and the future potential is discussed.
Gregor, Luke; Kok, Schalk; Monteiro, Pedro M. S. (2018). Interannual drivers of the seasonal cycle of CO2 in the Southern Ocean, Biogeosciences, 8 (15), 2361-2378, 10.5194/bg-15-2361-2018.
Title: Interannual drivers of the seasonal cycle of CO2 in the Southern Ocean
Type: Journal Article
Publication: Biogeosciences
Author(s): Gregor, Luke; Kok, Schalk; Monteiro, Pedro M. S.
Year: 2018
Formatted Citation: Gregor, L., S. Kok, and P. M. S. Monteiro, 2018: Interannual drivers of the seasonal cycle of CO2 in the Southern Ocean. Biogeosciences, 15(8), 2361-2378, doi:10.5194/bg-15-2361-2018
Abstract: Resolving and understanding the drivers of variability of CO2 in the Southern Ocean and its potential climate feedback is one of the major scientific challenges of the ocean-climate community. Here we use a regional approach on empirical estimates of pCO2 to understand the role that seasonal variability has in long-term CO2 changes in the Southern Ocean. Machine learning has become the preferred empirical modelling tool to interpolate time- and location-restricted ship measurements of pCO2. In this study we use an ensemble of three machine-learning products: support vector regression (SVR) and random forest regression (RFR) from Gregor et al. (2017), and the self-organising-map feed-forward neural network (SOM-FFN) method from Landschützer et al. (2016). The interpolated estimates of ΔpCO2 are separated into nine regions in the Southern Ocean defined by basin (Indian, Pacific, and Atlantic) and biomes (as defined by Fay and McKinley, 2014a). The regional approach shows that, while there is good agreement in the overall trend of the products, there are periods and regions where the confidence in estimated ΔpCO2 is low due to disagreement between the products. The regional breakdown of the data highlighted the seasonal decoupling of the modes for summer and winter interannual variability. Winter interannual variability had a longer mode of variability compared to summer, which varied on a 4-6-year timescale. We separate the analysis of the ΔpCO2 and its drivers into summer and winter. We find that understanding the variability of ΔpCO2 and its drivers on shorter timescales is critical to resolving the long-term variability of ΔpCO2. Results show that ΔpCO2 is rarely driven by thermodynamics during winter, but rather by mixing and stratification due to the stronger correlation of ΔpCO2 variability with mixed layer depth. Summer pCO2 variability is consistent with chlorophyll a variability, where higher concentrations of chlorophyll a correspond with lower pCO2 concentrations. In regions of low chlorophyll a concentrations, wind stress and sea surface temperature emerged as stronger drivers of ΔpCO2. In summary we propose that sub-decadal variability is explained by summer drivers, while winter variability contributes to the long-term changes associated with the SAM. This approach is a useful framework to assess the drivers of ΔpCO2 but would greatly benefit from improved estimates of ΔpCO2 and a longer time series.
Formatted Citation: Chen, X., B. Qiu, S. Chen, X. Cheng, and Y. Qi, 2018: Interannual Modulations of the 50-Day Oscillations in the Celebes Sea: Dynamics and Impact. J. Geophys. Res. Ocean., 123(7), 4666-4679, doi:10.1029/2018JC013960
Abstract: Intense 50-day oscillations have been previously observed at the entrance of Celebes Sea, and their formation has been suggested to be a result of Rossby wave resonance where the frequency of cyclonic eddy shedding by the intruding Mindanao Current matches that of the gravest Rossby mode of the semienclosed Celebes Sea basin. Using the ocean state estimate of 1993-2016 from the Estimating the Circulation and Climate of the Ocean, Phase II, we detected strong interannual modulations in the shedding of cyclonic eddies at the Celebes Sea entrance. Active eddy sheddings occurred during 1993, 2002-2003, 2006-2010, and 2013-2015. Southward shifting of the wind-driven North Pacific tropical gyre and the concurrent strengthening of the Mindanao Current southeast of the Mindanao Island in these years are found to be inducive for the generation of cyclonic eddies intruding into the Celebes Sea. Modulated by the activity of eddy sheddings, the upper ocean water mass properties in both the Celebes Sea and Makassar Strait exhibit noticeable interannual changes with less saline waters appearing in the 75- to 175-m layer during the active eddy shedding years.
Formatted Citation: Zhao, X., D. Yuan, G. Yang, J. Wang, H. Liu, R. Zhang, and W. Han, 2018: Interannual variability and dynamics of intraseasonal wind rectification in the equatorial Pacific Ocean. Climate Dynamics, doi:10.1007/s00382-018-4383-0
Pianezze, J.; Barthe, C.; Bielli, S.; Tulet, P.; Jullien, S.; Cambon, G.; Bousquet, O.; Claeys, M.; Cordier, E. (2018). A New Coupled Ocean-Waves-Atmosphere Model Designed for Tropical Storm Studies: Example of Tropical Cyclone Bejisa (2013-2014) in the South-West Indian Ocean, Journal of Advances in Modeling Earth Systems, 3 (10), 801-825, 10.1002/2017MS001177.
Title: A New Coupled Ocean-Waves-Atmosphere Model Designed for Tropical Storm Studies: Example of Tropical Cyclone Bejisa (2013-2014) in the South-West Indian Ocean
Type: Journal Article
Publication: Journal of Advances in Modeling Earth Systems
Author(s): Pianezze, J.; Barthe, C.; Bielli, S.; Tulet, P.; Jullien, S.; Cambon, G.; Bousquet, O.; Claeys, M.; Cordier, E.
Year: 2018
Formatted Citation: Pianezze, J. and Coauthors, 2018: A New Coupled Ocean-Waves-Atmosphere Model Designed for Tropical Storm Studies: Example of Tropical Cyclone Bejisa (2013-2014) in the South-West Indian Ocean. Journal of Advances in Modeling Earth Systems, 10(3), 801-825, doi:10.1002/2017MS001177
Belonenko, T. V.; Volkov, D. L.; Koldunov, A. V. (2018). Shelf Waves in the Beaufort Sea in a High-Resolution Ocean Model, Oceanology, 6 (58), 778-785, 10.1134/S0001437018060024.
Title: Shelf Waves in the Beaufort Sea in a High-Resolution Ocean Model
Type: Journal Article
Publication: Oceanology
Author(s): Belonenko, T. V.; Volkov, D. L.; Koldunov, A. V.
Year: 2018
Formatted Citation: Belonenko, T. V., D. L. Volkov, and A. V. Koldunov, 2018: Shelf Waves in the Beaufort Sea in a High-Resolution Ocean Model. Oceanology, 58(6), 778-785, doi:10.1134/S0001437018060024
Formatted Citation: Yang, H., B. Qiu, P. Chang, L. Wu, S. Wang, Z. Chen, and Y. Yang, 2018: Decadal Variability of Eddy Characteristics and Energetics in the Kuroshio Extension: Unstable Versus Stable States. J. Geophys. Res. Ocean., 123(9), 6653-6669, doi:10.1029/2018JC014081
Lyu, Yilong; Li, Yuanlong; Tang, Xiaohui; Wang, Fan; Wang, Jianing (2018). Contrasting Intraseasonal Variations of the Equatorial Pacific Ocean Between the 1997-1998 and 2015-2016 El Niño Events, Geophysical Research Letters, 18 (45), 9748-9756, 10.1029/2018GL078915.
Formatted Citation: Lyu, Y., Y. Li, X. Tang, F. Wang, and J. Wang, 2018: Contrasting Intraseasonal Variations of the Equatorial Pacific Ocean Between the 1997-1998 and 2015-2016 El Niño Events. Geophys. Res. Lett., 45(18), 9748-9756, doi:10.1029/2018GL078915
Title: Simulated impact of Southern Hemisphere westerlies on Antarctic Shelf Bottom Water temperature
Type: Journal Article
Publication: Advances in Polar Science
Author(s): Lin, Xia; Wang, Zhaomin
Year: 2018
Formatted Citation: Lin, X., and Z. Wang, 2018: Simulated impact of Southern Hemisphere westerlies on Antarctic Shelf Bottom Water temperature. Advances in Polar Science, 29(3), 3-19, doi:10.13679/j.advps.2018.3.00003
Abstract: The Southern Hemisphere (SH) westerly winds have intensified and shifted poleward since the 1970s and this trend is projected to sustain under future anthropogenic forcing. The influences of intensified SH westerlies on the Antarctic coastal waters are still not clear. The variability of Antarctic Continental Shelf Bottom Water (ASBW) temperature is crucial for ice shelf basal melting and hence ice shelf mass balance in Antarctica. In order to understand the impacts of SH westerlies on the variability of ASBW temperature, atmospheric forcing in 1992 with weak westerlies and in 1998 with strong westerlies are used to drive a high-resolution ocean-sea ice general circulation model, MITgcm-ECCO2. Our simulated results show that under the atmospheric forcing in 1998, the ASBW becomes warmer in most regions around Antarctica except the coastal region between 60°-150°W, than for the case under atmospheric forcing in 1992. The warming of ASBW around Antarctica is due to the intense shoaling and warming of CDW induced by enhanced Ekman pumping as well as strengthened subpolar gyres. The strengthened subpolar gyres favor the transportation of warm water to the coast of Antarctica. The cooling of ASBW along the coast of the western Antarctic Peninsula is caused by stronger coastal currents, which bring colder water downstream from the northwest flank of the Weddell Sea.
Keywords: Antarctic Shelf Bottom Water temperature, MITgcm-ECCO2, Southern Hemisphere westerlies
Formatted Citation: Mu, L., Q. Yang, M. Losch, S. N. Losa, R. Ricker, L. Nerger, and X. Liang, 2018: Improving sea ice thickness estimates by assimilating CryoSat-2 and SMOS sea ice thickness data simultaneously. Quarterly Journal of the Royal Meteorological Society, 144(711), 529-538, doi:10.1002/qj.3225
Kumar, Ravi Prakash; Nigam, Tanuja; Pant, Vimlesh (2018). Estimation of oceanic subsurface mixing under a severe cyclonic storm using a coupled atmosphere-ocean-wave model, Ocean Science, 2 (14), 259-272, 10.5194/os-14-259-2018.
Title: Estimation of oceanic subsurface mixing under a severe cyclonic storm using a coupled atmosphere-ocean-wave model
Type: Journal Article
Publication: Ocean Science
Author(s): Kumar, Ravi Prakash; Nigam, Tanuja; Pant, Vimlesh
Year: 2018
Formatted Citation: Kumar, R. P., T. Nigam, and V. Pant, 2018: Estimation of oceanic subsurface mixing under a severe cyclonic storm using a coupled atmosphere-ocean-wave model. Ocean Science, 14(2), 259-272, doi:10.5194/os-14-259-2018
Abstract: A coupled atmosphere-ocean-wave model was used to examine mixing in the upper-oceanic layers under the influence of a very severe cyclonic storm Phailin over the Bay of Bengal (BoB) during 10-14 October 2013. The coupled model was found to improve the sea surface temperature over the uncoupled model. Model simulations highlight the prominent role of cyclone-induced near-inertial oscillations in subsurface mixing up to the thermocline depth. The inertial mixing introduced by the cyclone played a central role in the deepening of the thermocline and mixed layer depth by 40 and 15m, respectively. For the first time over the BoB, a detailed analysis of inertial oscillation kinetic energy generation, propagation, and dissipation was carried out using an atmosphere-ocean-wave coupled model during a cyclone. A quantitative estimate of kinetic energy in the oceanic water column, its propagation, and its dissipation mechanisms were explained using the coupled atmosphere-ocean-wave model. The large shear generated by the inertial oscillations was found to overcome the stratification and initiate mixing at the base of the mixed layer. Greater mixing was found at the depths where the eddy kinetic diffusivity was large. The baroclinic current, holding a larger fraction of kinetic energy than the barotropic current, weakened rapidly after the passage of the cyclone. The shear induced by inertial oscillations was found to decrease rapidly with increasing depth below the thermocline. The dampening of the mixing process below the thermocline was explained through the enhanced dissipation rate of turbulent kinetic energy upon approaching the thermocline layer. The wave-current interaction and nonlinear wave-wave interaction were found to affect the process of downward mixing and cause the dissipation of inertial oscillations.
Naughten, Kaitlin A.; Meissner, Katrin J.; Galton-Fenzi, Benjamin K.; England, Matthew H.; Timmermann, Ralph; Hellmer, Hartmut H. (2018). Future Projections of Antarctic Ice Shelf Melting Based on CMIP5 Scenarios, Journal of Climate, 13 (31), 5243-5261, 10.1175/JCLI-D-17-0854.1.
Title: Future Projections of Antarctic Ice Shelf Melting Based on CMIP5 Scenarios
Type: Journal Article
Publication: Journal of Climate
Author(s): Naughten, Kaitlin A.; Meissner, Katrin J.; Galton-Fenzi, Benjamin K.; England, Matthew H.; Timmermann, Ralph; Hellmer, Hartmut H.
Year: 2018
Formatted Citation: Naughten, K. A., K. J. Meissner, B. K. Galton-Fenzi, M. H. England, R. Timmermann, and H. H. Hellmer, 2018: Future Projections of Antarctic Ice Shelf Melting Based on CMIP5 Scenarios. J. Clim., 31(13), 5243-5261, doi:10.1175/JCLI-D-17-0854.1
Greene, Chad A.; Young, Duncan A.; Gwyther, David E.; Galton-Fenzi, Benjamin K.; Blankenship, Donald D. (2018). Seasonal dynamics of Totten Ice Shelf controlled by sea ice buttressing, The Cryosphere, 9 (12), 2869-2882, 10.5194/tc-12-2869-2018.
Title: Seasonal dynamics of Totten Ice Shelf controlled by sea ice buttressing
Type: Journal Article
Publication: The Cryosphere
Author(s): Greene, Chad A.; Young, Duncan A.; Gwyther, David E.; Galton-Fenzi, Benjamin K.; Blankenship, Donald D.
Year: 2018
Formatted Citation: Greene, C. A., D. A. Young, D. E. Gwyther, B. K. Galton-Fenzi, and D. D. Blankenship, 2018: Seasonal dynamics of Totten Ice Shelf controlled by sea ice buttressing. Cryosph., 12(9), 2869-2882, doi:10.5194/tc-12-2869-2018
Abstract: Previous studies of Totten Ice Shelf have employed surface velocity measurements to estimate its mass balance and understand its sensitivities to interannual changes in climate forcing. However, displacement measurements acquired over timescales of days to weeks may not accurately characterize long-term flow rates wherein ice velocity fluctuates with the seasons. Quantifying annual mass budgets or analyzing interannual changes in ice velocity requires knowing when and where observations of glacier velocity could be aliased by subannual variability. Here, we analyze 16 years of velocity data for Totten Ice Shelf, which we generate at subannual resolution by applying feature-tracking algorithms to several hundred satellite image pairs. We identify a seasonal cycle characterized by a spring to autumn speedup of more than 100myr−1 close to the ice front. The amplitude of the seasonal cycle diminishes with distance from the open ocean, suggesting the presence of a resistive back stress at the ice front that is strongest in winter. Springtime acceleration precedes summer surface melt and is not attributable to thinning from basal melt. We attribute the onset of ice shelf acceleration each spring to the loss of buttressing from the breakup of seasonal landfast sea ice. ]]>
Title: Interannual Eddy Kinetic Energy Modulations in the Agulhas Return Current
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Zhu, Yanan; Qiu, Bo; Lin, Xiaopei; Wang, Fan
Year: 2018
Formatted Citation: Zhu, Y., B. Qiu, X. Lin, and F. Wang, 2018: Interannual Eddy Kinetic Energy Modulations in the Agulhas Return Current. J. Geophys. Res. Ocean., 123(9), 6449-6462, doi:10.1029/2018JC014333
Abstract: Interannual variability in the mesoscale eddy field in the Agulhas Return Current (ARC) of 32-42°S and 15-35°E is investigated based on satellite altimeter observations and state estimate from the Estimating the Circulation and Climate of the Ocean, Phase II from 1993 to 2016. It is found that the interannual modulation of eddy kinetic energy in the ARC region is externally mediated by the wind stress forcing that generates the westward propagating sea surface height anomalies across the South Indian Ocean subtropical gyre. The wind-forced sea surface height anomalies influence the upstream Agulhas Current volume transports. By modulating the intensity of barotropic instability of the ARC mean flow centered around the retroflection region, the Agulhas Current inflow variability leads to the downstream interannual eddy kinetic energy fluctuations in the ARC region.
Porter, David F.; Tinto, Kirsty J.; Boghosian, Alexandra L.; Csatho, Beata M.; Bell, Robin E.; Cochran, James R. (2018). Identifying Spatial Variability in Greenland’s Outlet Glacier Response to Ocean Heat, Frontiers in Earth Science (6), 10.3389/feart.2018.00090.
Title: Identifying Spatial Variability in Greenland’s Outlet Glacier Response to Ocean Heat
Type: Journal Article
Publication: Frontiers in Earth Science
Author(s): Porter, David F.; Tinto, Kirsty J.; Boghosian, Alexandra L.; Csatho, Beata M.; Bell, Robin E.; Cochran, James R.
Year: 2018
Formatted Citation: Porter, D. F., K. J. Tinto, A. L. Boghosian, B. M. Csatho, R. E. Bell, and J. R. Cochran, 2018: Identifying Spatial Variability in Greenland's Outlet Glacier Response to Ocean Heat. Frontiers in Earth Science, 6, doi:10.3389/feart.2018.00090
Gruszczynska, Marta; Rosat, Severine; Klos, Anna; Gruszczynski, Maciej; Bogusz, Janusz (2018). Multichannel Singular Spectrum Analysis in the Estimates of Common Environmental Effects Affecting GPS Observations, Pure and Applied Geophysics, 5 (175), 1805-1822, 10.1007/s00024-018-1814-0.
Formatted Citation: Gruszczynska, M., S. Rosat, A. Klos, M. Gruszczynski, and J. Bogusz, 2018: Multichannel Singular Spectrum Analysis in the Estimates of Common Environmental Effects Affecting GPS Observations. Pure and Applied Geophysics, 175(5), 1805-1822, doi:10.1007/s00024-018-1814-0
McParland, Erin L.; Levine, Naomi M. (2018). The role of differential DMSP production and community composition in predicting variability of global surface DMSP concentrations, Limnology and Oceanography, 10.1002/lno.11076.
Title: The role of differential DMSP production and community composition in predicting variability of global surface DMSP concentrations
Type: Journal Article
Publication: Limnology and Oceanography
Author(s): McParland, Erin L.; Levine, Naomi M.
Year: 2018
Formatted Citation: McParland, E. L., and N. M. Levine, 2018: The role of differential DMSP production and community composition in predicting variability of global surface DMSP concentrations. Limnology and Oceanography, doi:10.1002/lno.11076
Yang, Peiran; Jing, Zhao; Wu, Lixin (2018). An Assessment of Representation of Oceanic Mesoscale Eddy-Atmosphere Interaction in the Current Generation of General Circulation Models and Reanalyses, Geophysical Research Letters, 21 (45), 11,856-11,865, 10.1029/2018GL080678.
Title: An Assessment of Representation of Oceanic Mesoscale Eddy-Atmosphere Interaction in the Current Generation of General Circulation Models and Reanalyses
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Yang, Peiran; Jing, Zhao; Wu, Lixin
Year: 2018
Formatted Citation: Yang, P., Z. Jing, and L. Wu, 2018: An Assessment of Representation of Oceanic Mesoscale Eddy-Atmosphere Interaction in the Current Generation of General Circulation Models and Reanalyses. Geophys. Res. Lett., 45(21), 11,856-11,865, doi:10.1029/2018GL080678
Ungermann, Mischa; Losch, Martin (2018). An Observationally Based Evaluation of Subgrid Scale Ice Thickness Distributions Simulated in a Large-Scale Sea Ice-Ocean Model of the Arctic Ocean, Journal of Geophysical Research: Oceans, 11 (123), 8052-8067, 10.1029/2018JC014022.
Title: An Observationally Based Evaluation of Subgrid Scale Ice Thickness Distributions Simulated in a Large-Scale Sea Ice-Ocean Model of the Arctic Ocean
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Ungermann, Mischa; Losch, Martin
Year: 2018
Formatted Citation: Ungermann, M., and M. Losch, 2018: An Observationally Based Evaluation of Subgrid Scale Ice Thickness Distributions Simulated in a Large-Scale Sea Ice-Ocean Model of the Arctic Ocean. J. Geophys. Res. Ocean., 123(11), 8052-8067, doi:10.1029/2018JC014022
Bashmachnikov, I. L.; Yurova, A. Yu.; Bobylev, L. P.; Vesman, A. V. (2018). Seasonal and Interannual Variations of Heat Fluxes in the Barents Sea Region, Izvestiya, Atmospheric and Oceanic Physics, 2 (54), 213-222, 10.1134/S0001433818020032.
Title: Seasonal and Interannual Variations of Heat Fluxes in the Barents Sea Region
Type: Journal Article
Publication: Izvestiya, Atmospheric and Oceanic Physics
Author(s): Bashmachnikov, I. L.; Yurova, A. Yu.; Bobylev, L. P.; Vesman, A. V.
Year: 2018
Formatted Citation: Bashmachnikov, I. L., A. Y. Yurova, L. P. Bobylev, and A. V. Vesman, 2018: Seasonal and Interannual Variations of Heat Fluxes in the Barents Sea Region. Izvestiya, Atmospheric and Oceanic Physics, 54(2), 213-222, doi:10.1134/S0001433818020032
Keywords: and the atmosphere, barents sea, bjerknes compensation mechanism, coupled, cycles in the ocean, fluxes, mit eddy-permitting ocean model, oceanic and atmospheric heat, singular spec-, wavelet analysis
Le Fouest, Vincent; Matsuoka, Atsushi; Manizza, Manfredi; Shernetsky, Mona; Tremblay, Bruno; Babin, Marcel (2018). Towards an assessment of riverine dissolved organic carbon in surface waters of the western Arctic Ocean based on remote sensing and biogeochemical modeling, Biogeosciences, 5 (15), 1335-1346, 10.5194/bg-15-1335-2018.
Title: Towards an assessment of riverine dissolved organic carbon in surface waters of the western Arctic Ocean based on remote sensing and biogeochemical modeling
Formatted Citation: Le Fouest, V., A. Matsuoka, M. Manizza, M. Shernetsky, B. Tremblay, and M. Babin, 2018: Towards an assessment of riverine dissolved organic carbon in surface waters of the western Arctic Ocean based on remote sensing and biogeochemical modeling. Biogeosciences, 15(5), 1335-1346, doi:10.5194/bg-15-1335-2018
Abstract: Future climate warming of the Arctic could potentially enhance the load of terrigenous dissolved organic carbon (tDOC) of Arctic rivers due to increased carbon mobilization within watersheds. A greater flux of tDOC might impact the biogeochemical processes of the coastal Arctic Ocean (AO) and ultimately its capacity to absorb atmospheric CO2. In this study, we show that sea-surface tDOC concentrations simulated by a physical-biogeochemical coupled model in the Canadian Beaufort Sea for 2003-2011 compare favorably with estimates retrieved by satellite imagery. Our results suggest that, over spring-summer, tDOC of riverine origin contributes to 35% of primary production and that an equivalent of ∼10% of tDOC is exported westwards with the potential of fueling the biological production of the eastern Alaskan nearshore waters. The combination of model and satellite data provides promising results to extend this work to the entire AO so as to quantify, in conjunction with in situ data, the expected changes in tDOC fluxes and their potential impact on the AO biogeochemistry at basin scale.
Mu, Longjiang; Losch, Martin; Yang, Qinghua; Ricker, Robert; Loza, Svetlana N.; Nerger, Lars (2018). Arctic-Wide Sea Ice Thickness Estimates From Combining Satellite Remote Sensing Data and a Dynamic Ice-Ocean Model with Data Assimilation During the CryoSat-2 Period, Journal of Geophysical Research: Oceans, 10.1029/2018JC014316.
Title: Arctic-Wide Sea Ice Thickness Estimates From Combining Satellite Remote Sensing Data and a Dynamic Ice-Ocean Model with Data Assimilation During the CryoSat-2 Period
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Formatted Citation: Mu, L., M. Losch, Q. Yang, R. Ricker, S. N. Loza, and L. Nerger, 2018: Arctic-Wide Sea Ice Thickness Estimates From Combining Satellite Remote Sensing Data and a Dynamic Ice-Ocean Model with Data Assimilation During the CryoSat-2 Period. J. Geophys. Res. Ocean., doi:10.1029/2018JC014316
Bigdeli, A.; Hara, T.; Loose, B.; Nguyen, A. T. (2018). Wave Attenuation and Gas Exchange Velocity in Marginal Sea Ice Zone, Journal of Geophysical Research: Oceans, 3 (123), 2293-2304, 10.1002/2017JC013380.
Title: Wave Attenuation and Gas Exchange Velocity in Marginal Sea Ice Zone
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Bigdeli, A.; Hara, T.; Loose, B.; Nguyen, A. T.
Year: 2018
Formatted Citation: Bigdeli, A., T. Hara, B. Loose, and A. T. Nguyen, 2018: Wave Attenuation and Gas Exchange Velocity in Marginal Sea Ice Zone. J. Geophys. Res. Ocean., 123(3), 2293-2304, doi:10.1002/2017JC013380
Title: Properties, Mechanisms and Predictability of Eddies in the Red Sea
Type: Thesis
Publication:
Author(s): Zhan, Peng
Year: 2018
Formatted Citation: Zhan, P., 2018: Properties, Mechanisms and Predictability of Eddies in the Red Sea., 163 pp. doi:10.25781/KAUST-1IARG.
Abstract: Eddies are one of the key features of the Red Sea circulation. They are not only crucial for energy conversion among dynamics at different scales, but also for materials transport across the basin. This thesis focuses on studying the characteristics of Red Sea eddies, including their temporal and spatial properties, their energy budget, the mechanisms of their evolution, and their predictability. Remote sensing data, in-situ observations, the oceanic general circulation model, and data assimilation techniques were employed in this thesis. The eddies in the Red Sea were first identified using altimeter data by applying an improved winding-angle method, based on which the statistical properties of those eddies were derived. The results suggested that eddies occur more frequently in the central basin of the Red Sea and exhibit a significant seasonal variation. The mechanisms of the eddies' evolution, particularly the eddy kinetic energy budget, were then investigated based on the outputs of a long-term eddy resolving numerical model configured for the Red Sea with realistic forcing. Examination of the energy budget revealed that the eddies acquire the vast majority of kinetic energy through conversion of eddy available potential energy via baroclinic instability, which is intensified during winter. The possible factors modulating the behavior of the several observed eddies in the Red Sea were then revealed by conducting a sensitivity analysis using the adjoint model. These eddies were found to exhibit different sensitivities to external forcings, suggesting different mechanisms for their evolution. This is the first known adjoint sensitivity study on specific eddy events in the Red Sea and was hitherto not previously appreciated. The last chapter examines the predictability of Red Sea eddies using an ensemble-based forecasting and assimilation system. The forecast sea surface height was used to evaluate the overall performance of the short-term eddy predictability. Different ensemble sampling schemes were implemented, and the investigation among different schemes is followed by a discussion of performance and challenges based on the results of a case study. The thesis not only enhances understanding of the Red Sea dynamics, but also deepens knowledge of the physical-biological and air-sea interactions within the basin. Further, it is a stepping stone to building a robust regional operational system with refined forecasting skills.
Mohammadi-Aragh, M.; Goessling, H. F.; Losch, Martin; Hutter, N.; Jung, T. (2018). Predictability of Arctic sea ice on weather time scales, Scientific Reports, 1 (8), 6514, 10.1038/s41598-018-24660-0.
Title: Predictability of Arctic sea ice on weather time scales
Type: Journal Article
Publication: Scientific Reports
Author(s): Mohammadi-Aragh, M.; Goessling, H. F.; Losch, Martin; Hutter, N.; Jung, T.
Year: 2018
Formatted Citation: Mohammadi-Aragh, M., H. F. Goessling, M. Losch, N. Hutter, and T. Jung, 2018: Predictability of Arctic sea ice on weather time scales. Scientific Reports, 8(1), 6514, doi:10.1038/s41598-018-24660-0
Filmer, M. S.; Hughes, C. W.; Woodworth, P. L.; Featherstone, W. E.; Bingham, R. J. (2018). Comparison between geodetic and oceanographic approaches to estimate mean dynamic topography for vertical datum unification: evaluation of Australian tide gauges, Journal of Geodesy, 12 (92), 1413-1437.
Title: Comparison between geodetic and oceanographic approaches to estimate mean dynamic topography for vertical datum unification: evaluation of Australian tide gauges
Type: Journal Article
Publication: Journal of Geodesy
Author(s): Filmer, M. S.; Hughes, C. W.; Woodworth, P. L.; Featherstone, W. E.; Bingham, R. J.
Year: 2018
Formatted Citation: Filmer, M. S., C. W. Hughes, P. L. Woodworth, W. E. Featherstone, and R. J. Bingham, 2018: Comparison between geodetic and oceanographic approaches to estimate mean dynamic topography for vertical datum unification: evaluation of Australian tide gauges. Journal of Geodesy, 92(12), 1413-1437, https://link.springer.com/article/10.1007/s00190-018-1131-5
Title: Improving the Coastal Mean Dynamic Topography by Geodetic Combination of Tide Gauge and Satellite Altimetry
Type: Journal Article
Publication: Marine Geodesy
Author(s): Andersen, Ole Baltazar; Nielsen, Karina; Knudsen, Per; Hughes, Chris W.; Bingham, Rory; Fenoglio-Marc, Luciana; Gravelle, Médéric; Kern, Michael; Polo, Sara Padilla
Year: 2018
Formatted Citation: Andersen, O. B. and Coauthors, 2018: Improving the Coastal Mean Dynamic Topography by Geodetic Combination of Tide Gauge and Satellite Altimetry. Marine Geodesy, 1-29, doi:10.1080/01490419.2018.1530320
Liu, Junjie; Bowman, Kevin W.; Parazoo, Nicholas C; Bloom, A Anthony; Wunch, Debra; Jiang, Zhe; Gurney, Kevin R; Schimel, Dave (2018). Detecting drought impact on terrestrial biosphere carbon fluxes over contiguous US with satellite observations, Environmental Research Letters, 9 (13), 095003, 10.1088/1748-9326/aad5ef.
Title: Detecting drought impact on terrestrial biosphere carbon fluxes over contiguous US with satellite observations
Type: Journal Article
Publication: Environmental Research Letters
Author(s): Liu, Junjie; Bowman, Kevin W.; Parazoo, Nicholas C; Bloom, A Anthony; Wunch, Debra; Jiang, Zhe; Gurney, Kevin R; Schimel, Dave
Year: 2018
Formatted Citation: Liu, J., K. W. Bowman, N. C. Parazoo, A. A. Bloom, D. Wunch, Z. Jiang, K. R. Gurney, and D. Schimel, 2018: Detecting drought impact on terrestrial biosphere carbon fluxes over contiguous US with satellite observations. Environmental Research Letters, 13(9), 095003, doi:10.1088/1748-9326/aad5ef
Naughten, Kaitlin A.; Meissner, Katrin J.; Galton-Fenzi, Benjamin K.; England, Matthew H.; Timmermann, Ralph; Hellmer, Hartmut H.; Hattermann, Tore; Debernard, Jens B. (2018). Intercomparison of Antarctic ice-shelf, ocean, and sea-ice interactions simulated by MetROMS-iceshelf and FESOM 1.4, Geoscientific Model Development, 4 (11), 1257-1292, 10.5194/gmd-11-1257-2018.
Title: Intercomparison of Antarctic ice-shelf, ocean, and sea-ice interactions simulated by MetROMS-iceshelf and FESOM 1.4
Type: Journal Article
Publication: Geoscientific Model Development
Author(s): Naughten, Kaitlin A.; Meissner, Katrin J.; Galton-Fenzi, Benjamin K.; England, Matthew H.; Timmermann, Ralph; Hellmer, Hartmut H.; Hattermann, Tore; Debernard, Jens B.
Year: 2018
Formatted Citation: Naughten, K. A., K. J. Meissner, B. K. Galton-Fenzi, M. H. England, R. Timmermann, H. H. Hellmer, T. Hattermann, and J. B. Debernard, 2018: Intercomparison of Antarctic ice-shelf, ocean, and sea-ice interactions simulated by MetROMS-iceshelf and FESOM 1.4. Geoscientific Model Development, 11(4), 1257-1292, doi:10.5194/gmd-11-1257-2018
Abstract: An increasing number of Southern Ocean models now include Antarctic ice-shelf cavities, and simulate thermodynamics at the ice-shelf/ocean interface. This adds another level of complexity to Southern Ocean simulations, as ice shelves interact directly with the ocean and indirectly with sea ice. Here, we present the first model intercomparison and evaluation of present-day ocean/sea-ice/ice-shelf interactions, as simulated by two models: a circumpolar Antarctic configuration of MetROMS (ROMS: Regional Ocean Modelling System coupled to CICE: Community Ice CodE) and the global model FESOM (Finite Element Sea-ice Ocean Model), where the latter is run at two different levels of horizontal resolution. From a circumpolar Antarctic perspective, we compare and evaluate simulated ice-shelf basal melting and sub-ice-shelf circulation, as well as sea-ice properties and Southern Ocean water mass characteristics as they influence the sub-ice-shelf processes. Despite their differing numerical methods, the two models produce broadly similar results and share similar biases in many cases. Both models reproduce many key features of observations but struggle to reproduce others, such as the high melt rates observed in the small warm-cavity ice shelves of the Amundsen and Bellingshausen seas. Several differences in model design show a particular influence on the simulations. For example, FESOM's greater topographic smoothing can alter the geometry of some ice-shelf cavities enough to affect their melt rates; this improves at higher resolution, since less smoothing is required. In the interior Southern Ocean, the vertical coordinate system affects the degree of water mass erosion due to spurious diapycnal mixing, with MetROMS' terrain-following coordinate leading to more erosion than FESOM's z coordinate. Finally, increased horizontal resolution in FESOM leads to higher basal melt rates for small ice shelves, through a combination of stronger circulation and small-scale intrusions of warm water from offshore.
Schlegel, Nicole-Jeanne; Seroussi, Hélène; Schodlok, Michael P.; Larour, Eric Y.; Boening, Carmen; Limonadi, Daniel; Watkins, Michael M.; Morlighem, Mathieu; van den Broeke, Michiel R. (2018). Exploration of Antarctic Ice Sheet 100-year contribution to sea level rise and associated model uncertainties using the ISSM framework, The Cryosphere, 11 (12), 3511-3534, 10.5194/tc-12-3511-2018.
Title: Exploration of Antarctic Ice Sheet 100-year contribution to sea level rise and associated model uncertainties using the ISSM framework
Type: Journal Article
Publication: The Cryosphere
Author(s): Schlegel, Nicole-Jeanne; Seroussi, Hélène; Schodlok, Michael P.; Larour, Eric Y.; Boening, Carmen; Limonadi, Daniel; Watkins, Michael M.; Morlighem, Mathieu; van den Broeke, Michiel R.
Year: 2018
Formatted Citation: Schlegel, N. and Coauthors, 2018: Exploration of Antarctic Ice Sheet 100-year contribution to sea level rise and associated model uncertainties using the ISSM framework. Cryosph., 12(11), 3511-3534, doi:10.5194/tc-12-3511-2018
Abstract: Estimating the future evolution of the Antarctic Ice Sheet (AIS) is critical for improving future sea level rise (SLR) projections. Numerical ice sheet models are invaluable tools for bounding Antarctic vulnerability; yet, few continental-scale projections of century-scale AIS SLR contribution exist, and those that do vary by up to an order of magnitude. This is partly because model projections of future sea level are inherently uncertain and depend largely on the model's boundary conditions and climate forcing, which themselves are unknown due to the uncertainty in the projections of future anthropogenic emissions and subsequent climate response. Here, we aim to improve the understanding of how uncertainties in model forcing and boundary conditions affect ice sheet model simulations. With use of sampling techniques embedded within the Ice Sheet System Model (ISSM) framework, we assess how uncertainties in snow accumulation, ocean-induced melting, ice viscosity, basal friction, bedrock elevation, and the presence of ice shelves impact continental-scale 100-year model simulations of AIS future sea level contribution. Overall, we find that AIS sea level contribution is strongly affected by grounding line retreat, which is driven by the magnitude of ice shelf basal melt rates and by variations in bedrock topography. In addition, we find that over 1.2m of AIS global mean sea level contribution over the next century is achievable, but not likely, as it is tenable only in response to unrealistically large melt rates and continental ice shelf collapse. Regionally, we find that under our most extreme 100-year warming experiment generalized for the entire ice sheet, the Amundsen Sea sector is the most significant source of model uncertainty (1032mm 6σ spread) and the region with the largest potential for future sea level contribution (297mm). In contrast, under a more plausible forcing informed regionally by literature and model sensitivity studies, the Ronne basin has a greater potential for local increases in ice shelf basal melt rates. As a result, under this more likely realization, where warm waters reach the continental shelf under the Ronne ice shelf, it is the Ronne basin, particularly the Evans and Rutford ice streams, that are the greatest contributors to potential SLR (161mm) and to simulation uncertainty (420mm 6σ spread). ]]>
Title: Large-scale ocean connectivity and planktonic body size
Type: Journal Article
Publication: Nature Communications
Author(s): Villarino, Ernesto; Watson, James R.; Jönsson, Bror; Gasol, Josep M.; Salazar, Guillem; Acinas, Silvia G.; Estrada, Marta; Massana, Ramón; Logares, Ramiro; Giner, Caterina R.; Pernice, Massimo C.; Olivar, M. Pilar; Citores, Leire; Corell, Jon; Rodríguez-Ezpeleta, Naiara; Acuña, José Luis; Molina-Ramírez, Axayacatl; González-Gordillo, J. Ignacio; Cózar, Andrés; Martí, Elisa; Cuesta, José A.; Agustí, Susana; Fraile-Nuez, Eugenio; Duarte, Carlos M.; Irigoien, Xabier; Chust, Guillem
Year: 2018
Formatted Citation: Villarino, E. and Coauthors, 2018: Large-scale ocean connectivity and planktonic body size. Nature Communications, 9(1), 142, doi:10.1038/s41467-017-02535-8
Delman, Andrew S.; Lee, Tong; Qiu, Bo (2018). Interannual to Multidecadal Forcing of Mesoscale Eddy Kinetic Energy in the Subtropical Southern Indian Ocean, Journal of Geophysical Research: Oceans, 10.1029/2018JC013945.
Title: Interannual to Multidecadal Forcing of Mesoscale Eddy Kinetic Energy in the Subtropical Southern Indian Ocean
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Delman, Andrew S.; Lee, Tong; Qiu, Bo
Year: 2018
Formatted Citation: Delman, A. S., T. Lee, and B. Qiu, 2018: Interannual to Multidecadal Forcing of Mesoscale Eddy Kinetic Energy in the Subtropical Southern Indian Ocean. J. Geophys. Res. Ocean., doi:10.1029/2018JC013945
Abstract: A region of elevated mesoscale eddy activity spans the subtropical southern Indian Ocean (SSIO) between Madagascar and Australia. The interannual and decadal changes in eddy activity in the SSIO eddy band, as represented by the variability of eddy kinetic energy (EKE), have implications for the large-scale circulation, mixed-layer budgets, and biological activity. An analysis of nearly two and a half decades of sea level anomaly (SLA) data from merged satellite altimetry shows that, in the southeast Indian Ocean east of 90°E, the variations of EKE and SLA are positively correlated on interannual and decadal time scales. Moreover, EKE exhibits a multidecadal increasing linear trend that corresponds to an increasing trend of SLA in the region. The EKE-SLA covariability in the southeast Indian Ocean does not appear to be associated with a preference for anticyclonic over cyclonic eddy activity; rather, it can be attributed to the common remote forcing from the tropical Pacific associated with the El Niño-Southern Oscillation and the Pacific Decadal Oscillation. In the west central SSIO, wind stress curl just south of the eddy band forces potential vorticity anomalies that affect conditions for instability in the west central SSIO; potential density and potential vorticity gradient anomalies also suggest a remote forcing mechanism originating in the region southwest of Australia. The interannual to multidecadal variability of EKE in the SSIO and its relationship with large-scale SLA has implications for mixed-layer dynamics and biogeochemistry and provides a basis for assessment of model simulations of eddy activity in the region.
Formatted Citation: Andrei, C., S. Lahtinen, M. Nordman, J. Näränen, H. Koivula, M. Poutanen, and J. Hyyppä, 2018: GPS Time Series Analysis from Aboa the Finnish Antarctic Research Station. Remote Sensing, 10(12), 1937, doi:10.3390/rs10121937
Abstract: Continuous Global Positioning System (GPS) observations have been logged at the Finnish Antarctic research station (Aboa) since February 2003. The station is located in Dronning Maud Land, East Antarctica. Almost 5000 daily observation files have been archived based on yearly scientific expeditions. These files have not been fully analysed until now. This study reports for the first time on the consistent and homogeneous data processing and analysis of the 15-year long time series. Daily coordinates are obtained using Precise Point Positioning (PPP) processing based on two approaches. The first approach is based on the Kalman filter and uses the RTKLIB open source library to produce daily solutions by unconventionally running the filter in the forward and backward direction. The second approach uses APPS web service and is based on GIPSY scientific processing engine. The two approaches show an excellent agreement with less than 3 mm rms error horizontally and 6 mm rms error vertically. The derived position time series is analysed in terms of trend, periodicity and noise characteristics. The noise of the time series was found to be power-law noise model with spectral index closer to flicker noise. In addition, several periodic signals were found at 5, 14, 183 and 362 days. Furthermore, most of the horizontal movement was found to be in the North direction at a rate of 11.23 ± 0.09 mm/y, whereas the rate in the East direction was estimated to be 1.46 ± 0.05 mm/y. Lastly, the 15-year long time series revealed a movement upwards at a rate of 0.79 ± 0.35 mm/y. Despite being an unattended station, Aboa provides one of the most continuous and longest GPS time series in Antarctica. Therefore, we believe that this research increases the awareness of local geophysical phenomena in a less reported area of the Antarctic continent.
Kumar, Anurag; Dwivedi, Suneet; Pandey, Avinash C. (2018). Quantifying predictability of sea ice around the Indian Antarctic stations using coupled ocean sea ice model with shelf ice, Polar Science (18), 83-93, 10.1016/j.polar.2018.04.003.
Title: Quantifying predictability of sea ice around the Indian Antarctic stations using coupled ocean sea ice model with shelf ice
Type: Journal Article
Publication: Polar Science
Author(s): Kumar, Anurag; Dwivedi, Suneet; Pandey, Avinash C.
Year: 2018
Formatted Citation: Kumar, A., S. Dwivedi, and A. C. Pandey, 2018: Quantifying predictability of sea ice around the Indian Antarctic stations using coupled ocean sea ice model with shelf ice. Polar Science, 18, 83-93, doi:10.1016/j.polar.2018.04.003
Chen, Guo; Zhao, Qile; Wei, Na; Li, Min (2018). Effect of Helmert Transformation Parameters and Weight Matrix on Seasonal Signals in GNSS Coordinate Time Series, Sensors, 7 (18), 2127, 10.3390/s18072127.
Title: Effect of Helmert Transformation Parameters and Weight Matrix on Seasonal Signals in GNSS Coordinate Time Series
Type: Journal Article
Publication: Sensors
Author(s): Chen, Guo; Zhao, Qile; Wei, Na; Li, Min
Year: 2018
Formatted Citation: Chen, G., Q. Zhao, N. Wei, and M. Li, 2018: Effect of Helmert Transformation Parameters and Weight Matrix on Seasonal Signals in GNSS Coordinate Time Series. Sensors, 18(7), 2127, doi:10.3390/s18072127
Title: Estimates of Vertical Velocity Errors for IGS ITRF2014 Stations by Applying the Improved Singular Spectrum Analysis Method and Environmental Loading Models
Formatted Citation: Klos, A., M. Gruszczynska, M. S. Bos, J. Boy, and J. Bogusz, 2018: Estimates of Vertical Velocity Errors for IGS ITRF2014 Stations by Applying the Improved Singular Spectrum Analysis Method and Environmental Loading Models. Pure and Applied Geophysics, 175(5), 1823-1840, doi:10.1007/s00024-017-1494-1
Title: Ocean forced variability of Totten Glacier mass loss
Type: Journal Article
Publication: Geological Society, London, Special Publications
Author(s): Roberts, Jason; Galton-Fenzi, Benjamin K.; Paolo, Fernando S.; Donnelly, Claire; Gwyther, David E.; Padman, Laurie; Young, Duncan; Warner, Roland; Greenbaum, Jamin; Fricker, Helen A.; Payne, Antony J.; Cornford, Stephen; Le Brocq, Anne; van Ommen, Tas; Blankenship, Don; Siegert, Martin J.
Year: 2018
Formatted Citation: Roberts, J. and Coauthors, 2018: Ocean forced variability of Totten Glacier mass loss. Geological Society, London, Special Publications, 461(1), 175-186, doi:10.1144/SP461.6
Formatted Citation: Vaňková, I., 2018: Ice and Ocean Dynamics in a Glacier Fjord., 178 pp. https://drive.google.com/file/d/1BwrgBIl8jpqld8nKl6ldtyF1qRhfPRzT/view?usp=sharingl%0A.
Abstract: This dissertation consists of four topics in the dynamics of glacier fjords: (1) sources of hydrographic variability in deep glacier fjord waters, (2) dynamic interactions within the ice mélange, (3) englacial hydrology at a marine-terminating glacier, and (4) calving generated ocean waves. Greenland's fjords play the important role of connecting glacier termini with the con- tinental shelf and exposing them to oceanic variability, affecting ice-sheet stability via variable melt rates at the ice-ocean interface. Observations collected in Sermilik Fjord were used to identify timescales of hydrographic variability of deep, warm waters and an ocean state estimate was used to identify sources of this variability. It is shown that inter- annual variability is set by the extent of deep convection in the Irminger Sea. Furthermore, it is found that seasonal variability in fjord density is introduced at the continental shelf break by Ekman transport, which in turn governs seasonal variability of the fjord's deep hydrographic properties due to the presence of vertical temperature and salinity gradients. The ice mélange is a mixture of sea ice and icebergs, which can be important for glacier stability, due to its potential to provide backstress via buttressing, preventing calving. A new approach to modeling the ice mélange is developed here. The rheology of an existing continuum sea-ice model is modified to incorporate the mechanical effect of icebergs and a semi-Lagrangian time-stepping scheme is adopted to preserve iceberg shape through time. Meltwater transport through glaciers affects material properties of glacial ice and controls the ice flow by setting its boundary conditions. However, since the glacial interior is under-observed in both space and time, little is known about how this meltwater trans- port occurs. New observations of the glacier interior showed a diurnal signal consistent with the existence of an englacial diurnal meltwater cycle, indicating a dense and complex hydrologic network inside the glacier. Barotropic waves in glacier fjords and their relation to calving were explored. Observa- tional data from high-frequency pressure sensors placed in an array on the fjord sea floor captured tsunamis which were proceeded by large calving events. A numerical model was used to infer the forcing at the glacier-ocean boundary producing these tsunamis, yielding a timescale over which calving at Helheim Glacier occurs.
Liu, Chengyan; Wang, Zhaomin; Cheng, Chen; Wu, Yang; Xia, Ruibin; Li, Bingrui; Li, Xiang (2018). On the Modified Circumpolar Deep Water Upwelling Over the Four Ladies Bank in Prydz Bay, East Antarctica, Journal of Geophysical Research: Oceans, 10.1029/2018JC014026.
Formatted Citation: Liu, C., Z. Wang, C. Cheng, Y. Wu, R. Xia, B. Li, and X. Li, 2018: On the Modified Circumpolar Deep Water Upwelling Over the Four Ladies Bank in Prydz Bay, East Antarctica. J. Geophys. Res. Ocean., doi:10.1029/2018JC014026
Formatted Citation: Bashmachnikov, I., T. Belonenko, P. Kuibin, D. L. Volkov, and V. Foux, 2018: Pattern of vertical velocity in the Lofoten vortex (the Norwegian Sea). Ocean Dynamics, 68(12), 1711-1725, doi:10.1007/s10236-018-1213-1
Formatted Citation: Wei, J., X. Zhang, and Z. Wang, 2018: Impacts of extratropical storm tracks on Arctic sea ice export through Fram Strait. Climate Dynamics, doi:10.1007/s00382-018-4254-8
Abstract: Studies have indicated regime shifts in atmospheric circulation, and associated changes in extratropical storm tracks and Arctic storm activity, in particular on the North Atlantic side of the Arctic Ocean. To improve understanding of changes in Arctic sea ice mass balance, we examined the impacts of the changed storm tracks and cyclone activity on Arctic sea ice export through Fram Strait by using a high resolution global ocean-sea ice model, MITgcm-ECCO2. The model was forced by the Japanese 25-year Reanalysis (JRA-25) dataset. The results show that storm-induced strong northerly wind stress can cause simultaneous response of daily sea ice export and, in turn, exert cumulative effects on interannual variability and long-term changes of sea ice export. Further analysis indicates that storm impact on sea ice export is spatially dependent. The storms occurring southeast of Fram Strait exhibit the largest impacts. The weakened intensity of winter (in this study winter is defined as October-March and summer as April-September) storms in this region after 1994/95 could be responsible for the decrease of total winter sea ice export during the same time period.
Title: Ocean-Induced Melt Triggers Glacier Retreat in Northwest Greenland
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Wood, M; Rignot, E; Fenty, Ian; Menemenlis, Dimitris; Millan, R; Morlighem, M; Mouginot, J; Seroussi, Hélène
Year: 2018
Formatted Citation: Wood, M., E. Rignot, I. Fenty, D. Menemenlis, R. Millan, M. Morlighem, J. Mouginot, and H. Seroussi, 2018: Ocean-Induced Melt Triggers Glacier Retreat in Northwest Greenland. Geophys. Res. Lett., doi:10.1029/2018GL078024
Abstract: In recent decades, tidewater glaciers in Northwest Greenland contributed significantly to sea level rise but exhibited a complex spatial pattern of retreat. Here, we use novel observations of bathymetry and water temperature from NASA's Ocean Melting Greenland mission to quantify the role of warm, salty Atlantic Water in controlling the evolution of 37 glaciers. Modeled ocean-induced undercutting of calving margins compared with ice advection and ice-front retreat observed by satellites from 1985 to 2015 indicate that 35 glaciers retreated when cumulative anomalies in ocean-induced undercutting rose above the range of seasonal variability of calving-front positions, while 2 glaciers standing on shallow sills and colder water did not retreat. Deviations in the observed timing of retreat are explained by residual uncertainties in bathymetry, inefficient mixing of waters in shallow fjords, and the presence of small floating sections. Overall, warmer ocean temperature triggered the retreat, but calving processes dominate ablation (71%).
Mukherjee, A.; Shankar, D.; Chatterjee, Abhisek; Vinayachandran, P. N. (2018). Numerical simulation of the observed near-surface East India Coastal Current on the continental slope, Climate Dynamics, 11-12 (50), 3949-3980, 10.1007/s00382-017-3856-x.
Title: Numerical simulation of the observed near-surface East India Coastal Current on the continental slope
Type: Journal Article
Publication: Climate Dynamics
Author(s): Mukherjee, A.; Shankar, D.; Chatterjee, Abhisek; Vinayachandran, P. N.
Year: 2018
Formatted Citation: Mukherjee, A., D. Shankar, A. Chatterjee, and P. N. Vinayachandran, 2018: Numerical simulation of the observed near-surface East India Coastal Current on the continental slope. Climate Dynamics, 50(11-12), 3949-3980, doi:10.1007/s00382-017-3856-x
Formatted Citation: Mouyen, M., L. Longuevergne, P. Steer, A. Crave, J. Lemoine, H. Save, and C. Robin, 2018: Assessing modern river sediment discharge to the ocean using satellite gravimetry. Nature Communications, 9(1), 3384, doi:10.1038/s41467-018-05921-y
Choi, Youngmin; Morlighem, Mathieu; Wood, Michael; Bondzio, Johannes H. (2018). Comparison of four calving laws to model Greenland outlet glaciers, The Cryosphere, 12 (12), 3735-3746, 10.5194/tc-12-3735-2018.
Title: Comparison of four calving laws to model Greenland outlet glaciers
Type: Journal Article
Publication: The Cryosphere
Author(s): Choi, Youngmin; Morlighem, Mathieu; Wood, Michael; Bondzio, Johannes H.
Year: 2018
Formatted Citation: Choi, Y., M. Morlighem, M. Wood, and J. H. Bondzio, 2018: Comparison of four calving laws to model Greenland outlet glaciers. Cryosph., 12(12), 3735-3746, doi:10.5194/tc-12-3735-2018
Abstract: Calving is an important mechanism that controls the dynamics of marine terminating glaciers of Greenland. Iceberg calving at the terminus affects the entire stress regime of outlet glaciers, which may lead to further retreat and ice flow acceleration. It is therefore critical to accurately parameterize calving in ice sheet models in order to improve the projections of ice sheet change over the coming decades and reduce the uncertainty in their contribution to sea-level rise. Several calving laws have been proposed, but most of them have been applied only to a specific region and have not been tested on other glaciers, while some others have only been implemented in 1-D flowline or vertical flowband models. Here, we test and compare several calving laws recently proposed in the literature using the Ice Sheet System Model (ISSM). We test these calving laws on nine tidewater glaciers of Greenland. We compare the modeled ice front evolution to the observed retreat from Landsat data collected over the past 10 years, and assess which calving law has better predictive abilities for each glacier. Overall, the von Mises tensile stress calving law is more satisfactory than other laws for simulating observed ice front retreat, but new parameterizations that better capture the different modes of calving should be developed. Although the final positions of ice fronts are different for forecast simulations with different calving laws, our results confirm that ice front retreat highly depends on bed topography, irrespective of the calving law employed. This study also confirms that calving dynamics needs to be 3-D or in plan view in ice sheet models to account for complex bed topography and narrow fjords along the coast of Greenland. ]]>
Chi, Lequan; Wolfe, Christopher L.P.; Hameed, Sultan (2018). Intercomparison of the Gulf Stream in ocean reanalyses: 1993−2010, Ocean Modelling (125), 1-21, 10.1016/j.ocemod.2018.02.008.
Title: Intercomparison of the Gulf Stream in ocean reanalyses: 1993−2010
Type: Journal Article
Publication: Ocean Modelling
Author(s): Chi, Lequan; Wolfe, Christopher L.P.; Hameed, Sultan
Year: 2018
Formatted Citation: Chi, L., C. L. Wolfe, and S. Hameed, 2018: Intercomparison of the Gulf Stream in ocean reanalyses: 1993−2010. Ocean Modelling, 125, 1-21, doi:10.1016/j.ocemod.2018.02.008
Bondzio, Johannes H.; Morlighem, Mathieu; Seroussi, Hélène; Wood, Michael H.; Mouginot, Jérémie (2018). Control of Ocean Temperature on Jakobshavn Isbrae’s Present and Future Mass Loss, Geophysical Research Letters, 23 (45), 12,912-12,921, 10.1029/2018GL079827.
Title: Control of Ocean Temperature on Jakobshavn Isbrae’s Present and Future Mass Loss
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Bondzio, Johannes H.; Morlighem, Mathieu; Seroussi, Hélène; Wood, Michael H.; Mouginot, Jérémie
Year: 2018
Formatted Citation: Bondzio, J. H., M. Morlighem, H. Seroussi, M. H. Wood, and J. Mouginot, 2018: Control of Ocean Temperature on Jakobshavn Isbrae's Present and Future Mass Loss. Geophys. Res. Lett., 45(23), 12,912-12,921, doi:10.1029/2018GL079827
Castellani, Giulia; Losch, Martin; Ungermann, Mischa; Gerdes, Rüdiger (2018). Sea-ice drag as a function of deformation and ice cover: Effects on simulated sea ice and ocean circulation in the Arctic, Ocean Modelling (128), 48-66, 10.1016/j.ocemod.2018.06.002.
Formatted Citation: Castellani, G., M. Losch, M. Ungermann, and R. Gerdes, 2018: Sea-ice drag as a function of deformation and ice cover: Effects on simulated sea ice and ocean circulation in the Arctic. Ocean Modelling, 128, 48-66, doi:10.1016/j.ocemod.2018.06.002
Fu, Lee-Lueng; Lee, Tong; Liu, W. Timothy; Kwok, Ronald (2018). 50 Years of Satellite Remote Sensing of the Ocean, Meteorological Monographs (59), 5.1-5.46, 10.1175/AMSMONOGRAPHS-D-18-0010.1.
Title: 50 Years of Satellite Remote Sensing of the Ocean
Type: Journal Article
Publication: Meteorological Monographs
Author(s): Fu, Lee-Lueng; Lee, Tong; Liu, W. Timothy; Kwok, Ronald
Year: 2018
Formatted Citation: Fu, L., T. Lee, W. T. Liu, and R. Kwok, 2018: 50 Years of Satellite Remote Sensing of the Ocean. Meteorological Monographs, 59, 5.1-5.46, doi:10.1175/AMSMONOGRAPHS-D-18-0010.1
Liang, Xi; Losch, Martin (2018). On the effects of increased vertical mixing on the Arctic Ocean and sea ice, Journal of Geophysical Research: Oceans, April 2007 (2007), 1-17, 10.1029/2018JC014303.
Title: On the effects of increased vertical mixing on the Arctic Ocean and sea ice
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Liang, Xi; Losch, Martin
Year: 2018
Formatted Citation: Liang, X., and M. Losch, 2018: On the effects of increased vertical mixing on the Arctic Ocean and sea ice. J. Geophys. Res. Ocean., 2007(April 2007), 1-17, doi:10.1029/2018JC014303
Wunsch, Carl; Ferrari, Raffaele (2018). 100 Years of the Ocean General Circulation, Meteorological Monographs (59), 7.1-7.32, 10.1175/AMSMONOGRAPHS-D-18-0002.1.
Formatted Citation: Wunsch, C., and R. Ferrari, 2018: 100 Years of the Ocean General Circulation. Meteorological Monographs, 59, 7.1-7.32, doi:10.1175/AMSMONOGRAPHS-D-18-0002.1
Hartfield, Gail; Blunden, Jessica; Arndt, Derek S. (2018). State of the Climate in 2017, Bulletin of the American Meteorological Society, 8 (99), Si-S310, 10.1175/2018BAMSStateoftheClimate.1.
Publication: Bulletin of the American Meteorological Society
Author(s): Hartfield, Gail; Blunden, Jessica; Arndt, Derek S.
Year: 2018
Formatted Citation: Hartfield, G., J. Blunden, and D. S. Arndt, 2018: State of the Climate in 2017. Bull. Am. Meteorol. Soc., 99(8), Si-S310, doi:10.1175/2018BAMSStateoftheClimate.1
Abstract: Editor's note: For easy download the posted pdf of the State of the Climate for 2018 is a low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download.
Formatted Citation: Guo, Y., X. Lin, M. Wei, C. Liu, and G. Men, 2018: Decadal Variability of North Pacific Eastern Subtropical Mode Water. J. Geophys. Res. Ocean., 123(9), 6189-6206, doi:10.1029/2018JC013890
Piecuch, Christopher G; Landerer, Felix W; Ponte, Rui M (2018). Tide gauge records reveal improved processing of gravity recovery and climate experiment time-variable mass solutions over the coastal ocean, Geophysical Journal International, 2 (214), 1401-1412, 10.1093/gji/ggy207.
Title: Tide gauge records reveal improved processing of gravity recovery and climate experiment time-variable mass solutions over the coastal ocean
Type: Journal Article
Publication: Geophysical Journal International
Author(s): Piecuch, Christopher G; Landerer, Felix W; Ponte, Rui M
Year: 2018
Formatted Citation: Piecuch, C. G., F. W. Landerer, and R. M. Ponte, 2018: Tide gauge records reveal improved processing of gravity recovery and climate experiment time-variable mass solutions over the coastal ocean. Geophysical Journal International, 214(2), 1401-1412, doi:10.1093/gji/ggy207
Abstract: Monthly ocean bottom pressure solutions from the Gravity Recovery and Climate Experiment (GRACE), derived using surface spherical cap mass concentration (MC) blocks and spherical harmonics (SH) basis functions, are compared to tide gauge (TG) monthly averaged sea level data over 2003-2015 to evaluate improved gravimetric data processing methods near the coast. MC solutions can explain ≳ 42 per cent of the monthly variance in TG time-series over broad shelf regions and in semi-enclosed marginal seas. MC solutions also generally explain ~ 5-32 per cent more TG data variance than SH estimates. Applying a coastline resolution improvement algorithm in the GRACE data processing leads to ~ 31 per cent more variance in TG records explained by the MC solution on average compared to not using this algorithm. Synthetic observations sampled from an ocean general circulation model exhibit similar patterns of correspondence between modelled TG and MC time-series and differences between MC and SH time-series in terms of their relationship with TG time-series, suggesting that observational results here are generally consistent with expectations from ocean dynamics. This work demonstrates the improved quality of recent MC solutions compared to earlier SH estimates over the coastal ocean, and suggests that the MC solutions could be a useful tool for understanding contemporary coastal sea level variability and change.
Other URLs: https://academic.oup.com/gji/article/214/2/1401/5000174
Moteki, Qoosaku; Katsumata, Masaki; Yoneyama, Kunio; Ando, Kentaro; Hasegawa, Takuya (2018). Drastic thickening of the barrier layer off the western coast of Sumatra due to the Madden-Julian oscillation passage during the Pre-Years of the Maritime Continent campaign, Progress in Earth and Planetary Science, 1 (5), 35, 10.1186/s40645-018-0190-9.
Title: Drastic thickening of the barrier layer off the western coast of Sumatra due to the Madden-Julian oscillation passage during the Pre-Years of the Maritime Continent campaign
Type: Journal Article
Publication: Progress in Earth and Planetary Science
Formatted Citation: Moteki, Q., M. Katsumata, K. Yoneyama, K. Ando, and T. Hasegawa, 2018: Drastic thickening of the barrier layer off the western coast of Sumatra due to the Madden-Julian oscillation passage during the Pre-Years of the Maritime Continent campaign. Progress in Earth and Planetary Science, 5(1), 35, doi:10.1186/s40645-018-0190-9
Dwivedi, Suneet; Srivastava, Atul; Mishra, Alok Kumar (2018). Upper Ocean Four-Dimensional Variational Data Assimilation in the Arabian Sea and Bay of Bengal, Marine Geodesy, 3 (41), 230-257, 10.1080/01490419.2017.1405128.
Formatted Citation: Dwivedi, S., A. Srivastava, and A. K. Mishra, 2018: Upper Ocean Four-Dimensional Variational Data Assimilation in the Arabian Sea and Bay of Bengal. Marine Geodesy, 41(3), 230-257, doi:10.1080/01490419.2017.1405128
Benoiston, Anne-Sophie; Ibarbalz, Federico M.; Bittner, Lucie; Guidi, Lionel; Jahn, Oliver; Dutkiewicz, Stephanie; Bowler, Chris (2017). The evolution of diatoms and their biogeochemical functions, Philosophical Transactions of the Royal Society B: Biological Sciences, 1728 (372), 20160397, 10.1098/rstb.2016.0397.
Title: The evolution of diatoms and their biogeochemical functions
Type: Journal Article
Publication: Philosophical Transactions of the Royal Society B: Biological Sciences
Author(s): Benoiston, Anne-Sophie; Ibarbalz, Federico M.; Bittner, Lucie; Guidi, Lionel; Jahn, Oliver; Dutkiewicz, Stephanie; Bowler, Chris
Year: 2017
Formatted Citation: Benoiston, A., F. M. Ibarbalz, L. Bittner, L. Guidi, O. Jahn, S. Dutkiewicz, and C. Bowler, 2017: The evolution of diatoms and their biogeochemical functions. Philosophical Transactions of the Royal Society B: Biological Sciences, 372(1728), 20160397, doi:10.1098/rstb.2016.0397
Abstract: In contemporary oceans diatoms are an important group of eukaryotic phytoplankton that typically dominate in upwelling regions and at high latitudes. They also make significant contributions to sporadic blooms that often occur in springtime. Recent surveys have revealed global information about their abundance and diversity, as well as their contributions to biogeochemical cycles, both as primary producers of organic material and as conduits facilitating the export of carbon and silicon to the ocean interior. Sequencing of diatom genomes is revealing the evolutionary underpinnings of their ecological success by examination of their gene repertoires and the mechanisms they use to adapt to environmental changes. The rise of the diatoms over the last hundred million years is similarly being explored through analysis of microfossils and biomarkers that can be traced through geological time, as well as their contributions to seafloor sediments and fossil fuel reserves. The current review aims to synthesize current information about the evolution and biogeochemical functions of diatoms as they rose to prominence in the global ocean.
Title: Direct and Remote Effects of Topography and Orientation, and the Dynamics of Mesoscale Eddies
Type: Thesis
Publication:
Author(s): Gulliver, Larry T.
Year: 2017
Formatted Citation: Gulliver, L.T., 2017: Direct and Remote Effects of Topography and Orientation, and the Dynamics of Mesoscale Eddies,
Abstract: Baroclinic instability in the ocean is a primary cause of mesoscale eddies, which are pockets of water in the scale of 100km that have different density, thermal, and rotational characteristics than their surroundings. First observed in the early 1900s, eddies are thought to be a predominant reason for the heat flux between the equator and the poles in both the ocean and the atmosphere. In attempt to understand this process better, this study uses a series of numerical simulations performed on high performance computing systems. The calculations are based on the Massachusetts Institute of Technology general circulation model, which is used to compare lateral heat transport between different simulations. The specific objectives of this project include i) Comparison the direct and remote interactions of shear with topographic slope.The direct scenario is one in which the shear extends throughout the entire ocean depth and is therefore in direct contact with the sea floor, whereas in the remote scenario there is a spatial separation between the shear in the upper half of the basin and the bottom topography, ii) Analysis of the system response to changes in the zonal and meridionalseafloor slope, and iii) Investigation of the effect of orientation changes in the mean large-scale current on cross-flow fluxes. The lateral heat transport and diffusivity of these simulations are then compared to our analytic model, known as Growth Rate Balance, which is based on the balance between growth rate (primary) instabilities deduced from linear theory and numerically generated secondary instabilities.
Title: Rapid drawdown of Antarctica’s Wordie Ice Shelf glaciers in response to ENSO/Southern Annular Mode-driven warming in the Southern Ocean
Type: Journal Article
Publication: Earth and Planetary Science Letters
Author(s): Walker, C.C.; Gardner, A.S.
Year: 2017
Formatted Citation: Walker, C., and A. Gardner, 2017: Rapid drawdown of Antarctica's Wordie Ice Shelf glaciers in response to ENSO/Southern Annular Mode-driven warming in the Southern Ocean. Earth and Planetary Science Letters, 476, 100-110, doi:10.1016/j.epsl.2017.08.005
Ma, Qiang; Wang, Jianing; Wang, Fan (2017). Deep-layer circulations in Tropical Western Pacific Ocean based on six ocean models outputs, Oceanologia et Limnologia Sinica, 6 (48), 1302-1317, 10.11693/hyhz20170600159.
Title: Deep-layer circulations in Tropical Western Pacific Ocean based on six ocean models outputs
Type: Journal Article
Publication: Oceanologia et Limnologia Sinica
Author(s): Ma, Qiang; Wang, Jianing; Wang, Fan
Year: 2017
Formatted Citation: Ma, Q., J. Wang, and F. Wang, 2017: Deep-layer circulations in Tropical Western Pacific Ocean based on six ocean models outputs. Oceanologia et Limnologia Sinica, 48(6), 1302-1317, doi:10.11693/hyhz20170600159
Abstract: We conducted a preliminary analysis on deep-layer circulation in the tropical western Pacific using six ocean models outputs. In comparison with WOA13, the HYCOM's deep temperature deviation at 3000 m is mainly positive, while other five models' are negative. The deep temperature deviations increase with depth. The deep salinity deviations of HYCOM and OFES are mainly positive, while other models' are mainly negative. Both the temporal trends of mean temperature and salinity deviations are different from the observations. The currents between 1000 and 3000m are dominated by alternating westward and eastward zonal jets. The zonal velocity decreases quickly below 3000m, and the circulations are separated by different basins between 3000 and 5000m, but the seawater exchange can take place through deep-layer passages among basins. The transport in deep-layer passages shows seasonal variability; moreover, the direction of current in some deep layers could be opposite in different seasons. The pattern of circulation is controlled by potential vorticity constraint equation, and thus also shows seasonal variation, indicating temporal difference in the form of major rotations in these basins. In addition, we discussed the impacts of T/S initial value, tide, and other factors on the deep circulations, and proposed suggestions for future improvement in the modeling.
Keywords:
ECCO Products Used: ECCO2
URL:
Other URLs:
Chin, Toshio Michael; Vazquez-Cuervo, Jorge; Armstrong, Edward M. (2017). A multi-scale high-resolution analysis of global sea surface temperature, Remote Sensing of Environment (200), 154-169, 10.1016/j.rse.2017.07.029.
Title: A multi-scale high-resolution analysis of global sea surface temperature
Type: Journal Article
Publication: Remote Sensing of Environment
Author(s): Chin, Toshio Michael; Vazquez-Cuervo, Jorge; Armstrong, Edward M.
Year: 2017
Formatted Citation: Chin, T. M., J. Vazquez-Cuervo, and E. M. Armstrong, 2017: A multi-scale high-resolution analysis of global sea surface temperature. Remote Sensing of Environment, 200, 154-169, doi:10.1016/j.rse.2017.07.029
Title: Global coupled sea ice-ocean state estimation
Type: Journal Article
Publication: Climate Dynamics
Author(s): Fenty, Ian; Menemenlis, Dimitris; Zhang, Hong
Year: 2017
Formatted Citation: Fenty, I., D. Menemenlis, and H. Zhang, 2017: Global coupled sea ice-ocean state estimation. Climate Dynamics, 49(3), 931-956, doi:10.1007/s00382-015-2796-6
Other URLs: http://link.springer.com/10.1007/s00382-015-2796-6
Mu, Longjiang; Zhao, Jinping; Zhong, Wenli (2017). Regime shift of the dominant factor for halocline depth in the Canada Basin during 1990-2008, Acta Oceanologica Sinica, 1 (36), 35-43, 10.1007/s13131-016-0883-0.
Title: Regime shift of the dominant factor for halocline depth in the Canada Basin during 1990-2008
Formatted Citation: Mu, L., J. Zhao, and W. Zhong, 2017: Regime shift of the dominant factor for halocline depth in the Canada Basin during 1990-2008. Acta Oceanologica Sinica, 36(1), 35-43, doi:10.1007/s13131-016-0883-0
Seroussi, Hélène; Nakayama, Y.; Larour, E.; Menemenlis, Dimitris; Morlighem, M.; Rignot, E.; Khazendar, A. (2017). Continued retreat of Thwaites Glacier, West Antarctica, controlled by bed topography and ocean circulation, Geophysical Research Letters, 12 (44), 6191-6199, 10.1002/2017GL072910.
Title: Continued retreat of Thwaites Glacier, West Antarctica, controlled by bed topography and ocean circulation
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Seroussi, Hélène; Nakayama, Y.; Larour, E.; Menemenlis, Dimitris; Morlighem, M.; Rignot, E.; Khazendar, A.
Year: 2017
Formatted Citation: Seroussi, H., Y. Nakayama, E. Larour, D. Menemenlis, M. Morlighem, E. Rignot, and A. Khazendar, 2017: Continued retreat of Thwaites Glacier, West Antarctica, controlled by bed topography and ocean circulation. Geophys. Res. Lett., 44(12), 6191-6199, doi:10.1002/2017GL072910
Volkov, Denis L.; Lee, Sang-Ki; Landerer, Felix W.; Lumpkin, Rick (2017). Decade-long deep-ocean warming detected in the subtropical South Pacific, Geophysical Research Letters, 2 (44), 927-936, 10.1002/2016GL071661.
Title: Decade-long deep-ocean warming detected in the subtropical South Pacific
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Volkov, Denis L.; Lee, Sang-Ki; Landerer, Felix W.; Lumpkin, Rick
Year: 2017
Formatted Citation: Volkov, D. L., S. Lee, F. W. Landerer, and R. Lumpkin, 2017: Decade-long deep-ocean warming detected in the subtropical South Pacific. Geophys. Res. Lett., 44(2), 927-936, doi:10.1002/2016GL071661
Schwedes, Tobias; Ham, David A.; Funke, Simon W.; Piggott, Matthew D. (2017). Introduction to PDE-constrained optimisation, Mesh Dependence in PDE-Constrained Optimisation, 1-52, 10.1007/978-3-319-59483-5_1.
Title: Introduction to PDE-constrained optimisation
Type: Book Section
Publication: Mesh Dependence in PDE-Constrained Optimisation
Author(s): Schwedes, Tobias; Ham, David A.; Funke, Simon W.; Piggott, Matthew D.
Year: 2017
Formatted Citation: Schwedes, T., D. A. Ham, S. W. Funke, and M. D. Piggott, 2017: Introduction to PDE-constrained optimisation. Mesh Dependence in PDE-Constrained Optimisation, Springer International Publishing, 1-52, doi:10.1007/978-3-319-59483-5_1
Harrison, Daniel P. (2017). Global negative emissions capacity of ocean macronutrient fertilization, Environmental Research Letters, 3 (12), 035001, 10.1088/1748-9326/aa5ef5.
Title: Global negative emissions capacity of ocean macronutrient fertilization
Type: Journal Article
Publication: Environmental Research Letters
Author(s): Harrison, Daniel P.
Year: 2017
Formatted Citation: Harrison, D. P., 2017: Global negative emissions capacity of ocean macronutrient fertilization. Environmental Research Letters, 12(3), 035001, doi:10.1088/1748-9326/aa5ef5
Formatted Citation: Marshall, J., J. Scott, and A. Proshutinsky, 2017: "Climate response functions" for the Arctic Ocean: a proposed coordinated modelling experiment. Geoscientific Model Development, 10(7), 2833-2848, doi:10.5194/gmd-10-2833-2017
Abstract: A coordinated set of Arctic modelling experiments, which explore how the Arctic responds to changes in external forcing, is proposed. Our goal is to compute and compare climate response functions (CRFs) - the transient response of key observable indicators such as sea-ice extent, freshwater content of the Beaufort Gyre, etc. - to abrupt step changes in forcing fields across a number of Arctic models. Changes in wind, freshwater sources, and inflows to the Arctic basin are considered. Convolutions of known or postulated time series of these forcing fields with their respective CRFs then yield the (linear) response of these observables. This allows the project to inform, and interface directly with, Arctic observations and observers and the climate change community. Here we outline the rationale behind such experiments and illustrate our approach in the context of a coarse-resolution model of the Arctic based on the MITgcm. We conclude by summarizing the expected benefits of such an activity and encourage other modelling groups to compute CRFs with their own models so that we might begin to document their robustness to model formulation, resolution, and parameterization.
Title: Biogeochemical versus ecological consequences of modeled ocean physics
Type: Journal Article
Publication: Biogeosciences
Author(s): Clayton, Sophie; Dutkiewicz, Stephanie; Jahn, Oliver; Hill, Christopher; Heimbach, Patrick; Follows, Michael J.
Year: 2017
Formatted Citation: Clayton, S., S. Dutkiewicz, O. Jahn, C. Hill, P. Heimbach, and M. J. Follows, 2017: Biogeochemical versus ecological consequences of modeled ocean physics. Biogeosciences, 14(11), 2877-2889, doi:10.5194/bg-14-2877-2017
Abstract: We present a systematic study of the differences generated by coupling the same ecological-biogeochemical model to a 1°, coarse-resolution, and 1∕6°, eddy-permitting, global ocean circulation model to (a) biogeochemistry (e.g., primary production) and (b) phytoplankton community structure. Surprisingly, we find that the modeled phytoplankton community is largely unchanged, with the same phenotypes dominating in both cases. Conversely, there are large regional and seasonal variations in primary production, phytoplankton and zooplankton biomass. In the subtropics, mixed layer depths (MLDs) are, on average, deeper in the eddy-permitting model, resulting in higher nutrient supply driving increases in primary production and phytoplankton biomass. In the higher latitudes, differences in winter mixed layer depths, the timing of the onset of the spring bloom and vertical nutrient supply result in lower primary production in the eddy-permitting model. Counterintuitively, this does not drive a decrease in phytoplankton biomass but results in lower zooplankton biomass. We explain these similarities and differences in the model using the framework of resource competition theory, and find that they are the consequence of changes in the regional and seasonal nutrient supply and light environment, mediated by differences in the modeled mixed layer depths. Although previous work has suggested that complex models may respond chaotically and unpredictably to changes in forcing, we find that our model responds in a predictable way to different ocean circulation forcing, despite its complexity. The use of frameworks, such as resource competition theory, provides a tractable way to explore the differences and similarities that occur. As this model has many similarities to other widely used biogeochemical models that also resolve multiple phytoplankton phenotypes, this study provides important insights into how the results of running these models under different physical conditions might be more easily understood.
Other URLs: https://www.biogeosciences.net/14/2877/2017/
Bashmachnikov, I. L.; Belonenko, T. V.; Kuibin, P. A. (2017). Application of the theory of columnar Q-vortices with helical structure for the Lofoten vortex in the Norwegian Sea, Bulletin of Saint-Petersburg University Earth Sciences, 62 (3), 221-236.
Title: Application of the theory of columnar Q-vortices with helical structure for the Lofoten vortex in the Norwegian Sea
Type: Journal Article
Publication: Bulletin of Saint-Petersburg University Earth Sciences
Author(s): Bashmachnikov, I. L.; Belonenko, T. V.; Kuibin, P. A.
Year: 2017
Formatted Citation: Bashmachnikov, I. L., T. V. Belonenko, and P. A. Kuibin, 2017: Application of the theory of columnar Q-vortices with helical structure for the Lofoten vortex in the Norwegian Sea. Bulletin of Saint-Petersburg University Earth Sciences, 3(62), 221-236, https://dspace.spbu.ru/bitstream/11701/8985/1/01-Bashmachnikov.pdf
Abstract: In this paper, dynamic characteristics of mesoscale vortices in the ocean are considered using the theory of columnar vortices with a helical structure. The radial profile of the relative vorticity is ap- proximated with the Q-distribution. Expressions connecting the distributions of the horizontal and vertical velocity components in this type of vortices are obtained. The limitations for the applicability of the analytical solution are derived. The advantages and disadvantages of this model are shown in comparison with the radial distributions of the corresponding parameters in Scully and in Rayleigh vortices. In particular, it is shown that the Q-distribution can, in some sense, be considered as a com- promise solution between the two distributions above. The theory of columnar Q-vortices with helical structure is applied to the permanently existing anticyclonic Lofoten vortex of the Norwegian Sea. The mean radial distributions of various dynamics characteristics of the Lofoten vortex are obtained using simulations with the regional hydrodynamic model MIT. The reasons for formation of the observed vertical velocity structure are analyzed. It is shown that, in contrast to atmospheric synoptic structures, divergence of Ekman fluxes in the bottom layer affects only the lower part of the vortex. In the upper ocean, ascending vertical motion is observed in the Lofoten vortex. It is assumed that horizontal dis- persion of vortex energy, the most intense in the surface layer, plays an essential role in the formation of the field of vertical velocities in the upper part of its core.
Wagner, Till J. W.; Dell, Rebecca W.; Eisenman, Ian (2017). An Analytical Model of Iceberg Drift, Journal of Physical Oceanography, 7 (47), 1605-1616, 10.1175/JPO-D-16-0262.1.
Author(s): Wagner, Till J. W.; Dell, Rebecca W.; Eisenman, Ian
Year: 2017
Formatted Citation: Wagner, T. J. W., R. W. Dell, and I. Eisenman, 2017: An Analytical Model of Iceberg Drift. Journal of Physical Oceanography, 47(7), 1605-1616, doi:10.1175/JPO-D-16-0262.1
Title: The conversion rate of lee waves and the energetics of internal tides
Type: Thesis
Publication:
Author(s): Han, Bing
Year: 2017
Formatted Citation: Han, B., 2017: The conversion rate of lee waves and the energetics of internal tides., 130 pp.
Abstract: Tides and geostrophic flows are two important energy sources for the mixing in the deep ocean. The global conversion rate of internal lee waves generated by geostrophic flows, the baroclinic tide generated by the barotropic tide over sinusoidal topography and the energy budgets of internal waves at the Luzon ridge calculated from both two-dimensional and three-dimensional simulations are investigated in this paper. It is aimed to give us a better understanding of the role of tides and geostrophic flows in ocean dynamics. This paper consists of four parts. Firstly, the conversion rate of internal lee waves generated by geostrophic flows is calculated based on linear theory. In order to get a more precise value, we use two methods to deal with the topographic spectrum. The single beam sounding depth data, global predicted abyssal hill rms heights, WOCE hydrographic atlas, velocity data from SODA and ECCO2, mean flow and eddy velocity from the global eddy-permitting STORM model in a 1° × 1° grid are used for the calculations. By using these data, we can not only compare with the results from different velocity and topography databases, but also get the difference between the conversion rate from the eddies and from the mean flow. The results show that the conversion rates calculated using SODA, ECCO2, mean flow and eddy velocity from the global eddy-permitting STORM model are between 0.03 and 0.23 TW, and the difference between the conversion rate from the eddies and from the mean flow is between 0.05 and 0.11 TW. Secondly, a series of experiments are set up to investigate the baroclinic tide generated by barotropic tide over sinusoidal topography. The baroclinic velocity fields generated are quite different between in subcritical cases and in supercritical cases. The effects of the height of the topography, the amplitude of the barotropic tidal velocity, the stratification and the width of the topography on the baroclinic tide generated are studied in this chapter. The results show that the energy flux is almost proportional to the square of the height of the topography and the square of the amplitude of the barotropic tide; the energy flux will be larger when the width of topography is smaller and the stratification is stronger; there is almost no energy flux generated in experiments with too weak stratification or too wide topogaphy. The results predicted by the linear theory agree well with the results calculated by C1 (energy flux) in most cases, and the results calculated by C2 (conversion rate) are larger than the results calculated by C1 in most cases (the definitions of C1 and C2 could be found in Chapter 3). Thirdly, two-dimensional MIT General Circulation Model (MITgcm) is used to simulate internal waves at the Luzon ridge. Here, the topography is represented by two ideal Gaussian hills. The baroclinic energy budget of internal waves is studied and the conversion rate is mainly balanced by the energy flux. The effects of the height of the west ridge, the distance between the two ridges and the amplitude of the barotropic tide on the energy flux and conversion rate are also investigated. It is found that as the height of the west ridge increases, the westward energy flux increases; the internal tides can be enhanced due to a suitable distance between the two ridges; the amplitude of the barotropic tide is one of the crucial factors to determine whether the internal solitary waves would be generated or not, furthermore, when the amplitude of the barotropic tide is larger, the speed of the internal solitary waves generated will be larger. Finally, three-dimensional simulations of internal tides at the Luzon ridge are shown. The MITgcm is used to study the M2 and K1 internal tides and the data from WOCE and SODA are used to give the stratification here. In this chapter, not only the barotropic energy budget and baroclinic energy budget but also the barotropic kinetic energy budget and baroclinic kinetic energy budget are analyzed. About 15.1 GW is transferred from the M2 barotropic tide to the baroclinic tide, which is about 88% of the barotropic input. The energy flux is about 4.5 GW, and the total dissipation is about 11.3 GW. The formula (Nycander, 2005) may underestimate the conversion rate at the Luzon ridge.
Formatted Citation: Liu, C., Z. Wang, C. Cheng, R. Xia, B. Li, and Z. Xie, 2017: Modeling modified Circumpolar Deep Water intrusions onto the Prydz Bay continental shelf, East Antarctica. J. Geophys. Res. Ocean., 122(7), 5198-5217, doi:10.1002/2016JC012336
Blunden, Jessica; Arndt, Derek S. (2017). State of the Climate in 2016, Bulletin of the American Meteorological Society, 8 (98), Si-S280, 10.1175/2017BAMSStateoftheClimate.1.
Publication: Bulletin of the American Meteorological Society
Author(s): Blunden, Jessica; Arndt, Derek S.
Year: 2017
Formatted Citation: Blunden, J., and D. S. Arndt, 2017: State of the Climate in 2016. Bull. Am. Meteorol. Soc., 98(8), Si-S280, doi:10.1175/2017BAMSStateoftheClimate.1
Abstract: Editor's note: For easy download the posted pdf of the State of the Climate for 2017 is a low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download.
Formatted Citation: Chalamalla, V. K., E. Santilli, A. Scotti, M. Jalali, and S. Sarkar, 2017: SOMAR-LES: A framework for multi-scale modeling of turbulent stratified oceanic flows. Ocean Modelling, 120, 101-119, doi:10.1016/j.ocemod.2017.11.003
Wagner, Till J.W.; Stern, Alon A.; Dell, Rebecca W.; Eisenman, Ian (2017). On the representation of capsizing in iceberg models, Ocean Modelling (117), 88-96, 10.1016/j.ocemod.2017.07.003.
Title: On the representation of capsizing in iceberg models
Type: Journal Article
Publication: Ocean Modelling
Author(s): Wagner, Till J.W.; Stern, Alon A.; Dell, Rebecca W.; Eisenman, Ian
Year: 2017
Formatted Citation: Wagner, T. J., A. A. Stern, R. W. Dell, and I. Eisenman, 2017: On the representation of capsizing in iceberg models. Ocean Modelling, 117, 88-96, doi:10.1016/j.ocemod.2017.07.003
Bigdeli, Arash; Loose, Brice; Nguyen, An T.; Cole, Sylvia T. (2017). Numerical investigation of the Arctic ice-ocean boundary layer and implications for air-sea gas fluxes, Ocean Science, 1 (13), 61-75, 10.5194/os-13-61-2017.
Title: Numerical investigation of the Arctic ice-ocean boundary layer and implications for air-sea gas fluxes
Type: Journal Article
Publication: Ocean Science
Author(s): Bigdeli, Arash; Loose, Brice; Nguyen, An T.; Cole, Sylvia T.
Year: 2017
Formatted Citation: Bigdeli, A., B. Loose, A. T. Nguyen, and S. T. Cole, 2017: Numerical investigation of the Arctic ice-ocean boundary layer and implications for air-sea gas fluxes. Ocean Science, 13(1), 61-75, doi:10.5194/os-13-61-2017
Abstract: In ice-covered regions it is challenging to determine constituent budgets - for heat and momentum, but also for biologically and climatically active gases like carbon dioxide and methane. The harsh environment and relative data scarcity make it difficult to characterize even the physical properties of the ocean surface. Here, we sought to evaluate if numerical model output helps us to better estimate the physical forcing that drives the air-sea gas exchange rate (k) in sea ice zones. We used the budget of radioactive 222Rn in the mixed layer to illustrate the effect that sea ice forcing has on gas budgets and air-sea gas exchange. Appropriate constraint of the 222Rn budget requires estimates of sea ice velocity, concentration, mixed-layer depth, and water velocities, as well as their evolution in time and space along the Lagrangian drift track of a mixed-layer water parcel. We used 36, 9 and 2km horizontal resolution of regional Massachusetts Institute of Technology general circulation model (MITgcm) configuration with fine vertical spacing to evaluate the capability of the model to reproduce these parameters. We then compared the model results to existing field data including satellite, moorings and ice-tethered profilers. We found that mode sea ice coverage agrees with satellite-derived observation 88 to 98% of the time when averaged over the Beaufort Gyre, and model sea ice speeds have 82% correlation with observations. The model demonstrated the capacity to capture the broad trends in the mixed layer, although with a significant bias. Model water velocities showed only 29% correlation with point-wise in situ data. This correlation remained low in all three model resolution simulations and we argued that is largely due to the quality of the input atmospheric forcing. Overall, we found that even the coarse-resolution model can make a modest contribution to gas exchange parameterization, by resolving the time variation of parameters that drive the 222Rn budget, including rate of mixed-layer change and sea ice forcings.
Qiu, Bo; Chen, Shuiming; Schneider, Niklas (2017). Dynamical Links between the Decadal Variability of the Oyashio and Kuroshio Extensions, Journal of Climate, 23 (30), 9591-9605, 10.1175/jcli-d-17-0397.1.
Formatted Citation: Qiu, B., S. Chen, and N. Schneider, 2017: Dynamical Links between the Decadal Variability of the Oyashio and Kuroshio Extensions. J. Clim., 30(23), 9591-9605, doi:10.1175/jcli-d-17-0397.1
Abstract: Rather than a single and continuous boundary current outflow, long-term satellite observations reveal that the Oyashio Extension (OE) in the North Pacific Subarctic Gyre comprises two independent, northeast-southwest-slanted front systems. With a mean latitude along 40°N, the western OE front exists primarily west of 153°E and is a continuation of the subarctic gyre western boundary current. The eastern OE front, also appearing along 40°N, is located between 153° and 170°E, whose entity is disconnected from its western counterpart. During 1982-2016, both of the OE fronts exhibit prominent decadal fluctuations, although their signals show little contemporaneous correlation. An upper-ocean temperature budget analysis based on the Estimating the Circulation and Climate of the Ocean, phase II (ECCO2), state estimate reveals that the advective temperature flux convergence plays a critical role in determining the low-frequency temperature changes relating to the OE fronts. Specifically, the western OE front variability is controlled by the decadal mesoscale eddy modulations in the upstream Kuroshio Extension (KE). An enhanced eddy activity increases the poleward heat transport and works to strengthen the western OE front. The eastern OE front variability, on the other hand, is dictated by both the meridional shift of the KE position and the circulation intensity change immediately north of the eastern OE. Different baroclinic adjustment speeds for the KE and OE are found to cause the in-phase changes between these latter two processes. Lack of contemporaneous correlation between the decadal western and eastern OE variability is found to be related to the interaction of the meridionally migrating KE jet with the Shatsky Rise near 159°E.
Title: Intraseasonal variability of currents along east coast of India
Type: Thesis
Publication:
Author(s): Mukherjee, Arnab
Year: 2017
Formatted Citation: Mukherjee, A., 2017: Intraseasonal variability of currents along east coast of India., 194 pp. http://irgu.unigoa.ac.in/drs/bitstream/handle/unigoa/5539/mukherjee_a_2017.pdf?sequence=1.
Aguiar, Wilton; Mata, Mauricio M.; Kerr, Rodrigo (2017). On deep convection events and Antarctic Bottom Water formation in ocean reanalysis products, Ocean Science, 6 (13), 851-872, 10.5194/os-13-851-2017.
Title: On deep convection events and Antarctic Bottom Water formation in ocean reanalysis products
Type: Journal Article
Publication: Ocean Science
Author(s): Aguiar, Wilton; Mata, Mauricio M.; Kerr, Rodrigo
Year: 2017
Formatted Citation: Aguiar, W., M. M. Mata, and R. Kerr, 2017: On deep convection events and Antarctic Bottom Water formation in ocean reanalysis products. Ocean Science, 13(6), 851-872, doi:10.5194/os-13-851-2017
Abstract: Open ocean deep convection is a common source of error in the representation of Antarctic Bottom Water (AABW) formation in ocean general circulation models. Although those events are well described in non-assimilatory ocean simulations, the recent appearance of a massive open ocean polynya in the Estimating the Circulation and Climate of the Ocean Phase II reanalysis product (ECCO2) raises questions on which mechanisms are responsible for those spurious events and whether they are also present in other state-of-the-art assimilatory reanalysis products. To investigate this issue, we evaluate how three recently released high-resolution ocean reanalysis products form AABW in their simulations. We found that two of the products create AABW by open ocean deep convection events in the Weddell Sea that are triggered by the interaction of sea ice with the Warm Deep Water, which shows that the assimilation of sea ice is not enough to avoid the appearance of open ocean polynyas. The third reanalysis, My Ocean University Reading UR025.4, creates AABW using a rather dynamically accurate mechanism. The UR025.4 product depicts both continental shelf convection and the export of Dense Shelf Water to the open ocean. Although the accuracy of the AABW formation in this reanalysis product represents an advancement in the representation of the Southern Ocean dynamics, the differences between the real and simulated processes suggest that substantial improvements in the ocean reanalysis products are still needed to accurately represent AABW formation.
Formatted Citation: King, J., G. Spreen, S. Gerland, C. Haas, S. Hendricks, L. Kaleschke, and C. Wang, 2017: Sea-ice thickness from field measurements in the northwestern Barents Sea. J. Geophys. Res. Ocean., 122(2), 1497-1512, doi:10.1002/2016JC012199
Belonenko, T. V.; Bashmachnikov, I. L.; Koldunov, A. V.; Kuibin, P. A. (2017). On the vertical velocity component in the mesoscale Lofoten vortex of the Norwegian Sea, Izvestiya, Atmospheric and Oceanic Physics, 6 (53), 641-649, 10.1134/S0001433817060032.
Title: On the vertical velocity component in the mesoscale Lofoten vortex of the Norwegian Sea
Type: Journal Article
Publication: Izvestiya, Atmospheric and Oceanic Physics
Author(s): Belonenko, T. V.; Bashmachnikov, I. L.; Koldunov, A. V.; Kuibin, P. A.
Year: 2017
Formatted Citation: Belonenko, T. V., I. L. Bashmachnikov, A. V. Koldunov, and P. A. Kuibin, 2017: On the vertical velocity component in the mesoscale Lofoten vortex of the Norwegian Sea. Izvestiya, Atmospheric and Oceanic Physics, 53(6), 641-649, doi:10.1134/S0001433817060032
Cougnon, E. A.; Galton-Fenzi, B. K.; Rintoul, S. R.; Legrésy, B.; Williams, G. D.; Fraser, A. D.; Hunter, J. R. (2017). Regional Changes in Icescape Impact Shelf Circulation and Basal Melting, Geophysical Research Letters, 22 (44), 11,519-11,527, 10.1002/2017GL074943.
Title: Regional Changes in Icescape Impact Shelf Circulation and Basal Melting
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Cougnon, E. A.; Galton-Fenzi, B. K.; Rintoul, S. R.; Legrésy, B.; Williams, G. D.; Fraser, A. D.; Hunter, J. R.
Year: 2017
Formatted Citation: Cougnon, E. A., B. K. Galton-Fenzi, S. R. Rintoul, B. Legrésy, G. D. Williams, A. D. Fraser, and J. R. Hunter, 2017: Regional Changes in Icescape Impact Shelf Circulation and Basal Melting. Geophys. Res. Lett., 44(22), 11,519-11,527, doi:10.1002/2017GL074943
Santoso, Agus; Mcphaden, Michael J.; Cai, Wenju (2017). The Defining Characteristics of ENSO Extremes and the Strong 2015/2016 El Niño, Reviews of Geophysics, 4 (55), 1079-1129, 10.1002/2017RG000560.
Title: The Defining Characteristics of ENSO Extremes and the Strong 2015/2016 El Niño
Type: Journal Article
Publication: Reviews of Geophysics
Author(s): Santoso, Agus; Mcphaden, Michael J.; Cai, Wenju
Year: 2017
Formatted Citation: Santoso, A., M. J. Mcphaden, and W. Cai, 2017: The Defining Characteristics of ENSO Extremes and the Strong 2015/2016 El Niño. Reviews of Geophysics, 55(4), 1079-1129, doi:10.1002/2017RG000560
Other URLs: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017RG000560
Ungermann, Mischa; Tremblay, L. Bruno; Martin, Torge; Losch, Martin (2017). Impact of the ice strength formulation on the performance of a sea ice thickness distribution model in the Arctic, Journal of Geophysical Research: Oceans, 3 (122), 2090-2107, 10.1002/2016JC012128.
Title: Impact of the ice strength formulation on the performance of a sea ice thickness distribution model in the Arctic
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Ungermann, Mischa; Tremblay, L. Bruno; Martin, Torge; Losch, Martin
Year: 2017
Formatted Citation: Ungermann, M., L. B. Tremblay, T. Martin, and M. Losch, 2017: Impact of the ice strength formulation on the performance of a sea ice thickness distribution model in the Arctic. J. Geophys. Res. Ocean., 122(3), 2090-2107, doi:10.1002/2016JC012128
Formatted Citation: Timmermans, M., J. Marshall, A. Proshutinsky, and J. Scott, 2017: Seasonally derived components of the Canada Basin halocline. Geophys. Res. Lett., 44(10), 5008-5015, doi:10.1002/2017GL073042
Dushaw, Brian D. (2017). Acoustic tomography as a component the Atlantic Ocean Observing System: Opportunities and Challenges, 8th EuroGOOS Conference, October, 5.
Title: Acoustic tomography as a component the Atlantic Ocean Observing System: Opportunities and Challenges
Type: Conference Proceedings
Publication: 8th EuroGOOS Conference
Author(s): Dushaw, Brian D.
Year: 2017
Formatted Citation: Dushaw, B. D., 2017: Acoustic tomography as a component the Atlantic Ocean Observing System: Opportunities and Challenges. 8th EuroGOOS Conference Nansen Environmental and Remote Sensing Center, Bergen, Norway(October), 5 pp. http://staff.washington.edu/dushaw/epubs/Dushaw_Tomography_8thEuroGOOSConference_2017.pdf.
Abstract: Ocean acoustic tomography is a unique measurement of large-scale ocean variability. The travel times of acoustic signals measure large-scale temperature, barotropic current, and, with an array of transceivers, relative vorticity. Applications include measurements of currents in shallow harbors, basin- and global-scale temperature, and deep-water formation events at high latitudes. Acoustical observations in ice-covered regions are compelling. All such systems provide for underwater GPS. The common perception that the Argo float system obviates the need for acoustic tomography is an error. While tomographic systems as components of regional or global-scale Ocean Observing Systems represent real opportunities for new insights into long-term ocean variability, the practical implementations of sustained acoustical systems are challenging. Such challenges are programmatic or cultural, rather than scientific, however. Given the extraordinary climatological changes presently occurring, it is imperative that all available observational capabilities be thoroughly considered. Studies employing numerical ocean models are required to design optimal observing strategies that exploit the complementary nature of different measurements. Observing Systems require practical techniques to implement data assimilation with the tomographic measurements. Programmatic technical capability and manpower to sustain acoustical measurements is lacking. Successful implementation of tomographic systems will require a stronger symbiotic relation between acousticians and oceanographers.
Author(s): Naughten, Kaitlin A.; Galton-Fenzi, Benjamin K.; Meissner, Katrin J.; England, Matthew H.; Brassington, Gary B.; Colberg, Frank; Hattermann, Tore; Debernard, Jens B.
Year: 2017
Formatted Citation: Naughten, K. A., B. K. Galton-Fenzi, K. J. Meissner, M. H. England, G. B. Brassington, F. Colberg, T. Hattermann, and J. B. Debernard, 2017: Spurious sea ice formation caused by oscillatory ocean tracer advection schemes. Ocean Modelling, 116, 108-117, doi:10.1016/j.ocemod.2017.06.010
Liu, Chengyan; Wang, Zhaomin; Li, Bingrui; Cheng, Chen; Xia, Ruibin (2017). On the response of subduction in the South Pacific to an intensification of westerlies and heat flux in an eddy permitting ocean model, Advances in Atmospheric Sciences, 4 (34), 521-531, 10.1007/s00376-016-6021-2.
Formatted Citation: Liu, C., Z. Wang, B. Li, C. Cheng, and R. Xia, 2017: On the response of subduction in the South Pacific to an intensification of westerlies and heat flux in an eddy permitting ocean model. Advances in Atmospheric Sciences, 34(4), 521-531, doi:10.1007/s00376-016-6021-2
Title: Contrasting carbon cycle responses of the tropical continents to the 2015-2016 El Niño
Type: Journal Article
Publication: Science
Author(s): Liu, Junjie; Bowman, Kevin W.; Schimel, David S.; Parazoo, Nicolas C.; Jiang, Zhe; Lee, Meemong; Bloom, A. Anthony; Wunch, Debra; Frankenberg, Christian; Sun, Ying; O'Dell, Christopher W.; Gurney, Kevin R.; Menemenlis, Dimitris; Gierach, Michelle; Crisp, David; Eldering, Annmarie
Year: 2017
Formatted Citation: Liu, J. and Coauthors, 2017: Contrasting carbon cycle responses of the tropical continents to the 2015-2016 El Niño. Science, 358(6360), eaam5690, doi:10.1126/science.aam5690
Formatted Citation: Dushaw, B. D. and Coauthors, 2017: Ocean Acoustic Tomography : a Missing Element of the Ocean Observing System. Proceedings Underwater Acoustics Conference and Exhibition, 12 pp. http://staff.washington.edu/dushaw/epubs/Dushaw_Tomography_UACE2017.pdf.
Abstract: Ocean acoustic tomography now has a long history with many observations and experiments that highlight the unique capabilities of this approach to detecting and understanding ocean variability. Examples include observations of deep mixing in the Greenland Sea, mode-1 internal tides radiating far into the ocean interior (coherent in time and space), relative vorticity on multiple scales, basin-wide and antipodal measures of temperature, barotropic currents, coastal processes in shallow water, and Arctic climate change. Despite the capabilities, tomography, and its simplified form thermometry, are not yet core observations within the Ocean Observing Systems (OOS). These observing systems could benefit greatly from applied acoustical oceanography, and both the world's climatic circumstance and the difficulty in ocean observation argue that all available techniques should be implemented. A perception that the existence of the Argo float system obviates the need for the acoustical observations has been shown to be false; observations of ocean variability by tomography are distinct from those of floats or gliders. The growing application of acoustical measurements as part of the observing system (e.g., IQOE orunderwater GPS systems) make tomography a natural component of OOSes. The developing INTAROS system is demonstrating the integration of diverse observations, including passive and active acoustical applications, into a coherent, operational system - part of the Arctic Ocean Observing System. Within the Framework for Ocean Observing (FOO), we reiterate the recommendation of the OceanObs'99 conference and advocate a tomography system in the western North Atlantic as an initial contribution. Such a system would provide unique measurements of large-scale temperature, barotropic currents, vorticity, fluxes, and abyssal variability, while providing tracking capabilities for deep floats and gliders. This initial design, and the sustained system that would evolve from it, would result in a more complete fit-for-purpose overall observing system for essential ocean variables (EOVs) and derived quantities.
Harrison, Daniel P.; Hinton, Michael G.; Kohin, Suzanne; Armstrong, Edward M.; Snyder, Stephanie; O'Brien, Frank; Kiefer, Dale K. (2017). The pelagic habitat analysis module for ecosystem-based fisheries science and management, Fisheries Oceanography, 3 (26), 316-335, 10.1111/fog.12194.
Title: The pelagic habitat analysis module for ecosystem-based fisheries science and management
Type: Journal Article
Publication: Fisheries Oceanography
Author(s): Harrison, Daniel P.; Hinton, Michael G.; Kohin, Suzanne; Armstrong, Edward M.; Snyder, Stephanie; O'Brien, Frank; Kiefer, Dale K.
Year: 2017
Formatted Citation: Harrison, D. P., M. G. Hinton, S. Kohin, E. M. Armstrong, S. Snyder, F. O'Brien, and D. K. Kiefer, 2017: The pelagic habitat analysis module for ecosystem-based fisheries science and management. Fisheries Oceanography, 26(3), 316-335, doi:10.1111/fog.12194
Gregor, Luke; Kok, Schalk; Monteiro, Pedro M. S. (2017). Empirical methods for the estimation of Southern Ocean CO2: support vector and random forest regression, Biogeosciences, 23 (14), 5551-5569, 10.5194/bg-14-5551-2017.
Title: Empirical methods for the estimation of Southern Ocean CO2: support vector and random forest regression
Type: Journal Article
Publication: Biogeosciences
Author(s): Gregor, Luke; Kok, Schalk; Monteiro, Pedro M. S.
Year: 2017
Formatted Citation: Gregor, L., S. Kok, and P. M. S. Monteiro, 2017: Empirical methods for the estimation of Southern Ocean CO2: support vector and random forest regression. Biogeosciences, 14(23), 5551-5569, doi:10.5194/bg-14-5551-2017
Abstract: The Southern Ocean accounts for 40% of oceanic CO2 uptake, but the estimates are bound by large uncertainties due to a paucity in observations. Gap-filling empirical methods have been used to good effect to approximate pCO2 from satellite observable variables in other parts of the ocean, but many of these methods are not in agreement in the Southern Ocean. In this study we propose two additional methods that perform well in the Southern Ocean: support vector regression (SVR) and random forest regression (RFR). The methods are used to estimate ΔpCO2 in the Southern Ocean based on SOCAT v3, achieving similar trends to the SOM-FFN method by Landschützer et al. (2014). Results show that the SOM-FFN and RFR approaches have RMSEs of similar magnitude (14.84 and 16.45µatm, where 1atm = 101325Pa) where the SVR method has a larger RMSE (24.40µatm). However, the larger errors for SVR and RFR are, in part, due to an increase in coastal observations from SOCAT v2 to v3, where the SOM-FFN method used v2 data. The success of both SOM-FFN and RFR depends on the ability to adapt to different modes of variability. The SOM-FFN achieves this by having independent regression models for each cluster, while this flexibility is intrinsic to the RFR method. Analyses of the estimates shows that the SVR and RFR's respective sensitivity and robustness to outliers define the outcome significantly. Further analyses on the methods were performed by using a synthetic dataset to assess the following: which method (RFR or SVR) has the best performance? What is the effect of using time, latitude and longitude as proxy variables on ΔpCO2? What is the impact of the sampling bias in the SOCAT v3 dataset on the estimates? We find that while RFR is indeed better than SVR, the ensemble of the two methods outperforms either one, due to complementary strengths and weaknesses of the methods. Results also show that for the RFR and SVR implementations, it is better to include coordinates as proxy variables as RMSE scores are lowered and the phasing of the seasonal cycle is more accurate. Lastly, we show that there is only a weak bias due to undersampling. The synthetic data provide a useful framework to test methods in regions of sparse data coverage and show potential as a useful tool to evaluate methods in future studies.
Bashmachnikov, I.L.; Sokolovskiy, M.A.; Belonenko, T.V.; Volkov, Denis L.; Isachsen, P.E.; Carton, X. (2017). On the vertical structure and stability of the Lofoten vortex in the Norwegian Sea, Deep Sea Research Part I: Oceanographic Research Papers (128), 1-27, 10.1016/j.dsr.2017.08.001.
Formatted Citation: Bashmachnikov, I., M. Sokolovskiy, T. Belonenko, D. L. Volkov, P. Isachsen, and X. Carton, 2017: On the vertical structure and stability of the Lofoten vortex in the Norwegian Sea. Deep Sea Research Part I: Oceanographic Research Papers, 128, 1-27, doi:10.1016/j.dsr.2017.08.001
Wagner, Till J. W.; Eisenman, Ian (2017). How climate model biases skew the distribution of iceberg meltwater, Geophysical Research Letters, 8 (44), 3691-3699, 10.1002/2016GL071645.
Title: How climate model biases skew the distribution of iceberg meltwater
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Wagner, Till J. W.; Eisenman, Ian
Year: 2017
Formatted Citation: Wagner, T. J. W., and I. Eisenman, 2017: How climate model biases skew the distribution of iceberg meltwater. Geophys. Res. Lett., 44(8), 3691-3699, doi:10.1002/2016GL071645
Wu, Yang; Wang, Zhaomin; Liu, Chengyan (2017). On the response of the Lorenz energy cycle for the Southern Ocean to intensified westerlies, Journal of Geophysical Research: Oceans, 3 (122), 2465-2493, 10.1002/2016JC012539.
Title: On the response of the Lorenz energy cycle for the Southern Ocean to intensified westerlies
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Wu, Yang; Wang, Zhaomin; Liu, Chengyan
Year: 2017
Formatted Citation: Wu, Y., Z. Wang, and C. Liu, 2017: On the response of the Lorenz energy cycle for the Southern Ocean to intensified westerlies. J. Geophys. Res. Ocean., 122(3), 2465-2493, doi:10.1002/2016JC012539
Title: Modeling Gas Budgets in Marginal Sea Ice Zones
Type: Thesis
Publication:
Author(s): Bigdeli, Arash
Year: 2017
Formatted Citation: Bigdeli, A., 2017: Modeling Gas Budgets in Marginal Sea Ice Zones., 114 pp. https://digitalcommons.uri.edu/oa_diss/678https://digitalcommons.uri.edu/oa_diss/678.
Abstract: Biogeochemical gas budgets at high-latitude regions and sea ice zones are a source of uncertainty in climate models. The four main processes that regulate these budgets include advection, ventilation, mixing, and accumulation/release from sea ice. Considering the scarcity of data in sea ice zones, specifically during winter time, the environment is too poorly sampled to constrain these processes through direct measurements; hence we proposed models to systematically investigate these processes. The models proposed in this dissertation consist of regional numerical ice-ocean models, 1D forward and inversion numerical models, and analytical models.
Gelderloos, Renske; Haine, Thomas W. N.; Koszalka, Inga M.; Magaldi, Marcello G. (2017). Seasonal Variability in Warm-Water Inflow toward Kangerdlugssuaq Fjord, Journal of Physical Oceanography, 7 (47), 1685-1699, 10.1175/JPO-D-16-0202.1.
Title: Seasonal Variability in Warm-Water Inflow toward Kangerdlugssuaq Fjord
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Gelderloos, Renske; Haine, Thomas W. N.; Koszalka, Inga M.; Magaldi, Marcello G.
Year: 2017
Formatted Citation: Gelderloos, R., T. W. N. Haine, I. M. Koszalka, and M. G. Magaldi, 2017: Seasonal Variability in Warm-Water Inflow toward Kangerdlugssuaq Fjord. Journal of Physical Oceanography, 47(7), 1685-1699, doi:10.1175/JPO-D-16-0202.1
Yang, Yang; San Liang, X; Qiu, Bo; Chen, Shuiming (2017). On the Decadal Variability of the Eddy Kinetic Energy in the Kuroshio Extension, Journal of Physical Oceanography, 5 (47), 1169-1187, 10.1175/JPO-D-16-0201.1.
Title: On the Decadal Variability of the Eddy Kinetic Energy in the Kuroshio Extension
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Yang, Yang; San Liang, X; Qiu, Bo; Chen, Shuiming
Year: 2017
Formatted Citation: Yang, Y., X. San Liang, B. Qiu, and S. Chen, 2017: On the Decadal Variability of the Eddy Kinetic Energy in the Kuroshio Extension. Journal of Physical Oceanography, 47(5), 1169-1187, doi:10.1175/JPO-D-16-0201.1
Abstract: Previous studies have found that the decadal variability of eddy kinetic energy (EKE) in the upstream Kuroshio Extension is negatively correlated with the jet strength, which seems counterintuitive at first glance because linear stability analysis usually suggests that a stronger jet would favor baroclinic instability and thus lead to stronger eddy activities. Using a time-varying energetics diagnostic methodology, namely, the localized multiscale energy and vorticity analysis (MS-EVA), and the MS-EVA-based nonlinear instability theory, this study investigates the physical mechanism responsible for such variations with the state estimate from the Estimating the Circulation and Climate of the Ocean (ECCO), Phase II. For the first time, it is found that the decadal modulation of EKE is mainly controlled by the barotropic instability of the background flow. During the high-EKE state, violent meanderings efficiently induce strong barotropic energy transfer from mean kinetic energy (MKE) to EKE despite the rather weak jet strength. The reverse is true in the low-EKE state. Although the enhanced meander in the high-EKE state also transfers a significant portion of energy from mean available potential energy (MAPE) to eddy available potential energy (EAPE) through baroclinic instability, the EAPE is not efficiently converted to EKE as the two processes are not well correlated at low frequencies revealed in the time-varying energetics. The decadal modulation of barotropic instability is found to be in pace with the North Pacific Gyre Oscillation but with a time lag of approximately 2 years.
Spreen, Gunnar; Kwok, Ronald; Menemenlis, Dimitris; Nguyen, An T (2017). Sea-ice deformation in a coupled ocean-sea-ice model and in satellite remote sensing data, Cryosph., 1, 1-37, 10.5194/tc-2016-13.
Title: Sea-ice deformation in a coupled ocean-sea-ice model and in satellite remote sensing data
Type: Journal Article
Publication: Cryosph.
Author(s): Spreen, Gunnar; Kwok, Ronald; Menemenlis, Dimitris; Nguyen, An T
Year: 2017
Formatted Citation: Spreen, G., R. Kwok, D. Menemenlis, and A. T. Nguyen, 2017: Sea-ice deformation in a coupled ocean-sea-ice model and in satellite remote sensing data. Cryosph.(1), 1-37, doi:10.5194/tc-2016-13
Abstract: A realistic representation of sea-ice deformation in models is important for accurate simulation of the sea-ice mass balance. Simulated sea-ice deformation from numerical simulations with 4.5, 9, and 18 km horizontal grid spacing and a viscous-plastic (VP) sea-ice rheology are compared with synthetic aperture radar (SAR) satellite observations (RGPS, RADARSAT Geophysical Processor System) for the time period 1996-2008. All three simulations can reproduce the large-scale ice deformation patterns, but small-scale sea- ice deformations and linear kinematic features (LKFs) are not adequately reproduced. The mean sea-ice total deforma- tion rate is about 40 % lower in all model solutions than in the satellite observations, especially in the seasonal sea-ice zone. A decrease in model grid spacing, however, produces a higher density and more localized ice deformation fea- tures. The 4.5 km simulation produces some linear kinematic features, but not with the right frequency. The dependence on length scale and probability density functions (PDFs) of absolute divergence and shear for all three model solutions show a power-law scaling behavior similar to RGPS obser- vations, contrary to what was found in some previous studies. Overall, the 4.5km simulation produces the most realistic divergence, vorticity, and shear when compared with RGPS data. This study provides an evaluation of high and coarse- resolution viscous-plastic sea-ice simulations based on spa- tial distribution, time series, and power-law scaling metrics.
Jia, Fan; Hu, Dunxin; Hu, Shijian; Feng, Junqiao (2017). Niño4 as a Key Region for the Interannual Variability of the Western Pacific Warm Pool, Journal of Geophysical Research: Oceans, 11 (122), 9299-9314, 10.1002/2017JC013208.
Formatted Citation: Jia, F., D. Hu, S. Hu, and J. Feng, 2017: Niño4 as a Key Region for the Interannual Variability of the Western Pacific Warm Pool. J. Geophys. Res. Ocean., 122(11), 9299-9314, doi:10.1002/2017JC013208
Bowman, Kevin W.; Liu, J; Bloom, A A; Parazoo, N C; Lee, M; Jiang, Z; Menemenlis, Dimitris; Gierach, M M; Collatz, G J; Gurney, K R; Wunch, D (2017). Global and Brazilian Carbon Response to El Niño Modoki 2011-2010, Earth and Space Science, 10 (4), 637-660, 10.1002/2016EA000204.
Title: Global and Brazilian Carbon Response to El Niño Modoki 2011-2010
Type: Journal Article
Publication: Earth and Space Science
Author(s): Bowman, Kevin W.; Liu, J; Bloom, A A; Parazoo, N C; Lee, M; Jiang, Z; Menemenlis, Dimitris; Gierach, M M; Collatz, G J; Gurney, K R; Wunch, D
Year: 2017
Formatted Citation: Bowman, K. W. and Coauthors, 2017: Global and Brazilian Carbon Response to El Niño Modoki 2011-2010. Earth and Space Science, 4(10), 637-660, doi:10.1002/2016EA000204
Abstract: The El Niño Modoki in 2010 led to historic droughts in Brazil. In order to understand its impact on carbon cycle variability, we derive the 2011-2010 annual carbon flux change (δF↑) globally and specifically to Brazil using the NASA Carbon Monitoring System Flux (CMS-Flux) framework. Satellite observations of CO2, CO, and solar-induced fluorescence (SIF) are ingested into a 4D-variational assimilation system driven by carbon cycle models to infer spatially resolved carbon fluxes including net ecosystem production, biomass burning, and gross primary productivity (GPP). The global 2011-2010 net carbon flux change was estimated to be δF↑=-1.60 PgC, while the Brazilian carbon flux change was -0.24 ± 0.11 PgC. This estimate is broadly within the uncertainty of previous aircraft-based estimates restricted to the Amazon basin. The 2011-2010 biomass burning change in Brazil was -0.24 ± 0.036 PgC, which implies a near-zero 2011-2010 change of the net ecosystem production (NEP): The near-zero NEP change is the result of quantitatively comparable increases GPP (0.31 ± 0.20 PgC) and respiration in 2011. Comparisons between Brazilian and global component carbon flux changes reveal complex interactions between the processes controlling annual land-atmosphere CO2 exchanges. These results show the potential of multiple satellite observations to help quantify and spatially resolve the response of productivity and respiration fluxes to climate variability.
Title: Improved estimates and understanding of interannual trends of CO₂ fluxes in the Southern Ocean
Type: Thesis
Publication:
Author(s): Gregor, Luke
Year: 2017
Formatted Citation: Gregor, L., 2017: Improved estimates and understanding of interannual trends of CO₂ fluxes in the Southern Ocean., 176 pp.
Abstract: The Southern Ocean plays an important role in mitigating the effects of anthropogenically driven climate change. The region accounts for 43% of oceanic uptake of anthropogenic carbon dioxide (CO₂). This is foreseen to change with increasing greenhouse gas emissions due to ocean chemistry and climate feedbacks that regulate the carbon cycle in the Southern Ocean. Studies have already shown that Southern Ocean CO₂ is subject to interannual variability. Measuring and understanding this change has been difficult due to sparse observational data that is biased toward summer. This leaves a crucial gap in our understanding of the Southern Ocean CO₂ seasonal cycle, which needs to be resolved to adequately monitor change and gain insight into the drivers of interannual variability. Machine learning has been successful in estimating CO₂ in may parts of the ocean by extrapolating existing data with satellite measurements of proxy variables of CO₂. However, in the Southern Ocean machine learning has proven less successful. Large differences between machine learning estimates stem from the paucity of data and complexity of the mechanisms that drive CO₂. In this study the aim is to reduce the uncertainty of estimates, advance our understanding of the interannual drivers, and optimise sampling of CO₂ in the Southern Ocean. Improving the estimates of CO₂ was achieved by investigating: the impact of increasing the gridding resolution of input data and proxy variables, and Support vector regression (SVR) and Random Forest Regression (RFR) as alternate machine learning methods. It was found that the improvement gained by increasing gridding resolution was minimal and only RFR was able to improve on existing error estimates. Yet, there was good agreement of the seasonal cycle and interannual trends between RFR, SVR and estimates from the literature. The ensemble mean of these methods was used to investigate the variability and interannual trends of CO₂ in the Southern Ocean. The interannual trends of the ensemble confirmed trends reported in the literature. A weakening of the sink in the early 2000's, followed by a strengthening a strengthening of the sink into the early 2010's. Wind was the overall driver of dominant decadal interannual trends, being more important during winter due to the increased efficacy of entrainment processes. Summer interannual variability of CO₂ was driven primarily by chlorophyll, which responded to basin scale changes in drivers by the complex interaction with underlying physics and possibly sub-mesoscale processes. Lastly CO₂ sampling platforms, namely ships, profiling floats and moorings, were tested in an idealised simulated model environment using a machine learning approach. Ships, simulated from existing cruise tracks, failed to adequately resolve CO₂ below the uncertainty threshold that is required to resolve the seasonal cycle of Southern Ocean CO₂. Eight high frequency sampling moorings narrowly outperformed 200 profiling floats, which were both able to adequately resolve the seasonal cycle. Though, a combination of ships and profiling floats achieved the smallest error.
Title: Acoustic Tomography in the Canary Basin: Meddies and Tides
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Dushaw, Brian D.; Gaillard, Fabienne; Terre, Thierry
Year: 2017
Formatted Citation: Dushaw, B. D., F. Gaillard, and T. Terre, 2017: Acoustic Tomography in the Canary Basin: Meddies and Tides. J. Geophys. Res. Ocean., 122(11), 8983-9003, doi:10.1002/2017JC013356
Parkinson, Samuel D.; Funke, Simon W.; Hill, Jon; Piggott, Matthew D.; Allison, Peter A. (2017). Application of the adjoint approach to optimise the initial conditions of a turbidity current with the AdjointTurbidity 1.0 model, Geoscientific Model Development, 3 (10), 1051-1068, 10.5194/gmd-10-1051-2017.
Title: Application of the adjoint approach to optimise the initial conditions of a turbidity current with the AdjointTurbidity 1.0 model
Type: Journal Article
Publication: Geoscientific Model Development
Author(s): Parkinson, Samuel D.; Funke, Simon W.; Hill, Jon; Piggott, Matthew D.; Allison, Peter A.
Year: 2017
Formatted Citation: Parkinson, S. D., S. W. Funke, J. Hill, M. D. Piggott, and P. A. Allison, 2017: Application of the adjoint approach to optimise the initial conditions of a turbidity current with the AdjointTurbidity 1.0 model. Geoscientific Model Development, 10(3), 1051-1068, doi:10.5194/gmd-10-1051-2017
Abstract: Turbidity currents are one of the main drivers of sediment transport from the continental shelf to the deep ocean. The resulting sediment deposits can reach hundreds of kilometres into the ocean. Computer models that simulate turbidity currents and the resulting sediment deposit can help us to understand their general behaviour. However, in order to recreate real-world scenarios, the challenge is to find the turbidity current parameters that reproduce the observations of sediment deposits. This paper demonstrates a solution to the inverse sediment transportation problem: for a known sedimentary deposit, the developed model reconstructs details about the turbidity current that produced the deposit. The reconstruction is constrained here by a shallow water sediment-laden density current model, which is discretised by the finite-element method and an adaptive time-stepping scheme. The model is differentiated using the adjoint approach, and an efficient gradient-based optimisation method is applied to identify the turbidity parameters which minimise the misfit between the modelled and the observed field sediment deposits. The capabilities of this approach are demonstrated using measurements taken in the Miocene Marnoso-arenacea Formation (Italy). We find that whilst the model cannot match the deposit exactly due to limitations in the physical processes simulated, it provides valuable insights into the depositional processes and represents a significant advance in our toolset for interpreting turbidity current deposits.
Title: Modelling the long-term evolution of worst-case Arctic oil spills
Type: Journal Article
Publication: Marine Pollution Bulletin
Author(s): Blanken, Hauke; Tremblay, Louis Bruno; Gaskin, Susan; Slavin, Alexander
Year: 2017
Formatted Citation: Blanken, H., L. B. Tremblay, S. Gaskin, and A. Slavin, 2017: Modelling the long-term evolution of worst-case Arctic oil spills. Marine Pollution Bulletin, 116(1-2), 315-331, doi:10.1016/j.marpolbul.2016.12.070
Dushaw, Brian D.; Sagen, Hanne (2017). The role of simulated small-scale ocean variability in inverse computations for ocean acoustic tomography, The Journal of the Acoustical Society of America, 6 (142), 3541-3552, 10.1121/1.5016816.
Title: The role of simulated small-scale ocean variability in inverse computations for ocean acoustic tomography
Type: Journal Article
Publication: The Journal of the Acoustical Society of America
Author(s): Dushaw, Brian D.; Sagen, Hanne
Year: 2017
Formatted Citation: Dushaw, B. D., and H. Sagen, 2017: The role of simulated small-scale ocean variability in inverse computations for ocean acoustic tomography. The Journal of the Acoustical Society of America, 142(6), 3541-3552, doi:10.1121/1.5016816
Schwab, Julia Maria (2017). Sediment dynamic, slope instability and potential tsunami hazard at the outer Thai shelf margin, Mergui Ridge, Andaman Sea.
Title: Sediment dynamic, slope instability and potential tsunami hazard at the outer Thai shelf margin, Mergui Ridge, Andaman Sea
Type: Thesis
Publication:
Author(s): Schwab, Julia Maria
Year: 2017
Formatted Citation: Schwab, J. M., 2017: Sediment dynamic, slope instability and potential tsunami hazard at the outer Thai shelf margin, Mergui Ridge, Andaman Sea., 137 pp.
Abstract: The Thai Andaman Sea coast, located in the vicinity of the Sunda Trench, has been repeatedly struck by tsunamis, one of them being the catastrophic and highly destructive 2004 Indian Ocean Tsunami, which was caused by an extreme earthquake at the Sunda Trench. More than 227000 people lost their lives during this catastrophe, 8200 of them in Thailand alone. Based on tsunami event layers retrieved at the Thai coast, the geological record shows that this was not the first tsunami that hit the area, and possible predecessors to the 2004 Tsunami have been identified in the geological record for the last two millennia. Most of the tsunamis worldwide are of tectonic origin, but it is well known, that earthquakes are not the only source for tsunamis. Submarine landslides can cause destructive tsunamis as well. Submarine landslides occur when a slope becomes unstable and fails. The stability of a slope depends largely on the sedimentary conditions, as these conditions govern the properties and the morphology of the sedimentary deposits. Thereby they dictate, whether failure preconditioning factors, such as rapid sedimentation, overpressure buildup or the presence of weak layers are developed. In order to assess the tsunami potential that may arise from a specific slope it is hence crucial to know the sedimentary processes and conditions that shape a margin. Moreover, it is important to know the failure history in order to estimate the frequency of failures and their dimensions. All this information may also help to assess the potential for future failures and for landslide tsunamis. The outer Thai shelf margin in the Andaman Sea has previously not been investigated in detail with respect to sediment dynamics and associated slope stability. Therefore, it was unknown so far, whether submarine mass wasting at this margin does occur and whether it may add to the tsunami hazard potential for the adjacent coasts. In order to examine the sedimentary development of this slope and in order to evaluate the state of the slope with respect to its stability and tsunami potential a new multibeam bathymetry and high resolution 2D multichannel reflection seismic data set was acquired during three subsequent research cruises (MASS I, MASS II and MASS III) in 2006, 2007 and 2011 from the Mergui Ridge area at the Thai outer shelf approximately 250km west off Phuket. The analysis of the newly acquired data shows that the Mergui Ridge, an area of low sedimentary input, is today shaped by bottom currents. This can be concluded from the presence of drift deposits adjacent to areas of low sedimentation or erosion of old sediments. Along-slope currents, fluctuating with the monsoon seasons and potentially also internal waves may be responsible for shaping the margin today. After a phase of uplift and subaerial exposure at the end of the Late Miocene, marked by a pronounced erosive unconformity, the Mergui Ridge shelf area subsided in the Pliocene to its recent position in up to 800m water depth. Tectonic deformation today is ongoing but on a smaller scale than in the past. This geological development is reflected in the older sedimentary deposits present in the Mergui Ridge area. This led to the deposition of a sedimentary unit characterized by indicators of local erosion when the ridge was in shallow water. Today a thin drape of undisturbed sediments partially covers these older sediments. Within the sediments of the Mergui Ridge area, seventeen mass transport deposits have been identified. Most of these deposits occur within drift deposits. Their presence shows that the slope has been unstable and failures have taken place repeatedly. The presence of fluids, instability of drift deposits and ongoing tectonic activity are considered as most important preconditioning factors; this setting may lead to failures in the future. Based on their mostly relative small dimension with volumes between approximately 0.3 and 14km3 , and the large water depth where the failures occur, it is unlikely for most of these failures to have been tsunamigenic, but triggering of tsunamis by such failures cannot be excluded. Based on the thickness of hemipelagic layers between events, the recurrence of these failures seems to be long, especially compared to the recurrence of tectonic tsunamis. A simple numerical modeling of landslide tsunami propagation and estimation of run up heighs based on geometrical parameters of the previously identified mass transport deposits of up to between 1.0 and 25.8m shows that landslides in the area may produce tsunamis. However, modeled tsunamis represent worst case scenarios and wave heights may be overestimated in the simple model.
Other URLs: https://macau.uni-kiel.de/receive/dissertation_diss_00022126?lang=en
Xu, Houze (2017). Global unification problem of the height system, Acta Geodaetica et Cartographica Sinica, 8 (46), 939-944, 10.11947/j.AGCS.2017.20170406.
Title: Global unification problem of the height system
Type: Journal Article
Publication: Acta Geodaetica et Cartographica Sinica
Author(s): Xu, Houze
Year: 2017
Formatted Citation: Xu, H., 2017: Global unification problem of the height system. Acta Geodaetica et Cartographica Sinica, 46(8), 939-944, doi:10.11947/j.AGCS.2017.20170406
Abstract: Some fundamental problems on the establishment of the global unified height system, including the geometry and gravity definition of the normal height, the global unification of the regional height systems obtained from leveling measurements, and the determination of geoid potential W0 are discussed. The main conclusions are summarized:① The definition of normal height in the sense of geometry leveling and gravity theory is different, so that h-ζ≠HL, here h, ζ and HL are geodetic height, height anomaly and levelling height respectively. Instead of it, we found , in the mountain area, the last correction term have to be added. ② Based on the merging of GNSS/gravity/regional leveling, the regional leveling height can be transformed into a global relative unified height system, however the value of geoid potential W0 is still needed in order to establish an absolute height system. ③ W0 can be determinated from the modern geodetic techniques with a certain accuracy, but it is time variable, so that people may only define a global absolute unified height system in a fixed epoch. Some fundamental problems on the establishment of the global unified height system, including the geometry and gravity definition of the normal height, the global unification of the regional height systems obtained from leveling measurements, and the determination of geoid potential W0 are discussed. The main conclusions are summarized:① The definition of normal height in the sense of geometry leveling and gravity theory is different, so that h-ζ≠HL, here h, ζ and HL are geodetic height, height anomaly and levelling height respectively. Instead of it, we found , in the mountain area, the last correction term have to be added. ② Based on the merging of GNSS/gravity/regional leveling, the regional leveling height can be transformed into a global relative unified height system, however the value of geoid potential W0 is still needed in order to establish an absolute height system. ③ W0 can be determinated from the modern geodetic techniques with a certain accuracy, but it is time variable, so that people may only define a global absolute unified height system in a fixed epoch.
Wang, Zhaomin; Wu, Yang; Lin, Xia; Liu, Chengyan; Xie, Zelin (2017). Impacts of open-ocean deep convection in the Weddell Sea on coastal and bottom water temperature, Climate Dynamics, 9-10 (48), 2967-2981, 10.1007/s00382-016-3244-y.
Formatted Citation: Wang, Z., Y. Wu, X. Lin, C. Liu, and Z. Xie, 2017: Impacts of open-ocean deep convection in the Weddell Sea on coastal and bottom water temperature. Climate Dynamics, 48(9-10), 2967-2981, doi:10.1007/s00382-016-3244-y
Wu, Yang; Zhai, Xiaoming; Wang, Zhaomin (2017). Decadal-Mean Impact of Including Ocean Surface Currents in Bulk Formulas on Surface Air-Sea Fluxes and Ocean General Circulation, Journal of Climate, 23 (30), 9511-9525, 10.1175/JCLI-D-17-0001.1.
Formatted Citation: Wu, Y., X. Zhai, and Z. Wang, 2017: Decadal-Mean Impact of Including Ocean Surface Currents in Bulk Formulas on Surface Air-Sea Fluxes and Ocean General Circulation. J. Clim., 30(23), 9511-9525, doi:10.1175/JCLI-D-17-0001.1
Title: Submesoscale Sea Ice-Ocean Interactions in Marginal Ice Zones
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Manucharyan, Georgy E.; Thompson, Andrew F.
Year: 2017
Formatted Citation: Manucharyan, G. E., and A. F. Thompson, 2017: Submesoscale Sea Ice-Ocean Interactions in Marginal Ice Zones. J. Geophys. Res. Ocean., 122(12), 9455-9475, doi:10.1002/2017JC012895
Title: Stochastic Subgrid-Scale Ocean Mixing: Impacts on Low-Frequency Variability
Type: Journal Article
Publication: Journal of Climate
Author(s): Juricke, Stephan; Palmer, Tim N.; Zanna, Laure
Year: 2017
Formatted Citation: Juricke, S., T. N. Palmer, and L. Zanna, 2017: Stochastic Subgrid-Scale Ocean Mixing: Impacts on Low-Frequency Variability. J. Clim., 30(13), 4997-5019, doi:10.1175/JCLI-D-16-0539.1
Title: From Topographic Internal Gravity Waves to Turbulence
Type: Journal Article
Publication: Annual Review of Fluid Mechanics
Author(s): Sarkar, S.; Scotti, A.
Year: 2017
Formatted Citation: Sarkar, S., and A. Scotti, 2017: From Topographic Internal Gravity Waves to Turbulence. Annual Review of Fluid Mechanics, 49(1), 195-220, doi:10.1146/annurev-fluid-010816-060013
Stepanov, Vladimir Nikolaevich (2017). The Atlantic meridional heat and volume transports from ocean models and observations, Works of Hydrometeorological Research Center of the Russian Federation, 364, 104-130.
Title: The Atlantic meridional heat and volume transports from ocean models and observations
Type: Journal Article
Publication: Works of Hydrometeorological Research Center of the Russian Federation
Author(s): Stepanov, Vladimir Nikolaevich
Year: 2017
Formatted Citation: Stepanov, V. N., 2017: The Atlantic meridional heat and volume transports from ocean models and observations. Works of Hydrometeorological Research Center of the Russian Federation(364), 104-130, http://method.meteorf.ru/publ/tr/tr364/stepan.pdf
Abstract: Atlantic meridional circulation (AMOC) plays a major role in moving heat around in the ocean, which significantly affects the Earth's climate on different time scales. In this paper an overview of the modelled and observations-derived estimates of the AMOC and the meridional heat transport (MHT) at 26.5° N, 41° N and 34° S over the 2004-2013 period is presented with emphasis on the model calculations obtained with a 1/16° eddy-resolving global model.The reasons of discrepancy between the model values of the AMOC and the MHT and the observations-derived estimates are analysed. The findings in this paper provide guidance in understanding the AMOC and MHT dissimilarities at these three latitudes between ocean models and observation-basedestimates.
Malpress, Veda; Bestley, Sophie; Corney, Stuart; Welsford, Dirk; Labrousse, Sara; Sumner, Michael; Hindell, Mark (2017). Bio-physical characterisation of polynyas as a key foraging habitat for juvenile male southern elephant seals (Mirounga leonina) in Prydz Bay, East Antarctica, PLOS ONE, 9 (12), e0184536, 10.1371/journal.pone.0184536.
Title: Bio-physical characterisation of polynyas as a key foraging habitat for juvenile male southern elephant seals (Mirounga leonina) in Prydz Bay, East Antarctica
Formatted Citation: Malpress, V., S. Bestley, S. Corney, D. Welsford, S. Labrousse, M. Sumner, and M. Hindell, 2017: Bio-physical characterisation of polynyas as a key foraging habitat for juvenile male southern elephant seals (Mirounga leonina) in Prydz Bay, East Antarctica. PLOS ONE, 12(9), e0184536, doi:10.1371/journal.pone.0184536
Fogwill, Christopher J.; van Sebille, Erik; Cougnon, Eva A.; Turney, Chris S. M.; Rintoul, Steve R.; Galton-Fenzi, Benjamin K.; Clark, Graeme F.; Marzinelli, E. M.; Rainsley, Eleanor B.; Carter, Lionel (2016). Brief communication: Impacts of a developing polynya off Commonwealth Bay, East Antarctica, triggered by grounding of iceberg B09B, The Cryosphere, 6 (10), 2603-2609, 10.5194/tc-10-2603-2016.
Title: Brief communication: Impacts of a developing polynya off Commonwealth Bay, East Antarctica, triggered by grounding of iceberg B09B
Type: Journal Article
Publication: The Cryosphere
Author(s): Fogwill, Christopher J.; van Sebille, Erik; Cougnon, Eva A.; Turney, Chris S. M.; Rintoul, Steve R.; Galton-Fenzi, Benjamin K.; Clark, Graeme F.; Marzinelli, E. M.; Rainsley, Eleanor B.; Carter, Lionel
Year: 2016
Formatted Citation: Fogwill, C.J., E. van Sebille, E.A. Cougnon, C.S.M.Turney, S.R. Rintoul, B.K. Galton-Fenzi, G.F. Clark, E.M. Marzinelli, E.B. Rainsley, and L. Carter, 2016: Brief communication: Impacts of a developing polynya off Commonwealth Bay, East Antarctica, triggered by grounding of iceberg B09B, The Cryosphere, 10(6), 2603-2609, doi: 10.5194/tc-10-2603-2016
Abstract: The dramatic calving of the Mertz Glacier tongue in 2010, precipitated by the movement of iceberg B09B, reshaped the oceanographic regime across the Mertz Polynya and Commonwealth Bay, regions where high-salinity shelf water (HSSW) – the precursor to Antarctic bottom water (AABW) – is formed. Here we present post-calving observations that suggest that this reconfiguration and subsequent grounding of B09B have driven the development of a new polynya and associated HSSW production off Commonwealth Bay. Supported by satellite observations and modelling, our findings demonstrate how local icescape changes may impact the formation of HSSW, with potential implications for large-scale ocean circulation.
Mikolaj, M.; Meurers, B.; Güntner, A. (2016). Modelling of global mass effects in hydrology, atmosphere and oceans on surface gravity, Computers & Geosciences (93), 12-20, 10.1016/j.cageo.2016.04.014.
Title: Modelling of global mass effects in hydrology, atmosphere and oceans on surface gravity
Type: Journal Article
Publication: Computers & Geosciences
Author(s): Mikolaj, M.; Meurers, B.; Güntner, A.
Year: 2016
Formatted Citation: Mikolaj, M., B. Meurers, and A. Güntner, 2016: Modelling of global mass effects in hydrology, atmosphere and oceans on surface gravity. Computers & Geosciences, 93, 12-20, doi:10.1016/j.cageo.2016.04.014
Formatted Citation: Srivastava, A., S. Dwivedi, and A. K. Mishra, 2016: Intercomparison of High-Resolution Bay of Bengal Circulation Models Forced with Different Winds. Marine Geodesy, 39(3-4), 271-289, doi:10.1080/01490419.2016.1173606
Title: Utilization Of Satellite-Derived Salinity To Study Indian Ocean Climate Variability
Type: Thesis
Publication:
Author(s): D'Addezio, Joseph Matthew
Year: 2016
Formatted Citation: D'Addezio, J. M., 2016: Utilization Of Satellite-Derived Salinity To Study Indian Ocean Climate Variability. https://scholarcommons.sc.edu/etd/3772/.
Wunsch, C (2016). Global Ocean Integrals and Means, with Trend Implications, Ann Rev Mar Sci (8), 1-33, 10.1146/annurev-marine-122414-034040.
Title: Global Ocean Integrals and Means, with Trend Implications
Type: Journal Article
Publication: Ann Rev Mar Sci
Author(s): Wunsch, C
Year: 2016
Formatted Citation: Wunsch, C., 2016: Global Ocean Integrals and Means, with Trend Implications. Ann Rev Mar Sci, 8, 1-33, doi:10.1146/annurev-marine-122414-034040
Abstract: Understanding the ocean requires determining and explaining global integrals and equivalent average values of temperature (heat), salinity (freshwater and salt content), sea level, energy, and other properties. Attempts to determine means, integrals, and climatologies have been hindered by thinly and poorly distributed historical observations in a system in which both signals and background noise are spatially very inhomogeneous, leading to potentially large temporal bias errors that must be corrected at the 1% level or better. With the exception of the upper ocean in the current altimetric-Argo era, no clear documentation exists on the best methods for estimating means and their changes for quantities such as heat and freshwater at the levels required for anthropogenic signals. Underestimates of trends are as likely as overestimates; for example, recent inferences that multidecadal oceanic heat uptake has been greatly underestimated are plausible. For new or augmented observing systems, calculating the accuracies and precisions of global, multidecadal sampling densities for the full water column is necessary to avoid the irrecoverable loss of scientifically essential information.
Keywords:
ECCO Products Used: ECCO-V4;ECCO2
URL:
Other URLs:
Soccodato, Alice; D'Ovidio, Francesco; Lévy, Marina; Jahn, Oliver; Follows, Michael J.; De Monte, Silvia (2016). Estimating planktonic diversity through spatial dominance patterns in a model ocean, Marine Genomics (29), 9-17, 10.1016/j.margen.2016.04.015.
Title: Estimating planktonic diversity through spatial dominance patterns in a model ocean
Type: Journal Article
Publication: Marine Genomics
Author(s): Soccodato, Alice; D'Ovidio, Francesco; Lévy, Marina; Jahn, Oliver; Follows, Michael J.; De Monte, Silvia
Year: 2016
Formatted Citation: Soccodato, A., F. D'Ovidio, M. Lévy, O. Jahn, M. J. Follows, and S. De Monte, 2016: Estimating planktonic diversity through spatial dominance patterns in a model ocean. Marine Genomics, 29, 9-17, doi:10.1016/j.margen.2016.04.015
Formatted Citation: Heaney, K. D., 2016: Deep Water Ocean Acoustics., Arlington, VA, 27 pp. https://apps.dtic.mil/docs/citations/AD1025892.
Abstract: In this work for code 32 (Ocean Acoustics) of the Office of Naval Research, OASIS has focused on the development of new propagation models and their application to problems in acoustic propagation in deep water, including global scale acoustic propagation relevant to geophysics sound sources (volcanoes/earthquakes) and the detection of nuclear test event. The Peregrine PE model was developed as an re-coding in C of the Range-dependent Acoustic Model (RAM). This code was extended to 3-dimensions by applying the split-step Pade kernel in cross-range at each range step. The kernel of Peregrine (Seahawks) has been submitted to the Ocean Atmospheric Media Library (OAML). Peregrine was applied to hydroacoustic recordings from a Comprehensive Test Ban Treaty Organization (CTBTO) of a seismic tomography experiment off of Japan, with excellent quantitative agreement in both the energy received and the travel time, both exhibiting strong 3D propagation. A paper was published on using noise correlations to estimate local sound speed, as well as the horizontal deflection caused by mesoscale eddies as they traverse long ranges. Propagation and ambient noise analysis was conducted on the North Pacific Acoustics Laboratory Philippine Sea tests 2009 and 2010, both of which Dr. Heaney participated as a co-chief scientist.
Blunden, Jessica; Arndt, Derek S. (2016). State of the Climate in 2015, Bulletin of the American Meteorological Society, 8 (97), Si-S275, 10.1175/2016BAMSStateoftheClimate.1.
Publication: Bulletin of the American Meteorological Society
Author(s): Blunden, Jessica; Arndt, Derek S.
Year: 2016
Formatted Citation: Blunden, J., and D. S. Arndt, 2016: State of the Climate in 2015. Bull. Am. Meteorol. Soc., 97(8), Si-S275, doi:10.1175/2016BAMSStateoftheClimate.1
Abstract: Editor's note: For easy download the posted pdf of the State of the Climate for 2016 is a very low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download.
Formatted Citation: Zhang, M., L. Zhou, H. Fu, L. Jiang, and X. Zhang, 2016: Assessment of intraseasonal variabilities in China Ocean Reanalysis (CORA). Acta Oceanologica Sinica, 35(3), 90-101, doi:10.1007/s13131-016-0820-2
Title: Arctic pathways of Pacific Water: Arctic Ocean Model Intercomparison experiments
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Aksenov, Yevgeny; Karcher, Michael; Proshutinsky, Andrey; Gerdes, Rüdiger; de Cuevas, Beverly; Golubeva, Elena; Kauker, Frank; Nguyen, An T.; Platov, Gennady A.; Wadley, Martin; Watanabe, Eiji; Coward, Andrew C.; Nurser, A. J. George
Year: 2016
Formatted Citation: Aksenov, Y. and Coauthors, 2016: Arctic pathways of Pacific Water: Arctic Ocean Model Intercomparison experiments. J. Geophys. Res. Ocean., 121(1), 27-59, doi:10.1002/2015JC011299
Li, Xin; Rignot, Eric; Mouginot, Jeremie; Scheuchl, Bernd (2016). Ice flow dynamics and mass loss of Totten Glacier, East Antarctica, from 1989 to 2015, Geophysical Research Letters, 12 (43), 6366-6373, 10.1002/2016GL069173.
Formatted Citation: Li, X., E. Rignot, J. Mouginot, and B. Scheuchl, 2016: Ice flow dynamics and mass loss of Totten Glacier, East Antarctica, from 1989 to 2015. Geophys. Res. Lett., 43(12), 6366-6373, doi:10.1002/2016GL069173
Title: Utilization Of Satellite-Derived Salinity To Study Indian Ocean Climate Variability
Type: Thesis
Publication:
Author(s): D'Addezio, Joseph Matthew
Year: 2016
Formatted Citation: D'Addezio, J. M., 2016: Utilization Of Satellite-Derived Salinity To Study Indian Ocean Climate Variability. https://scholarcommons.sc.edu/etd/3772/.
Title: Mesoscale to Submesoscale Wavenumber Spectra in Drake Passage
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Rocha, Cesar B; Chereskin, Teresa K; Gille, Sarah T; Menemenlis, Dimitris
Year: 2016
Formatted Citation: Rocha, C. B., T. K. Chereskin, S. T. Gille, and D. Menemenlis, 2016: Mesoscale to Submesoscale Wavenumber Spectra in Drake Passage. Journal of Physical Oceanography, 46(2), 601-620, doi:10.1175/JPO-D-15-0087.1
Abstract: This study discusses the upper-ocean (0-200 m) horizontal wavenumber spectra in the Drake Passage from 13 yr of shipboard ADCP measurements, altimeter data, and a high-resolution numerical simulation. At scales between 10 and 200 km, the ADCP kinetic energy spectra approximately follow a k−3 power law. The observed flows are more energetic at the surface, but the shape of the kinetic energy spectra is independent of depth. These characteristics resemble predictions of isotropic interior quasigeostrophic turbulence. The ratio of across-track to along-track kinetic energy spectra, however, significantly departs from the expectation of isotropic interior quasigeostrophic turbulence. The inconsistency is dramatic at scales smaller than 40 km. A Helmholtz decomposition of the ADCP spectra and analyses of synthetic and numerical model data show that horizontally divergent, ageostrophic flows account for the discrepancy between the observed spectra and predictions of isotropic interior quasigeostrophic turbulence. In Drake Passage, ageostrophic motions appear to be dominated by inertia-gravity waves and account for about half of the near-surface kinetic energy at scales between 10 and 40 km. Model results indicate that ageostrophic flows imprint on the sea surface, accounting for about half of the sea surface height variance between 10 and 40 km.
Hughes, Chris W.; Williams, Joanne; Hibbert, Angela; Boening, Carmen; Oram, James (2016). A Rossby whistle: A resonant basin mode observed in the Caribbean Sea, Geophysical Research Letters, 13 (43), 7036-7043, 10.1002/2016GL069573.
Title: A Rossby whistle: A resonant basin mode observed in the Caribbean Sea
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Hughes, Chris W.; Williams, Joanne; Hibbert, Angela; Boening, Carmen; Oram, James
Year: 2016
Formatted Citation: Hughes, C. W., J. Williams, A. Hibbert, C. Boening, and J. Oram, 2016: A Rossby whistle: A resonant basin mode observed in the Caribbean Sea. Geophys. Res. Lett., 43(13), 7036-7043, doi:10.1002/2016GL069573
Yang, Qinghua; Losch, Martin; Losa, Svetlana N.; Jung, Thomas; Nerger, Lars; Lavergne, Thomas (2016). Brief communication: The challenge and benefit of using sea ice concentration satellite data products with uncertainty estimates in summer sea ice data assimilation, The Cryosphere, 2 (10), 761-774, 10.5194/tc-10-761-2016.
Title: Brief communication: The challenge and benefit of using sea ice concentration satellite data products with uncertainty estimates in summer sea ice data assimilation
Formatted Citation: Yang, Q., M. Losch, S. N. Losa, T. Jung, L. Nerger, and T. Lavergne, 2016: Brief communication: The challenge and benefit of using sea ice concentration satellite data products with uncertainty estimates in summer sea ice data assimilation. Cryosph., 10(2), 761-774, doi:10.5194/tc-10-761-2016
Abstract: Data assimilation experiments that aim at improving summer ice concentration and thickness forecasts in the Arctic are carried out. The data assimilation system used is based on the MIT general circulation model (MITgcm) and a local singular evolutive interpolated Kalman (LSEIK) filter. The effect of using sea ice concentration satellite data products with appropriate uncertainty estimates is assessed by three different experiments using sea ice concentration data of the European Space Agency Sea Ice Climate Change Initiative (ESA SICCI) which are provided with a per-grid-cell physically based sea ice concentration uncertainty estimate. The first experiment uses the constant uncertainty, the second one imposes the provided SICCI uncertainty estimate, while the third experiment employs an elevated minimum uncertainty to account for a representation error. Using the observation uncertainties that are provided with the data improves the ensemble mean forecast of ice concentration compared to using constant data errors, but the thickness forecast, based on the sparsely available data, appears to be degraded. Further investigating this lack of positive impact on the sea ice thicknesses leads us to a fundamental mismatch between the satellite-based radiometric concentration and the modeled physical ice concentration in summer: the passive microwave sensors used for deriving the vast majority of the sea ice concentration satellite-based observations cannot distinguish ocean water (in leads) from melt water (in ponds). New data assimilation methodologies that fully account or mitigate this mismatch must be designed for successful assimilation of sea ice concentration satellite data in summer melt conditions. In our study, thickness forecasts can be slightly improved by adopting the pragmatic solution of raising the minimum observation uncertainty to inflate the data error and ensemble spread.
Schodlok, M P; Menemenlis, Dimitris; Rignot, E J (2016). Ice shelf basal melt rates around Antarctica from simulations and observations, Journal of Geophysical Research: Oceans, 2 (121), 1085-1109, 10.1002/2015JC011117.
Title: Ice shelf basal melt rates around Antarctica from simulations and observations
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Schodlok, M P; Menemenlis, Dimitris; Rignot, E J
Year: 2016
Formatted Citation: Schodlok, M. P., D. Menemenlis, and E. J. Rignot, 2016: Ice shelf basal melt rates around Antarctica from simulations and observations. J. Geophys. Res. Ocean., 121(2), 1085-1109, doi:10.1002/2015JC011117
Abstract: We introduce an explicit representation of Antarctic ice shelf cavities in the Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2) ocean retrospective analysis; and compare resulting basal melt rates and patterns to independent estimates from satellite observations. Two simulations are carried out: the first is based on the original ECCO2 vertical discretization; the second has higher vertical resolution particularly at the depth range of ice shelf cavities. The original ECCO2 vertical discretization produces higher than observed melt rates and leads to a misrepresentation of Southern Ocean water mass properties and transports. In general, thicker levels at the base of the ice shelves lead to increased melting because of their larger heat capacity. This strengthens horizontal gradients and circulation within and outside the cavities and, in turn, warm water transports from the shelf break to the ice shelves. The simulation with more vertical levels produces basal melt rates (1735 ± 164 Gt/a) and patterns that are in better agreement with observations. Thinner levels in the sub-ice-shelf cavities improve the representation of a fresh/cold layer at the ice shelf base and of warm/salty water near the bottom, leading to a sharper pycnocline and reduced vertical mixing underneath the ice shelf. Improved water column properties lead to more accurate melt rates and patterns, especially for melt/freeze patterns under large cold-water ice shelves. At the 18 km grid spacing of the ECCO2 model configuration, the smaller, warm-water ice shelves cannot be properly represented, with higher than observed melt rates in both simulations.
Rocha, Cesar B; Gille, Sarah T; Chereskin, Teresa K; Menemenlis, Dimitris (2016). Seasonality of submesoscale dynamics in the Kuroshio Extension, Geophys. Res. Lett., 21 (43), 11304-11311, 10.1002/2016GL071349.
Title: Seasonality of submesoscale dynamics in the Kuroshio Extension
Type: Journal Article
Publication: Geophys. Res. Lett.
Author(s): Rocha, Cesar B; Gille, Sarah T; Chereskin, Teresa K; Menemenlis, Dimitris
Year: 2016
Formatted Citation: Rocha, C. B., S. T. Gille, T. K. Chereskin, and D. Menemenlis, 2016: Seasonality of submesoscale dynamics in the Kuroshio Extension. Geophys. Res. Lett., 43(21), 11304-11311, doi:10.1002/2016GL071349
Abstract: Recent studies show that the vigorous seasonal cycle of the mixed layer modulates upper ocean submesoscale turbulence. Here we provide model-based evidence that the seasonally changing upper ocean stratification in the Kuroshio Extension also modulates submesoscale (here 10-100 km) inertia-gravity waves. Summertime restratification weakens submesoscale turbulence but enhances inertia-gravity waves near the surface. Thus, submesoscale turbulence and inertia-gravity waves undergo vigorous out-of-phase seasonal cycles. These results imply a strong seasonal modulation of the accuracy of geostrophic velocity diagnosed from submesoscale sea surface height delivered by the SurfaceWater and Ocean Topography satellite mission.
Liu, Junjie; Bowman, Kevin W.; Lee, Meemong (2016). Comparison between the Local Ensemble Transform Kalman Filter (LETKF) and 4D-Var in atmospheric CO 2 flux inversion with the Goddard Earth Observing System-Chem model and the observation impact diagnostics from the LETKF, Journal of Geophysical Research: Atmospheres, 21 (121), 13,066-13,087, 10.1002/2016JD025100.
Title: Comparison between the Local Ensemble Transform Kalman Filter (LETKF) and 4D-Var in atmospheric CO 2 flux inversion with the Goddard Earth Observing System-Chem model and the observation impact diagnostics from the LETKF
Type: Journal Article
Publication: Journal of Geophysical Research: Atmospheres
Author(s): Liu, Junjie; Bowman, Kevin W.; Lee, Meemong
Year: 2016
Formatted Citation: Liu, J., K. W. Bowman, and M. Lee, 2016: Comparison between the Local Ensemble Transform Kalman Filter (LETKF) and 4D-Var in atmospheric CO 2 flux inversion with the Goddard Earth Observing System-Chem model and the observation impact diagnostics from the LETKF. Journal of Geophysical Research: Atmospheres, 121(21), 13,066-13,087, doi:10.1002/2016JD025100
Jönsson, Bror F.; Watson, James R. (2016). The timescales of global surface-ocean connectivity, Nature Communications, 1 (7), 11239, 10.1038/ncomms11239.
Title: The timescales of global surface-ocean connectivity
Type: Journal Article
Publication: Nature Communications
Author(s): Jönsson, Bror F.; Watson, James R.
Year: 2016
Formatted Citation: Jönsson, B. F., and J. R. Watson, 2016: The timescales of global surface-ocean connectivity. Nature Communications, 7(1), 11239, doi:10.1038/ncomms11239
Chowdary, Jasti; Srinivas, G.; Fousiya, T.S.; Parekh, Anant; Gnanaseelan, C.; Seo, Hyodae; MacKinnon, Jennifer (2016). Representation of Bay of Bengal Upper-Ocean Salinity in General Circulation Models, Oceanography, 2 (29), 38-49, 10.5670/oceanog.2016.37.
Title: Representation of Bay of Bengal Upper-Ocean Salinity in General Circulation Models
Type: Journal Article
Publication: Oceanography
Author(s): Chowdary, Jasti; Srinivas, G.; Fousiya, T.S.; Parekh, Anant; Gnanaseelan, C.; Seo, Hyodae; MacKinnon, Jennifer
Year: 2016
Formatted Citation: Chowdary, J., G. Srinivas, T. Fousiya, A. Parekh, C. Gnanaseelan, H. Seo, and J. MacKinnon, 2016: Representation of Bay of Bengal Upper-Ocean Salinity in General Circulation Models. Oceanography, 29(2), 38-49, doi:10.5670/oceanog.2016.37
Su, Zhan (2016). High-Latitude Ocean Convection and Gyre Dynamics.
Title: High-Latitude Ocean Convection and Gyre Dynamics
Type: Thesis
Publication:
Author(s): Su, Zhan
Year: 2016
Formatted Citation: Su, Z., 2016: High-Latitude Ocean Convection and Gyre Dynamics., 278 pp. doi:10.7907/Z9H12ZZ3.
Abstract: High-latitude ocean deep convection substantially contributes to vertical mixing, ver- tical heat transport, deep-water formation, and sea-ice budget in the World Ocean. However, the extent of this contribution remains poorly constrained. The concept of ocean convective available potential energy (OCAPE) is developed to improve the un- derstanding and the prediction for these deep convection events. The kinetic energy (KE) budget of deep convection is explored analytically and numerically based on the observations in the Weddell Sea. OCAPE, which is derived from thermobaricity, is identified as a critical KE source to power ocean deep convection. Other significant contributions to the energetics of convection, including diabatic processes related to cabbeling and stratification are also carefully quantified. An associated theory is de- veloped to predict the maximum depth of convection. This work may provide a useful basis for improving the convection parameterization in ocean models. As an application of the theory above, basin-scale OCAPE is found to be signifi- cantly built up in North Atlantic at the end of Heinrich Stadial 1 ( ∼17,000 years ago). This OCAPE is ultimately released to power strong ocean deep convection in North Atlantic as simulated by numerical models. This causes a ∼2 o C sea surface warming for the whole basin (∼700 km) within a month and exposes a huge heat reservoir to the atmosphere. This may invigorate the Atlantic meridional overturning circu- lation and provides an important mechanism to explain the abrupt Bolling-Allerod warming. Mesoscale turbulence is another crucial process for high-latitude ocean dynam- ics. From the physical nature of baroclinic instability, the framework of eddy-size- constrained Available Potential Energy (APE) density is developed, which is capable of well detecting individual eddies and local eddy kinetic energy (EKE) in the World Ocean. This new framework is likely useful in parameterizing mesoscale eddies in ocean GCMs. Mesoscale turbulence are found to be coupled to the wind-driven Ek- man pumping in determining the temperature and salinity budgets in subpolar gyres such as the Weddell Gyre. Topography is shown to be another crucial dynamic factor that modulates the potential vorticity budget and hence strongly influences the strati- fication of subpolar gyres. Considering these factors, a physical model is developed to predict the observed temperature and salinity variability around the Antarctic mar- gins. This model is useful for understanding and predicting the export of Antarctic Bottom Water and hence the associated high-latitude ocean transport of heat, salt and nutrients.
Keywords:
ECCO Products Used: ECCO2
URL:
Other URLs:
Pemberton, P.; Nilsson, J. (2016). The response of the central Arctic Ocean stratification to freshwater perturbations, Journal of Geophysical Research: Oceans, 1 (121), 792-817, 10.1002/2015JC011003.
Title: The response of the central Arctic Ocean stratification to freshwater perturbations
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Pemberton, P.; Nilsson, J.
Year: 2016
Formatted Citation: Pemberton, P., and J. Nilsson, 2016: The response of the central Arctic Ocean stratification to freshwater perturbations. J. Geophys. Res. Ocean., 121(1), 792-817, doi:10.1002/2015JC011003
DeVaney, Shannon C. (2016). Species Distribution Modeling of Deep Pelagic Eels, Integrative and Comparative Biology, 4 (56), 524-530, 10.1093/icb/icw032.
Title: Species Distribution Modeling of Deep Pelagic Eels
Type: Journal Article
Publication: Integrative and Comparative Biology
Author(s): DeVaney, Shannon C.
Year: 2016
Formatted Citation: DeVaney, S. C., 2016: Species Distribution Modeling of Deep Pelagic Eels. Integrative and Comparative Biology, 56(4), 524-530, doi:10.1093/icb/icw032
Title: Utilizing Cloud Computing to Support Scalable Atmospheric Modeling
Type: Book Section
Publication: Cloud Computing in Ocean and Atmospheric Sciences
Author(s): Li, J.; Liu, K.; Huang, Q.
Year: 2016
Formatted Citation: Li, J., K. Liu, and Q. Huang, 2016: Utilizing Cloud Computing to Support Scalable Atmospheric Modeling. Cloud Computing in Ocean and Atmospheric Sciences, Elsevier, 347-364, doi:10.1016/B978-0-12-803192-6.00017-7
Abstract: Atmospheric modeling is an important method to generate physical and numerical measurements of climate parameters, quantify the spatiotemporal changes of atmospheric phenomena over space and time, and predict their occurrences. With simulated data sets from atmospheric models, scientists are able to examine the driving forces of atmospheric phenomena and perform advanced analysis. Due to the inherent complexity and computational intensity of atmospheric models, running such models requires considerable amounts of computing resources. Traditionally, high-performance supercomputers or clusters have been used to perform atmospheric modeling. Recently, cloud computing solutions are emerged as a cost-effective approach to provide on-demand computing resources, remove the technical barriers, and reduce the high costs for computing facility management and maintenance. This chapter presents the design and implementation of a cloud-based framework to facilitate atmospheric modeling. The framework consists of a web portal, cloud instances, and a cloud-based data repository. To evaluate the feasibility of the framework, we have customized and deployed the serial processing version of ModelE onto our framework. Upon the deployment, we conducted two sets of experiments to evaluate the readiness of cloud computing resources to support large-scale atmospheric modeling. Experimental results demonstrate the framework provides scalable and customizable computing resources that meet the computational needs of atmospheric modeling.
Keywords: Atmospheric Modeling, Cloud computing, Data management, Model evaluation, ModelE, Visualization
Other URLs: https://www.sciencedirect.com/science/article/pii/B9780128031926000177, https://linkinghub.elsevier.com/retrieve/pii/B9780128031926000177
Bulgin, C.E.; Embury, O.; Merchant, C.J. (2016). Sampling uncertainty in gridded sea surface temperature products and Advanced Very High Resolution Radiometer (AVHRR) Global Area Coverage (GAC) data, Remote Sensing of Environment (177), 287-294, 10.1016/j.rse.2016.02.021.
Title: Sampling uncertainty in gridded sea surface temperature products and Advanced Very High Resolution Radiometer (AVHRR) Global Area Coverage (GAC) data
Formatted Citation: Bulgin, C., O. Embury, and C. Merchant, 2016: Sampling uncertainty in gridded sea surface temperature products and Advanced Very High Resolution Radiometer (AVHRR) Global Area Coverage (GAC) data. Remote Sensing of Environment, 177, 287-294, doi:10.1016/j.rse.2016.02.021
Cerovečki, Ivana; Giglio, Donata (2016). North Pacific Subtropical Mode Water Volume Decrease in 2006-09 Estimated from Argo Observations: Influence of Surface Formation and Basin-Scale Oceanic Variability, Journal of Climate, 6 (29), 2177-2199, 10.1175/JCLI-D-15-0179.1.
Title: North Pacific Subtropical Mode Water Volume Decrease in 2006-09 Estimated from Argo Observations: Influence of Surface Formation and Basin-Scale Oceanic Variability
Type: Journal Article
Publication: Journal of Climate
Author(s): Cerovečki, Ivana; Giglio, Donata
Year: 2016
Formatted Citation: Cerovečki, I., and D. Giglio, 2016: North Pacific Subtropical Mode Water Volume Decrease in 2006-09 Estimated from Argo Observations: Influence of Surface Formation and Basin-Scale Oceanic Variability. J. Clim., 29(6), 2177-2199, doi:10.1175/JCLI-D-15-0179.1
Hu, Shijian; Sprintall, Janet (2016). Interannual variability of the Indonesian Throughflow: The salinity effect, Journal of Geophysical Research: Oceans, 4 (121), 2596-2615, 10.1002/2015JC011495.
Title: Interannual variability of the Indonesian Throughflow: The salinity effect
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Hu, Shijian; Sprintall, Janet
Year: 2016
Formatted Citation: Hu, S., and J. Sprintall, 2016: Interannual variability of the Indonesian Throughflow: The salinity effect. J. Geophys. Res. Ocean., 121(4), 2596-2615, doi:10.1002/2015JC011495
Bloshkina, Ekaterina Vladimirovna; Makhotin, Mikhail S.; Volkov, Denis L.; Koldunov, N. V. (2016). Comparison the Arctic Ocean the thermohaline characteristics distribution from the observed data and MITgcm model simulated data, Scientific Records of the Russian State Hydrometeorological University, 67-88.
Title: Comparison the Arctic Ocean the thermohaline characteristics distribution from the observed data and MITgcm model simulated data
Type: Journal Article
Publication: Scientific Records of the Russian State Hydrometeorological University
Author(s): Bloshkina, Ekaterina Vladimirovna; Makhotin, Mikhail S.; Volkov, Denis L.; Koldunov, N. V.
Year: 2016
Formatted Citation: Bloshkina, E. V., M. S. Makhotin, D. L. Volkov, and N. V. Koldunov, 2016: Comparison the Arctic Ocean the thermohaline characteristics distribution from the observed data and MITgcm model simulated data. Scientific Records of the Russian State Hydrometeorological University, 67-88, http://www.rshu.ru/university/notes/archive/issue43/uz43-67-88.pdf
Abstract: Here we show weekly average distribution of temperature and salinity in the Arctic Ocean calculated by regional configuration of the MITgcm model between 2000 and 2012. Based on comparison simulated and observed data the model shows close approximation of temperature and salinity vertical distribution in the Arctic Basin. Calculated depths of the Atlantic water are close to observed data. Modeling results show local temperature maximum in the layer of Pacific origin water characterised by values close to measured.
Keywords: Arctic basin, Arctic ocean, Atlantic waters, ECCO2, Pacific waters, hydrodynamic model MITgcm, thermohalin characteristics, water masses
Su, Zhan; Ingersoll, Andrew P. (2016). On the Minimum Potential Energy State and the Eddy Size-Constrained APE Density, Journal of Physical Oceanography, 9 (46), 2663-2674, 10.1175/JPO-D-16-0074.1.
Title: On the Minimum Potential Energy State and the Eddy Size-Constrained APE Density
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Su, Zhan; Ingersoll, Andrew P.
Year: 2016
Formatted Citation: Su, Z., and A. P. Ingersoll, 2016: On the Minimum Potential Energy State and the Eddy Size-Constrained APE Density. Journal of Physical Oceanography, 46(9), 2663-2674, doi:10.1175/JPO-D-16-0074.1
Chen, Ru; Thompson, Andrew F.; Flierl, Glenn R. (2016). Time-Dependent Eddy-Mean Energy Diagrams and Their Application to the Ocean, Journal of Physical Oceanography, 9 (46), 2827-2850, 10.1175/JPO-D-16-0012.1.
Title: Time-Dependent Eddy-Mean Energy Diagrams and Their Application to the Ocean
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Chen, Ru; Thompson, Andrew F.; Flierl, Glenn R.
Year: 2016
Formatted Citation: Chen, R., A. F. Thompson, and G. R. Flierl, 2016: Time-Dependent Eddy-Mean Energy Diagrams and Their Application to the Ocean. Journal of Physical Oceanography, 46(9), 2827-2850, doi:10.1175/JPO-D-16-0012.1
Bloshkina, Ekaterina Vladimirovna; Ivanov, Vladimir Vladimirovich (2016). Convective structures in the Norwegian and Greenland Seas according to results of modeling with a high spatial resolution, Works of Hydrometeorological Research Center of the Russian Federation, 361, 146-168.
Title: Convective structures in the Norwegian and Greenland Seas according to results of modeling with a high spatial resolution
Type: Journal Article
Publication: Works of Hydrometeorological Research Center of the Russian Federation
Author(s): Bloshkina, Ekaterina Vladimirovna; Ivanov, Vladimir Vladimirovich
Year: 2016
Formatted Citation: Bloshkina, E. V., and V. V. Ivanov, 2016: Convective structures in the Norwegian and Greenland Seas according to results of modeling with a high spatial resolution. Works of Hydrometeorological Research Center of the Russian Federation(361), 146-168, http://method.meteorf.ru/publ/tr/tr361/blosh.pdf
Abstract: Vertical convection is one of the most important processes, which accounts for stable hydrographic conditions in the World Ocean. In winter, cold water descents in cyclonic gyres of the North-Eurоpean basin [Anna1] of the Arctic Ocean and in the Baffin Bay, thus feeding the southward moving deep branch of the global thermohaline circulation. Changes in the Arctic climate system in 1990-2000 had affected convective processes in the Nordic seas too. Instead of a massive penetration of surface water to a considerable depth in the Greenland Sea, as was observed in the 20th century, deep mesoscale eddies similar in structure to the intrapycnocline lenses in the Lofoten Basin of the Norwegian Sea started to appear in observations. It is impossible to judge from just formal resemblance whether the physical processes leading to the formation of anomalous structures in two deep-water North-European basins are similar. A possible approach to answering this question is mathematical modeling, which allows one to follow the evolution of the anomalies. The first step on this way is the most close to the reality model reconstruction of the thermohaline water structure. The article attempts to assess whether the results of the numerical simulation with high spatial resolution are adequate to observation-based features of the vertical thermohaline structure in Lofoten and Greenland basins.
Zhang, Yu; Chen, Changsheng; Beardsley, Robert C.; Gao, Guoping; Qi, Jianhua; Lin, Huichan (2016). Seasonal and interannual variability of the Arctic sea ice: A comparison between AO-FVCOM and observations, Journal of Geophysical Research: Oceans, 11 (121), 8320-8350, 10.1002/2016JC011841.
Formatted Citation: Zhang, Y., C. Chen, R. C. Beardsley, G. Gao, J. Qi, and H. Lin, 2016: Seasonal and interannual variability of the Arctic sea ice: A comparison between AO-FVCOM and observations. J. Geophys. Res. Ocean., 121(11), 8320-8350, doi:10.1002/2016JC011841
Sánchez, L.; Čunderlík, R.; Dayoub, N.; Mikula, K.; Minarechová, Z.; Šíma, Z.; Vatrt, V.; Vojtíšková, M. (2016). A conventional value for the geoid reference potential W 0, Journal of Geodesy, 9 (90), 815-835, 10.1007/s00190-016-0913-x.
Formatted Citation: Sánchez, L., R. Čunderlík, N. Dayoub, K. Mikula, Z. Minarechová, Z. Šíma, V. Vatrt, and M. Vojtíšková, 2016: A conventional value for the geoid reference potential W 0. Journal of Geodesy, 90(9), 815-835, doi:10.1007/s00190-016-0913-x
Huang, Xumei; Wang, Weiqiang; Liu, Hailong (2016). The dynamic characteristics of deep meridional overturning circulation in the Indian Ocean based on six reanalysis datasets, Journal of Tropical Oceanography, 4 (35), 11-20, 10.11978/2015126.
Formatted Citation: Huang, X., W. Wang, and H. Liu, 2016: The dynamic characteristics of deep meridional overturning circulation in the Indian Ocean based on six reanalysis datasets. Journal of Tropical Oceanography, 35(4), 11-20, doi:10.11978/2015126
Abstract: Based on six sets of model products, the dynamic characteristics of the deep meridional overturning circulation in the Indian Ocean under time-average conditions are studied. In the time-average state, the Meridional overturning circulation (MOC) of the Indian Ocean presents a consistent structure in each set of data, that is, the bottom and deep water bodies enter the Indian Ocean to the north, and the counter-clockwise structure of the Indian Ocean flows southward and southward. Through the dynamic decomposition of the meridional overturning circulation, the paper analyzes the similarities and differences of each power part in each set of data. In each set of data, the Ekman part of the South Indian Ocean presents a consistent counterclockwise flip structure with the highest intensity at 10°S; the ground rotation and the outer mold part exhibit similar clockwise and counterclockwise flip structures respectively at 10°S south. At 27°S, the intensity is the largest and the sign is opposite; relatively speaking, the Ekman part is more obvious between the 20°S and the equator, and the ground rotation and the outer part are more in the area south of 25°S. obvious. Based on different dynamic thermal forcings, there are significant differences in the spatial extent and intensity of each dynamic part of the flow function in each set of data: Since the wind fields of each set of data are not much different, the overall structure of the Ekman part is similar, and the intensity difference is small; In the geostrophic part, the difference in the strength of the clockwise flip structure exhibited by each data is mainly affected by the strength of the baroclinic flow field in the inner zone and the structure of the western boundary flow. The stronger the baroclinic flow field in the inner zone, the stronger the flip structure; the west boundary The wider the flow width, the greater the influence on the baroclinic flow field in the inner zone, and the greater the weakening of the inversion structure strength; the strength of the partially inverted structure of the outer die is affected by the strength of the western boundary flow: the greater the strength of the western boundary flow, the outer mode The greater the strength of the partially inverted structure.
Title: Dynamic modeling of the horizontal eddy viscosity coefficient for quasigeostrophic ocean circulation problems
Type: Journal Article
Publication: Journal of Ocean Engineering and Science
Author(s): Maulik, Romit; San, Omer
Year: 2016
Formatted Citation: Maulik, R., and O. San, 2016: Dynamic modeling of the horizontal eddy viscosity coefficient for quasigeostrophic ocean circulation problems. Journal of Ocean Engineering and Science, 1(4), 300-324, doi:10.1016/j.joes.2016.08.002
Wu, Yang; Zhai, Xiaoming; Wang, Zhaomin (2016). Impact of Synoptic Atmospheric Forcing on the Mean Ocean Circulation, Journal of Climate, 16 (29), 5709-5724, 10.1175/JCLI-D-15-0819.1.
Formatted Citation: Wu, Y., X. Zhai, and Z. Wang, 2016: Impact of Synoptic Atmospheric Forcing on the Mean Ocean Circulation. J. Clim., 29(16), 5709-5724, doi:10.1175/JCLI-D-15-0819.1
Title: Net primary productivity estimates and environmental variables in the Arctic Ocean: An assessment of coupled physical-biogeochemical models
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Lee, Younjoo J.; Matrai, Patricia A.; Friedrichs, Marjorie A. M.; Saba, Vincent S.; Aumont, Olivier; Babin, Marcel; Buitenhuis, Erik T.; Chevallier, Matthieu; de Mora, Lee; Dessert, Morgane; Dunne, John P.; Ellingsen, Ingrid H.; Feldman, Doron; Frouin, Robert; Gehlen, Marion; Gorgues, Thomas; Ilyina, Tatiana; Jin, Meibing; John, Jasmin G.; Lawrence, Jon; Manizza, Manfredi; Menkes, Christophe E.; Perruche, Coralie; Le Fouest, Vincent; Popova, Ekaterina E.; Romanou, Anastasia; Samuelsen, Annette; Schwinger, Jörg; Séférian, Roland; Stock, Charles A.; Tjiputra, Jerry; Tremblay, L. Bruno; Ueyoshi, Kyozo; Vichi, Marcello; Yool, Andrew; Zhang, Jinlun
Year: 2016
Formatted Citation: Lee, Y. J. and Coauthors, 2016: Net primary productivity estimates and environmental variables in the Arctic Ocean: An assessment of coupled physical-biogeochemical models. J. Geophys. Res. Ocean., 121(12), 8635-8669, doi:10.1002/2016JC011993
Formatted Citation: Jung, T. and Coauthors, 2016: Advancing Polar Prediction Capabilities on Daily to Seasonal Time Scales. Bull. Am. Meteorol. Soc., 97(9), 1631-1647, doi:10.1175/BAMS-D-14-00246.1
Proshutinsky, A.; Steele, M.; Timmermans, M.-L. (2016). Forum for Arctic Modeling and Observational Synthesis (FAMOS): Past, current, and future activities, Journal of Geophysical Research: Oceans, 6 (121), 3803-3819, 10.1002/2016JC011898.
Title: Forum for Arctic Modeling and Observational Synthesis (FAMOS): Past, current, and future activities
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Proshutinsky, A.; Steele, M.; Timmermans, M.-L.
Year: 2016
Formatted Citation: Proshutinsky, A., M. Steele, and M. Timmermans, 2016: Forum for Arctic Modeling and Observational Synthesis (FAMOS): Past, current, and future activities. J. Geophys. Res. Ocean., 121(6), 3803-3819, doi:10.1002/2016JC011898
Title: Global evaluation of new GRACE mascon products for hydrologic applications
Type: Journal Article
Publication: Water Resources Research
Author(s): Scanlon, Bridget R.; Zhang, Zizhan; Save, Himanshu; Wiese, David N.; Landerer, Felix W.; Long, Di; Longuevergne, Laurent; Chen, Jianli
Year: 2016
Formatted Citation: Scanlon, B. R., Z. Zhang, H. Save, D. N. Wiese, F. W. Landerer, D. Long, L. Longuevergne, and J. Chen, 2016: Global evaluation of new GRACE mascon products for hydrologic applications. Water Resources Research, 52(12), 9412-9429, doi:10.1002/2016WR019494
Title: Arctic circulation pathways, heat and freshwater fluxes: Results from numerical model
Type: Thesis
Publication:
Author(s): Whitefield, Jonathan David
Year: 2016
Formatted Citation: Whitefield, J. D., 2016: Arctic circulation pathways, heat and freshwater fluxes: Results from numerical model., 133 pp.
Abstract: With increasing attention on Arctic warming and consequent reductions of sea ice, many studies are focusing on the "gateways" to the Arctic Ocean - the regions where water enters and exits the Arctic Basin. The Chukchi Sea is the only pathway for Pacific water to enter the Arctic Ocean. While the Chukchi naturally undergoes large seasonal and interannual variability, currently it is also undergoing larger and rapid changes, which include transition to a longer ice-free season. Numerical models are often used to explore this region, due to observational restrictions associated with sea-ice. Most past and current models tend to represent riverine inputs in a non-realistic manner; adding freshwater on or past the shelf break, not accounting for seasonality of the river discharge, and omitting riverine heat content. In addition, in many of these models, buoyant coastal currents are not well resolved. Here, I present a new river discharge and river temperature data set (at 1/6° resolution). Employing this new data set within a high-resolution pan-Arctic model, freshwater content on the Arctic shelves increased by ~3600 km3 and summ er heat fluxes increased by 8 TW (compared to previous models), resulting in a reduction o f the Arctic-wide September sea ice extent by up to ~10%. With both the improved riverine forcing included in the model calculations, and the model's ability to resolve the Alaskan Coastal Current, the model suggests an additional 0.25 Sv of flow to the long-term Bering Strait volume transport. This translates to a 64% increase in the heat transport and a 32% increase in freshwater transport (including 4% from sea ice). The model also resolves individual transport pathways in the Chukchi Sea, including that of Bering Sea Water, which could influence species composition and distribution in the eastern Chukchi Sea. Increased computing power and improved observational tools lead to more accurate reproductions of coastal currents and riverine influences in these numerical models. Greater understanding of this near-shore region and its influences is vital to further interpret larger connections between terrestrial and marine ecosystems, as well as Arctic-wide and global oceanic changes.
Other URLs: https://scholarworks.alaska.edu/bitstream/handle/11122/6653/Whitefield_uaf_0006N_10478.pdf?sequence=1
McNeely, Jeffrey A. (2016). Biodiversity in a Changing Climate: Linking Science and Management in Conservation edited by Terry L. Root, Kimberly R. Hall, Mark P. Herzog and Christine A. Howell (2015), 244 pp., University of California Press, Oakland, USA. ISBN 978-0-520-28671-9 (pbk, Oryx, 02 (50), 375, 10.1017/S0030605316000168.
Title: Biodiversity in a Changing Climate: Linking Science and Management in Conservation edited by Terry L. Root, Kimberly R. Hall, Mark P. Herzog and Christine A. Howell (2015), 244 pp., University of California Press, Oakland, USA. ISBN 978-0-520-28671-9 (pbk
Type: Journal Article
Publication: Oryx
Author(s): McNeely, Jeffrey A.
Year: 2016
Formatted Citation: McNeely, J. A., 2016: Biodiversity in a Changing Climate: Linking Science and Management in Conservation edited by Terry L. Root, Kimberly R. Hall, Mark P. Herzog and Christine A. Howell (2015), 244 pp., University of California Press, Oakland, USA. ISBN 978-0-520-28671-9 (pbk. Oryx, 50(02), 375, doi:10.1017/S0030605316000168
Title: GOCE ++ Dynamic Topography at the coast and tide gauge unification
Type: Report
Publication:
Author(s): Fenoglio-Marc, Luciana
Year: 2016
Formatted Citation: Fenoglio-Marc, L., 2016: GOCE ++ Dynamic Topography at the coast and tide gauge unification., 1-13 pp. http://www.gocehsu.eu/DELIVERABLES/TechReportWP1300D2_Aug2016_v5.pdf.
Abstract: The objective of this activity is a consolidated and improved understanding and modelling of coastal processes and physics responsible for sea level changes on various temporal/spatial scales. In practice, this study shall combine several elements: Propose and develop an approach to estimate a consistent DT at tide gauges, coastal areas, and open ocean. Validate the approach in well-surveyed areas where DT can be determined at tide gauges. Determine a consistent MDT using GOCE with consistent error covariance fields. Connect measurements of a global set of tide gauges and investigate trends. Develop and outlook how the approach could be further improved using improved coastal altimetry.
Formatted Citation: Zhao, J., Q. Yang, M. Li, Q. Li, C. Li, Z. Tian, and L. Zhang, 2016: Improving Arctic sea ice concentration forecasts with a Nudging data assimilation method. Acta Oceanologica Sinica, 38(5), 70-82, doi:10.3969/j.issn.0253-4193.2016.05.007
Abstract: The rapid reduction of Arctic summer sea ice makes it possible to open the Arctic channel ahead of time. In order to provide timely and reliable sea ice forecast protection for the Arctic ice area shipping activities, it is urgent to improve the sea ice forecast level. This paper is based on the general circulation of MIT. Model (MIT-gcm), using the Newton Relaxation Approximation (Nudging) data assimilation method to assimilate the sea ice intensity data of the second generation advanced microwave radiation imager (AMSR2) of the University of Bremen, Germany, into the model, establishing Arctic sea ice Numerical prediction system. The design experiment compares the improvement effects of three different Nudging coefficient calculation schemes. The results show that different schemes can significantly improve the initial field of sea ice concentration after selecting appropriate parameters. By designing two groups of prediction experiments with or without Nudging assimilation, Combined with the satellite remote sensing sea ice intensity and the nautical ice intensity observation data of the "Snow Dragon" ship during the fifth Arctic scientific expedition in China, quantitative analysis of the 24-120 h forecast of the Arctic sea ice concentration by the Nudging assimilation program. The improvement results. The results show that the Nudging assimilation has a spatial distribution of the total Arctic sea ice concentration within 120 h and the sea ice intensification of the moving single point target. Prediction results were significantly improved; however, in the case of a small change in ice, 24 ~ 120 h forecast Nudging assimilation test results are inferior to the results of prediction of inertia, needs to be further improved forecasting techniques described numerical forecasting system based Nudging assimilation.
Keywords: Arctic sea ice, Nudging, concentration forecast, data assimilation
Rignot, E; Xu, Y; Menemenlis, Dimitris; Mouginot, J; Scheuchl, B; Li, X; Morlighem, M; Seroussi, Hélène; van den Broeke, M; Fenty, Ian; Cai, C; An, L; de Fleurian, B (2016). Modeling of ocean-induced ice melt rates of five west Greenland glaciers over the past two decades, Geophysical Research Letters, 12 (43), 6374-6382, 10.1002/2016GL068784.
Title: Modeling of ocean-induced ice melt rates of five west Greenland glaciers over the past two decades
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Rignot, E; Xu, Y; Menemenlis, Dimitris; Mouginot, J; Scheuchl, B; Li, X; Morlighem, M; Seroussi, Hélène; van den Broeke, M; Fenty, Ian; Cai, C; An, L; de Fleurian, B
Year: 2016
Formatted Citation: Rignot, E. and Coauthors, 2016: Modeling of ocean-induced ice melt rates of five west Greenland glaciers over the past two decades. Geophys. Res. Lett., 43(12), 6374-6382, doi:10.1002/2016GL068784
Abstract: High-resolution, three-dimensional simulations from the Massachusetts Institute of Technology general circulation model ocean model are used to calculate the subaqueous melt rate of the calving faces of Umiamako, Rinks, Kangerdlugssup, Store, and Kangilerngata glaciers, west Greenland, from 1992 to 2015. Model forcing is from monthly reconstructions of ocean state and ice sheet runoff. Results are analyzed in combination with observations of bathymetry, bed elevation, ice front retreat, and glacier speed. We calculate that subaqueous melt rates are 2-3 times larger in summer compared to winter and doubled in magnitude since the 1990s due to enhanced subglacial runoff and 1.6 ± 0.3°C warmer ocean temperature. Umiamako and Kangilerngata retreated rapidly in the 2000s when subaqueous melt rates exceeded the calving rates and ice front retreated to deeper bed elevation. In contrast, Store, Kangerdlugssup, and Rinks have remained stable because their subaqueous melt rates are 3-4 times lower than their calving rates, i.e., the glaciers are dominated by calving processes.
Keywords: calving, glaciology, greenland, ice-ocean interaction, mass balance, subaqueous melt
McGillicuddy, Dennis J. (2016). Mechanisms of Physical-Biological-Biogeochemical Interaction at the Oceanic Mesoscale, Annual Review of Marine Science, 1 (8), 125-159, 10.1146/annurev-marine-010814-015606.
Title: Mechanisms of Physical-Biological-Biogeochemical Interaction at the Oceanic Mesoscale
Type: Journal Article
Publication: Annual Review of Marine Science
Author(s): McGillicuddy, Dennis J.
Year: 2016
Formatted Citation: McGillicuddy, D. J., 2016: Mechanisms of Physical-Biological-Biogeochemical Interaction at the Oceanic Mesoscale. Annual Review of Marine Science, 8(1), 125-159, doi:10.1146/annurev-marine-010814-015606
Title: Ice Sheet Model Intercomparison Project (ISMIP6) contribution to CMIP6
Type: Journal Article
Publication: Geoscientific Model Development
Author(s): Nowicki, Sophie M. J.; Payne, Anthony; Larour, Eric; Seroussi, Helene; Goelzer, Heiko; Lipscomb, William; Gregory, Jonathan; Abe-Ouchi, Ayako; Shepherd, Andrew
Year: 2016
Formatted Citation: Nowicki, S. M. J. and Coauthors, 2016: Ice Sheet Model Intercomparison Project (ISMIP6) contribution to CMIP6. Geoscientific Model Development, 9(12), 4521-4545, doi:10.5194/gmd-9-4521-2016
Abstract: Reducing the uncertainty in the past, present, and future contribution of ice sheets to sea-level change requires a coordinated effort between the climate and glaciology communities. The Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) is the primary activity within the Coupled Model Intercomparison Project – phase 6 (CMIP6) focusing on the Greenland and Antarctic ice sheets. In this paper, we describe the framework for ISMIP6 and its relationship with other activities within CMIP6. The ISMIP6 experimental design relies on CMIP6 climate models and includes, for the first time within CMIP, coupled ice-sheet–climate models as well as standalone ice-sheet models. To facilitate analysis of the multi-model ensemble and to generate a set of standard climate inputs for standalone ice-sheet models, ISMIP6 defines a protocol for all variables related to ice sheets. ISMIP6 will provide a basis for investigating the feedbacks, impacts, and sea-level changes associated with dynamic ice sheets and for quantifying the uncertainty in ice-sheet-sourced global sea-level change.
Heaney, Kevin D.; Campbell, Richard L. (2016). Three-dimensional parabolic equation modeling of mesoscale eddy deflection, The Journal of the Acoustical Society of America, 2 (139), 918-926, 10.1121/1.4942112.
Title: Three-dimensional parabolic equation modeling of mesoscale eddy deflection
Type: Journal Article
Publication: The Journal of the Acoustical Society of America
Author(s): Heaney, Kevin D.; Campbell, Richard L.
Year: 2016
Formatted Citation: Heaney, K. D., and R. L. Campbell, 2016: Three-dimensional parabolic equation modeling of mesoscale eddy deflection. The Journal of the Acoustical Society of America, 139(2), 918-926, doi:10.1121/1.4942112
Chemke, R.; Kaspi, Y. (2016). The latitudinal dependence of the oceanic barotropic eddy kinetic energy and macroturbulence energy transport, Geophysical Research Letters, 6 (43), 2723-2731, 10.1002/2016GL067847.
Title: The latitudinal dependence of the oceanic barotropic eddy kinetic energy and macroturbulence energy transport
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Chemke, R.; Kaspi, Y.
Year: 2016
Formatted Citation: Chemke, R., and Y. Kaspi, 2016: The latitudinal dependence of the oceanic barotropic eddy kinetic energy and macroturbulence energy transport. Geophys. Res. Lett., 43(6), 2723-2731, doi:10.1002/2016GL067847
Yang, Qinghua; Losch, Martin; Losa, Svetlana N.; Jung, Thomas; Nerger, Lars (2016). Taking into Account Atmospheric Uncertainty Improves Sequential Assimilation of SMOS Sea Ice Thickness Data in an Ice-Ocean Model, Journal of Atmospheric and Oceanic Technology, 3 (33), 397-407, 10.1175/JTECH-D-15-0176.1.
Formatted Citation: Yang, Q., M. Losch, S. N. Losa, T. Jung, and L. Nerger, 2016: Taking into Account Atmospheric Uncertainty Improves Sequential Assimilation of SMOS Sea Ice Thickness Data in an Ice-Ocean Model. Journal of Atmospheric and Oceanic Technology, 33(3), 397-407, doi:10.1175/JTECH-D-15-0176.1
Title: Acoustic Tomography in Baffin Bay: A Preliminary Survey
Type: Report
Publication:
Author(s): Dushaw, Brian D.; Rehm, Eric
Year: 2016
Formatted Citation: Dushaw, B. D., and E. Rehm, 2016: Acoustic Tomography in Baffin Bay: A Preliminary Survey., Bergen, Norway, 34 pp. https://www.researchgate.net/profile/Eric_Rehm/publication/313844561_Acoustic_Tomography_in_Baffin_Bay_A_Preliminary_Survey/links/58aa48e7a6fdcc0e07982f9c/Acoustic-Tomography-in-Baffin-Bay-A-Preliminary-Survey.pdf.
Wiese, David N.; Landerer, Felix W.; Watkins, Michael M. (2016). Quantifying and reducing leakage errors in the JPL RL05M GRACE mascon solution, Water Resources Research, 9 (52), 7490-7502, 10.1002/2016WR019344.
Title: Quantifying and reducing leakage errors in the JPL RL05M GRACE mascon solution
Type: Journal Article
Publication: Water Resources Research
Author(s): Wiese, David N.; Landerer, Felix W.; Watkins, Michael M.
Year: 2016
Formatted Citation: Wiese, D. N., F. W. Landerer, and M. M. Watkins, 2016: Quantifying and reducing leakage errors in the JPL RL05M GRACE mascon solution. Water Resources Research, 52(9), 7490-7502, doi:10.1002/2016WR019344
Formatted Citation: Dobslaw, H., I. Bergmann-Wolf, E. Forootan, C. Dahle, T. Mayer-Gürr, J. Kusche, and F. Flechtner, 2016: Modeling of present-day atmosphere and ocean non-tidal de-aliasing errors for future gravity mission simulations. Journal of Geodesy, 90(5), 423-436, doi:10.1007/s00190-015-0884-3
Formatted Citation: Ubelmann, C., B. Cornuelle, and L. Fu, 2016: Dynamic Mapping of Along-Track Ocean Altimetry: Method and Performance from Observing System Simulation Experiments. Journal of Atmospheric and Oceanic Technology, 33(8), 1691-1699, doi:10.1175/JTECH-D-15-0163.1
Valsala, Vinu; Murtugudde, Raghu (2015). Mesoscale and intraseasonal air–sea CO2 exchanges in the western Arabian Sea during boreal summer, Deep Sea Research Part I: Oceanographic Research Papers (103), 101-113, 10.1016/j.dsr.2015.06.001.
Title: Mesoscale and intraseasonal air–sea CO2 exchanges in the western Arabian Sea during boreal summer
Type: Journal Article
Publication: Deep Sea Research Part I: Oceanographic Research Papers
Author(s): Valsala, Vinu; Murtugudde, Raghu
Year: 2015
Formatted Citation: Valsala, V., R. Murtugudde, Mesoscale and intraseasonal air–sea CO2 exchanges in the western Arabian Sea during boreal summer, Deep Sea Research Part I: Oceanographic Research Papers, 103, 101-113, doi: 10.1016/j.dsr.2015.06.001
Abstract: Intraseasonal variability, considered a coupled phenomenon, typically occurs in the 20-to-90 day-band and is seen in several of the air–sea interaction parameters over the Indian Ocean. The corresponding variability in the air–sea CO2 exchanges and oceanic pCO2 are not widely studied. In this study, we focus on the boreal summer season to find that there is a strong air–sea interaction of carbon cycle over the Somali region of the western Arabian Sea where the intraseasonal variability during this season is clearly evident in the intense variability in winds, the strength of the upwelling and the evolution of meso-scale eddies. The oceanic pCO2 variability in this intraseasonal band over the Somali region is also remarkably consistent with the other variables and is found to be driven by sea surface temperatures (SST) albeit with a counteracting but relatively minor influence from the dynamics of dissolved inorganic carbon (DIC). The 20-to-90 day-band in pCO2 accounts for about 40% of the monthly mean variability of the sea-to-air CO2 fluxes of this region in boreal summer. Ocean dynamic control on the atmospheric wind response at these mesoscales has been reported before and this study demonstrates that the ocean dynamics also control the seawater pCO2 and the air–sea CO2 fluxes in this region. Other regions with similar meso-scale dynamics must be analyzed for processes that determine air–sea CO2 exchanges and to determine whether the mesoscale fluxes contribute to the low-frequency CO2 fluxes. The role of the intraseasonal variability in atmospheric pCO2 in this exchange is not quantified here due to the lack of data at such high resolutions and needs to be considered in further observational and modeling efforts.
Title: Monitoring Atlantic overturning circulation and transport variability with GRACE-type ocean bottom pressure observations - a sensitivity study
Type: Journal Article
Publication: Ocean Science
Author(s): Bentel, K.; Landerer, F.W.; Boening, C.
Year: 2015
Formatted Citation: Bentel, K., F.W. Landerer, and C. Boening, 2015: Monitoring Atlantic overturning circulation and transport variability with GRACE-type ocean bottom pressure observations - a sensitivity study, Ocean Science, 11(6), 953-963, doi: 10.5194/os-11-953-2015
Abstract: The Atlantic Meridional Overturning Circulation (AMOC) is a key mechanism for large-scale northward heat transport and thus plays an important role for global climate. Relatively warm water is transported northward in the upper layers of the North Atlantic Ocean and, after cooling at subpolar latitudes, sinks down and is transported back south in the deeper limb of the AMOC. The utility of in situ ocean bottom pressure (OBP) observations to infer AMOC changes at single latitudes has been characterized in the recent literature using output from ocean models. We extend the analysis and examine the utility of space-based observations of time-variable gravity and the inversion for ocean bottom pressure to monitor AMOC changes and variability between 20 and 60° N. Consistent with previous results, we find a strong correlation between the AMOC signal and OBP variations, mainly along the western slope of the Atlantic Basin. We then use synthetic OBP data - smoothed and filtered to resemble the resolution of the GRACE (Gravity Recovery and Climate Experiment) gravity mission, but without errors - and reconstruct geostrophic AMOC transport. Due to the coarse resolution of GRACE-like OBP fields, we find that leakage of signal across the step slopes of the ocean basin is a significant challenge at certain latitudes. Transport signal rms is of a similar order of magnitude as error rms for the reconstructed time series. However, the interannual AMOC anomaly time series can be recovered from 20 years of monthly GRACE-like OBP fields with errors less than 1 sverdrup in many locations.
Formatted Citation: Cole, S. T., C. Wortham, E. Kunze, and W. B. Owens, 2015: Eddy stirring and horizontal diffusivity from Argo float observations: Geographic and depth variability. Geophys. Res. Lett., 42(10), 3989-3997, doi:10.1002/2015GL063827
Abstract: Stirring along isopycnals is a significant factor in determining the distribution of tracers within the ocean. Salinity anomalies on density surfaces from Argo float profiles are used to investigate horizontal stirring and estimate eddy mixing lengths. Eddy mixing length and velocity fluctuations from the ECCO2 global state estimate are used to estimate horizontal diffusivity at a 300 km scale in the upper 2000 m with near-global coverage. Diffusivity varies by over two orders of magnitude with latitude, longitude, and depth. In all basins, diffusivity is elevated in zonal bands corresponding to strong current regions, including western boundary current extension regions, the Antarctic Circumpolar Current, and equatorial current systems. The estimated mixing lengths and diffusivities provide an observationally based data set that can be used to test and constrain predictions and parameterizations of eddy stirring.
Yang, Qinghua; Losa, Svetlana N.; Losch, Martin; Jung, Thomas; Nerger, Lars (2015). The role of atmospheric uncertainty in Arctic summer sea ice data assimilation and prediction, Quarterly Journal of the Royal Meteorological Society, 691 (141), 2314-2323, 10.1002/qj.2523.
Formatted Citation: Yang, Q., S. N. Losa, M. Losch, T. Jung, and L. Nerger, 2015: The role of atmospheric uncertainty in Arctic summer sea ice data assimilation and prediction. Quarterly Journal of the Royal Meteorological Society, 141(691), 2314-2323, doi:10.1002/qj.2523
Wang, Zeliang; Han, Guoqi; Dupont, Frederic (2015). Effects of Spectral Nudging on Oceanic States in a Coarse-Resolution Model, Atmosphere-Ocean, 3 (53), 351-362, 10.1080/07055900.2015.1050352.
Formatted Citation: Wang, Z., G. Han, and F. Dupont, 2015: Effects of Spectral Nudging on Oceanic States in a Coarse-Resolution Model. Atmosphere-Ocean, 53(3), 351-362, doi:10.1080/07055900.2015.1050352
Le Fouest, V.; Manizza, M.; Tremblay, B.; Babin, M. (2015). Modelling the impact of riverine DON removal by marine bacterioplankton on primary production in the Arctic Ocean, Biogeosciences, 11 (12), 3385-3402, 10.5194/bg-12-3385-2015.
Title: Modelling the impact of riverine DON removal by marine bacterioplankton on primary production in the Arctic Ocean
Type: Journal Article
Publication: Biogeosciences
Author(s): Le Fouest, V.; Manizza, M.; Tremblay, B.; Babin, M.
Year: 2015
Formatted Citation: Le Fouest, V., M. Manizza, B. Tremblay, and M. Babin, 2015: Modelling the impact of riverine DON removal by marine bacterioplankton on primary production in the Arctic Ocean. Biogeosciences, 12(11), 3385-3402, doi:10.5194/bg-12-3385-2015
Abstract: The planktonic and biogeochemical dynamics of the Arctic shelves exhibit a strong variability in response to Arctic warming. In this study, we employ a biogeochemical model coupled to a pan-Arctic ocean-sea ice model (MITgcm) to elucidate the processes regulating the primary production (PP) of phytoplankton, bacterioplankton (BP), and their interactions. The model explicitly simulates and quantifies the contribution of usable dissolved organic nitrogen (DON) drained by the major circum-Arctic rivers to PP and BP in a scenario of melting sea ice (1998-2011). Model simulations suggest that, on average between 1998 and 2011, the removal of usable riverine dissolved organic nitrogen (RDON) by bacterioplankton is responsible for a ~ 26% increase in the annual BP for the whole Arctic Ocean. With respect to total PP, the model simulates an increase of ~ 8% on an annual basis and of ~ 18% in summer. Recycled ammonium is responsible for the PP increase. The recycling of RDON by bacterioplankton promotes higher BP and PP, but there is no significant temporal trend in the BP : PP ratio within the ice-free shelves over the 1998-2011 period. This suggests no significant evolution in the balance between autotrophy and heterotrophy in the last decade, with a constant annual flux of RDON into the coastal ocean, although changes in RDON supply and further reduction in sea-ice cover could potentially alter this delicate balance.
Brix, Holger; Menemenlis, Dimitris; Hill, Christopher N.; Dutkiewicz, Stephanie; Jahn, Oliver; Wang, D; Bowman, Kevin W.; Zhang, Hong (2015). Using Green’s Functions to initialize and adjust a global, eddying ocean biogeochemistry general circulation model, Ocean Modelling (95), 1-14, 10.1016/j.ocemod.2015.07.008.
Title: Using Green’s Functions to initialize and adjust a global, eddying ocean biogeochemistry general circulation model
Type: Journal Article
Publication: Ocean Modelling
Author(s): Brix, Holger; Menemenlis, Dimitris; Hill, Christopher N.; Dutkiewicz, Stephanie; Jahn, Oliver; Wang, D; Bowman, Kevin W.; Zhang, Hong
Year: 2015
Formatted Citation: Brix, H., D. Menemenlis, C. N. Hill, S. Dutkiewicz, O. Jahn, D. Wang, K. W. Bowman, and H. Zhang, 2015: Using Green's Functions to initialize and adjust a global, eddying ocean biogeochemistry general circulation model. Ocean Modelling, 95, 1-14, doi:10.1016/j.ocemod.2015.07.008
Abstract: The NASA Carbon Monitoring System (CMS) Flux Project aims to attribute changes in the atmospheric accumulation of carbon dioxide to spatially resolved fluxes by utilizing the full suite of NASA data, models, and assimilation capabilities. For the oceanic part of this project, we introduce ECCO2-Darwin, a new ocean biogeochemistry general circulation model based on combining the following pre-existing components: (i) a full-depth, eddying, global-ocean configuration of the Massachusetts Institute of Technology general circulation model (MITgcm), (ii) an adjoint-method-based estimate of ocean circulation from the Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2) project, (iii) the MIT ecosystem model "Darwin", and (iv) a marine carbon chemistry model. Air-sea gas exchange coefficients and initial conditions of dissolved inorganic carbon, alkalinity, and oxygen are adjusted using a Green's Functions approach in order to optimize modeled air-sea CO2 fluxes. Data constraints include observations of carbon dioxide partial pressure (pCO2) for 2009-2010, global air-sea CO2 flux estimates, and the seasonal cycle of the Takahashi et al. (2009) Atlas. The model sensitivity experiments (or Green's Functions) include simulations that start from different initial conditions as well as experiments that perturb air-sea gas exchange parameters and the ratio of particulate inorganic to organic carbon. The Green's Functions approach yields a linear combination of these sensitivity experiments that minimizes model-data differences. The resulting initial conditions and gas exchange coefficients are then used to integrate the ECCO2-Darwin model forward. Despite the small number (six) of control parameters, the adjusted simulation is significantly closer to the data constraints (37% cost function reduction, i.e., reduction in the model-data difference, relative to the baseline simulation) and to independent observations (e.g., alkalinity). The adjusted air-sea gas exchange parameter differs by only 3% from the baseline value and has little impact ( − 0.1 %) on the cost function. The particulate inorganic to organic carbon ratio was increased more than threefold and reduced the cost function by 22% relative to the baseline integration, indicating a significant influence of biology on air-sea gas exchange. The largest contribution to cost reduction (35%) comes from the adjustment of initial conditions. In addition to reducing biases relative to observations, the adjusted simulation exhibits smaller model drift than the baseline. We estimate drift by integrating the model with repeated 2009 atmospheric forcing for seven years and find a volume-weighted drift reduction of, for example, 12.5% for nitrate and 30% for oxygen in the top 300 m. Although there remain several regions with large model-data discrepancies, for example, overly strong carbon uptake in the Southern Ocean, the adjusted simulation is a first step towards a more accurate representation of the ocean carbon cycle at high spatial and temporal resolution.
Keywords: Carbon Monitoring System, Data assimilation, Green's Function, Ocean biogeochemical circulation model
D'Addezio, Joseph M.; Subrahmanyam, Bulusu; Nyadjro, Ebenezer S.; Murty, V. S. N. (2015). Seasonal Variability of Salinity and Salt Transport in the Northern Indian Ocean, Journal of Physical Oceanography, 7 (45), 1947-1966, 10.1175/JPO-D-14-0210.1.
Title: Seasonal Variability of Salinity and Salt Transport in the Northern Indian Ocean
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): D'Addezio, Joseph M.; Subrahmanyam, Bulusu; Nyadjro, Ebenezer S.; Murty, V. S. N.
Year: 2015
Formatted Citation: D'Addezio, J. M., B. Subrahmanyam, E. S. Nyadjro, and V. S. N. Murty, 2015: Seasonal Variability of Salinity and Salt Transport in the Northern Indian Ocean. Journal of Physical Oceanography, 45(7), 1947-1966, doi:10.1175/JPO-D-14-0210.1
Title: Modern Observational Physical Oceanography: Understanding the Global Ocean
Type: Book
Publication:
Author(s): Wunsch, Carl
Year: 2015
Formatted Citation: Wunsch, C., 2015: Modern Observational Physical Oceanography: Understanding the Global Ocean. Princeton University Press, 512 pp. https://books.google.com/books?id=8DFdBwAAQBAJ.
Yang, Tingting; Xu, Yongsheng (2015). Estimation of the time series of the meridional heat transport across 15°N in the Pacific Ocean from Argo and satellite data, Journal of Geophysical Research: Oceans, 4 (120), 3043-3060, 10.1002/2015JC010752.
Title: Estimation of the time series of the meridional heat transport across 15°N in the Pacific Ocean from Argo and satellite data
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Yang, Tingting; Xu, Yongsheng
Year: 2015
Formatted Citation: Yang, T., and Y. Xu, 2015: Estimation of the time series of the meridional heat transport across 15°N in the Pacific Ocean from Argo and satellite data. J. Geophys. Res. Ocean., 120(4), 3043-3060, doi:10.1002/2015JC010752
Wang, Shihong; Liu, Zhiliang; Pang, Chongguang (2015). Geographical distribution and anisotropy of the inverse kinetic energy cascade, and its role in the eddy equilibrium processes, Journal of Geophysical Research: Oceans, 7 (120), 4891-4906, 10.1002/2014JC010476.
Formatted Citation: Wang, S., Z. Liu, and C. Pang, 2015: Geographical distribution and anisotropy of the inverse kinetic energy cascade, and its role in the eddy equilibrium processes. J. Geophys. Res. Ocean., 120(7), 4891-4906, doi:10.1002/2014JC010476
Ostle, Clare; Johnson, Martin; Landschützer, Peter; Schuster, Ute; Hartman, Susan; Hull, Tom; Robinson, Carol (2015). Net community production in the North Atlantic Ocean derived from Volunteer Observing Ship data, Global Biogeochemical Cycles, 1 (29), 80-95, 10.1002/2014GB004868.
Formatted Citation: Ostle, C., M. Johnson, P. Landschützer, U. Schuster, S. Hartman, T. Hull, and C. Robinson, 2015: Net community production in the North Atlantic Ocean derived from Volunteer Observing Ship data. Global Biogeochemical Cycles, 29(1), 80-95, doi:10.1002/2014GB004868
Volkov, Denis L.; Kubryakov, Arseny A.; Lumpkin, Rick (2015). Formation and variability of the Lofoten basin vortex in a high-resolution ocean model, Deep Sea Research Part I: Oceanographic Research Papers (105), 142-157, 10.1016/j.dsr.2015.09.001.
Title: Formation and variability of the Lofoten basin vortex in a high-resolution ocean model
Type: Journal Article
Publication: Deep Sea Research Part I: Oceanographic Research Papers
Author(s): Volkov, Denis L.; Kubryakov, Arseny A.; Lumpkin, Rick
Year: 2015
Formatted Citation: Volkov, D. L., A. A. Kubryakov, and R. Lumpkin, 2015: Formation and variability of the Lofoten basin vortex in a high-resolution ocean model. Deep Sea Research Part I: Oceanographic Research Papers, 105, 142-157, doi:10.1016/j.dsr.2015.09.001
Lüpkes, Christof; Gryanik, Vladimir M. (2015). Parameterization of drag coefficients over polar sea ice for climate models, Mercator Ocean Quarterly Newsletter, 51, 29-34.
Title: Parameterization of drag coefficients over polar sea ice for climate models
Type: Magazine Article
Publication: Mercator Ocean Quarterly Newsletter
Author(s): Lüpkes, Christof; Gryanik, Vladimir M.
Year: 2015
Formatted Citation: Lüpkes, C., and V. M. Gryanik, 2015: Parameterization of drag coefficients over polar sea ice for climate models. Mercator Ocean Quarterly Newsletter(51), 29-34 pp.
Abstract: A parameterization of drag coefficients has been developed in recent years that accounts for the impact of edges at ice floes, leads, and melt ponds on momentum transport. Melt ponds are a common feature in the inner Arctic during summer while drifting ice floes and their edges influence the surface roughness especially in the marginal sea ice zones during all seasons. Governing parameters in the parameterization that can be easily applied to climate models are the sea ice concentration and aspect ratio h/D where h is the ice freeboard and D is the characteristic length of floes and ponds/leads. When these parameters are not available from a sea ice model, the aspect ratios can also be parameterized as a function of the sea ice concentration so that the new schemes can also be used in stand-alone atmospheric models using observed sea ice concentration. The parameterization is evaluated for idealized meteorological forcing and prescribed sea ice and melt pond concentration in the Siberian Arctic and in parts of the Central Arctic. The required sea ice data are available from remote sensing. The distributions of drag coefficients obtained from traditional parameterizations and from the new one show large differences in this test scenario especially in the region south of 80°N.
Other URLs: http://hdl.handle.net/10013/epic.45315.d001
Piecuch, C. G.; Ponte, R. M. (2015). A wind-driven nonseasonal barotropic fluctuation of the Canadian inland seas, Ocean Science, 1 (11), 175-185, 10.5194/os-11-175-2015.
Title: A wind-driven nonseasonal barotropic fluctuation of the Canadian inland seas
Type: Journal Article
Publication: Ocean Science
Author(s): Piecuch, C. G.; Ponte, R. M.
Year: 2015
Formatted Citation: Piecuch, C. G., and R. M. Ponte, 2015: A wind-driven nonseasonal barotropic fluctuation of the Canadian inland seas. Ocean Science, 11(1), 175-185, doi:10.5194/os-11-175-2015
Abstract: A wind-driven, spatially coherent mode of nonseasonal, depth-independent variability in the Canadian inland seas (i.e., the collective of Hudson Bay, James Bay, and Foxe Basin) is identified based on Gravity Recovery and Climate Experiment (GRACE) retrievals, a tide-gauge record, and a barotropic model over 2003-2013. This dominant mode of nonseasonal variability is correlated with the North Atlantic Oscillation and is associated with net flows into and out of the Canadian inland seas; the anomalous inflows and outflows, which are reflected in mean sea level and bottom pressure changes, are driven by wind stress anomalies over Hudson Strait, probably related to wind setup, as well as over the northern North Atlantic Ocean, possibly mediated by various wave mechanisms. The mode is also associated with mass redistribution within the Canadian inland seas, reflecting linear response to local wind stress variations under the combined influences of rotation, gravity, and variable bottom topography. Results exemplify the usefulness of GRACE for studying regional ocean circulation and climate.
Wang, Xiaochun; Zhao, Liqing; Li, Zhijin; Menemenlis, Dimitris (2015). Regional ocean forecasting systems and their applications: Design considerations of such a system for the South China Sea, Aquatic Ecosystem Health & Management, 4 (18), 443-453, 10.1080/14634988.2015.1112123.
Formatted Citation: Wang, X., L. Zhao, Z. Li, and D. Menemenlis, 2015: Regional ocean forecasting systems and their applications: Design considerations of such a system for the South China Sea. Aquatic Ecosystem Health & Management, 18(4), 443-453, doi:10.1080/14634988.2015.1112123
Halpern, David; Menemenlis, Dimitris; Wang, Xiaochun (2015). Impact of Data Assimilation on ECCO2 Equatorial Undercurrent and North Equatorial Countercurrent in the Pacific Ocean, Journal of Atmospheric and Oceanic Technology, 1 (32), 131-143, 10.1175/JTECH-D-14-00025.1.
Formatted Citation: Halpern, D., D. Menemenlis, and X. Wang, 2015: Impact of Data Assimilation on ECCO2 Equatorial Undercurrent and North Equatorial Countercurrent in the Pacific Ocean. Journal of Atmospheric and Oceanic Technology, 32(1), 131-143, doi:10.1175/JTECH-D-14-00025.1
Abstract: The impact of data assimilation on the transports of eastward-flowing Equatorial Undercurrent (EUC) and North Equatorial Countercurrent (NECC) in the Pacific Ocean from 145°E to 95°W during 2004-05 and 2009-11 was assessed. Two Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2), solutions were analyzed: one with data assimilation and one without. Assimilated data included satellite observations of sea surface temperature and ocean surface topography, in which the sampling patterns were approximately uniform over the 5 years, and in situ measurements of subsurface salinity and temperature profiles, in which the sampling patterns varied considerably in space and time throughout the 5 years. Velocity measurements were not assimilated. The impact of data assimilation was considered significant when the difference between the transports computed with and without data assimilation was greater than 5.5 × 106 m3 s−1 (or 5.5 Sv; 1 Sv ≡ 106 m3 s−1) for the EUC and greater than 5.0 Sv for the NECC. In addition, the difference of annual-mean transports computed from 3-day-averaged data was statistically significant at the 95% level. The impact of data assimilation ranged from no impact to very substantial impact when data assimilation increased the EUC transport and decreased the NECC transport. The study's EUC results had some correspondence with other studies and no simple agreement or disagreement pattern emerged among all studies of the impact of data assimilation. No comparable study of the impact of data assimilation on the NECC has been made.
Keywords: Atmosphere-ocean i, Ocean circulation, Pacific Ocean
Duarte, Pedro; Assmy, Philipp; Hop, Haakon; Spreen, Gunnar; Gerland, Sebastian; Hudson, Stephen R. (2015). The importance of vertical resolution in sea ice algae production models, Journal of Marine Systems (145), 69-90, 10.1016/j.jmarsys.2014.12.004.
Title: The importance of vertical resolution in sea ice algae production models
Type: Journal Article
Publication: Journal of Marine Systems
Author(s): Duarte, Pedro; Assmy, Philipp; Hop, Haakon; Spreen, Gunnar; Gerland, Sebastian; Hudson, Stephen R.
Year: 2015
Formatted Citation: Duarte, P., P. Assmy, H. Hop, G. Spreen, S. Gerland, and S. R. Hudson, 2015: The importance of vertical resolution in sea ice algae production models. Journal of Marine Systems, 145, 69-90, doi:10.1016/j.jmarsys.2014.12.004
Forget, G; Fukumori, I; Heimbach, P; Lee, T; Menemenlis, Dimitris; Ponte, R M (2015). Estimating the Circulation and Climate of the Ocean (ECCO): Advancing CLIVAR Science, CLIVAR Exchanges, 2 (19), 41-45.
Title: Estimating the Circulation and Climate of the Ocean (ECCO): Advancing CLIVAR Science
Type: Magazine Article
Publication: CLIVAR Exchanges
Author(s): Forget, G; Fukumori, I; Heimbach, P; Lee, T; Menemenlis, Dimitris; Ponte, R M
Year: 2015
Formatted Citation: Forget, G., I. Fukumori, P. Heimbach, T. Lee, D. Menemenlis, and R. M. Ponte, 2015: Estimating the Circulation and Climate of the Ocean (ECCO): Advancing CLIVAR Science. CLIVAR Exchanges, 19(2), 41-45 pp.
Abstract:
Keywords:
ECCO Products Used: ECCO-V4;ECCO2
URL:
Other URLs:
Hill, Christopher N. (2015). Abrupt Climate Change and the Atlantic Meridional Overturning Circulation: sensitivity and non-linear response to Arctic/sub-Arctic freshwater pulses.
Title: Abrupt Climate Change and the Atlantic Meridional Overturning Circulation: sensitivity and non-linear response to Arctic/sub-Arctic freshwater pulses
Type: Report
Publication:
Author(s): Hill, Christopher N.
Year: 2015
Formatted Citation: Hill, C. N., 2015: Abrupt Climate Change and the Atlantic Meridional Overturning Circulation: sensitivity and non-linear response to Arctic/sub-Arctic freshwater pulses., Cambridge, MA, 5 pp. https://www.osti.gov/biblio/1184378.
Abstract: This project investigated possible mechanisms by which melt-water pulses can induce abrupt change in the Atlantic Meridional Overturning Circulation (AMOC) magnitude. AMOC magnitude is an important ingredient in present day climate. Previous studies have hypothesized abrupt reduction in AMOC magnitude in response to influxes of glacial melt water into the North Atlantic. Notable fresh-water influxes are associated with the terminus of the last ice age. During this period large volumes of melt water accumulated behind retreating ice sheets and subsequently drained rapidly when the ice weakened sufficiently. Rapid draining of glacial lakes into the North Atlantic is a possible origin of a number of paleo-record abrupt climate shifts. These include the Younger-Dryas cooling event and the 8,200 year cooling event. The studies undertaken focused on whether the mechanistic sequence by which glacial melt-water impacts AMOC, which then impacts Northern Hemisphere global mean surface temperature, is dynamically plausible. The work has implications for better understanding past climate stability. The work also has relevance for today's environment, in which high-latitude ice melting in Greenland appears to be driving fresh water outflows at an accelerating pace.
Chen, Zhaohui; Wu, Lixin (2015). Seasonal Variation of the Pacific South Equatorial Current Bifurcation, Journal of Physical Oceanography, 6 (45), 1757-1770, 10.1175/JPO-D-14-0085.1.
Title: Seasonal Variation of the Pacific South Equatorial Current Bifurcation
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Chen, Zhaohui; Wu, Lixin
Year: 2015
Formatted Citation: Chen, Z., and L. Wu, 2015: Seasonal Variation of the Pacific South Equatorial Current Bifurcation. Journal of Physical Oceanography, 45(6), 1757-1770, doi:10.1175/JPO-D-14-0085.1
Dushaw, Brian D. (2015). The Predictability of Large-Scale , Short-Period Ocean Variability in the Philippine Sea and the Influence of Such Variability on Long-Range Acoustic Propagation.
Title: The Predictability of Large-Scale , Short-Period Ocean Variability in the Philippine Sea and the Influence of Such Variability on Long-Range Acoustic Propagation
Type: Report
Publication:
Author(s): Dushaw, Brian D.
Year: 2015
Formatted Citation: Dushaw, B. D., 2015: The Predictability of Large-Scale , Short-Period Ocean Variability in the Philippine Sea and the Influence of Such Variability on Long-Range Acoustic Propagation., Seattle, WA, 10 pp. https://apps.dtic.mil/dtic/tr/fulltext/u2/a622959.pdf.
Volkov, Denis L.; Landerer, Felix W. (2015). Internal and external forcing of sea level variability in the Black Sea, Climate Dynamics, 9-10 (45), 2633-2646, 10.1007/s00382-015-2498-0.
Title: Internal and external forcing of sea level variability in the Black Sea
Type: Journal Article
Publication: Climate Dynamics
Author(s): Volkov, Denis L.; Landerer, Felix W.
Year: 2015
Formatted Citation: Volkov, D. L., and F. W. Landerer, 2015: Internal and external forcing of sea level variability in the Black Sea. Climate Dynamics, 45(9-10), 2633-2646, doi:10.1007/s00382-015-2498-0
Abstract: The variability of sea level in the Black Sea is forced by a combination of internal and external processes of atmospheric, oceanic, and terrestrial origin. We use a combination of satellite altimetry and gravity, tide gauge, river discharge, and atmospheric re-analysis data to provide a comprehensive up-to-date analysis of sea level variability in the Black Sea and to quantify the role of different environmental factors that force the variability. The Black Sea is part of a large-scale climatic system that includes the Mediterranean and the North Atlantic. The seasonal sea level budget shows similar contributions of fresh water fluxes (precipitation, evaporation, and river discharge) and the Black Sea outflow, while the impact of the net surface heat flux is smaller although not negligible. We find that the nonseasonal sea level time series in the Black and Aegean seas are significantly correlated, the latter leading by 1 month. This lag is attributed to the adjustment of sea level in the Black Sea to externally forced changes of sea level in the Aegean Sea and to the impact of river discharge. The nonseasonal sea level budget in the Black Sea is dominated by precipitation and evaporation over the sea itself, but external processes such as river discharge and changes in the outflow can also cause some large synoptic-scale sea level anomalies. Sea level is strongly coupled to terrestrial water storage over the Black Sea drainage basin, which is modulated by the North Atlantic Oscillation\n(NAO). We show that during the low/high NAO southwesterly/northeasterly winds near the Strait of Gibraltar and southerly/northerly winds over the Aegean Sea are able to dynamically increase/decrease sea level in the Mediterranean and Black seas, respectively.
Mu, Longjiang; Zhao, Jinping (2015). Analysis of the response of an Arctic icea-ocean coupled model to two different atmospheric reanalysis datasets, Haiyang Xuebao, 11 (37), 79-91, 10.3969/j.issn.0253-4193.2015.11.008.
Title: Analysis of the response of an Arctic icea-ocean coupled model to two different atmospheric reanalysis datasets
Type: Journal Article
Publication: Haiyang Xuebao
Author(s): Mu, Longjiang; Zhao, Jinping
Year: 2015
Formatted Citation: Mu, L., and J. Zhao, 2015: Analysis of the response of an Arctic icea-ocean coupled model to two different atmospheric reanalysis datasets. Haiyang Xuebao, 37(11), 79-91, doi:10.3969/j.issn.0253-4193.2015.11.008
Abstract: The downward radiative fluxes, wind speed, near surface temperature, precipitation, humidity got from Climate Forecast System Reanalysis (CFSR) and the Japanese 25-year Reanalysis Project (JRA25) are compared in this article. We find that most significant biases between the two datasets are precipitation, downward fluxes for both shortwave and longwave radiation. Driving by these two datasets, model results forced by CFSR shows big differences on sea ice, Atlantic water and thermohaline structure in Canada basin compared to in situ observations, with the simulated geostrophic current on isopycnal surface 20% higher than that forced by JRA25and a larger volume fluxes than that derived from SODA data. Sensitivity experiment forced by downward radiative fluxes from CFSR, which have been evaluated to be close to observed values, demonstrates comparable results to observational results. The cloud data plays a key role in modeling sea ice while freshwater flux brought by precipitation can change the heat transport of Atlantic inflow prominently and carry a further effect on sea ice in the Arctic. The overestimated precipitation in CFSR is the major for large biases of volume flux through Fram Strait, geostropic current on isopycnal surface and thermohaline structure in central Arctic. Although reanalysis wind have different resolution for the two datasets, our results indicates that it carries an ignorable effect on modeling sea ice and thermohaline structure on basin scale.
Keywords:
ECCO Products Used: ECCO2
URL:
Other URLs:
Seo, Gwang-Ho; Choi, Byoung-Ju; Cho, Yang-Ki; Kim, Young Ho; Kim, Sangil (2015). Evaluation of a regional ocean reanalysis system for the East Asian Marginal Seas based on the ensemble Kalman filter, Ocean Science Journal, 1 (50), 29-48, 10.1007/s12601-015-0003-7.
Title: Evaluation of a regional ocean reanalysis system for the East Asian Marginal Seas based on the ensemble Kalman filter
Type: Journal Article
Publication: Ocean Science Journal
Author(s): Seo, Gwang-Ho; Choi, Byoung-Ju; Cho, Yang-Ki; Kim, Young Ho; Kim, Sangil
Year: 2015
Formatted Citation: Seo, G., B. Choi, Y. Cho, Y. H. Kim, and S. Kim, 2015: Evaluation of a regional ocean reanalysis system for the East Asian Marginal Seas based on the ensemble Kalman filter. Ocean Science Journal, 50(1), 29-48, doi:10.1007/s12601-015-0003-7
Formatted Citation: Yang, Q., S. N. Losa, M. Losch, J. Liu, Z. Zhang, L. Nerger, and H. Yang, 2015: Assimilating summer sea-ice concentration into a coupled ice-ocean model using a LSEIK filter. Annals of Glaciology, 56(69), 38-44, doi:10.3189/2015AoG69A740
Abstract: The decrease in summer sea-ice extent in the Arctic Ocean opens shipping routes and creates potential for many marine operations. For these activities accurate predictions of sea-ice conditions are required to maintain marine safety. In an attempt at Arctic sea-ice prediction, the summer of 2010 is selected to implement an Arctic sea-ice data assimilation (DA) study. The DA system is based on a regional Arctic configuration of the Massachusetts Institute of Technology general circulation model (MITgcm) and a local singular evolutive interpolated Kalman (LSEIK) filter to assimilate Special Sensor Microwave Imager/Sounder (SSMIS) sea-ice concentration operational products from the US National Snow and Ice Data Center (NSIDC). Based on comparisons with both the assimilated NSIDC SSMIS concentration and concentration data from the Ocean and Sea Ice Satellite Application Facility, the forecasted sea-ice edge and concentration improve upon simulations without data assimilation. By the nature of the assimilation algorithm with multivariate covariance between ice concentration and thickness, sea-ice thickness fields are also updated, and the evaluation with in situ observation shows some improvement compared to the forecast without data assimilation.
Brown, Peter J.; Jullion, Loïc; Landschützer, Peter; Bakker, Dorothee C. E.; Naveira Garabato, Alberto C.; Meredith, Michael P.; Torres-Valdés, Sinhue; Watson, Andrew J.; Hoppema, Mario; Loose, Brice; Jones, Elizabeth M.; Telszewski, Maciej; Jones, Steve D.; Wanninkhof, Rik (2015). Carbon dynamics of the Weddell Gyre, Southern Ocean, Global Biogeochemical Cycles, 3 (29), 288-306, 10.1002/2014GB005006.
Title: Carbon dynamics of the Weddell Gyre, Southern Ocean
Type: Journal Article
Publication: Global Biogeochemical Cycles
Author(s): Brown, Peter J.; Jullion, Loïc; Landschützer, Peter; Bakker, Dorothee C. E.; Naveira Garabato, Alberto C.; Meredith, Michael P.; Torres-Valdés, Sinhue; Watson, Andrew J.; Hoppema, Mario; Loose, Brice; Jones, Elizabeth M.; Telszewski, Maciej; Jones, Steve D.; Wanninkhof, Rik
Year: 2015
Formatted Citation: Brown, P. J. and Coauthors, 2015: Carbon dynamics of the Weddell Gyre, Southern Ocean. Global Biogeochemical Cycles, 29(3), 288-306, doi:10.1002/2014GB005006
Title: Initial Validation of Surface Ocean Properties in MITgcm Arctic Regional Model
Type: Thesis
Publication:
Author(s): Bigdeli, Arash
Year: 2015
Formatted Citation: Bigdeli, A., 2015: Initial Validation of Surface Ocean Properties in MITgcm Arctic Regional Model. http://digitalcommons.uri.edu/theses/819.
Abstract: In ice-covered regions it can be challenging to determine air-sea exchange - for heat and momentum, but also for gases like carbon dioxide and methane. The harsh environment and relative data scarcity make it difficult to characterize even the physical properties. Here, we seek a mechanistic interpretation for the rate of air-sea gas exchange (k) derived from radon-deficits. These require an estimate of the water column history extending 30 days prior to sampling. We used coarse resolution (36km) regional configuration of the MITgcm with fine near surface vertical spacing (2m) to evaluate the capability of the model to reproduce conditions prior to sampling. The model is used to estimates sea-ice velocity, concentration and mixed-layer depth experienced by the water column .We then compared the model results to existing field data including satellite, moorings and Ice-tethered profilers. We found that sea- ice coverage have 88 to 98% accuracy, sea-ice velocities have 78% correlation which resulted in 2 km/day error in 30 day trajectory of sea-ice. Model showed the capacity to capture mixed layer evolution trends although with a bias and water velocities showed only 29% correlation with actual data. Using the capacity of the model to produce same order of magnitude of water speed we calculated an average radius of possible origins of water parcel equal to 10.3 km.
Chen, Zhaohui; Wu, Lixin; Qiu, Bo; Li, Lei; Hu, Dunxin; Liu, Chengyan; Jia, Fan; Liang, Xi (2015). Strengthening Kuroshio observed at its origin during November 2010 to October 2012, Journal of Geophysical Research: Oceans, 4 (120), 2460-2470, 10.1002/2014JC010590.
Formatted Citation: Chen, Z., L. Wu, B. Qiu, L. Li, D. Hu, C. Liu, F. Jia, and X. Liang, 2015: Strengthening Kuroshio observed at its origin during November 2010 to October 2012. J. Geophys. Res. Ocean., 120(4), 2460-2470, doi:10.1002/2014JC010590
Forget, G; Campin, Jean-Michel; Heimbach, P; Hill, C N; Ponte, R M; Wunsch, C (2015). ECCO version 4: an integrated framework for non-linear inverse modeling and global ocean state estimation, Geosci. Model Dev., 10 (8), 3071-3104, 10.5194/gmd-8-3071-2015.
Title: ECCO version 4: an integrated framework for non-linear inverse modeling and global ocean state estimation
Type: Journal Article
Publication: Geosci. Model Dev.
Author(s): Forget, G; Campin, Jean-Michel; Heimbach, P; Hill, C N; Ponte, R M; Wunsch, C
Year: 2015
Formatted Citation: Forget, G., J. Campin, P. Heimbach, C. N. Hill, R. M. Ponte, and C. Wunsch, 2015: ECCO version 4: an integrated framework for non-linear inverse modeling and global ocean state estimation. Geosci. Model Dev., 8(10), 3071-3104, doi:10.5194/gmd-8-3071-2015
Higginson, S.; Thompson, K. R.; Woodworth, P. L.; Hughes, C. W. (2015). The tilt of mean sea level along the east coast of North America, Geophysical Research Letters, 5 (42), 1471-1479, 10.1002/2015GL063186.
Title: The tilt of mean sea level along the east coast of North America
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Higginson, S.; Thompson, K. R.; Woodworth, P. L.; Hughes, C. W.
Year: 2015
Formatted Citation: Higginson, S., K. R. Thompson, P. L. Woodworth, and C. W. Hughes, 2015: The tilt of mean sea level along the east coast of North America. Geophys. Res. Lett., 42(5), 1471-1479, doi:10.1002/2015GL063186
Chen, Ru; Flierl, Glenn R.; Wunsch, Carl (2015). Quantifying and Interpreting Striations in a Subtropical Gyre: A Spectral Perspective, Journal of Physical Oceanography, 2 (45), 387-406, 10.1175/JPO-D-14-0038.1.
Title: Quantifying and Interpreting Striations in a Subtropical Gyre: A Spectral Perspective
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Chen, Ru; Flierl, Glenn R.; Wunsch, Carl
Year: 2015
Formatted Citation: Chen, R., G. R. Flierl, and C. Wunsch, 2015: Quantifying and Interpreting Striations in a Subtropical Gyre: A Spectral Perspective. Journal of Physical Oceanography, 45(2), 387-406, doi:10.1175/JPO-D-14-0038.1
Title: Finescale Water-Mass Variability from ARGO Profiling Floats
Type: Report
Publication:
Author(s): Kunze, Eric
Year: 2015
Formatted Citation: Kunze, E., 2015: Finescale Water-Mass Variability from ARGO Profiling Floats., 4 pp.
Abstract: LONGTERM GOALS. My longterm goals are understanding the processes responsible for stirring and mixing in the ocean in order to better parameterize their impacts on larger scales. OBJECTIVES. To obtain a global assessment of mesoscale water-mass variability lengthscales and diffusivities, as well as density ratio statistics from the ARGO profiling float data set.
Keywords: data bases, density, eddy currents, floats, global, impact, oceans, ratios, statistics, water masses
Other URLs: https://apps.dtic.mil/docs/citations/ADA624695
Zemskova, Varvara E.; White, Brian L.; Scotti, Alberto (2015). Available Potential Energy and the General Circulation: Partitioning Wind, Buoyancy Forcing, and Diapycnal Mixing, Journal of Physical Oceanography, 6 (45), 1510-1531, 10.1175/JPO-D-14-0043.1.
Title: Available Potential Energy and the General Circulation: Partitioning Wind, Buoyancy Forcing, and Diapycnal Mixing
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Zemskova, Varvara E.; White, Brian L.; Scotti, Alberto
Year: 2015
Formatted Citation: Zemskova, V. E., B. L. White, and A. Scotti, 2015: Available Potential Energy and the General Circulation: Partitioning Wind, Buoyancy Forcing, and Diapycnal Mixing. Journal of Physical Oceanography, 45(6), 1510-1531, doi:10.1175/JPO-D-14-0043.1
Watkins, Michael M.; Wiese, David N.; Yuan, Dah-Ning; Boening, Carmen; Landerer, Felix W. (2015). Improved methods for observing Earth’s time variable mass distribution with GRACE using spherical cap mascons, Journal of Geophysical Research: Solid Earth, 4 (120), 2648-2671, 10.1002/2014JB011547.
Title: Improved methods for observing Earth’s time variable mass distribution with GRACE using spherical cap mascons
Type: Journal Article
Publication: Journal of Geophysical Research: Solid Earth
Author(s): Watkins, Michael M.; Wiese, David N.; Yuan, Dah-Ning; Boening, Carmen; Landerer, Felix W.
Year: 2015
Formatted Citation: Watkins, M. M., D. N. Wiese, D. Yuan, C. Boening, and F. W. Landerer, 2015: Improved methods for observing Earth's time variable mass distribution with GRACE using spherical cap mascons. Journal of Geophysical Research: Solid Earth, 120(4), 2648-2671, doi:10.1002/2014JB011547
Flexas, M. M.; Schodlok, M. P.; Padman, L.; Menemenlis, Dimitris; Orsi, A. H. (2015). Role of tides on the formation of the Antarctic Slope Front at the Weddell-Scotia Confluence, Journal of Geophysical Research: Oceans, 5 (120), 3658-3680, 10.1002/2014JC010372.
Title: Role of tides on the formation of the Antarctic Slope Front at the Weddell-Scotia Confluence
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Flexas, M. M.; Schodlok, M. P.; Padman, L.; Menemenlis, Dimitris; Orsi, A. H.
Year: 2015
Formatted Citation: Flexas, M. M., M. P. Schodlok, L. Padman, D. Menemenlis, and A. H. Orsi, 2015: Role of tides on the formation of the Antarctic Slope Front at the Weddell-Scotia Confluence. J. Geophys. Res. Ocean., 120(5), 3658-3680, doi:10.1002/2014JC010372
Liu, Junjie; Bowman, Kevin W.; Henze, Daven K. (2015). Source-receptor relationships of column-average CO 2 and implications for the impact of observations on flux inversions, Journal of Geophysical Research: Atmospheres, 10 (120), 5214-5236, 10.1002/2014JD022914.
Title: Source-receptor relationships of column-average CO 2 and implications for the impact of observations on flux inversions
Type: Journal Article
Publication: Journal of Geophysical Research: Atmospheres
Author(s): Liu, Junjie; Bowman, Kevin W.; Henze, Daven K.
Year: 2015
Formatted Citation: Liu, J., K. W. Bowman, and D. K. Henze, 2015: Source-receptor relationships of column-average CO 2 and implications for the impact of observations on flux inversions. Journal of Geophysical Research: Atmospheres, 120(10), 5214-5236, doi:10.1002/2014JD022914
Whitefield, Jonathan; Winsor, Peter; McClelland, James; Menemenlis, Dimitris (2015). A new river discharge and river temperature climatology data set for the pan-Arctic region, Ocean Modelling (88), 1-15, 10.1016/j.ocemod.2014.12.012.
Formatted Citation: Whitefield, J., P. Winsor, J. McClelland, and D. Menemenlis, 2015: A new river discharge and river temperature climatology data set for the pan-Arctic region. Ocean Modelling, 88, 1-15, doi:10.1016/j.ocemod.2014.12.012
Abstract: Most regional ocean models that use discharge as part of the forcing use relatively coarse river discharge data sets (1°, or ∼110 km) compared to the model resolution (typically 1/4° or less), and do not account for seasonal changes in river water temperature. We introduce a new climatological data set of river discharge and river water temperature with 1/6° grid spacing over the Arctic region (Arctic River Discharge and Temperature; ARDAT), incorporating observations from 30 Arctic rivers. The annual mean discharge for all rivers in ARDAT is 2817 ± 330 km3 yr−1. River water temperatures range between 0 °C in winter to 14.0-17.6 °C in July, leading to a long-term mean monthly heat flux from all rivers of 3.2 ± 0.6 TW, of which 31% is supplied by Alaskan rivers and 69% is supplied by Eurasian rivers. This riverine heat flux is equivalent to 44% of the estimated ocean heat flux associated with the Bering Strait throughflow, but during the spring freshet can be ∼10 times as large, suggesting that heat flux associated with Arctic rivers is an important component of the Arctic heat budget on seasonal time scales. We apply the ARDAT data set to a high-resolution regional ocean-ice model, and compare results to a model integration using a 1° resolution discharge data set. Integrated freshwater content on the Arctic shelves (<200 m) increases by ∼3600 km3 in the ARDAT forced model run compared to the coarser forcing, suggesting that river discharge is contained on the Arctic shelves when forced with the ARDAT data set. Modelled summer heat fluxes over the shelves increase by 8 TW when river water temperature is included, which subsequently reduces basin-wide September sea ice extent by ∼10%. Regional differences are larger, where e.g., sea ice extent on the Beaufort shelf is reduced by ∼36%. Using a non-linear free surface parameterization along with the ARDAT data set, we find an increase in the sea surface height gradient around river mouths. Geostrophic velocities increase to form quasi-continuous, fast-moving near-shore boundary currents not reproduced using the 1° resolution data set. Omitting river water temperature, or using a lower resolution data set, can therefore lead to incorrect model estimates of coastal transport, sea ice formation/melt rates, and other regional and basin scale processes. Using a high-resolution discharge data set, and accounting for the considerable heat carried by the Arctic rivers is recommended for future modelling efforts.
Title: Biodiversity in a Changing Climate: Linking Science and Management in Conservation
Type: Book
Publication:
Author(s): Root, T L; Hall, K R; Herzog, M P; Howell, C A
Year: 2015
Formatted Citation: Root, T. L., K. R. Hall, M. P. Herzog, and C. A. Howell, 2015: Biodiversity in a Changing Climate: Linking Science and Management in Conservation. University of California Press https://books.google.com/books?id=LfDLBwAAQBAJ.
Wang, Yonggang; Wei, Zexun; Lian, Zhan; Yang, Yongzeng (2015). Development of an Ocean Current Forecast System for the South China Sea, Aquatic Procedia (3), 157-164, 10.1016/j.aqpro.2015.02.206.
Formatted Citation: Wang, Y., Z. Wei, Z. Lian, and Y. Yang, 2015: Development of an Ocean Current Forecast System for the South China Sea. Aquatic Procedia, 3, 157-164, doi:10.1016/j.aqpro.2015.02.206
Dinniman, Michael S.; Klinck, John M.; Bai, Le-Sheng; Bromwich, David H.; Hines, Keith M.; Holland, David M. (2015). The Effect of Atmospheric Forcing Resolution on Delivery of Ocean Heat to the Antarctic Floating Ice Shelves, Journal of Climate, 15 (28), 6067-6085, 10.1175/JCLI-D-14-00374.1.
Title: The Effect of Atmospheric Forcing Resolution on Delivery of Ocean Heat to the Antarctic Floating Ice Shelves
Type: Journal Article
Publication: Journal of Climate
Author(s): Dinniman, Michael S.; Klinck, John M.; Bai, Le-Sheng; Bromwich, David H.; Hines, Keith M.; Holland, David M.
Year: 2015
Formatted Citation: Dinniman, M. S., J. M. Klinck, L. Bai, D. H. Bromwich, K. M. Hines, and D. M. Holland, 2015: The Effect of Atmospheric Forcing Resolution on Delivery of Ocean Heat to the Antarctic Floating Ice Shelves. J. Clim., 28(15), 6067-6085, doi:10.1175/JCLI-D-14-00374.1
Stroh, J. N.; Panteleev, Gleb; Kirillov, Sergey; Makhotin, Mikhail; Shakhova, Natalia (2015). Sea-surface temperature and salinity product comparison against external in situ data in the Arctic Ocean, Journal of Geophysical Research: Oceans, 11 (120), 7223-7236, 10.1002/2015JC011005.
Formatted Citation: Stroh, J. N., G. Panteleev, S. Kirillov, M. Makhotin, and N. Shakhova, 2015: Sea-surface temperature and salinity product comparison against external in situ data in the Arctic Ocean. J. Geophys. Res. Ocean., 120(11), 7223-7236, doi:10.1002/2015JC011005
Title: Biological and environmental drivers of mangrove propagule dispersal: A field and modeling approach
Type: Thesis
Publication:
Author(s): Van der Stocken, Tom
Year: 2015
Formatted Citation: Van der Stocken, T., 2015: Biological and environmental drivers of mangrove propagule dispersal: A field and modeling approach. Vrije Universiteit Brussel and the Universite Libre de Bruxelles, Ph.D., 190 pp. http://www.vliz.be/en/imis?module=ref&refid=289661.
Abstract: Mangrove ecosystems function at the edge of land and sea, often covering large intertidal areasalong (sub)tropical coastal regions worldwide but also in a wide array of other topographical settings. Once or twice a day, tides move seawater in and out, consecutively submerging and exposing the intertidal surface, while freshwater now and then, at moments of heavy rainfall, may enter the system from the land. Mangroves can live in these highly dynamic and demanding environmental conditions via a series of remarkable adaptations such as aerial roots (pneumatophores), specialized cells in their leaves to excrete salt and the production of buoyant seeds and fruits (propagules) that disperse at the ocean surface (i.e. hydrochory). With their dense root networks, mangroves present a natural breeding ground and nursery for juvenile fish and provide shelter to many other animal species, rendering mangrove systems ecologically invaluable. From a socio-economical point of view, these forests sustain fisheries, provide firewood and wood for charcoal and construction. They may offer coastal protection to natural disasters such as storm surges and under certain conditions against tsunami. Despite their ecological and economical value, about 40 % of original mangroves have been lost worldwide during the last 50 years due to excessive exploitation and development. Deforestation, degradation and conversion to other land uses like intensive shrimp farming and agriculture have reduced and fragmented these ecosystems at an alarming rate. Climate change, probably most pronouncedly via changes in sea level, poses another important threat. In this dissertation we investigate some understudied but important aspects of the dispersal process in mangroves, with as the main objective the reduction of parameter and model uncertainty. In this way more reliable predictions of dispersal patterns and long-term population dynamics under different climate change scenarios can be expected.
Halkides, D J; Waliser, Duane E; Lee, Tong; Menemenlis, Dimitris; Guan, Bin (2015). Quantifying the processes controlling intraseasonal mixed-layer temperature variability in the tropical Indian Ocean, Journal of Geophysical Research: Oceans, 2 (120), 692-715, 10.1002/2014JC010139.
Title: Quantifying the processes controlling intraseasonal mixed-layer temperature variability in the tropical Indian Ocean
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Halkides, D J; Waliser, Duane E; Lee, Tong; Menemenlis, Dimitris; Guan, Bin
Year: 2015
Formatted Citation: Halkides, D. J., D. E. Waliser, T. Lee, D. Menemenlis, and B. Guan, 2015: Quantifying the processes controlling intraseasonal mixed-layer temperature variability in the tropical Indian Ocean. J. Geophys. Res. Ocean., 120(2), 692-715, doi:10.1002/2014JC010139
Abstract: Spatial and temporal variation of processes that determine ocean mixed-layer (ML) temperature (MLT) variability on the timescale of the Madden-Julian Oscillation (MJO) in the Tropical Indian Ocean (TIO) are examined in a heat-conserving ocean state estimate for years 1993-2011. We introduce a new metric for representing spatial variability of the relative importance of processes. In general, horizontal advection is most important at the Equator. Subsurface processes and surface heat flux are more important away from the Equator, with surface heat flux being the more dominant factor. Analyses at key sites are discussed in the context of local dynamics and literature. At 0°, 80.5°E, for MLT events > 2 standard deviations, ocean dynamics account for more than two thirds of the net tendency during cooling and warming phases. Zonal advection alone accounts for ∼40% of the net tendency. Moderate events (1-2 standard deviations) show more differences between events, and some are dominated by surface heat flux. At 8°S, 67°E in the Seychelles-Chagos Thermocline Ridge (SCTR) area, surface heat flux accounts for ∼70% of the tendency during strong cooling and warming phases; subsurface processes linked to ML depth (MLD) deepening (shoaling) during cooling (warming) account for ∼30%. MLT is more sensitive to subsurface processes in the SCTR, due to the thin MLD, thin barrier layer and raised thermocline. Results for 8°S, 67°E support assertions by Vialard et al. (2008) not previously confirmed due to measurement error that prevented budget closure and the small number of events studied. The roles of MLD, barrier layer thickness, and thermocline depth on different timescales are examined.
Keywords: 4223 Descriptive and regional oceanography, 4231 Equatorial oceanography, 4260 Ocean data assimilation and reanalysis, 4504 Air/sea interactions, 4572 Upper ocean and mixed layer processes, ECCO, Indian Ocean, MJO, intraseasonal, mixed-layer, temperature budget
Ott, Lesley E; Pawson, Steven; Collatz, George J; Gregg, Watson W; Menemenlis, Dimitris; Brix, Holger; Rousseaux, Cecile S; Bowman, Kevin W.; Liu, Junjie; Eldering, Annmarie; Gunson, Michael R; Kawa, Stephan R (2015). Assessing the magnitude of CO2 flux uncertainty in atmospheric CO2 records using products from NASA’s Carbon Monitoring Flux Pilot Project, Journal of Geophysical Research: Atmospheres, 2 (120), 734-765, 10.1002/2014JD022411.
Title: Assessing the magnitude of CO2 flux uncertainty in atmospheric CO2 records using products from NASA’s Carbon Monitoring Flux Pilot Project
Type: Journal Article
Publication: Journal of Geophysical Research: Atmospheres
Author(s): Ott, Lesley E; Pawson, Steven; Collatz, George J; Gregg, Watson W; Menemenlis, Dimitris; Brix, Holger; Rousseaux, Cecile S; Bowman, Kevin W.; Liu, Junjie; Eldering, Annmarie; Gunson, Michael R; Kawa, Stephan R
Year: 2015
Formatted Citation: Ott, L. E. and Coauthors, 2015: Assessing the magnitude of CO2 flux uncertainty in atmospheric CO2 records using products from NASA's Carbon Monitoring Flux Pilot Project. Journal of Geophysical Research: Atmospheres, 120(2), 734-765, doi:10.1002/2014JD022411
Abstract: NASA's Carbon Monitoring System Flux Pilot Project (FPP) was designed to better understand contemporary carbon fluxes by bringing together state-of-the art models with remote sensing data sets. Here we report on simulations using NASA's Goddard Earth Observing System Model, version 5 (GEOS-5) which was used to evaluate the consistency of two different sets of observationally informed land and ocean fluxes with atmospheric CO2 records. Despite the observation inputs, the average difference in annual terrestrial biosphere flux between the two land (NASA Ames Carnegie-Ames-Stanford-Approach (CASA) and CASA-Global Fire Emissions Database version 3 (GFED)) models is 1.7 Pg C for 2009-2010. Ocean models (NASA's Ocean Biogeochemical Model (NOBM) and Estimating the Circulation and Climate of the Ocean Phase II (ECCO2)-Darwin) differ by 35% in their global estimates of carbon flux with particularly strong disagreement in high latitudes. Based upon combinations of terrestrial and ocean fluxes, GEOS-5 reasonably simulated the seasonal cycle observed at Northern Hemisphere surface sites and by the Greenhouse gases Observing SATellite (GOSAT) while the model struggled to simulate the seasonal cycle at Southern Hemisphere surface locations. Though GEOS-5 was able to reasonably reproduce the patterns of XCO2 observed by GOSAT, it struggled to reproduce these aspects of Atmospheric Infrared Sounder observations. Despite large differences between land and ocean flux estimates, resulting differences in atmospheric mixing ratio were small, typically less than 5 ppm at the surface and 3 ppm in the XCO2 column. A statistical analysis based on the variability of observations shows that flux differences of these magnitudes are difficult to distinguish from inherent measurement variability, regardless of the measurement platform.
Dorman, Jeffrey G. (2015). Modeling Krill in the California Current: A 2005 Case Study, Conserving Biodiversity in a Changing Climate: Linking Science and Management in Conservation, 43-60.
Title: Modeling Krill in the California Current: A 2005 Case Study
Type: Book Section
Publication: Conserving Biodiversity in a Changing Climate: Linking Science and Management in Conservation
Author(s): Dorman, Jeffrey G.
Year: 2015
Formatted Citation: Dorman, J. G., 2015: Modeling Krill in the California Current: A 2005 Case Study. Conserving Biodiversity in a Changing Climate: Linking Science and Management in Conservation, T. L. Root, K. R. Hall, M. P. Herzog, and C. A. Howell, Eds., Univ of California Press, 43-60, https://www.ucpress.edu/book/9780520286719/biodiversity-in-a-changing-climate
Peña-Izquierdo, Jesús; van Sebille, Erik; Pelegrí, Josep L.; Sprintall, Janet; Mason, Evan; Llanillo, Pedro J.; Machín, Francisco (2015). Water mass pathways to the North Atlantic oxygen minimum zone, Journal of Geophysical Research: Oceans, 5 (120), 3350-3372, 10.1002/2014JC010557.
Title: Water mass pathways to the North Atlantic oxygen minimum zone
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Peña-Izquierdo, Jesús; van Sebille, Erik; Pelegrí, Josep L.; Sprintall, Janet; Mason, Evan; Llanillo, Pedro J.; Machín, Francisco
Year: 2015
Formatted Citation: Peña-Izquierdo, J., E. van Sebille, J. L. Pelegrí, J. Sprintall, E. Mason, P. J. Llanillo, and F. Machín, 2015: Water mass pathways to the North Atlantic oxygen minimum zone. J. Geophys. Res. Ocean., 120(5), 3350-3372, doi:10.1002/2014JC010557
Muller-Karger, Frank E.; Smith, Joseph P.; Werner, Sandra; Chen, Robert; Roffer, Mitchell; Liu, Yanyun; Muhling, Barbara; Lindo-Atichati, David; Lamkin, John; Cerdeira-Estrada, Sergio; Enfield, David B. (2015). Natural variability of surface oceanographic conditions in the offshore Gulf of Mexico, Progress in Oceanography (134), 54-76, 10.1016/j.pocean.2014.12.007.
Title: Natural variability of surface oceanographic conditions in the offshore Gulf of Mexico
Type: Journal Article
Publication: Progress in Oceanography
Author(s): Muller-Karger, Frank E.; Smith, Joseph P.; Werner, Sandra; Chen, Robert; Roffer, Mitchell; Liu, Yanyun; Muhling, Barbara; Lindo-Atichati, David; Lamkin, John; Cerdeira-Estrada, Sergio; Enfield, David B.
Year: 2015
Formatted Citation: Muller-Karger, F. E. and Coauthors, 2015: Natural variability of surface oceanographic conditions in the offshore Gulf of Mexico. Progress in Oceanography, 134, 54-76, doi:10.1016/j.pocean.2014.12.007
Koldunov, A.V.; Koldunov, N.V.; Volkov, Denis L.; Belonenko, T.V. (2015). Applying satellite data for validation of the hydrodynamic model for the Arctic Ocean, Current Problems in Remote Sensing of the Earth from Space, 6 (12), 53-66.
Formatted Citation: Koldunov, A., N. Koldunov, D. L. Volkov, and T. Belonenko, 2015: Applying satellite data for validation of the hydrodynamic model for the Arctic Ocean. Current Problems in Remote Sensing of the Earth from Space, 12(6), 53-66
Abstract: The aim of this work is to test the performance of the MITgcm hydrodynamic model setup for the Arctic Ocean which is installed and runs in Resource Center "Computer Center of the St. Petersburg State University". The setup is created in the framework of the ECCO2 project that aims to simulate global high-resolution fields of oceanographic characteristics with linear approximation to oceanographic observations. Satellite data are used to validate several oceanographic features simulated by the model: the sea ice extent and concentration, sea level and sea surface temperature. The model is able to successfully reproduce spatial and temporal variability of sea ice characteristics and give adequate estimates of seasonal variability and trend of the sea ice extent in the Arctic Ocean. Simulation of sea surface height anomalies associated with mass change is satisfactory for the Arctic Ocean regions located away from the North Pole, particularly for the Barents Sea. Simulation of sea surface temperature demonstrates good results for both interannual variability and trend. Comparison of the satellite- and model-derived data proves that the model reproduces the above mentioned oceanographic features reasonably well. Therefore, this model may be used in further studies different scientific and practical problems of the Arctic Ocean.
Other URLs: https://elibrary.ru/item.asp?id=25017456
Zhang, Yanxu; Jacob, Daniel J.; Dutkiewicz, Stephanie; Amos, Helen M.; Long, Michael S.; Sunderland, Elsie M. (2015). Biogeochemical drivers of the fate of riverine mercury discharged to the global and Arctic oceans, Global Biogeochemical Cycles, 6 (29), 854-864, 10.1002/2015GB005124.
Title: Biogeochemical drivers of the fate of riverine mercury discharged to the global and Arctic oceans
Type: Journal Article
Publication: Global Biogeochemical Cycles
Author(s): Zhang, Yanxu; Jacob, Daniel J.; Dutkiewicz, Stephanie; Amos, Helen M.; Long, Michael S.; Sunderland, Elsie M.
Year: 2015
Formatted Citation: Zhang, Y., D. J. Jacob, S. Dutkiewicz, H. M. Amos, M. S. Long, and E. M. Sunderland, 2015: Biogeochemical drivers of the fate of riverine mercury discharged to the global and Arctic oceans. Global Biogeochemical Cycles, 29(6), 854-864, doi:10.1002/2015GB005124
Chen, Ru; Flierl, Glenn R. (2015). The Contribution of Striations to the Eddy Energy Budget and Mixing: Diagnostic Frameworks and Results in a Quasigeostrophic Barotropic System with Mean Flow, Journal of Physical Oceanography, 8 (45), 2095-2113, 10.1175/JPO-D-14-0199.1.
Title: The Contribution of Striations to the Eddy Energy Budget and Mixing: Diagnostic Frameworks and Results in a Quasigeostrophic Barotropic System with Mean Flow
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Chen, Ru; Flierl, Glenn R.
Year: 2015
Formatted Citation: Chen, R., and G. R. Flierl, 2015: The Contribution of Striations to the Eddy Energy Budget and Mixing: Diagnostic Frameworks and Results in a Quasigeostrophic Barotropic System with Mean Flow. Journal of Physical Oceanography, 45(8), 2095-2113, doi:10.1175/JPO-D-14-0199.1
Formatted Citation: Xu, C., X. Shang, and R. X. Huang, 2014: Horizontal eddy energy flux in the world oceans diagnosed from altimetry data. Scientific Reports, 4(1), 5316, doi:10.1038/srep05316
Title: Freshwater processes and water mass transformation in the Arctic Ocean
Type: Thesis
Publication:
Author(s): Pemberton, Per
Year: 2014
Formatted Citation: Pemberton, P., 2014: Freshwater processes and water mass transformation in the Arctic Ocean., 54 pp. http://www.diva-portal.org/smash/record.jsf?pid=diva2%3A751037.
Abstract: This thesis explores freshwater-related processes and water mass transforma- tion in the Arctic Ocean. Knowledge of these processes is important from both a local and a global perspective. Globally, because the export of cold and low saline water and sea ice might influence the North Atlantic and global merid- ional overturning circulation. Locally, because freshwater processes affect the vertical stratification and permit favorable conditions for the ice cover. Models of different complexity are the main tools of the present work. A part of the material considers how these models can be used to examine the key processes governing freshwater balance. Additionally, the freshwater budgets amongst 10 different ocean general circulation models (OGCMs) are compared and robust features and weaknesses identified. A large part considers the freshwater processes governing the stratifica- tion with an emphasis on the low saline upper parts. The interactions between freshwater sources and sinks are studied in an OGCM using passive tracers. It is found that the composition, pathways and shelf-basin exchange of low saline water primarily involve processes linked to Siberian runoff, Pacific wa- ter and sea-ice melting and formation. Motivated by observed changes and paleorecords the sensitivity of the stratification is further explored in fresh- water perturbation experiments with an OGCM. The response yields a deeper halocline for decreasing freshwater input, in line with a theoretical model. The final part focuses on a new framework for analyzing water mass trans- formations. In the framework volume, heat and salt budgets are computed in salinity-temperature space. Using different OGCMs it is shown how surface and interior processes transform inflowing waters towards colder and fresher waters and how the halocline renewal rate can be estimated. Limiting cases for the water mass transformation balance are identified by separating contri- butions from surface, internal and boundary fluxes.
Amol, P; Shankar, D; Fernando, V; Mukherjee, A; Aparna, S G; Fernandes, R; Michael, G S; Khalap, S T; Satelkar, N P; Agarvadekar, Y; Gaonkar, M G; Tari, A P; Kankonkar, A; Vernekar, S P (2014). Observed intraseasonal and seasonal variability of the West India Coastal Current on the continental slope, Journal of Earth System Science, 5 (123), 1045-1074, 10.1007/s12040-014-0449-5.
Title: Observed intraseasonal and seasonal variability of the West India Coastal Current on the continental slope
Type: Journal Article
Publication: Journal of Earth System Science
Author(s): Amol, P; Shankar, D; Fernando, V; Mukherjee, A; Aparna, S G; Fernandes, R; Michael, G S; Khalap, S T; Satelkar, N P; Agarvadekar, Y; Gaonkar, M G; Tari, A P; Kankonkar, A; Vernekar, S P
Year: 2014
Formatted Citation: Amol, P. and Coauthors, 2014: Observed intraseasonal and seasonal variability of the West India Coastal Current on the continental slope. Journal of Earth System Science, 123(5), 1045-1074, doi:10.1007/s12040-014-0449-5
Azaneu, M; Kerr, R; Mata, M M (2014). Assessment of the representation of Antarctic Bottom Water properties in the ECCO2 reanalysis, Ocean Sci., 6 (10), 923-946, 10.5194/os-10-923-2014.
Title: Assessment of the representation of Antarctic Bottom Water properties in the ECCO2 reanalysis
Type: Journal Article
Publication: Ocean Sci.
Author(s): Azaneu, M; Kerr, R; Mata, M M
Year: 2014
Formatted Citation: Azaneu, M., R. Kerr, and M. M. Mata, 2014: Assessment of the representation of Antarctic Bottom Water properties in the ECCO2 reanalysis. Ocean Sci., 10(6), 923-946, doi:10.5194/os-10-923-2014
Goes, Marlos; Wainer, Ilana; Signorelli, Natalia (2014). Investigation of the causes of historical changes in the subsurface salinity minimum of the South Atlantic, Journal of Geophysical Research: Oceans, 9 (119), 5654-5675, 10.1002/2014JC009812.
Formatted Citation: Goes, M., I. Wainer, and N. Signorelli, 2014: Investigation of the causes of historical changes in the subsurface salinity minimum of the South Atlantic. J. Geophys. Res. Ocean., 119(9), 5654-5675, doi:10.1002/2014JC009812
Title: Dynamics and estimation of the Agulhas leakage
Type: Thesis
Publication:
Author(s): Le Bars, D. M.
Year: 2014
Formatted Citation: Le Bars, D. M., 2014: Dynamics and estimation of the Agulhas leakage., 101 pp. https://dspace.library.uu.nl/handle/1874/290255.
Abstract: The Agulhas Current is a powerful boundary current that flows southward on the eastern coast of South Africa. At the southern termination of the continental shelf, most of the current turns back to the Indian Ocean in the Agulhas Return Current, this is called the Agulhas retroflection. In this process some eddies are shed from the current and propagate westward in the Atlantic Ocean. The water that originates from the Indian Ocean and enters the South Atlantic Ocean is called the Agulhas leakage. It is believed that this flux of relatively warm and salty water plays an important role in the Atlantic Meridional Overturning Circulation. In this thesis the dynamics of the retroflection process is studied. A new regime of retroflection is found for highly turbulent flows. In this regime the volume of leakage reaches a maximum and stays unchanged while both the wind stress curl and the Agulhas Current transport increase. This is found to be due to an increase of the interactions with the northern branch of the Antarctic Circumpolar Current. The importance of the Indonesian Throughflow, the equatorial flux of water from the Pacific Ocean to the Indian Ocean, is also explored using numerical models. It is shown that it leads to strengthen the leakage but does not change the proportion of retroflection. On the way from the Indonesian Through flow to the Agulhas Current an important passage is the South East Madagascar Current. Using dynamic topography data from satellite altimetry, dipolar structures are found to form continuously at the southern tip of Madagascar. The perturbations induced by these structures contributed to the two early retroflections of the Agulhas Current observed over the last 20 years. Finally, a method is developed and validated to measure the Agulhas leakage volume transport from satellite altimetry data.
Chen, Ru; Flierl, Glenn R.; Wunsch, Carl (2014). A Description of Local and Nonlocal Eddy-Mean Flow Interaction in a Global Eddy-Permitting State Estimate, Journal of Physical Oceanography, 9 (44), 2336-2352, 10.1175/JPO-D-14-0009.1.
Title: A Description of Local and Nonlocal Eddy-Mean Flow Interaction in a Global Eddy-Permitting State Estimate
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Chen, Ru; Flierl, Glenn R.; Wunsch, Carl
Year: 2014
Formatted Citation: Chen, R., G. R. Flierl, and C. Wunsch, 2014: A Description of Local and Nonlocal Eddy-Mean Flow Interaction in a Global Eddy-Permitting State Estimate. Journal of Physical Oceanography, 44(9), 2336-2352, doi:10.1175/JPO-D-14-0009.1
Abstract: The assumption that local baroclinic instability dominates eddy-mean flow interactions is tested on a global scale using a dynamically consistent eddy-permitting state estimate. Interactions are divided into local and nonlocal. If all the energy released from the mean flow through eddy-mean flow interaction is used to support eddy growth in the same region, or if all the energy released from eddies through eddy-mean flow interaction is used to feed back to the mean flow in the same region, eddy-mean flow interaction is local; otherwise, it is nonlocal. Different regions have different characters: in the subtropical region studied in detail, interactions are dominantly local. In the Southern Ocean and Kuroshio and Gulf Stream Extension regions, they are mainly nonlocal. Geographical variability of dominant eddy-eddy and eddy-mean flow processes is a dominant factor in understanding ocean energetics.
Keywords: Circulation/ Dynamics, Eddies, Energy transport, Phys
Porter, David F.; Tinto, Kirsty J.; Boghosian, Alexandra; Cochran, James R.; Bell, Robin E.; Manizade, Serdar S.; Sonntag, John G. (2014). Bathymetric control of tidewater glacier mass loss in northwest Greenland, Earth and Planetary Science Letters (401), 40-46, 10.1016/j.epsl.2014.05.058.
Title: Bathymetric control of tidewater glacier mass loss in northwest Greenland
Type: Journal Article
Publication: Earth and Planetary Science Letters
Author(s): Porter, David F.; Tinto, Kirsty J.; Boghosian, Alexandra; Cochran, James R.; Bell, Robin E.; Manizade, Serdar S.; Sonntag, John G.
Year: 2014
Formatted Citation: Porter, D. F., K. J. Tinto, A. Boghosian, J. R. Cochran, R. E. Bell, S. S. Manizade, and J. G. Sonntag, 2014: Bathymetric control of tidewater glacier mass loss in northwest Greenland. Earth and Planetary Science Letters, 401, 40-46, doi:10.1016/j.epsl.2014.05.058
Title: A parallel Jacobian-free Newton-Krylov solver for a coupled sea ice-ocean model
Type: Journal Article
Publication: Journal of Computational Physics
Author(s): Losch, Martin; Fuchs, Annika; Lemieux, Jean-François; Vanselow, Anna
Year: 2014
Formatted Citation: Losch, M., A. Fuchs, J. Lemieux, and A. Vanselow, 2014: A parallel Jacobian-free Newton-Krylov solver for a coupled sea ice-ocean model. Journal of Computational Physics, 257, 901-911, doi:10.1016/j.jcp.2013.09.026
Nieves, V.; Wang, J.; Willis, J. K. (2014). A conceptual model of ocean freshwater flux derived from sea surface salinity, Geophysical Research Letters, 18 (41), 6452-6458, 10.1002/2014GL061365.
Title: A conceptual model of ocean freshwater flux derived from sea surface salinity
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Nieves, V.; Wang, J.; Willis, J. K.
Year: 2014
Formatted Citation: Nieves, V., J. Wang, and J. K. Willis, 2014: A conceptual model of ocean freshwater flux derived from sea surface salinity. Geophys. Res. Lett., 41(18), 6452-6458, doi:10.1002/2014GL061365
Gwyther, D. E.; Galton-Fenzi, B. K.; Hunter, J. R.; Roberts, J. L. (2014). Simulated melt rates for the Totten and Dalton ice shelves, Ocean Science, 3 (10), 267-279, 10.5194/os-10-267-2014.
Title: Simulated melt rates for the Totten and Dalton ice shelves
Type: Journal Article
Publication: Ocean Science
Author(s): Gwyther, D. E.; Galton-Fenzi, B. K.; Hunter, J. R.; Roberts, J. L.
Year: 2014
Formatted Citation: Gwyther, D. E., B. K. Galton-Fenzi, J. R. Hunter, and J. L. Roberts, 2014: Simulated melt rates for the Totten and Dalton ice shelves. Ocean Science, 10(3), 267-279, doi:10.5194/os-10-267-2014
Abstract: The Totten Glacier is rapidly losing mass. It has been suggested that this mass loss is driven by changes in oceanic forcing; however, the details of the ice-ocean interaction are unknown. Here we present results from an ice shelf-ocean model of the region that includes the Totten, Dalton and Moscow University ice shelves, based on the Regional Oceanic Modeling System for the period 1992-2007. Simulated area-averaged basal melt rates (net basal mass loss) for the Totten and Dalton ice shelves are 9.1 m ice yr−1 (44.5 Gt ice yr−1) and 10.1 m ice yr−1 (46.6 Gt ice yr−1), respectively. The melting of the ice shelves varies strongly on seasonal and interannual timescales. Basal melting (mass loss) from the Totten ice shelf spans a range of 5.7 m ice yr−1 (28 Gt ice yr−1) on interannual timescales and 3.4 m ice yr−1 (17 Gt ice yr−1) on seasonal timescales. This study links basal melt of the Totten and Dalton ice shelves to warm water intrusions across the continental shelf break and atmosphere-ocean heat exchange. Totten ice shelf melting is high when the nearby Dalton polynya interannual strength is below average, and vice versa. Melting of the Dalton ice shelf is primarily controlled by the strength of warm water intrusions across the Dalton rise and into the ice shelf cavity. During periods of strong westward coastal current flow, Dalton melt water flows directly under the Totten ice shelf further reducing melting. This is the first such modelling study of this region to provide a valuable framework for directing future observational and modelling efforts.
Title: Ocean Surface Carbon Dioxide Fugacity Observed from Space
Type: Report
Publication:
Author(s): Liu, W Timothy; Xie, Xiaosu
Year: 2014
Formatted Citation: Liu, W. T., and X. Xie, 2014: Ocean Surface Carbon Dioxide Fugacity Observed from Space., Pasadena, CA, 1-24 pp. doi:20160009379.
Abstract: We have developed and validated a statistical model to estimate the fugacity (or partial pressure) of carbon dioxide (CO 2 ) at sea surface (pCO2sea) from space-based observations of sea surface temperature (SST), chlorophyll, and salinity. More than a quarter million in situ measurements coincident with satellite data were compiled to train and validate the model. We have produced and made accessible 9 years (2002-2010) of the pCO2sea at 0.5 degree resolutions daily over the global ocean. The data were used to reveal multi-year and regional variability of pCO2sea in relation to ocean parameters. The data also identify uncertainties in the current JPL Carbon Monitoring System (CMS) model-based and bottom-up estimates over the ocean in the subtropical oligotrophic oceans where biological production is not a significant factor in pCO2sea changes.
Title: Modeled Trends in Antarctic Sea Ice Thickness
Type: Journal Article
Publication: Journal of Climate
Author(s): Holland, Paul R.; Bruneau, Nicolas; Enright, Clare; Losch, Martin; Kurtz, Nathan T.; Kwok, Ron
Year: 2014
Formatted Citation: Holland, P. R., N. Bruneau, C. Enright, M. Losch, N. T. Kurtz, and R. Kwok, 2014: Modeled Trends in Antarctic Sea Ice Thickness. J. Clim., 27(10), 3784-3801, doi:10.1175/JCLI-D-13-00301.1
Dushaw, Brian D.; Menemenlis, Dimitris (2014). Antipodal acoustic thermometry: 1960, 2004, Deep Sea Research Part I: Oceanographic Research Papers (86), 1-20, 10.1016/j.dsr.2013.12.008.
Publication: Deep Sea Research Part I: Oceanographic Research Papers
Author(s): Dushaw, Brian D.; Menemenlis, Dimitris
Year: 2014
Formatted Citation: Dushaw, B. D., and D. Menemenlis, 2014: Antipodal acoustic thermometry: 1960, 2004. Deep Sea Research Part I: Oceanographic Research Papers, 86, 1-20, doi:10.1016/j.dsr.2013.12.008
Abstract: On 21 March 1960, sounds from three 300-lb depth charges deployed at 5.5-min intervals off Perth, Australia were recorded by the SOFAR station at Bermuda. The recorded travel time of these signals, about 13,375 s, is a historical measure of the ocean temperature averaged across several ocean basins. The 1960 travel time measurement has about 3-s precision. High-resolution global ocean state estimates for 2004 from the "Estimating the Circulation and Climate of the Ocean, Phase II" (ECCO2) project were combined with ray tracing to determine the paths followed by the acoustic signals. The acoustic paths are refracted geodesics that are slightly deflected by either small-scale topographic features in the Southern Ocean or the coast of Brazil. The refractive influences of intense, small-scale oceanographic features, such as Agulhas Rings or eddies in the Antarctic Circumpolar Current, greatly reduce the necessary topographic deflection and cause the acoustic paths to meander in time. The ECCO2 ocean state estimates, which are constrained by model dynamics and available data, were used to compute present-day travel times. Measured and computed arrival coda were in good agreement. Based on recent estimates of warming of the upper ocean, the travel-time change over the past half-century was nominally expected to be about −9 s, but little difference between measured (1960) and computed (2004) travel times was found. Taking into account uncertainties in the 1960 measurements, the 2004 ocean state estimates, and other approximations, the ocean temperature averaged along the sound channel axis over the antipodal paths has warmed at a rate less than about 4.6 m °C yr−1 (95% confidence). At this time, the estimated uncertainties are comparable in size to the expected warming signal, however.
Mukherjee, A; Shankar, D; Fernando, V; Amol, P; Aparna, S G; Fernandes, R; Michael, G S; Khalap, S T; Satelkar, N P; Agarvadekar, Y; Gaonkar, M G; Tari, A P; Kankonkar, A; Vernekar, S (2014). Observed seasonal and intraseasonal variability of the East India Coastal Current on the continental slope, Journal of Earth System Science, 6 (123), 1197-1232, 10.1007/s12040-014-0471-7.
Title: Observed seasonal and intraseasonal variability of the East India Coastal Current on the continental slope
Type: Journal Article
Publication: Journal of Earth System Science
Author(s): Mukherjee, A; Shankar, D; Fernando, V; Amol, P; Aparna, S G; Fernandes, R; Michael, G S; Khalap, S T; Satelkar, N P; Agarvadekar, Y; Gaonkar, M G; Tari, A P; Kankonkar, A; Vernekar, S
Year: 2014
Formatted Citation: Mukherjee, A. and Coauthors, 2014: Observed seasonal and intraseasonal variability of the East India Coastal Current on the continental slope. Journal of Earth System Science, 123(6), 1197-1232, doi:10.1007/s12040-014-0471-7
Hamilton, Stephen G.; Castro de la Guardia, Laura; Derocher, Andrew E.; Sahanatien, Vicki; Tremblay, Bruno; Huard, David (2014). Projected Polar Bear Sea Ice Habitat in the Canadian Arctic Archipelago, PLoS ONE, 11 (9), e113746, 10.1371/journal.pone.0113746.
Title: Projected Polar Bear Sea Ice Habitat in the Canadian Arctic Archipelago
Type: Journal Article
Publication: PLoS ONE
Author(s): Hamilton, Stephen G.; Castro de la Guardia, Laura; Derocher, Andrew E.; Sahanatien, Vicki; Tremblay, Bruno; Huard, David
Year: 2014
Formatted Citation: Hamilton, S. G., L. Castro de la Guardia, A. E. Derocher, V. Sahanatien, B. Tremblay, and D. Huard, 2014: Projected Polar Bear Sea Ice Habitat in the Canadian Arctic Archipelago. PLoS ONE, 9(11), e113746, doi:10.1371/journal.pone.0113746
Title: A unified vertical reference system for South America within a global elevation system
Type: Thesis
Publication:
Author(s): Sánchez-Drewes, Laura Marlene
Year: 2014
Formatted Citation: Sánchez-Drewes, L. M., 2014: A unified vertical reference system for South America within a global elevation system., 165 pp.
Abstract: The objective of this study is the unification of the South American height systems into a global vertical reference system satisfying the requirements of modern Geodesy. The following topics are discussed: a) Definition and realisation of a conventional global vertical reference system; b) Review and standardisation of the geodetic data referring to the South American height systems; c) Strategies for the precise transformation of the local height datums into the global vertical reference system. It is expected that a modern vertical reference system supports the combination of physical and geometric heights with high accuracy globally. Therefore, two components are considered: a) A geometric component consisting of ellipsoidal heights as coordinates and a level ellipsoid as the reference surface, and b) A physical component comprising geopotential numbers as coordinates and an equipotential surface defined by a conventional W0 value as the reference surface. The definition of the physical component is based on potential parameters in order to provide reference to any type of physical heights (normal, orthometric, etc.). The conversion of geopotential numbers into metric heights and the modelling of the reference surface (geoid or quasigeoid determination) are considered as steps of the realisation. Since the approach developed in this study is based on the combination of geometric and physical parameters, it was necessary to include an inventory of the standards used in the determination of the vertical coordinates. This inventory is the basis for the identification and consequent removal of systematic errors caused by the application of different models and methods in the generation of the data available for this study. The main results of this study are: a) A detailed description of the characteristics to be satisfied by the reference stations realising the global vertical reference system. This description includes the needed conventions for the standardisation of the vertical coordinates and the computation of normal equations for the national levelling networks. These equations are required to integrate the local height systems into the global one. b) Estimation of the reference value W0 following different approaches and applying the latest geodetic models of the Earth\'s surface and gravity field. This procedure also includes a rigorous error propagation analysis to assess the reliability of the W0 estimate. c) Observation equations for the determination of the level discrepancies between the local height datums and the global W0. This is performed in three approaches: in the ocean areas around the reference tide gauges (ocean approach), at the reference tide gauges (coastal approach), and at the reference stations of the geocentric reference system (continental approach). d) Vertical datum parameters for the unification of the South American height systems into a global vertical reference system. The accuracy is assessed to be about ±5 cm for those countries with a good coverage of measurements (Argentina, Brazil-Imbituba, Colombia, Ecuador, Uruguay, and Venezuela). For those regions with poor data coverage or high uncertainties in the data quality (Brazil-Santana, Bolivia, Peru, and Chile), the accuracy is estimated to be about ±2 ... 3 dm. The obtained level differences are in general positive, i.e., local vertical datums are above the global reference level W0. This and the north-south increase along the Atlantic coast and the south-north increase along the Pacific coast reflect well the behaviour of the sea surface topography in these regions. e) A description of the further activities to be developed by each country to improve the results of this study.
Other URLs: http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-162350
Tett, S F B; Sherwin, T J; Shravat, A; Browne, O (2014). How Much Has the North Atlantic Ocean Overturning Circulation Changed in the Last 50 Years?, Journal of Climate, 16 (27), 6325-6342, 10.1175/jcli-d-12-00095.1.
Title: How Much Has the North Atlantic Ocean Overturning Circulation Changed in the Last 50 Years?
Type: Journal Article
Publication: Journal of Climate
Author(s): Tett, S F B; Sherwin, T J; Shravat, A; Browne, O
Year: 2014
Formatted Citation: Tett, S. F. B., T. J. Sherwin, A. Shravat, and O. Browne, 2014: How Much Has the North Atlantic Ocean Overturning Circulation Changed in the Last 50 Years? J. Clim., 27(16), 6325-6342, doi:10.1175/jcli-d-12-00095.1
Abstract: Volume transports from six ocean reanalyses are compared with four sets of in situ observations: across the Greenland-Scotland ridge (GSR), in the Labrador Sea boundary current, in the deep western boundary current at 43 degrees N, and in the Atlantic meridional overturning circulation (AMOC) at 26 degrees N in the North Atlantic. The higher-resolution reanalyses (on the order of 1/4 degrees X 1/4 degrees) are better at reproducing the circulation pattern in the subpolar gyre than those with lower resolution (on the order of 1 degrees). Simple Ocean Data Assimilation (SODA) and Estimating the Circulation and Climate of the Ocean (ECCO)-Jet Propulsion Laboratory (JPL) produce transports at 26 degrees N that are close to those observed [17 Sv (1 Sv equivalent to 10(6) m(3) s(-1))]. ECCO, version 2, and SODA produce northward transports across the GSR (observed transport of 8.2 Sv) that are 22% and 29% too big, respectively. By contrast, the low-resolution reanalyses have transports that are either too small [by 31% for ECCO-JPL and 49% for Ocean Reanalysis, system 3 (ORA-S3)] or much too large [Decadal Prediction System (DePreSys)]. SODA had the best simulations of mixed layer depth and with two coarse grid long-term reanalyses (DePreSys and ORA-S3) is used to examine changes in North Atlantic circulation from 1960 to 2008. Its results suggest that the AMOC increased by about 20% at 26 degrees N while transport across the GSR hardly altered. The other (less reliable) long-term reanalyses also had small changes across the GSR but changes of +10% and -20%, respectively, at 26 degrees N. Thus, it appears that changes in the overturning circulation at 26 degrees N are decoupled from the flow across the GSR. It is recommended that transport observations should not be assimilated in ocean reanalyses but used for validation instead.
Keywords: channel, flow, nordic seas, overflow, thermohaline circulation, variability, water
ECCO Products Used: ECCO-KFS;ECCO2
URL:
Other URLs:
Kenitz, Katarzyna M. (2014). The paradox of the plankton: Investigating the effect of inter-species competition of phytoplankton and its sensitivity to nutrient supply and external forcing.
Title: The paradox of the plankton: Investigating the effect of inter-species competition of phytoplankton and its sensitivity to nutrient supply and external forcing
Type: Thesis
Publication:
Author(s): Kenitz, Katarzyna M.
Year: 2014
Formatted Citation: Kenitz, K. M., 2014: The paradox of the plankton: Investigating the effect of inter-species competition of phytoplankton and its sensitivity to nutrient supply and external forcing., 270 pp. https://core.ac.uk/download/pdf/80771980.pdf.
Abstract: Hutchinson (1961) first posed the paradox of the plankton: Why do so many phytoplankton species coexist while competing for a limited number of resources? High biodiversity has been explained in terms of the phytoplankton system not reaching an equilibrium state. Spatial and temporal variability can be achieved through externally imposed physical variability or internally-induced behaviour including periodic oscillations or irregular, chaotic behaviour. The research presented in this thesis investigates whether the non-equilibrium, chaotic response of the phytoplankton community is a likely outcome within the aquatic ecosystems. The thesis addresses the extent that chaotic behaviour remains a robust response with externally-imposed environmental variability. The sparsity of long-term time-series data and infrequent sampling inhibits the ability to verify whether marine ecosystems exhibit complex behaviour. The analysis of the timeseries records of phytoplankton taxa in the English Channel suggests that chaos might occur within diatom and dinoflagellates abundance time series. However, simulations using a chemostat model for phytoplankton and nutrients suggests that time series sampled every 1-2 days for more than 5 years are required to confidently distinguish deterministic chaos from noise. The model simulations suggest that the community response depends on the phytoplankton requirement for nutrients and attributed physiological traits allowing each species to be a stronger competitor for a different resource. A wider inter-species specialization increases the likelihood of oscillatory and chaotic responses, with competitive exclusion decreasing from 50% to 20% of the cases. Higher departures from the Redfield ratio in the elemental composition of species favour complex community behaviour and act to increase biodiversity. Whether chaotic response can be sustained is sensitive to the strength of the diffusive feedback between nutrient supply and ambient nutrient concentration that acts to sustain steady-state nutrient concentrations. Including seasonal and stochastic variability in the nutrient supply reveals that the frequency of chaotic dynamics increases by 20% and 45% respectively. In addition, seasonal forcing leads to temporal variability in the strength of the chaotic response, with chaos becoming more prevalent in the summer. In contrast to a well-mixed, homogeneous environment, physical dispersal can stir different phytoplankton communities together, which might act to inhibit chaos, but at the same time enhance phytoplankton diversity. Idealised model simulations are conducted to mimic the small and large scale transport processes by including 2 or 3 well-mixed boxes. Locally generated chaotic response is sustained if: 1) there is a low rate of exchange with a strong nutrient competitor that maintains the contrasts in the community structure; 2) a strong competitor is inhibited by a high mortality rate. In addition, if the local community is outcompeted, chaos can be exported through the advection of stronger competitors that exhibit chaotic fluctuations. This study highlights the importance of understanding the interactions between ambient nutrients and phytoplankton community. The variability in the nutrient supply and connectivity between ecosystems shape the community response to inter-species competition. Complex behaviour arising from inter-species competition is suggested to have a significant contribution in driving biodiversity. Future research on assessing the extent of chaos requires extending and analysing the available time-series data obtained from stable or isolated marine provinces.
Williams, Joanne; Hughes, C. W.; Tamisiea, M. E.; Williams, S. D. P. (2014). Weighing the ocean with bottom-pressure sensors: robustness of the ocean mass annual cycle estimate, Ocean Science, 4 (10), 701-718, 10.5194/os-10-701-2014.
Title: Weighing the ocean with bottom-pressure sensors: robustness of the ocean mass annual cycle estimate
Type: Journal Article
Publication: Ocean Science
Author(s): Williams, Joanne; Hughes, C. W.; Tamisiea, M. E.; Williams, S. D. P.
Year: 2014
Formatted Citation: Williams, J., C. W. Hughes, M. E. Tamisiea, and S. D. P. Williams, 2014: Weighing the ocean with bottom-pressure sensors: robustness of the ocean mass annual cycle estimate. Ocean Science, 10(4), 701-718, doi:10.5194/os-10-701-2014
Abstract: We use ocean bottom-pressure measurements from 17 tropical sites to determine the annual cycle of ocean mass. We show that such a calculation is robust, and use three methods to estimate errors in the mass determination. Our final best estimate, using data from the best sites and two ocean models, is that the annual cycle has an amplitude of 0.85 mbar (equivalent to 8.4 mm of sea level, or 3100 Gt of water), with a 95% chance of lying within the range 0.61-1.17 mbar. The time of the peak in ocean mass is 10 October, with 95% chance of occurring between 21 September and 25 October. The simultaneous fitting of annual ocean mass also improves the fitting of bottom-pressure instrument drift.
Formatted Citation: Bates, M., R. Tulloch, J. Marshall, and R. Ferrari, 2014: Rationalizing the Spatial Distribution of Mesoscale Eddy Diffusivity in Terms of Mixing Length Theory. Journal of Physical Oceanography, 44(6), 1523-1540, doi:10.1175/JPO-D-13-0130.1
Landschützer, Peter; Gruber, N.; Bakker, D. C. E.; Schuster, U. (2014). Recent variability of the global ocean carbon sink, Global Biogeochemical Cycles, 9 (28), 927-949, 10.1002/2014GB004853.
Title: Recent variability of the global ocean carbon sink
Type: Journal Article
Publication: Global Biogeochemical Cycles
Author(s): Landschützer, Peter; Gruber, N.; Bakker, D. C. E.; Schuster, U.
Year: 2014
Formatted Citation: Landschützer, P., N. Gruber, D. C. E. Bakker, and U. Schuster, 2014: Recent variability of the global ocean carbon sink. Global Biogeochemical Cycles, 28(9), 927-949, doi:10.1002/2014GB004853
Peralta-Ferriz, Cecilia; Morison, James H.; Wallace, John M.; Bonin, Jennifer A.; Zhang, Jinlun (2014). Arctic Ocean Circulation Patterns Revealed by GRACE, Journal of Climate, 4 (27), 1445-1468, 10.1175/JCLI-D-13-00013.1.
Title: Arctic Ocean Circulation Patterns Revealed by GRACE
Type: Journal Article
Publication: Journal of Climate
Author(s): Peralta-Ferriz, Cecilia; Morison, James H.; Wallace, John M.; Bonin, Jennifer A.; Zhang, Jinlun
Year: 2014
Formatted Citation: Peralta-Ferriz, C., J. H. Morison, J. M. Wallace, J. A. Bonin, and J. Zhang, 2014: Arctic Ocean Circulation Patterns Revealed by GRACE. J. Clim., 27(4), 1445-1468, doi:10.1175/JCLI-D-13-00013.1
Zhang, Dongxiao; McPhaden, Michael J.; Lee, Tong (2014). Observed interannual variability of zonal currents in the equatorial Indian Ocean thermocline and their relation to Indian Ocean Dipole, Geophysical Research Letters, 22 (41), 7933-7941, 10.1002/2014GL061449.
Title: Observed interannual variability of zonal currents in the equatorial Indian Ocean thermocline and their relation to Indian Ocean Dipole
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Zhang, Dongxiao; McPhaden, Michael J.; Lee, Tong
Year: 2014
Formatted Citation: Zhang, D., M. J. McPhaden, and T. Lee, 2014: Observed interannual variability of zonal currents in the equatorial Indian Ocean thermocline and their relation to Indian Ocean Dipole. Geophys. Res. Lett., 41(22), 7933-7941, doi:10.1002/2014GL061449
Sánchez, L.; Dayoub, N.; Čunderlík, R.; Minarechová, Z.; Mikula, K.; Vatrt, V.; Vojtíšková, M.; Šíma, Z. (2014). W0 Estimates in the Frame of the GGOS Working Group on Vertical Datum Standardisation.
Title: W0 Estimates in the Frame of the GGOS Working Group on Vertical Datum Standardisation
Type: Book Section
Publication:
Author(s): Sánchez, L.; Dayoub, N.; Čunderlík, R.; Minarechová, Z.; Mikula, K.; Vatrt, V.; Vojtíšková, M.; Šíma, Z.
Year: 2014
Formatted Citation: Sánchez, L., N. Dayoub, R. Čunderlík, Z. Minarechová, K. Mikula, V. Vatrt, M. Vojtíšková, and Z. Šíma, 2014: W0 Estimates in the Frame of the GGOS Working Group on Vertical Datum Standardisation., 203-210, doi:10.1007/978-3-319-10837-7_26
Formatted Citation: Yang, Q. and Coauthors, 2014: Sensitivity of the Arctic sea ice concentration forecasts to different atmospheric forcing: a case study. Acta Oceanologica Sinica, 33(12), 15-23, doi:10.1007/s13131-014-0566-7
Title: The deep ocean density structure at the Last Glacial Maximum: What was it and why?
Type: Thesis
Publication:
Author(s): Miller, Madeline Diane
Year: 2014
Formatted Citation: Miller, M. D., 2014: The deep ocean density structure at the Last Glacial Maximum: What was it and why?., 257 pp. https://core.ac.uk/download/pdf/33749802.pdf.
Abstract: The search for reliable proxies of past deep ocean temperature and salinity has proved difficult, thereby limiting our ability to understand the coupling of ocean circulation and climate over glacial-interglacial timescales. Previous inferences of deep ocean temperature and salinity from sediment pore fluid oxygen isotopes and chlorinity indicate that the deep ocean density structure at the Last Glacial Maximum (LGM, ∼20,000 years BP) was set by salinity, and that the density contrast between northern and southern sourced deep waters was markedly greater than in the modern ocean. High density stratification could help explain the marked contrast in carbon isotope distribution recorded in the LGM ocean relative to that we observe today, but what made the ocean's density structure so different at the LGM? How did it evolve from one state to another? Further, given the sparsity of the LGM temperature and salinity data set, what else can we learn by increasing the spatial density of proxy records? We investigate the cause and feasibility of a highly and salinity stratified deep ocean at the LGM and we work to increase the amount of information we can glean about the past ocean from pore fluid profiles of oxygen isotopes and chloride. Using a coupled ocean- sea ice-ice shelf cavity model we test whether the deep ocean density structure at the LGM can be explained by ice-ocean interactions over the Antarctic continental shelves, and show that a large contribution of the LGM salinity stratification can be explained through lower ocean temperature. In order to extract the maximum information from pore fluid profiles of oxygen isotopes and chloride we evaluate several inverse methods for ill-posed problems and their ability to recover bottom water histories from sediment pore fluid profiles. We demonstrate that Bayesian Markov Chain Monte Carlo parameter estimation techniques enable us to robustly recover the full solution space of bottom water histories, not only at the LGM, but through the most recent deglaciation and the Holocene up to the present. Finally, we evaluate a non-destructive pore fluid sampling technique, Rhizon samplers, in comparison to traditional squeezing methods and show that despite their promise, Rhizons are unlikely to be a good sampling tool for pore fluid measurements of oxygen isotopes and chloride.
Moholdt, Geir; Padman, Laurie; Fricker, Helen Amanda (2014). Basal mass budget of Ross and Filchner-Ronne ice shelves, Antarctica, derived from Lagrangian analysis of ICESat altimetry, Journal of Geophysical Research: Earth Surface, 11 (119), 2361-2380, 10.1002/2014JF003171.
Title: Basal mass budget of Ross and Filchner-Ronne ice shelves, Antarctica, derived from Lagrangian analysis of ICESat altimetry
Type: Journal Article
Publication: Journal of Geophysical Research: Earth Surface
Author(s): Moholdt, Geir; Padman, Laurie; Fricker, Helen Amanda
Year: 2014
Formatted Citation: Moholdt, G., L. Padman, and H. A. Fricker, 2014: Basal mass budget of Ross and Filchner-Ronne ice shelves, Antarctica, derived from Lagrangian analysis of ICESat altimetry. Journal of Geophysical Research: Earth Surface, 119(11), 2361-2380, doi:10.1002/2014JF003171
Title: Variability of the Global Ocean Carbon Sink (1998 through 2011)
Type: Thesis
Publication:
Author(s): Landschützer, Peter
Year: 2014
Formatted Citation: Landschützer, P., 2014: Variability of the Global Ocean Carbon Sink (1998 through 2011).(April), 184 pp. https://ueaeprints.uea.ac.uk/48677/1/2014LandschuetzerPPhD.pdf.
Abstract: In this thesis a newly developed 2-step neural network approach is used to reconstruct basin-wide monthly maps of the sea surface partial pressure of CO 2 (pCO 2 ) at a resolution of 1 ◦ ×1 ◦ for both the Atlantic Ocean from 1998 through 2007 and the global ocean from 1998 through 2011. From those, air-sea CO 2 flux maps are computed using a standard gas exchange parameterization and high-resolution wind speeds. Observations form the basis of the studies conducted in this thesis. The neural net- work estimates benefit from a continuous improvement of the observations, i.e., the Sur- face Ocean CO 2 Atlas (SOCAT) database. Additionally, bottle samples were collected along the UK-Caribbean line to investigate the variability of the sea surface pCO 2 and its drivers. The neural network derived pCO 2 estimates fit the observed pCO 2 data with a root mean square error (RMSE) of about 10 μatm in the Atlantic Ocean from 1998 through 2007 and about 12 μatm in the global ocean from 1998 through 2011, with almost no bias in both studies. A check against independent pCO 2 data reveals a larger RMSE, in particular in regions with strong pCO 2 variability and gradients. Temporal mean contemporary flux estimates for the Atlantic Ocean (-0.45±0.15 Pg C yr −1 ) and the global ocean (-1.54±0.65 Pg C yr −1 ) agree well with recent studies. Trends and variabilities within the considered time periods are strongly influenced by climate modes. The global results from 1998 through 2011 reveal the strongest variability of the air-sea CO 2 fluxes in the Equatorial Pacific (±0.12 Pg C yr −1 , ±1σ), mainly driven by the El Niño Southern Oscillation (ENSO) climate mode. Trends towards a strengthening of the Southern Ocean carbon sink (-0.36±0.07 Pg C yr −1 decade −1 ) from 1998 through 2011 are potentially linked to the recent weakening of the Southern Annular Mode (SAM) index.
Clement Kinney, Jaclyn; Maslowski, Wieslaw; Aksenov, Yevgeny; de Cuevas, Beverly; Jakacki, Jaromir; Nguyen, An; Osinski, Robert; Steele, Michael; Woodgate, Rebecca A.; Zhang, Jinlun (2014). On the Flow Through Bering Strait: A Synthesis of Model Results and Observations, The Pacific Arctic Region, 167-198, 10.1007/978-94-017-8863-2_7.
Formatted Citation: Clement Kinney, J. and Coauthors, 2014: On the Flow Through Bering Strait: A Synthesis of Model Results and Observations. The Pacific Arctic Region, Springer Netherlands, 167-198, doi:10.1007/978-94-017-8863-2_7
Formatted Citation: Dushaw, B. D., 2014: Acoustic Tomography, Ocean. Encyclopedia of Remote Sensing, E. G. Njoku, Eds., Springer, 4-11
Abstract: Ocean acoustic tomography is a remote sensing technique that employs the transmission of sound over large dis- tances within the ocean to precisely estimate averages of temperature and current. Acoustic tomography data usu- ally consist of time-of-flight travel times of acoustic pulses, which represent natural integrating measures of sound speed and current along acoustic paths. Variations in sound speed are predominantly caused by variations in temperature.
Other URLs: https://doi.org/10.1007/978-0-387-36699-9_211
Blunden, Jessica; Arndt, Derek S. (2014). State of the Climate in 2013, Bulletin of the American Meteorological Society, 7 (95), S1-S279, 10.1175/2014BAMSStateoftheClimate.1.
Publication: Bulletin of the American Meteorological Society
Author(s): Blunden, Jessica; Arndt, Derek S.
Year: 2014
Formatted Citation: Blunden, J., and D. S. Arndt, 2014: State of the Climate in 2013. Bull. Am. Meteorol. Soc., 95(7), S1-S279, doi:10.1175/2014BAMSStateoftheClimate.1
Title: Arctic Oil Spills: A Risk Assessment of Transport in Sea Ice and Ocean Surface Waters from Current Exploration Sites
Type: Thesis
Publication:
Author(s): Blanken, Hauke
Year: 2014
Formatted Citation: Blanken, H., 2014: Arctic Oil Spills: A Risk Assessment of Transport in Sea Ice and Ocean Surface Waters from Current Exploration Sites., 147 pp. http://digitool.library.mcgill.ca/webclient/StreamGate?folder_id=0&dvs=1544930911444~777.
Abstract: In recent years the level of oil and gas activity in the Arctic Ocean Basin has increased significantly. Permitting and reasonably safe execution of these activities in ice-infested waters require risk assessments that stretch the limits of currently available oil spill trajectory models. Research has suggested that using a coupled atmosphere-ice-ocean model to simulate oil spill trajectories in ice-infested waters could provide higher accuracy than traditionally parameterized models. This study is a first step towards the development of such a model within the framework of the MIT general circulation model. Oil spills are simulated by continuous release of passive tracers at ten locations in the Arctic Ocean Basin, and tracked in the ocean and sea ice for one year starting at the end of the drilling season, using classical parameterizations to model oil-ice interaction. Trajectories in sea ice are compared to historical sea ice drift data and found to agree reasonably well. 31 simulations with differing sets of historical environmental forcing are carried out to quantify inter-annual variability. Sensitivity to the key parameter, fraction of ice coverage, is found to be low. In general it is concluded that, depending on location, oil spills may be advected up to ∼1,700km over a winter season and ∼3,500km over one year. The furthest advection of spilled oil is observed in the Beaufort and Chukchi Seas, Baffin Bay, and East Greenland. Oil spills originating in the Beaufort, Chukchi, and Barents Seas are confirmed to cross international boundaries, and all spills are found to have potentially severe impact on coastlines. Where mobile drift ice is present, transport with sea ice is more extensive than transport with ocean currents.
Dushaw, Brian D. (2014). Assessing the horizontal refraction of ocean acoustic tomography signals using high-resolution ocean state estimates, The Journal of the Acoustical Society of America, 1 (136), 122-129, 10.1121/1.4881928.
Title: Assessing the horizontal refraction of ocean acoustic tomography signals using high-resolution ocean state estimates
Type: Journal Article
Publication: The Journal of the Acoustical Society of America
Author(s): Dushaw, Brian D.
Year: 2014
Formatted Citation: Dushaw, B. D., 2014: Assessing the horizontal refraction of ocean acoustic tomography signals using high-resolution ocean state estimates. The Journal of the Acoustical Society of America, 136(1), 122-129, doi:10.1121/1.4881928
Wunsch, Carl; Heimbach, Patrick (2014). Bidecadal Thermal Changes in the Abyssal Ocean, Journal of Physical Oceanography, 8 (44), 2013-2030, 10.1175/JPO-D-13-096.1.
Title: Bidecadal Thermal Changes in the Abyssal Ocean
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Wunsch, Carl; Heimbach, Patrick
Year: 2014
Formatted Citation: Wunsch, C., and P. Heimbach, 2014: Bidecadal Thermal Changes in the Abyssal Ocean. Journal of Physical Oceanography, 44(8), 2013-2030, doi:10.1175/JPO-D-13-096.1
Abstract: A dynamically consistent state estimate is used for the period 1992-2011 to describe the changes in oceanic temperatures and heat content, with an emphasis on determining the noise background in the abyssal (below 2000 m) depths. Interpretation requires close attention to the long memory of the deep ocean, implying that meteorological forcing of decades to thousands of years ago should still be producing trendlike changes in abyssal heat content. Much of the deep-ocean volume remained unobserved. At the present time, warming is seen in the deep western Atlantic and Southern Oceans, roughly consistent with those regions of the ocean expected to display the earliest responses to surface disturbances. Parts of the deeper ocean, below 3600 m, show cooling. Most of the variation in the abyssal Pacific Ocean is comparatively featureless, consistent with the slow, diffusive approach to a steady state expected there. In the global average, changes in heat content below 2000 m are roughly 10% of those inferred for the upper ocean over the 20-yr period. A useful global observing strategy for detecting future change has to be designed to account for the different time and spatial scales manifested in the observed changes. If the precision estimates of heat content change are independent of systematic errors, determining oceanic heat uptake values equivalent to 0.1 W m(-2) is possibly attainable over future bidecadal periods.
Wortham, C; Wunsch, C (2014). A Multidimensional Spectral Description of Ocean Variability, Journal of Physical Oceanography, 3 (44), 944-966, 10.1175/jpo-d-13-0113.1.
Title: A Multidimensional Spectral Description of Ocean Variability
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Wortham, C; Wunsch, C
Year: 2014
Formatted Citation: Wortham, C., and C. Wunsch, 2014: A Multidimensional Spectral Description of Ocean Variability. Journal of Physical Oceanography, 44(3), 944-966, doi:10.1175/jpo-d-13-0113.1
Abstract: An updated empirical, analytical model for the frequency and wavenumber distribution of balanced motion in the ocean is presented. The spectrum model spans periods longer than the inertial but shorter than a decade and wavelengths between 100 and 10 000 km. Assuming geostrophic dynamics, a spectrum model for the streamfunction is constructed to be consistent with a range of observations, including sea surface height from satellite altimetry, velocity from moored and shipboard instruments, and temperature from moorings. First-order characteristics of the observed spectra, including amplitude and spectral moments, vary slowly geographically. The spectrum model is horizontally anisotropic, accommodating observations that zonal wavenumber-frequency spectra are dominated by a nondispersive line. Qualitative and quantitative agreement is found with one-dimensional frequency and wavenumber spectra and observed vertical profiles of variance. Illustrative application is made of the model spectrum to observing-system design, data mapping, and uncertainty estimation for trends.
Landschützer, Peter; Gruber, N.; Bakker, D.C.E.; Schuster, U. (2014). An observation-based global monthly gridded sea surface pCO2 product from 1998 through 2011 and its monthly climatology.
Title: An observation-based global monthly gridded sea surface pCO2 product from 1998 through 2011 and its monthly climatology
Type: Report
Publication:
Author(s): Landschützer, Peter; Gruber, N.; Bakker, D.C.E.; Schuster, U.
Year: 2014
Formatted Citation: Landschützer, P., N. Gruber, D. Bakker, and U. Schuster, 2014: An observation-based global monthly gridded sea surface pCO2 product from 1998 through 2011 and its monthly climatology., Oak Ridge, Tennessee, 3 pp. doi:10.3334/CDIAC/OTG.SPCO2_1998_2011_ETH_SOM-FFN.
Title: Capturing the Impact of Riverine Nutrient Delivery on Coastal Ocean Biogeochemistry
Type: Thesis
Publication:
Author(s): Olhsson, Elizabeth Halley
Year: 2014
Formatted Citation: Olhsson, E. H., 2014: Capturing the Impact of Riverine Nutrient Delivery on Coastal Ocean Biogeochemistry., 168 pp. https://escholarship.org/uc/item/34k135nq.
Abstract: Rivers smaller than the Amazon tend to be excluded from earth system modeling efforts. Does it matter? Do sub-grid-scale rivers have significant impacts on offshore primary productivity? Using the Eel River in northern California, the river with the largest sediment yield per drainage area in the continental United States, as a test case, this question is explored using two approaches. First, a data-driven analysis of relevant time series taken on land, by buoy, and from space, demonstrates very little evidence of direct impact of Eel River discharge on contemporaneous coastal ocean primary productivity - but to the extent that that evidence exists, it seems to occur during years of greatest river discharge. To further analyze mechanistic drivers, a coupled mesoscale modeling framework unifying ocean, watershed and atmospheric representations is formulated and run in hindcast over the 2002-2010 period. Monthly average climatologies, interannual variabilities, and event-driven analysis of each year's largest river discharge are all examined for evidence of a river-ocean connection expressed through primary production. Storm event-generated turbulence appears to dominate the primary productivity during the winter months. The impact of the river seems to be largely independent of nutrient load, because its dissolved nitrate is less than that of the coastal ocean. There is no evidence that riverine delivery of gradually bioavailable detritus has a significant effect. Although a sufficiently super-nitrous river shows the ability to sustain a plume-nutrient-driven-bloom even at periods of extremely low flow, this is not currently a realistic scenario for the Eel River. The possibility remains that another micronutrient not studied in the modeling framework, such as iron, could be important to this system.
Yang, Qinghua; Locean data assimilation in osa, Svetlana N.; Losch, Martin; Tian-Kunze, Xiangshan; Nerger, Lars; Liu, Jiping; Kaleschke, Lars; Zhang, Zhanhai (2014). Assimilating SMOS sea ice thickness into a coupled ice-ocean model using a local SEIK filter, Journal of Geophysical Research: Oceans, 10 (119), 6680-6692, 10.1002/2014JC009963.
Title: Assimilating SMOS sea ice thickness into a coupled ice-ocean model using a local SEIK filter
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Yang, Qinghua; Locean data assimilation in osa, Svetlana N.; Losch, Martin; Tian-Kunze, Xiangshan; Nerger, Lars; Liu, Jiping; Kaleschke, Lars; Zhang, Zhanhai
Year: 2014
Formatted Citation: Yang, Q., S. N. Locean data assimilation in osa, M. Losch, X. Tian-Kunze, L. Nerger, J. Liu, L. Kaleschke, and Z. Zhang, 2014: Assimilating SMOS sea ice thickness into a coupled ice-ocean model using a local SEIK filter. J. Geophys. Res. Ocean., 119(10), 6680-6692, doi:10.1002/2014JC009963
Seroussi, Hélène; Morlighem, M; Rignot, E; Mouginot, J; Larour, E; Schodlok, M; Khazendar, A (2014). Sensitivity of the dynamics of Pine Island Glacier, West Antarctica, to climate forcing for the next 50 years, The Cryosphere, 5 (8), 1699-1710, 10.5194/tc-8-1699-2014.
Title: Sensitivity of the dynamics of Pine Island Glacier, West Antarctica, to climate forcing for the next 50 years
Type: Journal Article
Publication: The Cryosphere
Author(s): Seroussi, Hélène; Morlighem, M; Rignot, E; Mouginot, J; Larour, E; Schodlok, M; Khazendar, A
Year: 2014
Formatted Citation: Seroussi, H., M. Morlighem, E. Rignot, J. Mouginot, E. Larour, M. Schodlok, and A. Khazendar, 2014: Sensitivity of the dynamics of Pine Island Glacier, West Antarctica, to climate forcing for the next 50 years. Cryosph., 8(5), 1699-1710, doi:10.5194/tc-8-1699-2014
Brzeziński, A.; Rajner, M. (2014). Estimation of the Chandler wobble parameters by the use of the Kalman deconvolution filter, Proc Journées 2013 Systèmes de référence spatio-temporels, 189-192.
Title: Estimation of the Chandler wobble parameters by the use of the Kalman deconvolution filter
Type: Conference Proceedings
Publication: Proc Journées 2013 Systèmes de référence spatio-temporels
Author(s): Brzeziński, A.; Rajner, M.
Year: 2014
Formatted Citation: Brzeziński, A., and M. Rajner, 2014: Estimation of the Chandler wobble parameters by the use of the Kalman deconvolution filter. Proc Journées 2013 Systèmes de référence spatio-temporels, N. Capitaine, Eds. Observatoire de Paris, 189-192 pp. https://syrte.obspm.fr/jsr/journees2013/pdf/Brzezinski.pdf.
Belonenko, T V; Volkov, Denis L.; Norden, Y E; Ozhigin, V K (2014). Water Circulation in the Lofoten Basin of the Norwegian Sea, St. Petersburg University Bulletin. Earth Sciences, 2 (7), 108-121.
Title: Water Circulation in the Lofoten Basin of the Norwegian Sea
Type: Journal Article
Publication: St. Petersburg University Bulletin. Earth Sciences
Author(s): Belonenko, T V; Volkov, Denis L.; Norden, Y E; Ozhigin, V K
Year: 2014
Formatted Citation: Belonenko, T. V., D. L. Volkov, Y. E. Norden, and V. K. Ozhigin, 2014: Water Circulation in the Lofoten Basin of the Norwegian Sea. St. Petersburg University Bulletin. Earth Sciences, 7(2), 108-121, https://cyberleninka.ru/article/n/tsirkulyatsiya-vod-v-lofotenskoy-kotlovine-norvezhskogo-morya
Abstract: I t has been known for decades that Lofoten Basin (LB) is a region of high mesoscale activity. Th is large topographic depression with a maximum depth of 3250 m located in the Norwegian sea is associated with amplifi cation of EKE (eddy kinetic energy) and has some peculiar features of the circulation pattern. Quasi-permanent vortex in the center of the basin is studied with data from ECCO2 eddy-permitting circulation model, altimeter data and trajectories of ARGO buoys. In this study a comprehensive review of all the surveys related to the circulation in LB for the last 50 years is presented in order to structure knowledge and supplement it with the results of new research. Th e data used in this paper confi rm that general water movement in LB is cyclonic along the boundaries of the basin with the distinguishing anticyclonic vortex in the center of the basin. Th e explanation of this phenomenon is a subject for future research.
Childers, Katelin; Flagg, Charles N (2014). Circulation and Transport Across the Iceland Faroes Shetland Ridge, Marine and Atmospheric Science, 3684409 (Ph.D.), 122.
Title: Circulation and Transport Across the Iceland Faroes Shetland Ridge
Type: Thesis
Publication: Marine and Atmospheric Science
Author(s): Childers, Katelin; Flagg, Charles N
Year: 2014
Formatted Citation: Childers, K., and C. N. Flagg, 2014: Circulation and Transport Across the Iceland Faroes Shetland Ridge. Marine and Atmospheric Science State University of New York at Stony Brook, Ann Arbor, Ph.D.(3684409), 122 pp. http://hdl.handle.net/11401/77790.
Abstract: The pathways and variability of warm Atlantic Water crossing over the Iceland Faroes Scotland Ridge to the Nordic Seas are an important component of the large scale Atlantic circulation. This dissertation presents the spatial and temporal characteristics of the currents crossing the ridge from both an observational and modeling perspective. Previous analyses of the volume flux across the ridge have relied on moored velocity data and standard hydrographic sections. A unique velocity dataset collected weekly by the M/F Norrona along repeated routes significantly improves the spatial resolution of observations between Iceland and Denmark. Output from a global climate model complements this work by establishing the mean circulation between the observational sections. Following an introduction in Chapter 1, an analysis of the first 4.5 years of weekly observational data collected by the Norrona program is presented in Chapter 2. Surface inflows enter over the eastern half of each section and transport 1.5± 0.19 and 4.6± 0.46 Sv through the Faroe Shetland Channel (FSC) and across the Iceland Faroes Ridge (IFR), respectively. Fluctuations in the FSC inflows depend primarily on the southward flux over the Faroe shelf and slope, while the inflow width drives IFR interannual variability. The description of regional circulation is expanded southward in Chapter 3, using historic data from an additional ship of opportunity. Inflow paths from the North Atlantic Current to the Nordic Seas are presented. Output from a high resolution (1/12o), hourly, data assimilating run of the ECCO2 configuration of the MITgcm enhances the description of the mean flow between the observational routes and offers insight into the mesoscale features which perturb the time averaged circulation in Chapter 4. A streamline analysis in Chapter 5, predicts the flow paths from the IFR around the north of the Faroes and into the FSC. The recirculation of Atlantic Water onto the Faroes shelf and slope is shown to be split between a larger component (~1 Sv) , which is entrained into the Shetland Slope Current over the eastern FSC, and a smaller flow (~0.5 Sv), which circulates anticyclonically around the Faroes.
Liu, Junjie; Bowman, Kevin W.; Lee, Meemong; Henze, Daven K; Bousserez, Nicolas; Brix, Holger; James Collatz, G; Menemenlis, Dimitris; Ott, Lesley; Pawson, Steven; Jones, Dylan; Nassar, Ray (2014). Carbon monitoring system flux estimation and attribution: impact of ACOS-GOSAT XCO2 sampling on the inference of terrestrial biospheric sources and sinks, Tellus B: Chemical and Physical Meteorology, 1 (66), 22486, 10.3402/tellusb.v66.22486.
Title: Carbon monitoring system flux estimation and attribution: impact of ACOS-GOSAT XCO2 sampling on the inference of terrestrial biospheric sources and sinks
Type: Journal Article
Publication: Tellus B: Chemical and Physical Meteorology
Author(s): Liu, Junjie; Bowman, Kevin W.; Lee, Meemong; Henze, Daven K; Bousserez, Nicolas; Brix, Holger; James Collatz, G; Menemenlis, Dimitris; Ott, Lesley; Pawson, Steven; Jones, Dylan; Nassar, Ray
Year: 2014
Formatted Citation: Liu, J. and Coauthors, 2014: Carbon monitoring system flux estimation and attribution: impact of ACOS-GOSAT XCO2 sampling on the inference of terrestrial biospheric sources and sinks. Tellus B: Chemical and Physical Meteorology, 66(1), 22486, doi:10.3402/tellusb.v66.22486
Abstract: Using an Observing System Simulation Experiment (OSSE), we investigate the impact of JAXA Greenhouse gases Observing SATellite 'IBUKI' (GOSAT) sampling on the estimation of terrestrial biospheric flux with the NASA Carbon Monitoring System Flux (CMS-Flux) estimation and attribution strategy. The simulated observations in the OSSE use the actual column carbon dioxide (XCO2 ) b2.9 retrieval sensitivity and quality control for the year 2010 processed through the Atmospheric CO2 Observations from Space algorithm. CMS-Flux is a variational inversion system that uses the GEOS-Chem forward and adjoint model forced by a suite of observationally constrained fluxes from ocean, land and anthropogenic models. We investigate the impact of GOSAT sampling on flux estimation in two aspects: 1) random error uncertainty reduction and 2) the global and regional bias in posterior flux resulted from the spatiotemporally biased GOSAT sampling. Based on Monte Carlo calculations, we find that global average flux uncertainty reduction ranges from 25% in September to 60% in July. When aggregated to the 11 land regions designated by the phase 3 of the Atmospheric Tracer Transport Model Intercomparison Project, the annual mean uncertainty reduction ranges from 10% over North American boreal to 38% over South American temperate, which is driven by observational coverage and the magnitude of prior flux uncertainty. The uncertainty reduction over the South American tropical region is 30%, even with sparse observation coverage. We show that this reduction results from the large prior flux uncertainty and the impact of non-local observations. Given the assumed prior error statistics, the degree of freedom for signal is ~1132 for 1-yr of the 74 055 GOSAT XCO2 observations, which indicates that GOSAT provides ~1132 independent pieces of information about surface fluxes. We quantify the impact of GOSAT's spatiotemporally sampling on the posterior flux, and find that a 0.7 gigatons of carbon bias in the global annual posterior flux resulted from the seasonally and diurnally biased sampling when using a diagonal prior flux error covariance.
Title: Intraseasonal variability of currents along west coast of India
Type: Thesis
Publication: Goa University
Author(s): Prakash, Amol
Year: 2014
Formatted Citation: Prakash, A., 2014: Intraseasonal variability of currents along west coast of India., Goa University. 134 pp.
Abstract: Ocean currents transport both mass and energy from one location to another around the world. This transport may be in form of heat, salt, nutrients, larvae, debris or oil spills. The large movement of heat and salt makes currents one of the most important driving forces of climate. This circulation not only stabilizes the global atmospheric circulation, but also regulates the local weather, temperature extrema and air-sea gas exchanges. Currents also play an important role in the distribution of marine life around the world. They bring cold nutrient-rich water from deeper depths to the surface by a process known as upwelling. Such an ecosystem can support marine fish catches that are nearly 100 times the global mean. Today, ocean currents are thought to be the future for alternative energy. As water is almost 800 times denser than air, ocean currents can generate extremely high hydrokinetic power even at very low flow rates. Whether the application is climate, marine biodiversity or clean energy source, knowledge of currents has been important to the earth scientists, and to understand them one has to start by observing the oceans.
Elipot, Shane; Frajka-Williams, Eleanor; Hughes, Chris W.; Willis, Josh K. (2014). The Observed North Atlantic Meridional Overturning Circulation: Its Meridional Coherence and Ocean Bottom Pressure, Journal of Physical Oceanography, 2 (44), 517-537, 10.1175/JPO-D-13-026.1.
Title: The Observed North Atlantic Meridional Overturning Circulation: Its Meridional Coherence and Ocean Bottom Pressure
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Elipot, Shane; Frajka-Williams, Eleanor; Hughes, Chris W.; Willis, Josh K.
Year: 2014
Formatted Citation: Elipot, S., E. Frajka-Williams, C. W. Hughes, and J. K. Willis, 2014: The Observed North Atlantic Meridional Overturning Circulation: Its Meridional Coherence and Ocean Bottom Pressure. Journal of Physical Oceanography, 44(2), 517-537, doi:10.1175/JPO-D-13-026.1
Lipinski, Doug; Mohseni, Kamran (2014). Observations on the flow structures and transport in a simulated warm-core ring in the Gulf of Mexico, Ocean Dynamics, 1 (64), 79-88, 10.1007/s10236-013-0674-5.
Title: Observations on the flow structures and transport in a simulated warm-core ring in the Gulf of Mexico
Type: Journal Article
Publication: Ocean Dynamics
Author(s): Lipinski, Doug; Mohseni, Kamran
Year: 2014
Formatted Citation: Lipinski, D., and K. Mohseni, 2014: Observations on the flow structures and transport in a simulated warm-core ring in the Gulf of Mexico. Ocean Dynamics, 64(1), 79-88, doi:10.1007/s10236-013-0674-5
Formatted Citation: Renner, A. H. H., S. Gerland, C. Haas, G. Spreen, J. F. Beckers, E. Hansen, M. Nicolaus, and H. Goodwin, 2014: Evidence of Arctic sea ice thinning from direct observations. Geophys. Res. Lett., 41(14), 5029-5036, doi:10.1002/2014GL060369
Formatted Citation: Burchard, H., U. Gräwe, P. Holtermann, K. Klingbeil, and E. Umlauf, 2014: Turbulence closure modelling in coastal waters. Kuste, 81(81), 69-87
Abstract: In this paper the use of turbulence closure models in coastal ocean models is reviewed. Two-equation turbulence closure models are argued to be an optimal compromise between efficiency and accuracy for the purpose of calculating diapycnal fluxes of momenturn, heat and tracers in coastal ocean modelling. They provide enough degrees of freedom to be calibrated to the most prominent properties of coastal ocean mixing, but are still numerically robust and computationally efficient. Isopycnal mixing schemes are briefly reviewed as well. Major implementational and numerical aspects are presented, with some focus on the inherent problem of numerically-induced mixing which together with the physically-induced mixing gives the effective mixing in ocean models. Vertically adaptive coordinates are presented as one possibility to reduce numerical mixing. Finally, three coastal ocean simulation examples from the General Estuarine Transport Model (GETM) which is coupled to the turbulence module of the General Ocean Turbulence Model . (GOTM) are given. These examples include thermocline mixing in the Northern North Sea, physically and numerically induced mixing in the Western Baltic Sea as well as basinwide mixing in the Central Baltic Sea. All three examples highlight the importance of using well-calibrated turbulence closure models together with vertically adaptive coordinates.
Keywords: Adaptive coordinates, Coastal ocean modelling, General Estuarine Transport Model (GETM), General Ocean Turbulence Model (GOTM), Numerical mixing, Turbulence closure modelling
ECCO Products Used: ECCO2
URL:
Other URLs:
Hill, Jenna C.; Condron, Alan (2014). Subtropical iceberg scours and meltwater routing in the deglacial western North Atlantic, Nature Geoscience, 11 (7), 806-810, 10.1038/ngeo2267.
Title: Subtropical iceberg scours and meltwater routing in the deglacial western North Atlantic
Type: Journal Article
Publication: Nature Geoscience
Author(s): Hill, Jenna C.; Condron, Alan
Year: 2014
Formatted Citation: Hill, J. C., and A. Condron, 2014: Subtropical iceberg scours and meltwater routing in the deglacial western North Atlantic. Nature Geoscience, 7(11), 806-810, doi:10.1038/ngeo2267
Dotto, T S; Kerr, R; Mata, M M; Azaneu, M; Wainer, I; Fahrbach, E; Rohardt, G (2014). Assessment of the structure and variability of Weddell Sea water masses in distinct ocean reanalysis products, Ocean Sci., 3 (10), 523-546, 10.5194/os-10-523-2014.
Title: Assessment of the structure and variability of Weddell Sea water masses in distinct ocean reanalysis products
Type: Journal Article
Publication: Ocean Sci.
Author(s): Dotto, T S; Kerr, R; Mata, M M; Azaneu, M; Wainer, I; Fahrbach, E; Rohardt, G
Year: 2014
Formatted Citation: Dotto, T. S., R. Kerr, M. M. Mata, M. Azaneu, I. Wainer, E. Fahrbach, and G. Rohardt, 2014: Assessment of the structure and variability of Weddell Sea water masses in distinct ocean reanalysis products. Ocean Sci., 10(3), 523-546, doi:10.5194/os-10-523-2014
Xu, Yun (2013). Subaqueous Melting of Greenland Tidewater Glaciers.
Title: Subaqueous Melting of Greenland Tidewater Glaciers
Type: Thesis
Publication:
Author(s): Xu, Yun
Year: 2013
Formatted Citation: Xu, Y., 2013: Subaqueous Melting of Greenland Tidewater Glaciers., 131 pp.
Abstract: The Greenland Ice Sheet has been experiencing accelerating mass loss in the past decades, due to enhanced surface melting and accelerated ice discharge into the ocean through tidewater glaciers. Many tidewater glaciers accelerated as anomalous warm water intruded the glacial fjords. Subaqueous melting of the glaciers in the ocean is a potential trigger of glacier acceleration. However, processes of subaqueous melting are not well understood. In this dissertation, we modify an ocean general circulation model, MITgcm, to include the melting/freezing processes on the vertical calving face of tidewater glaciers. We simulate the subaqueous melting using 2D and 3D con gurations of the numerical model at high resolution (20-m to 1-m grid spacing). The model well represents the turbulent buoyant plume we simulate in a laboratory tank, and is then applied to a glacial fjord domain con gured from oceanographic data we collected in several Greenland tidewater glacier fjords in August 2010 and 2012. The rate and distribution of subglacial freshwater discharge is estimated and to force model simulations. The numerical simulations show the turbulent upwelling and expansion of subglacial freshwater plumes, which induce high rates of subaqueous melting along their routes. Average rates of subaqueous melting of Greenland tidewater glaciers could be several meters per day in summer and an order of magnitude smaller in winter. The melt rate increases less than linearly with subglacial freshwater discharge and more than linearly with the ocean thermal forcing. The uncertainty of the distribution of subglacial freshwater discharge leads to % error on the melt rate. We derive a sensitivity relationship between the melt rate and ocean thermal forcing and subglacial water discharge for Store Glacier, and calculate the daily melt rate of Store Glacier between 2008 and 2011. The simulated melt rate in August 2010 compares well with the melt rate derived from the oceanographic data. This study provides simple guidelines for interpreting recent changes in glacier fronts as a result of climate warming and the inclusion of ice-ocean interactions along the calving fronts of Greenland glaciers in ice sheet numerical models.
Keywords:
ECCO Products Used: ECCO2;IceSheet
URL:
Other URLs:
Le Bars, D.; Dijkstra, H. A.; De Ruijter, W. P. M. (2013). Impact of the Indonesian throughflow on Agulhas leakage, Ocean Science Discussions, 1 (10), 353-391, 10.5194/osd-10-353-2013.
Title: Impact of the Indonesian throughflow on Agulhas leakage
Type: Journal Article
Publication: Ocean Science Discussions
Author(s): Le Bars, D.; Dijkstra, H. A.; De Ruijter, W. P. M.
Year: 2013
Formatted Citation: Le Bars, D., H. A. Dijkstra, and W. P. M. De Ruijter, 2013: Impact of the Indonesian throughflow on Agulhas leakage. Ocean Science Discussions, 10(1), 353-391, doi:10.5194/osd-10-353-2013
Dushaw, Brian D.; Worcester, P F; Dzieciuch, M A; Menemenlis, Dimitris (2013). On the time-mean state of ocean models and the properties of long range acoustic propagation, Journal of Geophysical Research: Oceans, 9 (118), 4346-4362, 10.1002/jgrc.20325.
Title: On the time-mean state of ocean models and the properties of long range acoustic propagation
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Dushaw, Brian D.; Worcester, P F; Dzieciuch, M A; Menemenlis, Dimitris
Year: 2013
Formatted Citation: Dushaw, B. D., P. F. Worcester, M. A. Dzieciuch, and D. Menemenlis, 2013: On the time-mean state of ocean models and the properties of long range acoustic propagation. J. Geophys. Res. Ocean., 118(9), 4346-4362, doi:10.1002/jgrc.20325
Abstract: Receptions on three vertical hydrophone arrays from basin-scale acoustic transmissions in the North Pacific during 1996 and 1998 are used to test the time-mean sound-speed properties of the World Ocean Atlas 2005 (WOA05), of an eddying unconstrained simulation of the Parallel Ocean Program (POP), and of three data-constrained solutions provided by the estimating the circulation and climate of the ocean (ECCO) project: a solution based on an approximate Kalman filter from the Jet Propulsion Laboratory (ECCO-JPL), a solution based on the adjoint method from the Massachusetts Institute of Technology (ECCO-MIT), and an eddying solution based on a Green's function approach from ECCO, Phase II (ECCO2). Predictions for arrival patterns using annual average WOA05 fields match observations to within small travel time offsets (0.3-1.0 s). Predictions for arrival patterns from the models differ substantially from the measured arrival patterns, from the WOA05 climatology, and from each other, both in terms of travel time and in the structure of the arrival patterns. The acoustic arrival patterns are sensitive to the vertical gradients of sound speed that govern acoustic propagation. Basin-scale acoustic transmissions, therefore, provide stringent tests of the vertical temperature structure of ocean state estimates. This structure ultimately influences the mixing between the surface waters and the ocean interior. The relatively good agreement of the acoustic data with the more recent ECCO solutions indicates that numerical ocean models have reached a level of accuracy where the acoustic data can provide useful additional constraints for ocean state estimation.
Keywords: 4255 Numerical modeling, 4259 Ocean acoustics, 4260 Ocean data assimilation and reanalysis, 4262 Ocean observing systems, acoustic thermometry, model testing, ocean models
Blunden, Jessica; Arndt, Derek S. (2013). State of the Climate in 2012, Bulletin of the American Meteorological Society, 8 (94), S1-S258, 10.1175/2013BAMSStateoftheClimate.1.
Publication: Bulletin of the American Meteorological Society
Author(s): Blunden, Jessica; Arndt, Derek S.
Year: 2013
Formatted Citation: Blunden, J., and D. S. Arndt, 2013: State of the Climate in 2012. Bull. Am. Meteorol. Soc., 94(8), S1-S258, doi:10.1175/2013BAMSStateoftheClimate.1
Abstract: Editors note: For easy download the posted pdf of the State of the Climate for 2012 is a very low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download.
Other URLs: http://journals.ametsoc.org/doi/abs/10.1175/2013BAMSStateoftheClimate.1, https://journals.ametsoc.org/bams/article/94/8/S1/60367/State-of-the-Climate-in-2012
Li, Qun; Zhang, Zhanhai; Wu, Huiding (2013). Interaction of an anticyclonic eddy with sea ice in the western Arctic Ocean: an eddy-resolving model study, Acta Oceanologica Sinica, 3 (32), 54-62, 10.1007/s13131-013-0289-1.
Title: Interaction of an anticyclonic eddy with sea ice in the western Arctic Ocean: an eddy-resolving model study
Type: Journal Article
Publication: Acta Oceanologica Sinica
Author(s): Li, Qun; Zhang, Zhanhai; Wu, Huiding
Year: 2013
Formatted Citation: Li, Q., Z. Zhang, and H. Wu, 2013: Interaction of an anticyclonic eddy with sea ice in the western Arctic Ocean: an eddy-resolving model study. Acta Oceanologica Sinica, 32(3), 54-62, doi:10.1007/s13131-013-0289-1
Li, Qun; WU, Huiding; Zhang, Lu (2013). Modeling Seasonal Variation of Sea Ice in Prydz Bay, Antarctica, International Journal of Offshore and Polar Engineering, 1 (23), 15-21.
Title: Modeling Seasonal Variation of Sea Ice in Prydz Bay, Antarctica
Type: Journal Article
Publication: International Journal of Offshore and Polar Engineering
Author(s): Li, Qun; WU, Huiding; Zhang, Lu
Year: 2013
Formatted Citation: Li, Q., H. WU, and L. Zhang, 2013: Modeling Seasonal Variation of Sea Ice in Prydz Bay, Antarctica. International Journal of Offshore and Polar Engineering, 23(1), 15-21, https://www.onepetro.org/journal-paper/ISOPE-13-23-1-015
Taylor, Marc H.; Losch, Martin; Bracher, Astrid (2013). On the drivers of phytoplankton blooms in the Antarctic marginal ice zone: A modeling approach, Journal of Geophysical Research: Oceans, 1 (118), 63-75, 10.1029/2012JC008418.
Title: On the drivers of phytoplankton blooms in the Antarctic marginal ice zone: A modeling approach
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Taylor, Marc H.; Losch, Martin; Bracher, Astrid
Year: 2013
Formatted Citation: Taylor, M. H., M. Losch, and A. Bracher, 2013: On the drivers of phytoplankton blooms in the Antarctic marginal ice zone: A modeling approach. J. Geophys. Res. Ocean., 118(1), 63-75, doi:10.1029/2012JC008418
Formatted Citation: Peralta Ferriz, A. C., 2013: Arctic Ocean Circulation Patterns Revealed by Ocean Bottom Pressure Anomalies. http://hdl.handle.net/1773/22539.
Abstract: Over the last few decades, the Arctic Ocean has experienced drastic changes that include increased temperature, changes in freshwater distribution, and decrease in sea ice extent and thickness. These changes, which potentially affect global climate, are intimately linked to changes in the Arctic Ocean circulation. Thus, understanding Arctic Ocean circulation patterns is fundamental to monitoring and predicting the fate of the Arctic System. Since 2002, NASA's Gravity Recovery and Climate Experiment (GRACE) has provided continuous measurements of the time-varying gravity field of the Arctic Ocean. The gravitational variations represent mass variations, or the time-varying ocean bottom pressure (OBP) field. OBP variations are the sum of the mass change due to the sea surface height change and the integrated density variations through the water column. In this dissertation, in situ and GRACE measurements of OBP anomalies, complemented by information from ocean models, are used to investigate the relative contribution of sea surface height and density-variations on the Arctic OBP field. The dynamics associated with the observed OBP changes are investigated. Major findings include the identification of three primary temporal-spatial modes of OBP variability at monthly to inter-annual timescales with the following characteristics: - Mode 1 is a wintertime basin-coherent Arctic mass change forced by southerly winds through Bering and Fram Straits. - Mode 2 reveals mass change along the Siberian shelves, driven by surface Ekman dynamics and associated with the Arctic Oscillation. - Mode 3 reveals a mass drop in Western Arctic shelves forced by the strengthening of the anticyclonic Beaufort Gyre, and wintertime along-shore westerly winds that increase OBP in the Eastern Arctic shelves. The OBP changes in the Kara Sea reveal a more baroclinic ocean character than modeling results have previously suggested, due to the complex bathymetry of this region and runoff-derived large density changes through the water column. This work integrates the character of the Arctic mass changes at different timescales, and provides information about the ocean mass re-distribution during years of rapidly thinning and disappearing seasonal sea ice.
Formatted Citation: Schiller, A., T. Lee, and S. Masuda, 2013: Methods and Applications of Ocean Synthesis in Climate Research. Ocean Circulation and Climate, 581-608, doi:10.1016/B978-0-12-391851-2.00022-2
Msadek, Rym; Johns, William E.; Yeager, Stephen G.; Danabasoglu, Gokhan; Delworth, Thomas L.; Rosati, Anthony (2013). The Atlantic Meridional Heat Transport at 26.5°N and Its Relationship with the MOC in the RAPID Array and the GFDL and NCAR Coupled Models, Journal of Climate, 12 (26), 4335-4356, 10.1175/JCLI-D-12-00081.1.
Title: The Atlantic Meridional Heat Transport at 26.5°N and Its Relationship with the MOC in the RAPID Array and the GFDL and NCAR Coupled Models
Type: Journal Article
Publication: Journal of Climate
Author(s): Msadek, Rym; Johns, William E.; Yeager, Stephen G.; Danabasoglu, Gokhan; Delworth, Thomas L.; Rosati, Anthony
Year: 2013
Formatted Citation: Msadek, R., W. E. Johns, S. G. Yeager, G. Danabasoglu, T. L. Delworth, and A. Rosati, 2013: The Atlantic Meridional Heat Transport at 26.5°N and Its Relationship with the MOC in the RAPID Array and the GFDL and NCAR Coupled Models. J. Clim., 26(12), 4335-4356, doi:10.1175/JCLI-D-12-00081.1
Volkov, Denis L.; Landerer, Felix W (2013). Nonseasonal fluctuations of the Arctic Ocean mass observed by the GRACE satellites, Journal of Geophysical Research: Oceans, 12 (118), 6451-6460, 10.1002/2013JC009341.
Title: Nonseasonal fluctuations of the Arctic Ocean mass observed by the GRACE satellites
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Volkov, Denis L.; Landerer, Felix W
Year: 2013
Formatted Citation: Volkov, D. L., and F. W. Landerer, 2013: Nonseasonal fluctuations of the Arctic Ocean mass observed by the GRACE satellites. J. Geophys. Res. Ocean., 118(12), 6451-6460, doi:10.1002/2013JC009341
Abstract: Time variable gravity observations from the GRACE satellites reveal strong nonseasonal fluctuations of bottom pressure in the Arctic Ocean on the time scales from 2 to 6 months and a record-high bottom pressure anomaly in February of 2011. Here, we examine the nature and driving forces behind those fluctuations. We find that the nonseasonal variability of the Arctic Ocean mass is strongly coupled to wind forcing. The zonal wind pattern is correlated with a dipole pattern of Arctic Ocean mass changes. Westerly wind intensification over the North Atlantic at about 60°N as well as over the Russian Arctic continental shelf break cause the ocean mass to decrease in the Nordic seas and in the central Arctic, and to increase over the Russian Arctic shelf. Basin-wide Arctic Ocean mass fluctuations are correlated with northward wind anomalies over the northeastern North Atlantic and Nordic seas, and over the Bering Sea. We show that positive (negative) Arctic Ocean mass anomalies are associated with anticyclonic (cyclonic) anomalies of the large-scale ocean circulation pattern. Based on ocean model simulations, we conclude that the observed nonseasonal Arctic Ocean mass variability is mostly explained by the net horizontal wind-driven transports, and the contribution of fresh water fluxes is negligible. We demonstrate that transport anomalies across both the Atlantic and Pacific gateways were equally important for generating large Arctic Ocean mass anomalies in 2011.
Keywords: 1217 Time variable gravity, 1223 Ocean/Earth/atmosphere/hydrosphere/cryosphere, 4207 Arctic and Antarctic oceanography, 4556 Sea level: variations and mean, Arctic Ocean, ECCO2, GRACE, nonseasonal variability, ocean mass, sea level
Title: Reproduction of sea ice coverage in the Pan-Arctic Sea using an ice-ocean coupled model
Type: Thesis
Publication:
Author(s): Hwang, Kyeong
Year: 2013
Formatted Citation: Hwang, K., 2013: Reproduction of sea ice coverage in the Pan-Arctic Sea using an ice-ocean coupled model., 67 pp.
Abstract: The Arctic Ocean is the region most sensitive to the effects of global warming, and the reduction of sea ice in the Arctic Ocean affects seawater circulation and global climate. Therefore, the study of the Arctic Ocean is very important, and studies on the Arctic sea ice fluctuation based on the model are being actively carried out abroad. However, in Korea, there is no research on the Arctic Ocean. Therefore, in this paper, we tried to understand the present level of the model by simulating ocean Arctic sea ice distribution and comparing it with observation and AOMIP model results. Sea-Ice Hindcast model calculations were carried out for 33 years from 1979 to 2011 using ROMS (Regional Ocean Modeling System), which is a 3D ocean-sea joining model. The model area is 55 ° N-90 ° N latitude, 180 ° W-180 ° E, excluding the Baltic Sea and the Okhotsk Sea. The sea ice concentration and area are more consistent with the AOMIP model in winter than in the AOMIP model, but are calculated in summer and less volatilized in the East Siberian Sea and the Rapphev Sea. For the thickness of the sea ice, the distribution pattern was reproduced similar to the observations and AOMIP model results, but the thick sea ice near the Canadian islands was not reproduced well. It is considered that the sea ice was not accumulated in the vicinity of the Canadian islands because the sea ice velocity was simulated more than the observation. In addition, the oceanic heat of the Pacific and Atlantic waters did not flow well into the Arctic Ocean and rapidly disappeared, affecting the sea ice in the East Siberian Sea, the Raphaet Sea, and the Chichic Sea. . Therefore, if we reproduce thick sea ice near the Canadian islands by improving the sea ice velocity and improve the flux of the Pacific and Atlantic waters flowing from the Barring and Phram Strait to better reproduce the water mass distributions.
Other URLs: http://repository.kmou.ac.kr/bitstream?type=link&id=8130&url=http://kmou.dcollection.net/jsp/common/DcLoOrgPer.jsp?sItemId=000002174138, http://repository.kmou.ac.kr/bitstream/2014.
Fenty, Ian; Heimbach, Patrick (2013). Hydrographic Preconditioning for Seasonal Sea Ice Anomalies in the Labrador Sea, Journal of Physical Oceanography, 5 (43), 863-883, 10.1175/jpo-d-12-064.1.
Title: Hydrographic Preconditioning for Seasonal Sea Ice Anomalies in the Labrador Sea
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Fenty, Ian; Heimbach, Patrick
Year: 2013
Formatted Citation: Fenty, I., and P. Heimbach, 2013: Hydrographic Preconditioning for Seasonal Sea Ice Anomalies in the Labrador Sea. Journal of Physical Oceanography, 43(5), 863-883, doi:10.1175/jpo-d-12-064.1
Abstract: This study investigates the hydrographic processes involved in setting the maximum wintertime sea ice (SI) extent in the Labrador Sea and Baffin Bay. The analysis is based on an ocean and sea ice state estimate covering the summer-to-summer 1996/97 annual cycle. The estimate is a synthesis of in situ and satellite hydrographic and ice data with a regional coupled 1/3 degrees ocean-sea ice model. SI advective processes are first demonstrated to be required to reproduce the observed ice extent. With advection, the marginal ice zone (MIZ) location stabilizes where ice melt balances ice mass convergence, a quasi-equilibrium condition achieved via the convergence of warm subtropical-origin subsurface waters into the mixed layer seaward of the MIZ. An analysis of ocean surface buoyancy fluxes reveals a critical role of low-salinity upper ocean (100 m) anomalies for the advancement of SI seaward of the Arctic Water-Irminger Water Thermohaline Front. Anomalous low-salinity waters slow the rate of buoyancy loss-driven mixed layer deepening, shielding an advancing SI pack from the warm subsurface waters, and are conducive to a positive surface meltwater stabilization enhancement (MESEM) feedback driven by SI meltwater release. The low-salinity upper-ocean hydrographic conditions in which the MESEM efficiently operates are termed sea ice-preconditioned waters (SIPW). The SI extent seaward of the Thermohaline Front is shown to closely correspond to the distribution of SIPW. The analysis of two additional state estimates (1992/93, 2003/04) suggests that interannual hydrographic variability provides a first-order explanation for SI maximum extent anomalies in the region.
Borstad, C. P.; Rignot, E.; Mouginot, J.; Schodlok, M. P. (2013). Creep deformation and buttressing capacity of damaged ice shelves: theory and application to Larsen C ice shelf, The Cryosphere, 6 (7), 1931-1947, 10.5194/tc-7-1931-2013.
Title: Creep deformation and buttressing capacity of damaged ice shelves: theory and application to Larsen C ice shelf
Type: Journal Article
Publication: The Cryosphere
Author(s): Borstad, C. P.; Rignot, E.; Mouginot, J.; Schodlok, M. P.
Year: 2013
Formatted Citation: Borstad, C. P., E. Rignot, J. Mouginot, and M. P. Schodlok, 2013: Creep deformation and buttressing capacity of damaged ice shelves: theory and application to Larsen C ice shelf. Cryosph., 7(6), 1931-1947, doi:10.5194/tc-7-1931-2013
Abstract: Around the perimeter of Antarctica, much of the ice sheet discharges to the ocean through floating ice shelves. The buttressing provided by ice shelves is critical for modulating the flux of ice into the ocean, and the presently observed thinning of ice shelves is believed to be reducing their buttressing capacity and contributing to the acceleration and thinning of the grounded ice sheet. However, relatively little attention has been paid to the role that fractures play in the ability of ice shelves to sustain and transmit buttressing stresses. Here, we present a new framework for quantifying the role that fractures play in the creep deformation and buttressing capacity of ice shelves. We apply principles of continuum damage mechanics to derive a new analytical relation for the creep of an ice shelf that accounts for the softening influence of fractures on longitudinal deformation using a state damage variable. We use this new analytical relation, combined with a temperature calculation for the ice, to partition an inverse method solution for ice shelf rigidity into independent solutions for softening damage and stabilizing backstress. Using this new approach, field and remote sensing data can be utilized to monitor the structural integrity of ice shelves, their ability to buttress the flow of ice at the grounding line, and thus their indirect contribution to ice sheet mass balance and global sea level. We apply this technique to the Larsen C ice shelf using remote sensing and Operation IceBridge data, finding damage in areas with known crevasses and rifts. Backstress is highest near the grounding line and upstream of ice rises, in agreement with patterns observed on other ice shelves. The ice in contact with the Bawden ice rise is weakened by fractures, and additional damage or thinning in this area could diminish the backstress transmitted upstream. We model the consequences for the ice shelf if it loses contact with this small ice rise, finding that flow speeds would increase by 25% or more over an area the size of the former Larsen B ice shelf. Such a perturbation could potentially destabilize the northern part of Larsen C along pre-existing lines of weakness, highlighting the importance of the feedback between buttressing and fracturing in an ice shelf.
Manizza, M; Follows, Michael J.; Dutkiewicz, Stephanie; Menemenlis, Dimitris; Hill, C N; Key, R M (2013). Changes in the Arctic Ocean CO 2 sink (1996-2007): A regional model analysis, Global Biogeochemical Cycles, 4 (27), 1108-1118, 10.1002/2012GB004491.
Title: Changes in the Arctic Ocean CO 2 sink (1996-2007): A regional model analysis
Type: Journal Article
Publication: Global Biogeochemical Cycles
Author(s): Manizza, M; Follows, Michael J.; Dutkiewicz, Stephanie; Menemenlis, Dimitris; Hill, C N; Key, R M
Year: 2013
Formatted Citation: Manizza, M., M. J. Follows, S. Dutkiewicz, D. Menemenlis, C. N. Hill, and R. M. Key, 2013: Changes in the Arctic Ocean CO 2 sink (1996-2007): A regional model analysis. Global Biogeochemical Cycles, 27(4), 1108-1118, doi:10.1002/2012GB004491
Abstract: The rapid recent decline of Arctic Ocean sea ice area increases the flux of solar radiation available for primary production and the area of open water for air-sea gas exchange. We use a regional physical-biogeochemical model of the Arctic Ocean, forced by the National Centers for Environmental Prediction/National Center for Atmospheric Research atmospheric reanalysis, to evaluate the mean present-day CO2 sink and its temporal evolution. During the 1996-2007 period, the model suggests that the Arctic average sea surface temperature warmed by 0.04°C a−1, that sea ice area decreased by ∼0.1 × 106 km2 a−1, and that the biological drawdown of dissolved inorganic carbon increased. The simulated 1996-2007 time-mean Arctic Ocean CO2 sink is 58 ± 6 Tg C a−1. The increase in ice-free ocean area and consequent carbon drawdown during this period enhances the CO2 sink by ∼1.4 Tg C a−1, consistent with estimates based on extrapolations of sparse data. A regional analysis suggests that during the 1996-2007 period, the shelf regions of the Laptev, East Siberian, Chukchi, and Beaufort Seas experienced an increase in the efficiency of their biological pump due to decreased sea ice area, especially during the 2004-2007 period, consistent with independently published estimates of primary production. In contrast, the CO2 sink in the Barents Sea is reduced during the 2004-2007 period due to a dominant control by warming and decreasing solubility. Thus, the effect of decreasing sea ice area and increasing sea surface temperature partially cancel, though the former is dominant.
Formatted Citation: Zhai, F., D. Hu, and Q. Wang, 2013: Study on the seasonal variability of the Halmahera Eddy. Marine Sciences, 37(11), 85-94, http://qdhys.ijournal.cn/hykxen/ch/reader/create_pdf.aspx?file_no=20131115
Abstract: In this paper, the seasonal variability of the Halmahera Eddy (HE) in the upper 50 m was investigated by using oceanic assimilation data of ECCO2 from January 1992 to November 2006. The results show that the HE first appears around May, peaks in July, and dies out in March and April of the following year, which are mainly resulted from the New Guinea Coastal Current (NGCC) seasonality driven by monsoon. The NGCC flows northwestward from April to November, while southeastward from December to next year February. The HE begins to form and intensify with the strengthening of the northwestward NGCC, but decay and disappear with the weakening and re- versing of the northwestward NGCC. In summer, the Mindanao Current strengthens and enhances the HE.
Keywords: Halmahera Eddy, New Guinea coastal current, seasonal variability
Sturges, Wilton; Bozec, Alexandra (2013). A Puzzling Disagreement between Observations and Numerical Models in the Central Gulf of Mexico, Journal of Physical Oceanography, 12 (43), 2673-2681, 10.1175/JPO-D-13-081.1.
Title: A Puzzling Disagreement between Observations and Numerical Models in the Central Gulf of Mexico
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Sturges, Wilton; Bozec, Alexandra
Year: 2013
Formatted Citation: Sturges, W., and A. Bozec, 2013: A Puzzling Disagreement between Observations and Numerical Models in the Central Gulf of Mexico. Journal of Physical Oceanography, 43(12), 2673-2681, doi:10.1175/JPO-D-13-081.1
Title: Physical influences on phytoplankton ecology : models and observations
Type: Thesis
Publication:
Author(s): Clayton, Sophie
Year: 2013
Formatted Citation: Clayton, S., 2013: Physical influences on phytoplankton ecology : models and observations. http://hdl.handle.net/1721.1/82320.
Abstract: The physical environment in the oceans dictates not only how phytoplankton cells are dispersed and their populations intermingled, but also mediates the supply of nutrients to the surface mixed layer. In this thesis I explore both of these aspects of the interaction between phytoplankton ecology and ocean physics, and have approached this topic in two distinct but complementary ways, working with a global ocean ecosystem model, and collecting data at sea. In the first half of the thesis, I examine the role of mesoscale physical features in shaping phytoplankton community structure and influencing rates of primary production. I compare the output of a complex marine ecosystem model coupled to coarse resolution and eddy-permitting physical models. Explicitly resolving eddies resulted in marked regional variations in primary production, zooplankton and phytoplankton biomass. The same phytoplankton phenotypes persisted in both cases, and were dominant in the same regions. Global phytoplankton diversity was unchanged. However, levels of local phytoplankton diversity were markedly different, with a large increase in local diversity in the higher resolution model. Increased diversity could be attributed to a combination of enhanced dispersal, environmental variability and nutrient supply in the higher resolution model. Diversity "hotspots" associated with western boundary currents and coastal upwelling zones are sustained through a combination of all of these factors. In the second half of the thesis I describe the results of a fine scale ecological and biogeochemical survey of the Kuroshio Extension Front. I found fine scale patterns in physical, chemical and biological properties that can be linked back to both the large scale horizontal and smaller scale vertical physical dynamics of the study region. A targeted genomic analysis of samples focused on the ecology of the picoeukaryote Ostreococcus clade distributions strongly supports the model derived hypotheses about the mechanisms supporting diversity hotspots. Strikingly, two distinct clades of Ostreococcus co-occur in more than half of the samples. A "hotspot" of Ostreococcus diversity appears to be supported by a confluence of water masses containing either clade, as well as a local nutrient supply at the front and the mesoscale variability of the region.
Formatted Citation: Huard, D., and B. Tremblay, 2013: WWF Last Ice Area., Montreal, Canada, 36 pp. http://awsassets.panda.org/downloads/projected_arctic_sea_ice_conditions___full_english.pdf.
Abstract: The purpose of this project is to illustrate the fate of Arctic sea ice over the next decades. Part A of the project looks at results from an ensemble of global climate model projec- tions. The objective of Part A is to explore the various pathways of future ice loss as simulated by different climate models driven by two radiative forcing scenarios. The im- pact of climate change on Arctic conditions is diagnosed through sea ice concentration, sea ice thickness and snow depth over ice. Part B completes the picture by running a high-resolution (18km) regional ocean and ice model, providing finer spatial details of ice conditions projected by the GFDL Climate Model version 3 under the business-as-usual RCP8.5 forcing scenario.
Landschützer, Peter; Gruber, N.; Bakker, D. C. E.; Schuster, U.; Nakaoka, S.; Payne, M. R.; Sasse, T. P.; Zeng, J. (2013). A neural network-based estimate of the seasonal to inter-annual variability of the Atlantic Ocean carbon sink, Biogeosciences, 11 (10), 7793-7815, 10.5194/bg-10-7793-2013.
Title: A neural network-based estimate of the seasonal to inter-annual variability of the Atlantic Ocean carbon sink
Type: Journal Article
Publication: Biogeosciences
Author(s): Landschützer, Peter; Gruber, N.; Bakker, D. C. E.; Schuster, U.; Nakaoka, S.; Payne, M. R.; Sasse, T. P.; Zeng, J.
Year: 2013
Formatted Citation: Landschützer, P., N. Gruber, D. C. E. Bakker, U. Schuster, S. Nakaoka, M. R. Payne, T. P. Sasse, and J. Zeng, 2013: A neural network-based estimate of the seasonal to inter-annual variability of the Atlantic Ocean carbon sink. Biogeosciences, 10(11), 7793-7815, doi:10.5194/bg-10-7793-2013
Abstract: The Atlantic Ocean is one of the most important sinks for atmospheric carbon dioxide (CO2), but this sink has been shown to vary substantially in time. Here we use surface ocean CO2 observations to estimate this sink and the temporal variability from 1998 through 2007 in the Atlantic Ocean. We benefit from (i) a continuous improvement of the observations, i.e. the Surface Ocean CO2 Atlas (SOCAT) v1.5 database and (ii) a newly developed technique to interpolate the observations in space and time. In particular, we use a two-step neural network approach to reconstruct basin-wide monthly maps of the sea surface partial pressure of CO2 (pCO2) at a resolution of 1° × 1°. From those, we compute the air-sea CO2 flux maps using a standard gas exchange parameterization and high-resolution wind speeds. The neural networks fit the observed pCO2 data with a root mean square error (RMSE) of about 10 μatm and with almost no bias. A check against independent time-series data and new data from SOCAT v2 reveals a larger RMSE of 22.8 μatm for the entire Atlantic Ocean, which decreases to 16.3 μatm for data south of 40° N. We estimate a decadal mean uptake flux of −0.45 ± 0.15 Pg C yr−1 for the Atlantic between 44° S and 79° N, representing the sum of a strong uptake north of 18° N (−0.39 ± 0.10 Pg C yr−1), outgassing in the tropics (18° S-18° N, 0.11 ± 0.07 Pg C yr−1), and uptake in the subtropical/temperate South Atlantic south of 18° S (−0.16 ± 0.06 Pg C yr−1), consistent with recent studies. The strongest seasonal variability of the CO2 flux occurs in the temperature-driven subtropical North Atlantic, with uptake in winter and outgassing in summer. The seasonal cycle is antiphased in the subpolar latitudes relative to the subtropics largely as a result of the biologically driven winter-to-summer drawdown of CO2. Over the 10 yr analysis period (1998 through 2007), sea surface pCO2 increased faster than that of the atmosphere in large areas poleward of 40° N, while in other regions of the North Atlantic the sea surface pCO2 increased at a slower rate, resulting in a barely changing Atlantic carbon sink north of the Equator (−0.01 ± 0.02 Pg C yr−1 decade−1). Surface ocean pCO2 increased at a slower rate relative to atmospheric CO2 over most of the Atlantic south of the Equator, leading to a substantial trend toward a stronger CO2 sink for the entire South Atlantic (−0.14 ± 0.02 Pg C yr−1 decade−1). In contrast to the 10 yr trends, the Atlantic Ocean carbon sink varies relatively little on inter-annual timescales (±0.04 Pg C yr−1; 1 σ).
Cougnon, E. A.; Galton-Fenzi, B. K.; Meijers, A. J. S.; Legrésy, B. (2013). Modeling interannual dense shelf water export in the region of the Mertz Glacier Tongue (1992-2007), Journal of Geophysical Research: Oceans, 10 (118), 5858-5872, 10.1002/2013JC008790.
Title: Modeling interannual dense shelf water export in the region of the Mertz Glacier Tongue (1992-2007)
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Cougnon, E. A.; Galton-Fenzi, B. K.; Meijers, A. J. S.; Legrésy, B.
Year: 2013
Formatted Citation: Cougnon, E. A., B. K. Galton-Fenzi, A. J. S. Meijers, and B. Legrésy, 2013: Modeling interannual dense shelf water export in the region of the Mertz Glacier Tongue (1992-2007). J. Geophys. Res. Ocean., 118(10), 5858-5872, doi:10.1002/2013JC008790
Title: Energy Pathways and Structures of Oceanic Eddies from the ECCO2 State Estimate and Simplified Models
Type: Thesis
Publication:
Author(s): Chen, Ru
Year: 2013
Formatted Citation: Chen, R., 2013: Energy Pathways and Structures of Oceanic Eddies from the ECCO2 State Estimate and Simplified Models. MIT-WHOI Joint Program, Ph.D. http://hdl.handle.net/1721.1/79154.
Clayton, Sophie; Dutkiewicz, Stephanie; Jahn, Oliver; Follows, Michael J. (2013). Dispersal, eddies, and the diversity of marine phytoplankton, Limnology and Oceanography: Fluids and Environments, 1 (3), 182-197, 10.1215/21573689-2373515.
Title: Dispersal, eddies, and the diversity of marine phytoplankton
Type: Journal Article
Publication: Limnology and Oceanography: Fluids and Environments
Author(s): Clayton, Sophie; Dutkiewicz, Stephanie; Jahn, Oliver; Follows, Michael J.
Year: 2013
Formatted Citation: Clayton, S., S. Dutkiewicz, O. Jahn, and M. J. Follows, 2013: Dispersal, eddies, and the diversity of marine phytoplankton. Limnology and Oceanography: Fluids and Environments, 3(1), 182-197, doi:10.1215/21573689-2373515
Abstract: We examined the role of physical dispersal in regulating patterns of diversity of marine phytoplankton in the context of global ocean simulations at eddy-permitting and coarse resolutions. Swifter current speeds, faster dispersal, and increased environmental variability in the higher-resolution model enhanced local diversity almost everywhere. In the numerical simulations, each resolved phytoplankton type was characterized as "locally adapted" at any geographical location (i.e., having net local biological production and physical export) or "immigrant" (i.e., net local biological loss but a population sustained by immigration via physical transport). Immigrants accounted for a higher fraction of the total diversity in the equatorial and subtropical regions, where the exclusion timescale is long relative to the physical transport between "provinces." Hotspots of diversity were associated with western boundary currents and coastal upwelling regions. The former had high locally adapted diversity within the core of the current system, maintained by confluence of upstream populations and the induction of nutrient resources, as well as environmental variability associated with mesoscale eddies. Downstream of strong nutrient sources, convergence of populations led to immigrant-dominated diversity. The numerical simulations provide testable predictions of patterns in diversity and hypotheses regarding the mechanisms that control them. Molecular approaches to characterizing diversity in microbial populations will provide a means to test these hypotheses.
Fenty, Ian; Heimbach, Patrick (2013). Coupled Sea Ice-Ocean-State Estimation in the Labrador Sea and Baffin Bay, Journal of Physical Oceanography, 5 (43), 884-904, 10.1175/jpo-d-12-065.1.
Title: Coupled Sea Ice-Ocean-State Estimation in the Labrador Sea and Baffin Bay
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Fenty, Ian; Heimbach, Patrick
Year: 2013
Formatted Citation: Fenty, I., and P. Heimbach, 2013: Coupled Sea Ice-Ocean-State Estimation in the Labrador Sea and Baffin Bay. Journal of Physical Oceanography, 43(5), 884-904, doi:10.1175/jpo-d-12-065.1
Abstract: Sea ice variability in the Labrador Sea is of climatic interest because of its relationship to deep convection, mode-water formation, and the North Atlantic atmospheric circulation. Historically, quantifying the relationship between sea ice and ocean variability has been difficult because of in situ observation paucity and technical challenges associated with synthesizing observations with numerical models. Here the relationship between ice and ocean variability is explored by analyzing new estimates of the ocean-ice state in the northwest North Atlantic. The estimates are syntheses of in situ and satellite hydrographic and ice data with a regional 1/3 degrees coupled ocean-sea ice model. The synthesis of sea ice data is achieved with an improved adjoint of a thermodynamic ice model. Model and data are made consistent, in a least squares sense, by iteratively adjusting control variables, including ocean initial and lateral boundary conditions and the atmospheric state, to minimize an uncertainty-weighted model-data misfit cost function. The utility of the state estimate is demonstrated in an analysis of energy and buoyancy budgets in the marginal ice zone (MIZ). In mid-March the system achieves a state of quasi-equilibrium during which net ice growth and melt approaches zero; newly formed ice diverges from coastal areas and converges via wind and ocean forcing in the MIZ. The convergence of ice mass in the MIZ is ablated primarily by turbulent ocean-ice enthalpy fluxes. The primary source of the enthalpy required for sustained MIZ ice ablation is the sensible heat reservoir of the subtropical-origin subsurface waters.
Keywords: cover, deep convection, eddies, fresh-water, greenland, heat fluxes, model, north-atlantic sst, sea, western boundary currents, winter circulation
ECCO Products Used: ECCO2;SeaIce
URL:
Other URLs:
Reynolds, Richard W; Chelton, Dudley B; Roberts-Jones, Jonah; Martin, Matthew J; Menemenlis, Dimitris; Merchant, Christopher John (2013). Objective Determination of Feature Resolution in Two Sea Surface Temperature Analyses, Journal of Climate, 8 (26), 2514-2533, 10.1175/JCLI-D-12-00787.1.
Title: Objective Determination of Feature Resolution in Two Sea Surface Temperature Analyses
Type: Journal Article
Publication: Journal of Climate
Author(s): Reynolds, Richard W; Chelton, Dudley B; Roberts-Jones, Jonah; Martin, Matthew J; Menemenlis, Dimitris; Merchant, Christopher John
Year: 2013
Formatted Citation: Reynolds, R. W., D. B. Chelton, J. Roberts-Jones, M. J. Martin, D. Menemenlis, and C. J. Merchant, 2013: Objective Determination of Feature Resolution in Two Sea Surface Temperature Analyses. J. Clim., 26(8), 2514-2533, doi:10.1175/JCLI-D-12-00787.1
Abstract: Considerable effort is presently being devoted to producing high-resolution sea surface temperature (SST) analyses with a goal of spatial grid resolutions as low as 1 km. Because grid resolution is not the same as feature resolution, a method is needed to objectively determine the resolution capability and accuracy of SST analysis products. Ocean model SST fields are used in this study as simulated "true" SST data and subsampled based on actual infrared and microwave satellite data coverage. The subsampled data are used to simulate sampling errors due to missing data. Two different SST analyses are considered and run using both the full and the subsampled model SST fields, with and without additional noise. The results are compared as a function of spatial scales of variability using wavenumber auto- and cross-spectral analysis.The spectral variance at high wavenumbers (smallest wavelengths) is shown to be attenuated relative to the true SST because of smoothing that is inherent to both analysis procedures. Comparisons of the two analyses (both having grid sizes of roughly ) show important differences. One analysis tends to reproduce small-scale features more accurately when the high-resolution data coverage is good but produces more spurious small-scale noise when the high-resolution data coverage is poor. Analysis procedures can thus generate small-scale features with and without data, but the small-scale features in an SST analysis may be just noise when high-resolution data are sparse. Users must therefore be skeptical of high-resolution SST products, especially in regions where high-resolution (~5 km) infrared satellite data are limited because of cloud cover.
Keywords: Numerical analysis/modeling, Surface temperature
Kwon, Eun Young; Downes, Stephanie M.; Sarmiento, Jorge L.; Farneti, Riccardo; Deutsch, Curtis (2013). Role of the Seasonal Cycle in the Subduction Rates of Upper-Southern Ocean Waters, Journal of Physical Oceanography, 6 (43), 1096-1113, 10.1175/JPO-D-12-060.1.
Formatted Citation: Kwon, E. Y., S. M. Downes, J. L. Sarmiento, R. Farneti, and C. Deutsch, 2013: Role of the Seasonal Cycle in the Subduction Rates of Upper-Southern Ocean Waters. Journal of Physical Oceanography, 43(6), 1096-1113, doi:10.1175/JPO-D-12-060.1
Title: Modelling the sensitivity of dense shelf water formation in the Mertz Glacier region, East Antarctica
Type: Thesis
Publication:
Author(s): Cougnon, Eva Audrey
Year: 2013
Formatted Citation: Cougnon, E. A., 2013: Modelling the sensitivity of dense shelf water formation in the Mertz Glacier region, East Antarctica., 177 pp. https://eprints.utas.edu.au/23427/.
Abstract: Given the importance of the overturning circulation to global climate, there is a need to improve our understanding of Antarctic Bottom Water (AABW) formation and its sensitivity to change. The offshore properties of AABW are changing. Within the Australian-Antarctic basin AABW has freshened and decreased in volume by about 50% over the last few decades. Understanding what is driving these changes requires focusing on the key formation region along the Adélie and George V Land (AGVL) coast. Here, the intense production of sea ice in the Mertz Glacier Polynya system drives Dense Shelf Water (DSW) formation, the precursor to AABW. This thesis uses a version of the Regional Ocean Modeling System (ROMS) that has been adapted for ocean/ice-shelf interactions to explore the sensitivity of DSW formation to surface heat and salt fluxes and ice shelf basal melting. Interannual variability in surface heat and salt fluxes drives DSW export and ice shelf basal melting variability in the AGVL region. DSW export decreases by 86% during a sustained period (2000-2002) of weak polynya activity (sea ice production) before recovering during a sustained period of stronger polynya activity (2003-2005). Basal melting of the Mertz Glacier Tongue (MGT) doubles under weak polynya activity because more warm water reaches the base of the ice shelf. Idealised simulations highlight the importance of the air/sea fluxes on DSW formation and ice shelf basal melting. A mean to strong air/sea forcing drives convection of dense water to sink at the sea floor and drives melt near the deep grounding line. Weaker air/sea forcing limits the depth of the convection and allows greater intrusions of warm modified Circumpolar Deep Water within the ice shelf cavity and increases basal melting. The resultant input of glacial meltwater produces a buoyant plume that stratifies the water column. Two simulations are run to investigate the impact of the calving of the MGT in 2010. Weaker polynya activity after calving results in an 89% increase in area averaged ice shelf basal melting and an 80% decrease of DSW export from the Adélie depression. Most importantly a distinct warming of the exported DSW leads to a decrease in AABW production downstream. This thesis demonstrates the sensitivity of Antarctic ocean-cryosphere interactions to interannual variability and episodic changes to the local icescape (ice shelves, icebergs and sea ice), finding that ice shelf basal melting and DSW formation in the AGVL region is dramatically impacted by the MGT calving.
Title: Profiling tropospheric CO2 using Aura TES and TCCON instruments
Type: Journal Article
Publication: Atmospheric Measurement Techniques
Author(s): Kuai, L.; Worden, J.; Kulawik, S.; Bowman, K.; Lee, M.; Biraud, S. C.; Abshire, J. B.; Wofsy, S. C.; Natraj, V.; Frankenberg, C.; Wunch, D.; Connor, B.; Miller, C.; Roehl, C.; Shia, R.-L.; Yung, Y.
Year: 2013
Formatted Citation: Kuai, L. and Coauthors, 2013: Profiling tropospheric CO2 using Aura TES and TCCON instruments. Atmospheric Measurement Techniques, 6(1), 63-79, doi:10.5194/amt-6-63-2013
Abstract: Monitoring the global distribution and long-term variations of CO2 sources and sinks is required for characterizing the global carbon budget. Total column measurements are useful for estimating regional-scale fluxes; however, model transport remains a significant error source, particularly for quantifying local sources and sinks. To improve the capability of estimating regional fluxes, we estimate lower tropospheric CO2 concentrations from ground-based near-infrared (NIR) measurements with space-based thermal infrared (TIR) measurements. The NIR measurements are obtained from the Total Carbon Column Observing Network (TCCON) of solar measurements, which provide an estimate of the total CO2 column amount. Estimates of tropospheric CO2 that are co-located with TCCON are obtained by assimilating Tropospheric Emission Spectrometer (TES) free tropospheric CO2 estimates into the GEOS-Chem model. We find that quantifying lower tropospheric CO2 by subtracting free tropospheric CO2 estimates from total column estimates is a linear problem, because the calculated random uncertainties in total column and lower tropospheric estimates are consistent with actual uncertainties as compared to aircraft data. For the total column estimates, the random uncertainty is about 0.55 ppm with a bias of −5.66 ppm, consistent with previously published results. After accounting for the total column bias, the bias in the lower tropospheric CO2 estimates is 0.26 ppm with a precision (one standard deviation) of 1.02 ppm. This precision is sufficient for capturing the winter to summer variability of approximately 12 ppm in the lower troposphere; double the variability of the total column. This work shows that a combination of NIR and TIR measurements can profile CO2 with the precision and accuracy needed to quantify lower tropospheric CO2 variability.
Xie, Qiang; Xiao, JinGen; Wang, DongXiao; Yu, YongQiang (2013). Analysis of deep-layer and bottom circulations in the South China Sea based on eight quasi-global ocean model outputs, Chinese Science Bulletin, 32 (58), 4000-4011, 10.1007/s11434-013-5791-5.
Formatted Citation: Xie, Q., J. Xiao, D. Wang, and Y. Yu, 2013: Analysis of deep-layer and bottom circulations in the South China Sea based on eight quasi-global ocean model outputs. Chinese Science Bulletin, 58(32), 4000-4011, doi:10.1007/s11434-013-5791-5
Abstract: This study is a preliminary analysis of the South China Sea (SCS) deep circulations using eight quasi-global high-resolution ocean model outputs. The goal is to assess models' ability to simulate these deep circulations. The analysis reveals that models' deep temperatures are colder than the observations in the World Ocean Atlas, while most models' deep salinity values are higher than the observations, indicating models' deep water is generally colder and saltier than the reality. Moreover, there are long-term trends in both temperature and salinity simulations. The Luzon Strait transport below 1500 m is 0.36 Sv when averaged for all models, smaller compared with the observation, which is about 2.5 Sv. Four assimilated models and one unassimilated (OCCAM) display that the Luzon deep-layer overflow reaches its minimum in spring and its maximum in winter. The vertically integrated streamfunctions below 2400 m from these models show a deep cyclonic circulation in the SCS on a large scale)
Keywords: deep-layer and bottom SCS circulations, model evaluation, quasi-global ocean model
Title: The production of temperature and salinity variance and covariance: implications for mixing
Type: Thesis
Publication:
Author(s): Schanze, Julian J.
Year: 2013
Formatted Citation: Schanze, J. J., 2013: The production of temperature and salinity variance and covariance: implications for mixing., 195 pp. https://hdl.handle.net/1912/5741.
Abstract: Large-scale thermal forcing and freshwater fluxes play an essential role in setting temperature and salinity in the ocean. A number of recent estimates of the global oceanic freshwater balance as well as the global oceanic surface net heat flux are used to investigate the effects of heat- and freshwater forcing at the ocean surface. Such forcing induces changes in both density and density-compensated temperature and salinity changes ('spice'). The ratio of the relative contributions of haline and thermal forcing in the mixed layer is maintained by large-scale surface fluxes, leading to important consequences for mixing in the ocean interior. In a stratified ocean, mixing processes can be either along lines of constant density (isopycnal) or across those lines (diapycnal). The contribution of these processes to the total mixing rate in the ocean can be estimated from the large-scale forcing by evaluating the production of thermal variance, salinity variance and temperature-salinity covariance. Here, I use new estimates of surface fluxes to evaluate these terms and combine them to generate estimates of the production of density and spice variance under the assumption of a linear equation of state. As a consequence, it is possible to estimate the relative importance of isopycnal and diapycnal mixing in the ocean. While isopycnal and diapycnal processes occur on very different length scales, I find that the surface-driven production of density and spice variance requires an approximate equipartition between isopycnal and diapycnal mixing in the ocean interior. In addition, consideration of the full nonlinear equation of state reveals that surface fluxes require an apparent buoyancy gain (expansion) of the ocean, which allows an estimate of the amount of contraction on mixing due to cabbeling in the ocean interior.
Weigelt, Patrick; Kreft, Holger (2013). Quantifying island isolation - insights from global patterns of insular plant species richness, Ecography, 4 (36), 417-429, 10.1111/j.1600-0587.2012.07669.x.
Title: Quantifying island isolation - insights from global patterns of insular plant species richness
Type: Journal Article
Publication: Ecography
Author(s): Weigelt, Patrick; Kreft, Holger
Year: 2013
Formatted Citation: Weigelt, P., and H. Kreft, 2013: Quantifying island isolation - insights from global patterns of insular plant species richness. Ecography, 36(4), 417-429, doi:10.1111/j.1600-0587.2012.07669.x
Title: A multi-dimensional spectral description of ocean variability with application
Type: Thesis
Publication:
Author(s): Wortham IV, Cimarron James Lemuel
Year: 2013
Formatted Citation: Wortham IV, C. J. L., 2013: A multi-dimensional spectral description of ocean variability with application. MIT-WHOI Joint Program, 184 pp. https://hdl.handle.net/1912/5662.
Abstract: Efforts to monitor the ocean for signs of climate change are hampered by ever-present noise, in the form of stochastic ocean variability, and detailed knowledge of the char- acter of this noise is necessary for estimating the significance of apparent trends. Typ- ically, uncertainty estimates are made by a variety of ad hoc methods, often based on numerical model results or the variability of the data set being analyzed. We provide a systematic approach based on the four-dimensional frequency-wavenumber spec- trum of low-frequency ocean variability. This thesis presents an empirical model of the spectrum of ocean variability for periods between about 20 days and 15 years and wavelengths of about 200-10,000 km, and describes applications to ocean circulation trend detection, observing system design, and satellite data processing. The horizontal wavenumber-frequency part of the model spectrum is based on satellite altimetry, current meter data, moored temperature records, and shipboard ADCP data. The spectrum is dominated by motions along a "nondispersive line". The observations considered are consistent with a universal ω −2 power law at the high end of the frequency range, but inconsistent with a universal wavenumber power law. The model spectrum is globally varying and accounts for changes in dominant phase speed, period, and wavelength with location. The vertical structure of the model spectrum is based on numerical model results, current meter data, and theo- retical considerations. We find that the vertical structure of kinetic energy is surface intensified relative to the simplest theoretical predictions. We present a theory for the interaction of linear Rossby waves with rough topography; rough topography can explain both the observed phase speeds and vertical structure of variability. The improved description of low-frequency ocean variability presented here will serve as a useful tool for future oceanographic studies.
LI, Qun; ZHANG, Zhanhai; SUN, Li; WU, Huiding (2013). Ice concentration assimilation in a regional ice-ocean coupled model and its application in sea ice forecasting, Advances in Polar Science, 4 (24), 258, 10.3724/SP.J.1085.2013.00258.
Formatted Citation: LI, Q., Z. ZHANG, L. SUN, and H. WU, 2013: Ice concentration assimilation in a regional ice-ocean coupled model and its application in sea ice forecasting. Advances in Polar Science, 24(4), 258, doi:10.3724/SP.J.1085.2013.00258
Volkov, Denis L.; Landerer, Felix W; Kirillov, Sergey A (2013). The genesis of sea level variability in the Barents Sea, Continental Shelf Research (66), 92-104, 10.1016/j.csr.2013.07.007.
Title: The genesis of sea level variability in the Barents Sea
Type: Journal Article
Publication: Continental Shelf Research
Author(s): Volkov, Denis L.; Landerer, Felix W; Kirillov, Sergey A
Year: 2013
Formatted Citation: Volkov, D. L., F. W. Landerer, and S. A. Kirillov, 2013: The genesis of sea level variability in the Barents Sea. Continental Shelf Research, 66, 92-104, doi:10.1016/j.csr.2013.07.007
Abstract: The regional variability of sea level is an integral indicator of changing oceanographic conditions due to different processes of oceanic, atmospheric, and terrestrial origin. The present study explores the nature of sea level variability in the Barents Sea-a marginal shelf sea of the Arctic Ocean. A characteristic feature that distinguishes this sea from other Arctic shelf seas is that it is largely ice free throughout the year. This allows continuous monitoring of sea level by space-borne altimeters. In this work we combine satellite altimetry, ocean gravity measurements by GRACE satellites, available hydrography data, and a high-resolution ocean data synthesis product to estimate the steric and mass-related components of sea level in the Barents Sea. We present one of the first observational evidence of the local importance of the mass-related sea level changes. The observed 1-3 month phase lag between the annual cycles of sea level in the Barents Sea and in the Nordic seas (Norwegian, Iceland, Greenland seas) is explained by the annual mass-related changes. The analysis of the barotropic vorticity budget shows that the mass-related sea level variability in the central part of the Barents Sea is determined by the combined effect of wind stress, flow over the varying bottom topography, and dissipation, while the impact of vorticity fluxes is negligible. Overall, the steric sea level has smaller amplitudes and mainly varies on the seasonal time scale. The thermosteric sea level is the main contributor to the steric sea level along the pathways of the Atlantic inflow into the Barents Sea. The relative contribution of the halosteric sea level is dominant in the southeastern, eastern, and northern parts of the Barents Sea, modulated by the seasonal sea ice formation/melt as well as by continental runoff. The variability of the thermosteric sea level in the Barents Sea is mostly driven by variations in the net surface heat flux, whereas the contribution of heat advection becomes as important as the ocean-atmosphere heat exchange at interannual time scales.
Condron, Alan; Renfrew, Ian A (2013). The impact of polar mesoscale storms on northeast Atlantic Ocean circulation, Nature Geosci, 1 (6), 34-37, 10.1038/ngeo1661.
Title: The impact of polar mesoscale storms on northeast Atlantic Ocean circulation
Type: Journal Article
Publication: Nature Geosci
Author(s): Condron, Alan; Renfrew, Ian A
Year: 2013
Formatted Citation: Condron, A., and I. A. Renfrew, 2013: The impact of polar mesoscale storms on northeast Atlantic Ocean circulation. Nature Geosci, 6(1), 34-37, doi:10.1038/ngeo1661
Khazendar, A; Schodlok, M P; Fenty, Ian; Ligtenberg, S R M; Rignot, E; van den Broeke, M R (2013). Observed thinning of Totten Glacier is linked to coastal polynya variability, Nat Commun (4), 10.1038/ncomms3857.
Title: Observed thinning of Totten Glacier is linked to coastal polynya variability
Type: Journal Article
Publication: Nat Commun
Author(s): Khazendar, A; Schodlok, M P; Fenty, Ian; Ligtenberg, S R M; Rignot, E; van den Broeke, M R
Year: 2013
Formatted Citation: Khazendar, A., M. P. Schodlok, I. Fenty, S. R. M. Ligtenberg, E. Rignot, and M. R. van den Broeke, 2013: Observed thinning of Totten Glacier is linked to coastal polynya variability. Nat Commun, 4, doi:10.1038/ncomms3857
Abstract: Analysis of ICESat-1 data (2003-2008) shows significant surface lowering of Totten Glacier, the glacier discharging the largest volume of ice in East Antarctica, and less change on nearby Moscow University Glacier. After accounting for firn compaction anomalies, the thinning appears to coincide with fast-flowing ice indicating a dynamical origin. Here, to elucidate these observations, we apply high-resolution ice-ocean modelling. Totten Ice Shelf is simulated to have higher, more variable basal melting rates. We link this variability to the volume of cold water, originating in polynyas upon sea ice formation, reaching the sub-ice-shelf cavity. Hence, we propose that the observed increased thinning of Totten Glacier is due to enhanced basal melting caused by a decrease in cold polynya water reaching its cavity. We support this hypothesis with passive microwave data of polynya extent variability. Considering the widespread changes in sea ice conditions, this mechanism could be contributing extensively to ice-shelf instability.
Schanze, Julian J.; Schmitt, Raymond W. (2013). Estimates of Cabbeling in the Global Ocean, Journal of Physical Oceanography, 4 (43), 698-705, 10.1175/JPO-D-12-0119.1.
Author(s): Schanze, Julian J.; Schmitt, Raymond W.
Year: 2013
Formatted Citation: Schanze, J. J., and R. W. Schmitt, 2013: Estimates of Cabbeling in the Global Ocean. Journal of Physical Oceanography, 43(4), 698-705, doi:10.1175/JPO-D-12-0119.1
Wunsch, Carl; Heimbach, Patrick (2013). Two Decades of the Atlantic Meridional Overturning Circulation: Anatomy, Variations, Extremes, Prediction, and Overcoming Its Limitations, Journal of Climate, 18 (26), 7167-7186, 10.1175/JCLI-D-12-00478.1.
Title: Two Decades of the Atlantic Meridional Overturning Circulation: Anatomy, Variations, Extremes, Prediction, and Overcoming Its Limitations
Type: Journal Article
Publication: Journal of Climate
Author(s): Wunsch, Carl; Heimbach, Patrick
Year: 2013
Formatted Citation: Wunsch, C., and P. Heimbach, 2013: Two Decades of the Atlantic Meridional Overturning Circulation: Anatomy, Variations, Extremes, Prediction, and Overcoming Its Limitations. J. Clim., 26(18), 7167-7186, doi:10.1175/JCLI-D-12-00478.1
Abstract: The zonally integrated meridional volume transport in the North Atlantic [Atlantic meridional overturning circulation (AMOC)] is described in a 19-yr-long ocean-state estimate, one consistent with a diverse global dataset. Apart from a weak increasing trend at high northern latitudes, the AMOC appears statistically stable over the last 19 yr with fluctuations indistinguishable from those of a stationary Gaussian stochastic process. This characterization makes it possible to study (using highly developed tools) extreme values, predictability, and the statistical significance of apparent trends. Gaussian behavior is consistent with the central limit theorem for a process arising from numerous independent disturbances. In this case, generators include internal instabilities, changes in wind and buoyancy forcing fields, boundary waves, the Gulf Stream and deep western boundary current transports, the interior fraction in Sverdrup balance, and all similar phenomena arriving as summation effects from long distances and times. As a zonal integral through the sum of the large variety of physical processes in the three-dimensional ocean circulation, understanding of the AMOC, if it is of central climate importance, requires breaking it down into its unintegrated components over the entire basin.
Szymczak, Andrzej; Sipeki, Levente (2013). Visualization of morse connection graphs for topologically rich 2D vector fields, IEEE Transactions on Visualization and Computer Graphics, 12 (19), 2763-2772, 10.1109/TVCG.2013.229.
Title: Visualization of morse connection graphs for topologically rich 2D vector fields
Type: Journal Article
Publication: IEEE Transactions on Visualization and Computer Graphics
Author(s): Szymczak, Andrzej; Sipeki, Levente
Year: 2013
Formatted Citation: Szymczak, A., and L. Sipeki, 2013: Visualization of morse connection graphs for topologically rich 2D vector fields. IEEE Transactions on Visualization and Computer Graphics, 19(12), 2763-2772, doi:10.1109/TVCG.2013.229
Abstract: Recent advances in vector field topologymake it possible to compute its multi-scale graph representations for autonomous 2D vector fields in a robust and efficient manner. One of these representations is a Morse Connection Graph (MCG), a directed graph whose nodes correspond to Morse sets, generalizing stationary points and periodic trajectories, and arcs - to trajectories connecting them. While being useful for simple vector fields, the MCG can be hard to comprehend for topologically rich vector fields, containing a large number of features. This paper describes a visual representation of the MCG, inspired by previous work on graph visualization. Our approach aims to preserve the spatial relationships between the MCG arcs and nodes and highlight the coherent behavior of connecting trajectories. Using simulations of ocean flow, we show that it can provide useful information on the flow structure. This paper focuses specifically on MCGs computed for piecewise constant (PC) vector fields. In particular, we describe extensions of the PC framework that make it more flexible and better suited for analysis of data on complex shaped domains with a boundary. We also describe a topology simplification scheme that makes our MCG visualizations less ambiguous. Despite the focus on the PC framework, our approach could also be applied to graph representations or topological skeletons computed using different methods.
Keywords: Morse connection graph, Vector field topology
ECCO Products Used: ECCO2
URL:
Other URLs:
Baringer, M O; Johns, W E; McCarthy, G D; Willis, J; Garzoli, S; Lankhorst, M; Meinen, C S; Send, U; Hobbs, W R; Cunningham, S A; Rayner, D; Smeed, D A; Kanzow, T; Heimbach, P; Frajka-Williams, E; Macdonald, A; Dong, S; Marotzke, J (2013). Meridional overturning circulation and heat transport observations in the Atlantic Ocean, State of the Climate in 2012, 8 (94), S65--S68.
Title: Meridional overturning circulation and heat transport observations in the Atlantic Ocean
Type: Book Section
Publication: State of the Climate in 2012
Author(s): Baringer, M O; Johns, W E; McCarthy, G D; Willis, J; Garzoli, S; Lankhorst, M; Meinen, C S; Send, U; Hobbs, W R; Cunningham, S A; Rayner, D; Smeed, D A; Kanzow, T; Heimbach, P; Frajka-Williams, E; Macdonald, A; Dong, S; Marotzke, J
Year: 2013
Formatted Citation: Baringer, M. O. and Coauthors, 2013: Meridional overturning circulation and heat transport observations in the Atlantic Ocean. State of the Climate in 2012, 94(8), S65--S68
Other URLs: https://pure.mpg.de/rest/items/item_1838285/component/file_1838284/content
Tenzer, Robert; Dayoub, Nadim; Abdalla, Ahmed (2013). Analysis of a relative offset between vertical datums at the North and South Islands of New Zealand, Applied Geomatics, 2 (5), 133-145, 10.1007/s12518-013-0106-8.
Title: Analysis of a relative offset between vertical datums at the North and South Islands of New Zealand
Type: Journal Article
Publication: Applied Geomatics
Author(s): Tenzer, Robert; Dayoub, Nadim; Abdalla, Ahmed
Year: 2013
Formatted Citation: Tenzer, R., N. Dayoub, and A. Abdalla, 2013: Analysis of a relative offset between vertical datums at the North and South Islands of New Zealand. Applied Geomatics, 5(2), 133-145, doi:10.1007/s12518-013-0106-8
Abstract: The leveling networks realized by 13 different local vertical datums were jointly readjusted at the South and North Islands of New Zealand. The relation between these two leveling networks and the Word Height System was then defined using GPS-leveling data and the EGM08 global geopotential model. In this study, we investigate the relative offset between these two vertical datum realizations. This is done based on comparison of the geometric geoid/quasigeoid heights (obtained from GPS and newly adjusted leveling data) with the regional gravimetric geoid/quasigeoid solutions. Moreover, oceanographic and geodetic models of mean dynamic topography (MDT) are used to assess the relative offset between these two vertical datum realizations through the analysis of regional spatial variations of mean sea level (MSL). The comparison of GPS-leveling data with regional gravimetric solutions reveals large systematic distortions (exceeding several decimeters across New Zealand) between the geometric and gravimetric geoid/quasigeoid heights attributed mainly to systematic errors within regional gravimetric solutions. The presence of a significant offset between the vertical datum realizations at the North and South Islands is not confirmed. The MSL difference between tide gauges in Wellington and Dunedin of ∼24 cm is estimated based on the analysis of MDT models.
Title: Dynamically and Kinematically Consistent Global Ocean Circulation and Ice State Estimates
Type: Book Section
Publication:
Author(s): Wunsch, Carl; Heimbach, Patrick
Year: 2013
Formatted Citation: Wunsch, C., and P. Heimbach, 2013: Dynamically and Kinematically Consistent Global Ocean Circulation and Ice State Estimates., 553-579, doi:10.1016/B978-0-12-391851-2.00021-0
Zlotnicki, Victor; Bettadpur, Srinivas; Landerer, Felix W.; Watkins, Michael M. (2012). Gravity Recovery and Climate Experiment (GRACE): Detection of Ice Mass Loss, Terrestrial Mass Changes, and Ocean Mass Gains, Encyclopedia of Sustainability Science and Technology, 4563-4584, 10.1007/978-1-4419-0851-3_745.
Title: Gravity Recovery and Climate Experiment (GRACE): Detection of Ice Mass Loss, Terrestrial Mass Changes, and Ocean Mass Gains
Type: Book Section
Publication: Encyclopedia of Sustainability Science and Technology
Author(s): Zlotnicki, Victor; Bettadpur, Srinivas; Landerer, Felix W.; Watkins, Michael M.
Year: 2012
Formatted Citation: Zlotnicki, V., S. Bettadpur, F. W. Landerer, and M. M. Watkins, 2012: Gravity Recovery and Climate Experiment (GRACE): Detection of Ice Mass Loss, Terrestrial Mass Changes, and Ocean Mass Gains. Encyclopedia of Sustainability Science and Technology, Springer New York, 4563-4584, doi:10.1007/978-1-4419-0851-3_745
Title: Combining Stationary Ocean Modelsand Mean Dynamic Topography Data
Type: Thesis
Publication: Universität Bremen
Author(s): Freiwald, Grit
Year: 2012
Formatted Citation: Freiwald, G., 2012: Combining Stationary Ocean Modelsand Mean Dynamic Topography Data, Universität Bremen. 139
Abstract: In this study, a new estimate for the Mean Dynamic Topography (MDT) and its error description is analysed in terms of its impact on the performance of ocean models. This MDT estimate is primarily designed for the combination with ocean models. For the first time, a full error covariance matrix is available whose inverse can readily be used as weighting matrix in the optimization. Two different steady-state inverse ocean models are analysed in terms of their response to the new MDT data set. The 2D model FEMSECT is a section model which is applied to the SR3 hydrographic section in the Southern Ocean in this study. The 3D model IFEOM is a finite element model for the North Atlantic. The output of each of these ocean models in turn provides a combined satellite-ocean model MDT. This combined MDT contains information from satellites, physical principles, hydrographic atlas data and the prior knowledge that is assumed for the model setup. This study investigates whether the inverse ocean models benefit from the new MDT data set and its error covariance. It is verified that the resulting combined MDT is more realistic than both the pure model MDT and the pure observational MDT. It is examined whether oceanographic features such as the ocean current structure, the overturning circulation and heat transports are also improved by the assimilated MDT data set. Special focus is given to the MDT error covariance estimate as it is crucial in the optimization. Its impact on the result is studied in detail. In the FEMSECT model optimization, three commonly known problems were identified, two of which could be solved by the application of Kimura's method forestimating surface velocities from sea ice drift data. The issue of resolution of the satellite geoid data could not be solved due to lack of small-scale data for the model region. A series of solutions was computed with the IFEOM model. The assimilation of the new combined MDT data improved the circulation estimate considerably. More details of the ocean currents are revealed and increased velocities and temperature gradients appear that had not been visible in previous model runs. The formal errorestimate for the new MDT data set is too small to be utilized by the IFEOM model to its full extent of possible accuracy. Therefore it must be downweighted in the optimization process. Different downweighting approaches for extracting the most suitable amount of information from the data are proposed. It was found that the MDT error covariances are of overall importance for smoothness and for the mean diagonal weight in the optimization. It was shown that a decomposition of the covariance matrix and subsequent reinterpretation of the geodetic normal equations and the cost function is possible. The resulting optimized model solution is the best IFEOM solution in terms of selected oceanographic features. Most improvements regarding the IFEOM model output were observed by refining the omission error model and by increasing the model resolution. It is suggested to further explore the MDT error covariance structure and to use more complex ocean models to fully exploit the value of the new spaceborne data.
Formatted Citation: Johnson, M. and Coauthors, 2012: Evaluation of Arctic sea ice thickness simulated by Arctic Ocean Model Intercomparison Project models. J. Geophys. Res. Ocean., 117(C8), n/a-n/a, doi:10.1029/2011JC007257
Volkov, Denis L.; Zlotnicki, Victor (2012). Performance of GOCE and GRACE-derived mean dynamic topographies in resolving Antarctic Circumpolar Current fronts, Ocean Dynamics, 6 (62), 893-905, 10.1007/s10236-012-0541-9.
Title: Performance of GOCE and GRACE-derived mean dynamic topographies in resolving Antarctic Circumpolar Current fronts
Type: Journal Article
Publication: Ocean Dynamics
Author(s): Volkov, Denis L.; Zlotnicki, Victor
Year: 2012
Formatted Citation: Volkov, D. L., and V. Zlotnicki, 2012: Performance of GOCE and GRACE-derived mean dynamic topographies in resolving Antarctic Circumpolar Current fronts. Ocean Dynamics, 62(6), 893-905, doi:10.1007/s10236-012-0541-9
Abstract: Presently, two satellite missions, Gravity Recovery and Climate Experiment (GRACE) and Gravity field and steady-state Ocean Circulation Explorer (GOCE), are making detailed measurements of the Earth's gravity field, from which the geoid can be obtained. The mean dynamic topography (MDT) is the difference between the time-averaged sea surface height and the geoid. The GOCE mission is aimed at determining the geoid with superior accuracy and spatial resolution, so that a more accurate MDT can be estimated. In this study, we determine the mean positions of the Antarctic Circumpolar Current fronts using the purely geodetic estimates of the MDT constructed from an altimetric mean sea surface and GOCE and GRACE geoids. Overall, the frontal positions obtained from the GOCE and GRACE MDTs are close to each other. This means that these independent estimates are robust and can potentially be used to validate frontal positions obtained from sparse and irregular in situ measurements. The geodetic frontal positions are compared to earlier estimates as well as to those derived from MDTs based on satellite and in situ measurements and those obtained from an ocean data synthesis product. The position of the Sub-Antarctic Front identified in the GOCE MDT is found to be in better agreement with the previous estimates than that identified in the GRACE MDT. The geostrophic velocities derived from the GOCE MDT are also closer to observations than those derived from the GRACE MDT. Our results thus show that the GOCE mission represents an improvement upon GRACE in terms of the time-averaged geoid.
Rignot, E; Fenty, Ian; Menemenlis, Dimitris; Xu, Y (2012). Spreading of warm ocean waters around Greenland as a possible cause for glacier acceleration, Annals of Glaciology, 60 (53), 257-266, 10.3189/2012AoG60A136.
Title: Spreading of warm ocean waters around Greenland as a possible cause for glacier acceleration
Type: Journal Article
Publication: Annals of Glaciology
Author(s): Rignot, E; Fenty, Ian; Menemenlis, Dimitris; Xu, Y
Year: 2012
Formatted Citation: Rignot, E., I. Fenty, D. Menemenlis, and Y. Xu, 2012: Spreading of warm ocean waters around Greenland as a possible cause for glacier acceleration. Annals of Glaciology, 53(60), 257-266, doi:10.3189/2012AoG60A136
Abstract: We examine the pattern of spreading of warm subtropical-origin waters around Greenland for the years 1992-2009 using a high-resolution (4 km horizontal grid) coupled ocean and sea-ice simulation. The simulation, provided by the Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2) project, qualitatively reproduces the observed warming of subsurface waters in the subpolar gyre associated with changes of the North Atlantic atmospheric state that occurred in the mid-1990s. The modeled subsurface ocean temperature warmed by 1.5°C in southeast and southwest Greenland during 1994-2005 and subsequently cooled by 0.5°C; modeled subsurface ocean temperature increased by 2-2.5°C in central and then northwest Greenland during 1997-2005 and stabilized thereafter, while it increased after 2005 by <0.5°C in north Greenland. Comparisons with in situ measurements off the continental shelf in the Labrador and Irminger Seas indicate that the model initial conditions were 0.4°C too warm in the south but the simulated warming is correctly reproduced; while measurements from eastern Baffin Bay reveal that the model initial conditions were 1.0°C too cold in the northwest but the simulated ocean warming brought modeled temperature closer to observations, i.e. the simulated warming is 1.0°C too large. At several key locations, the modeled oceanic changes off the shelf and below the seasonal mixed layer were rapidly transmitted to the shelf within troughs towards (model-unresolved) fjords. Unless blocked in the fjords by shallow sills, these warm subsurface waters had potential to propagate down the fjords and melt the glacier fronts. Based on model sensitivity simulations from an independent study (Xu and others, 2012), we show that the oceanic changes have very likely increased the subaqueous melt rates of the glacier fronts, and in turn impacted the rates of glacier flow.
Keywords:
ECCO Products Used: ECCO2;IceSheet
URL:
Other URLs:
Mata, Aitor; Muñoz, M. Dolores; Corchado, Emilio; Corchado, Juan M. (2012). Isotropic Image Analysis for Improving CBR Forecasting, Journal of Mathematical Imaging and Vision, 2-3 (42), 212-224, 10.1007/s10851-011-0315-x.
Title: Isotropic Image Analysis for Improving CBR Forecasting
Type: Journal Article
Publication: Journal of Mathematical Imaging and Vision
Author(s): Mata, Aitor; Muñoz, M. Dolores; Corchado, Emilio; Corchado, Juan M.
Year: 2012
Formatted Citation: Mata, A., M. D. Muñoz, E. Corchado, and J. M. Corchado, 2012: Isotropic Image Analysis for Improving CBR Forecasting. Journal of Mathematical Imaging and Vision, 42(2-3), 212-224, doi:10.1007/s10851-011-0315-x
Volkov, Denis L.; Pujol, M Isabelle (2012). Quality assessment of a satellite altimetry data product in the Nordic, Barents, and Kara seas, Journal of Geophysical Research: Oceans, C3 (117), 10.1029/2011JC007557.
Title: Quality assessment of a satellite altimetry data product in the Nordic, Barents, and Kara seas
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Volkov, Denis L.; Pujol, M Isabelle
Year: 2012
Formatted Citation: Volkov, D. L., and M. I. Pujol, 2012: Quality assessment of a satellite altimetry data product in the Nordic, Barents, and Kara seas. J. Geophys. Res. Ocean., 117(C3), doi:10.1029/2011JC007557
Abstract: Satellite altimetry provides high-quality sea surface height data that have been successfully used to study the variability of sea level and surface geostrophic circulation at different spatial and temporal scales. However, the high-latitude regions have traditionally been avoided due to the persistent sea ice cover. Most of the validation studies have focused on the areas below the polar circles. In this paper we examine the quality and performance of a gridded satellite altimetry product in the Nordic, Barents, and Kara seas. The altimetric sea level in coastal areas is validated using available tide gauge records. We show that at most locations in the Nordic seas the altimetry and tide gauge measurements are in a good agreement in terms of the root-mean square differences and the amplitudes and phases of the seasonal cycle. The agreement deteriorates in the shallow areas of the Barents and Kara seas subject to the seasonal presence of sea ice, and where the altimetry data are contaminated by the residual aliasing of unresolved high-frequency signals. The comparison of linear trends at the locations of tide gauges reveals discrepancies that need to be taken into account when interpreting long-term changes of sea level in the region. Away from the coast the altimetry data are compared to drifter trajectories, corrected for Ekman currents. The drifter trajectories are found consistent with the mesoscale variability of the altimetric sea level. This study provides the first comprehensive validation of a gridded satellite altimetry data product in the high-latitude seas.
Keywords: 4207 Arctic and Antarctic oceanography, 4262 Ocean observing systems, 4275 Remote sensing and electromagnetic processes, 4556 Sea level: variations and mean, Arctic seas, Nordic seas, sea level, surface drifters, tide gauges, validation of altimetry data
Borstad, C P; Khazendar, A; Larour, E; Morlighem, M; Rignot, E; Schodlok, M P; Seroussi, Hélène (2012). A damage mechanics assessment of the Larsen B ice shelf prior to collapse: Toward a physically-based calving law, Geophysical Research Letters, 18 (39), 10.1029/2012GL053317.
Title: A damage mechanics assessment of the Larsen B ice shelf prior to collapse: Toward a physically-based calving law
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Borstad, C P; Khazendar, A; Larour, E; Morlighem, M; Rignot, E; Schodlok, M P; Seroussi, Hélène
Year: 2012
Formatted Citation: Borstad, C. P., A. Khazendar, E. Larour, M. Morlighem, E. Rignot, M. P. Schodlok, and H. Seroussi, 2012: A damage mechanics assessment of the Larsen B ice shelf prior to collapse: Toward a physically-based calving law. Geophys. Res. Lett., 39(18), doi:10.1029/2012GL053317
Abstract: Calving is a primary process of mass ablation for glaciers and ice sheets, though it still eludes a general physical law. Here, we propose a calving framework based on continuum damage mechanics coupled with the equations of viscous deformation of glacier ice. We introduce a scalar damage variable that quantifies the loss of load-bearing surface area due to fractures and that feeds back with ice viscosity to represent fracture-induced softening. The calving law is a standard failure criterion for viscous damaging materials and represents a macroscopic brittle instability quantified by a critical or threshold damage. We constrain this threshold using the Ice Sheet System Model (ISSM) by inverting for damage on the Larsen B ice shelf prior to its 2002 collapse. By analyzing the damage distribution in areas that subsequently calved, we conclude that calving occurs after fractures have reduced the load-bearing capacity of the ice by 60 ± 10%.
Title: Arctic Ocean freshwater: How robust are model simulations?
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Jahn, A.; Aksenov, Y.; de Cuevas, B. A.; de Steur, L.; Häkkinen, S.; Hansen, E.; Herbaut, C.; Houssais, M.-N.; Karcher, M.; Kauker, F.; Lique, C.; Nguyen, A.; Pemberton, P.; Worthen, D.; Zhang, J.
Year: 2012
Formatted Citation: Jahn, A. and Coauthors, 2012: Arctic Ocean freshwater: How robust are model simulations? J. Geophys. Res. Ocean., 117(C8), doi:10.1029/2012JC007907
Yang, Duo; Saenko, Oleg A. (2012). Ocean Heat Transport and Its Projected Change in CanESM2, Journal of Climate, 23 (25), 8148-8163, 10.1175/JCLI-D-11-00715.1.
Title: Ocean Heat Transport and Its Projected Change in CanESM2
Type: Journal Article
Publication: Journal of Climate
Author(s): Yang, Duo; Saenko, Oleg A.
Year: 2012
Formatted Citation: Yang, D., and O. A. Saenko, 2012: Ocean Heat Transport and Its Projected Change in CanESM2. J. Clim., 25(23), 8148-8163, doi:10.1175/JCLI-D-11-00715.1
Schodlok, Michael P; Menemenlis, Dimitris; Rignot, Eric; Studinger, Michael (2012). Sensitivity of the ice-shelf/ocean system to the sub-ice-shelf cavity shape measured by NASA IceBridge in Pine Island Glacier, West Antarctica, Annals of Glaciology, 60 (53), 156-162, 10.3189/2012AoG60A073.
Title: Sensitivity of the ice-shelf/ocean system to the sub-ice-shelf cavity shape measured by NASA IceBridge in Pine Island Glacier, West Antarctica
Type: Journal Article
Publication: Annals of Glaciology
Author(s): Schodlok, Michael P; Menemenlis, Dimitris; Rignot, Eric; Studinger, Michael
Year: 2012
Formatted Citation: Schodlok, M. P., D. Menemenlis, E. Rignot, and M. Studinger, 2012: Sensitivity of the ice-shelf/ocean system to the sub-ice-shelf cavity shape measured by NASA IceBridge in Pine Island Glacier, West Antarctica. Annals of Glaciology, 53(60), 156-162, doi:10.3189/2012AoG60A073
Abstract: Two high-resolution (1 km grid) numerical model simulations of the Amundsen Sea, West Antarctica, are used to study the role of the ocean in the mass loss and grounding line retreat of Pine Island Glacier. The first simulation uses BEDMAP bathymetry under the Pine Island ice shelf, and the second simulation uses NASA IceBridge-derived bathymetry. The IceBridge data reveal the existence of a trough from the ice-shelf edge to the grounding line, enabling warm Circumpolar Deep Water to penetrate to the grounding line, leading to higher melt rates than previously estimated. The mean melt rate for the simulation with NASA IceBridge data is 28 ma -1 , much higher than previous model estimates but closer to estimates from remote sensing. Although the mean melt rate is 25% higher than in the simulation with BEDMAP bathymetry, the temporal evolution remains unchanged between the two simulations. This indicates that temporal variability of melting is mostly driven by processes outside the cavity. Spatial melt rate patterns of BEDMAP and IceBridge simulations differ significantly, with the latter in closer agreement with satellite-derived melt rate estimates of ~50ma -1 near the grounding line. Our simulations confirm that knowledge of the cavity shape and its time evolution are essential to accurately capture basal mass loss of Antarctic ice shelves.
Ponte, Rui M (2012). An assessment of deep steric height variability over the global ocean, Geophysical Research Letters, 4 (39), 10.1029/2011GL050681.
Title: An assessment of deep steric height variability over the global ocean
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Ponte, Rui M
Year: 2012
Formatted Citation: Ponte, R. M., 2012: An assessment of deep steric height variability over the global ocean. Geophys. Res. Lett., 39(4), doi:10.1029/2011GL050681
Abstract: An ocean state estimate constrained by most available data is explored to assess characteristics of variability in deep steric height-a mostly unobserved quantity, yet important for understanding the relation between sea level, heat content and other ocean climate parameters. Results are based on monthly-averaged steric height anomalies, vertically integrated over the "unobserved" deep ocean (below ∼1700 m). Excluding linear trends, variability in deep steric height is typically 10-20% of that in the upper ocean, with larger values seen in extensive regions. Enhanced deep variability, at monthly to interannual time scales, occurs in areas of strong eddy energy. Deep signals are mostly thermosteric in nature, with halosteric contributions tightly correlated and generally compensating in the Atlantic and Indian oceans and adding in the Pacific. Potential inference of deep signals from knowledge of the upper ocean is hampered by poor correlations, and regressions based on upper ocean steric height fail to represent the estimated deep variability. Monthly sampling at ∼2° scales would allow for best determination of deep variability and long term trends.
Keywords: 4215 Climate and interannual variability, 4260 Ocean data assimilation and reanalysis, 4262 Ocean observing systems, 4520 Eddies and mesoscale processes, 4556 Sea level: variations and mean, deep ocean, steric height
Passos, Elisa Nóbrega; Sancho, Lívia Maria Barbosa; Decco, Hatsue Takanaka de; Assad, Luiz Paulo; Landau, Luiz (2012). Analysis of Ocean Circulation Behavior and Atmospheric Events of El Niño and La Niña, Congresso Brasileiro de Oceanografia - CBOʹ2012, 2407-2413.
Formatted Citation: The El Niño Southern Oscillation and La Niña are phenomena capable of alter significantly the world climate. Through currents and wind surface anomaly fields obtained from results of a high resolution ocean model and the NCEP/NCAR reanalysis data, it was possible to identify intensifications and weakness of several atmospheric and oceanographic features.
Abstract: The El Niño Southern Oscillation and La Niña are phenomena capable of alter significantly the world climate. Through currents and wind surface anomaly fields obtained from results of a high resolution ocean model and the NCEP/NCAR reanalysis data, it was possible to identify intensifications and weakness of several atmospheric and oceanographic features.
Hobbs, Will R.; Willis, Joshua K. (2012). Midlatitude North Atlantic heat transport: A time series based on satellite and drifter data, Journal of Geophysical Research: Oceans, C1 (117), 10.1029/2011JC007039.
Title: Midlatitude North Atlantic heat transport: A time series based on satellite and drifter data
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Hobbs, Will R.; Willis, Joshua K.
Year: 2012
Formatted Citation: Hobbs, W. R., and J. K. Willis, 2012: Midlatitude North Atlantic heat transport: A time series based on satellite and drifter data. J. Geophys. Res. Ocean., 117(C1), doi:10.1029/2011JC007039
Galton-Fenzi, B. K.; Hunter, J. R.; Coleman, R.; Marsland, S. J.; Warner, R. C. (2012). Modeling the basal melting and marine ice accretion of the Amery Ice Shelf, Journal of Geophysical Research: Oceans, C9 (117), n/a-n/a, 10.1029/2012JC008214.
Title: Modeling the basal melting and marine ice accretion of the Amery Ice Shelf
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Galton-Fenzi, B. K.; Hunter, J. R.; Coleman, R.; Marsland, S. J.; Warner, R. C.
Year: 2012
Formatted Citation: Galton-Fenzi, B. K., J. R. Hunter, R. Coleman, S. J. Marsland, and R. C. Warner, 2012: Modeling the basal melting and marine ice accretion of the Amery Ice Shelf. J. Geophys. Res. Ocean., 117(C9), n/a-n/a, doi:10.1029/2012JC008214
Title: The automation of PDE-constrained optimisation and its applications
Type: Thesis
Publication:
Author(s): Funke, Simon W.
Year: 2012
Formatted Citation: Funke, S. W., 2012: The automation of PDE-constrained optimisation and its applications., 207 pp.
Abstract: This thesis is concerned with the automation of solving optimisation prob- lems constrained by partial differential equations (PDEs). Gradient-based optimisation algorithms are the key to solve optimisation problems of prac- tical interest. The required derivatives can be efficiently computed with the adjoint approach. However, current methods for the development of adjoint models often require a significant amount of effort and expertise, in particular for non-linear time-dependent problems. This work presents a new high-level reinterpretation of algorithmic dif- ferentiation to develop adjoint models. This reinterpretation considers the discrete system as a sequence of equation solves. Applying this approach to a general finite-element framework results in an automatic and robust way of deriving and solving adjoint models. This drastically reduces the development effort compared to traditional methods. Based on this result, a new framework for rapidly defining and solving optimisation problems constrained by PDEs is developed. The user spec- ifies the discrete optimisation problem in a compact high-level language that resembles the mathematical structure of the underlying system. All remaining steps, including parameter updates, PDE solves and derivative computations, are performed without user intervention. The framework can be applied to a wide range of governing PDEs, and interfaces to various gradient-free and gradient-based optimisation algorithms. The capabilities of this framework are demonstrated through the applica- tion to two PDE-constrained optimisation problems. The first is concerned with the optimal layout of turbines in tidal stream farms; this optimisation problem is one of the main challenges facing the marine renewable energy iiiindustry. The second application applies data assimilation to reconstruct the profile of tsunami waves based on inundation observations. This pro- vides the first step towards the general reconstruction of tsunami signals from satellite information.
Dushaw, Brian D. (2012). The 1960 Perth to Bermuda antipodal acoustic propagation experiment : A measure of a half-century of ocean warming?, Proceedings of the 35th Scandinavian Symposium on Physical Acoustics, Geilo 29 January - 1 February, April.
Title: The 1960 Perth to Bermuda antipodal acoustic propagation experiment : A measure of a half-century of ocean warming?
Type: Conference Proceedings
Publication: Proceedings of the 35th Scandinavian Symposium on Physical Acoustics, Geilo 29 January - 1 February
Author(s): Dushaw, Brian D.
Year: 2012
Formatted Citation: Dushaw, B. D., 2012: The 1960 Perth to Bermuda antipodal acoustic propagation experiment : A measure of a half-century of ocean warming?. Proceedings of the 35th Scandinavian Symposium on Physical Acoustics, Geilo 29 January - 1 February(April) https://www.ntnu.edu/documents/14687435/14716676/SSPA_2012_Dushaw_Acoustic_Propagation_Experiment_6p.pdf.
Hughes, Chris W.; Tamisiea, Mark E.; Bingham, Rory J.; Williams, Joanne (2012). Weighing the ocean: Using a single mooring to measure changes in the mass of the ocean, Geophysical Research Letters, 17 (39), 6, 10.1029/2012GL052935.
Title: Weighing the ocean: Using a single mooring to measure changes in the mass of the ocean
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Hughes, Chris W.; Tamisiea, Mark E.; Bingham, Rory J.; Williams, Joanne
Year: 2012
Formatted Citation: Hughes, C. W., M. E. Tamisiea, R. J. Bingham, and J. Williams, 2012: Weighing the ocean: Using a single mooring to measure changes in the mass of the ocean. Geophys. Res. Lett., 39(17), 6, doi:10.1029/2012GL052935
Abstract: Combining ocean and earth models, we show that there is a region in the central Pacific ocean where ocean bottom pressure is a direct measure of interannual changes in ocean mass, with a noise level for annual means below 3 mm water equivalent, and a trend error below 1 mm/yr. We demon- strate this concept using existing ocean bottom pressure measurements from the region, from which we extract the annual cycle of ocean mass (amplitude 8.5 mm, peaking in late September), which is in agreement with previous determinations based on complex combinations of global data sets. This method sidesteps a number of limitations in satellite gravity-based calculations, but its direct implemen- tation is currently limited by the precision of pressure sen- sors, which suffer from significant drift. Development of a low-drift method to measure ocean bottom pressure at a few sites could provide an important geodetic constraint on the earth system. Citation: Hughes, C. W., M. E. Tamisiea, R. J. Bingham, and J. Williams (2012), Weighing the ocean: Using a single mooring to measure changes in the mass of the ocean,
Woodworth, P.L.; Hughes, C.W.; Bingham, R.J.; Gruber, T. (2012). Towards worldwide height system unification using ocean information, Journal of Geodetic Science, 4 (2), 10.2478/v10156-012-0004-8.
Title: Towards worldwide height system unification using ocean information
Type: Journal Article
Publication: Journal of Geodetic Science
Author(s): Woodworth, P.L.; Hughes, C.W.; Bingham, R.J.; Gruber, T.
Year: 2012
Formatted Citation: Woodworth, P., C. Hughes, R. Bingham, and T. Gruber, 2012: Towards worldwide height system unification using ocean information. Journal of Geodetic Science, 2(4), doi:10.2478/v10156-012-0004-8
Abstract: We describe the application of ocean levelling to worldwide height system uniöcation. The study involves a comparison of 'geodetic' and 'ocean' approaches to determination of the mean dynamic topography (MDT) at the coast, from which conödence in the accuracy of stateof-the-art ocean and geoid models can be obtained. We conclude that models are consistent at the sub-decimetre level for the regions that we have studied (North Atlantic coastlines and islands, North American Paciöc coast and Mediterranean). That level of consistency provides an estimate of the accuracy of using the ocean models to provide an MDT correction to the national datums of countries with coastlines, and thereby of achieving uniöcation. It also provides a validation of geoid model accuracy for application to height system uniöcation in general. We show how our methods can be applied worldwide, as long as the necessary data sets are available, and explain why such an extension of the present study is necessary if worldwide height system uniöcation is to be realised.
Other URLs: https://www.degruyter.com/view/j/jogs.2012.2.issue-4/v10156-012-0004-8/v10156-012-0004-8.xml, https://www.degruyter.com/downloadpdf/j/jogs.2012.2.issue-4/v10156-012
Tank, Suzanne E; Manizza, Manfredi; Holmes, Robert Max; McClelland, James W; Peterson, Bruce J (2012). The Processing and Impact of Dissolved Riverine Nitrogen in the Arctic Ocean, Estuaries and Coasts, 2 (35), 401-415, 10.1007/s12237-011-9417-3.
Title: The Processing and Impact of Dissolved Riverine Nitrogen in the Arctic Ocean
Type: Journal Article
Publication: Estuaries and Coasts
Author(s): Tank, Suzanne E; Manizza, Manfredi; Holmes, Robert Max; McClelland, James W; Peterson, Bruce J
Year: 2012
Formatted Citation: Tank, S. E., M. Manizza, R. M. Holmes, J. W. McClelland, and B. J. Peterson, 2012: The Processing and Impact of Dissolved Riverine Nitrogen in the Arctic Ocean. Estuaries and Coasts, 35(2), 401-415, doi:10.1007/s12237-011-9417-3
Abstract: Although the Arctic Ocean is the most riverine-influenced of all of the world's oceans, the importance of terrigenous nutrients in this environment is poorly understood. This study couples estimates of circumpolar riverine nutrient fluxes from the PARTNERS (Pan-Arctic River Transport of Nutrients, Organic Matter, and Suspended Sediments) Project with a regionally configured version of the MIT general circulation model to develop estimates of the distribution and availability of dissolved riverine N in the Arctic Ocean, assess its importance for primary production, and compare these estimates to potential bacterial production fueled by riverine C. Because riverine dissolved organic nitrogen is remineralized slowly, riverine N is available for uptake well into the open ocean. Despite this, we estimate that even when recycling is considered, riverine N may support 0.5-1.5 Tmol C year−1 of primary production, a small proportion of total Arctic Ocean photosynthesis. Rapid uptake of dissolved inorganic nitrogen coupled with relatively high rates of dissolved organic nitrogen regeneration in N-limited nearshore regions, however, leads to potential localized rates of riverine-supported photosynthesis that represent a substantial proportion of nearshore production.
Dayoub, N.; Edwards, S. J.; Moore, P. (2012). The Gauss-Listing geopotential value W 0 and its rate from altimetric mean sea level and GRACE, Journal of Geodesy, 9 (86), 681-694, 10.1007/s00190-012-0547-6.
Title: The Gauss-Listing geopotential value W 0 and its rate from altimetric mean sea level and GRACE
Type: Journal Article
Publication: Journal of Geodesy
Author(s): Dayoub, N.; Edwards, S. J.; Moore, P.
Year: 2012
Formatted Citation: Dayoub, N., S. J. Edwards, and P. Moore, 2012: The Gauss-Listing geopotential value W 0 and its rate from altimetric mean sea level and GRACE. Journal of Geodesy, 86(9), 681-694, doi:10.1007/s00190-012-0547-6
Miller, M D; Adkins, J F; Menemenlis, Dimitris; Schodlok, M P (2012). The role of ocean cooling in setting glacial southern source bottom water salinity, Paleoceanography, 3 (27), 10.1029/2012PA002297.
Title: The role of ocean cooling in setting glacial southern source bottom water salinity
Type: Journal Article
Publication: Paleoceanography
Author(s): Miller, M D; Adkins, J F; Menemenlis, Dimitris; Schodlok, M P
Year: 2012
Formatted Citation: Miller, M. D., J. F. Adkins, D. Menemenlis, and M. P. Schodlok, 2012: The role of ocean cooling in setting glacial southern source bottom water salinity. Paleoceanography, 27(3), doi:10.1029/2012PA002297
Abstract: At the Last Glacial Maximum (LGM), the salinity contrast between northern source deep water and southern source bottom water was reversed with respect to the contrast today. Additionally, Glacial Southern Source Bottom Water (GSSBW) was saltier than Antarctic Bottom Water (AABW), over and above the difference implied by the mean sea level change. This study examines to what extent cold temperatures, through their effect on ice formation and melting, could have caused these differences. Computational sensitivity experiments using a coupled ice shelf cavity-sea ice-ocean model are performed in a Weddell Sea domain, as a representative case study for bottom water formation originating from Antarctic continental shelves. Ocean temperatures at the domain open boundaries are systematically lowered to determine the sensitivity of Weddell Sea water mass properties to a range of cool ocean temperatures. The steady state salinities differ between experiments due to temperature-induced responses of ice shelf and sea ice melting and freezing, evaporation and open boundary fluxes. The results of the experiments indicate that reduced ocean temperature can explain up to 30% of the salinity difference between GSSBW and AABW, primarily due to decreased ice shelf melting. The smallest and most exposed ice shelves, which abut narrow continental shelves, have the greatest sensitivity to the ocean temperature changes, suggesting that at the LGM there could have been a shift in geographical site dominance in bottom water formation. More sea ice is formed and exported in the cold ocean experiments, but the effect of this on salinity is negated by an equal magnitude reduction in evaporation.
Keywords: 4207 Arctic and Antarctic oceanography, 4219 Continental shelf and slope processes, 4283 Water masses, 4926 Glacial, 4962 Thermohaline, Antarctic Bottom Water, Last Glacial Maximum, Weddell Sea, ice shelves, salinity, sea ice
Bolkas, D.; Fotopoulos, G.; Sideris, M. G. (2012). Referencing regional geoid-based vertical datums to national tide gauge networks, Journal of Geodetic Science, 4 (2), 10.2478/v10156-011-0050-7.
Title: Referencing regional geoid-based vertical datums to national tide gauge networks
Type: Journal Article
Publication: Journal of Geodetic Science
Author(s): Bolkas, D.; Fotopoulos, G.; Sideris, M. G.
Year: 2012
Formatted Citation: Bolkas, D., G. Fotopoulos, and M. G. Sideris, 2012: Referencing regional geoid-based vertical datums to national tide gauge networks. Journal of Geodetic Science, 2(4), doi:10.2478/v10156-011-0050-7
Sánchez, L. (2012). Towards a vertical datum standardisation under the umbrella of Global Geodetic Observing System, Journal of Geodetic Science, 4 (2), 10.2478/v10156-012-0002-x.
Title: Towards a vertical datum standardisation under the umbrella of Global Geodetic Observing System
Type: Journal Article
Publication: Journal of Geodetic Science
Author(s): Sánchez, L.
Year: 2012
Formatted Citation: Sánchez, L., 2012: Towards a vertical datum standardisation under the umbrella of Global Geodetic Observing System. Journal of Geodetic Science, 2(4), doi:10.2478/v10156-012-0002-x
Title: Assessment of Model Performance in Simulating Arctic Sea Ice Using Taylor Diagrams
Type: Thesis
Publication:
Author(s): Al-janabi, Rusul
Year: 2012
Formatted Citation: Al-janabi, R., 2012: Assessment of Model Performance in Simulating Arctic Sea Ice Using Taylor Diagrams.(August), 1-38 pp. http://epic.awi.de/32176/1/Al_Janabi_Master_Thesis.pdf.
Sreenivas, P.; Chowdary, J. S.; Gnanaseelan, C. (2012). Impact of tropical cyclones on the intensity and phase propagation of fall Wyrtki jets, Geophysical Research Letters, 22 (39), n/a-n/a, 10.1029/2012GL053974.
Title: Impact of tropical cyclones on the intensity and phase propagation of fall Wyrtki jets
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Sreenivas, P.; Chowdary, J. S.; Gnanaseelan, C.
Year: 2012
Formatted Citation: Sreenivas, P., J. S. Chowdary, and C. Gnanaseelan, 2012: Impact of tropical cyclones on the intensity and phase propagation of fall Wyrtki jets. Geophys. Res. Lett., 39(22), n/a-n/a, doi:10.1029/2012GL053974
Nguyen, A T; Kwok, R; Menemenlis, Dimitris (2012). Source and Pathway of the Western Arctic Upper Halocline in a Data-Constrained Coupled Ocean and Sea Ice Model, Journal of Physical Oceanography, 5 (42), 802-823, 10.1175/jpo-d-11-040.1.
Title: Source and Pathway of the Western Arctic Upper Halocline in a Data-Constrained Coupled Ocean and Sea Ice Model
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Nguyen, A T; Kwok, R; Menemenlis, Dimitris
Year: 2012
Formatted Citation: Nguyen, A. T., R. Kwok, and D. Menemenlis, 2012: Source and Pathway of the Western Arctic Upper Halocline in a Data-Constrained Coupled Ocean and Sea Ice Model. Journal of Physical Oceanography, 42(5), 802-823, doi:10.1175/jpo-d-11-040.1
Abstract: A coupled ocean and sea ice model is used to investigate dense water (DW) formation in the Chukchi and Bering shelves and the pathways by which this water feeds the upper halocline. Two 1992-2008 data-constrained solutions at 9- and 4-km horizontal grid spacing show that 1) winter sea ice growth results in brine rejection and DW formation; 2) the DW flows primarily down Barrow and Central-Herald Canyons in the form of bottom-trapped, intermittent currents to depths of 50-150 m from the late winter to late summer seasons; and 3) eddies with diameters similar to 30 km carry the cold DW from the shelf break into the Canada Basin interior at depths of 50-150 m. The 4-km data-constrained solution does not show eddy transport across the Chukchi Shelf at shallow depths; instead, advection of DW downstream of polynya regions is driven by a strong (similar to 0.1 m s(-1)) mean current on the Chukchi Shelf. Upper halocline water (UHW) formation rate was obtained from two methods: one is based on satellite data and on a simple parameterized approach, and the other is computed from the authors' model solution. The two methods yield 5740 +/- 61420 km(3) yr(-1) and 4190-4860 +/- 61440 km(3) yr(-1), respectively. These rates imply a halocline replenishment period of 10-21 yr. Passive tracers also show that water with highest density forms in the Gulf of Anadyr and along the eastern Siberian coast immediately north of the Bering Strait. These results provide a coherent picture of the seasonal development of UHW at high spatial and temporal resolutions and serve as a guide for improving understanding of water-mass formation in the western Arctic Ocean.
Fu, Lee-Lueng; Alsdorf, Douglas; Morrow, Rosemary; Rodriguez, Ernesto; Mognard, Nelly (2012). SWOT: The Surface Water and Ocean Topography Mission: Wide-Swath Altimetric Measurement of Water Elevation on Earth.
Formatted Citation: Fu, L., D. Alsdorf, R. Morrow, E. Rodriguez, and N. Mognard, 2012: SWOT: The Surface Water and Ocean Topography Mission: Wide-Swath Altimetric Measurement of Water Elevation on Earth., L. Fu, D. Alsdorf, R. Morrow, E. Rodriguez, and N. Mognard, Eds. National Aeronautics and Space Administration, Pasadena, CA, 228 pp. http://hdl.handle.net/2014/41996.
Abstract: The elevation of the surface of the ocean and freshwater bodies on land holds key information on many important processes of the Earth System. The elevation of the ocean surface, called ocean surface topography, has been measured by conventional nadir- looking radar altimeter for the past two decades. The data collected have been used for the study of large-scale circulation and sea level change. However, the spatial resolution of the observations has limited the study to scales larger than about 200 km, leaving the smaller scales containing substantial kinetic energy of ocean circulation that is responsible for the flux of heat, dissolved gas and nutrients between the upper and the deep ocean. This flux is important to the understanding of the ocean's role in regulating future climate change. The elevation of the water bodies on land is a key parameter required for the computation of storage and discharge of freshwater in rivers, lakes, and wetlands. Globally, the spatial and temporal variability of water storage and discharge is poorly known due to the lack of well-sampled observations. In situ networks measuring river flows are declining worldwide due to economic and political reasons. Conventional altimeter observations suffers from the complexity of multiple peaks caused by the reflections from water, vegetation canopy and rough topography, resulting in much less valid data over land than over the ocean. Another major limitation is the large inter track distance preventing good coverage of rivers and other water bodies. This document provides descriptions of a new measurement technique using radar interferometry to obtain wide-swath measurement of water elevation at high resolution over both the ocean and land. Making this type of measurement, which addresses the shortcomings of conventional altimetry in both oceanographic and hydrologic applications, is the objective of a mission concept called Surface Water and Ocean Topography (SWOT), which was recommended by the National Research Council's first decadal survey of NASA's Earth science program. This document provides wide-ranging examples of research opportunities in oceanography and land hydrology that would be enabled by the new type of measurement. Additional applications in many other branches of Earth System science ranging from ocean bathymetry to sea ice dynamics are also discussed. Many of the technical issues in making the measurement are discussed as well. Also presented is a preliminary design of the SWOT Mission concept, which is being jointly developed by NASA and CNES, with contributions from the Canadian Space Agency.
Ma, J.; Liao, I.; Kwan-Liu Ma; Frazier, J. (2012). Living Liquid: Design and Evaluation of an Exploratory Visualization Tool for Museum Visitors, IEEE Transactions on Visualization and Computer Graphics, 12 (18), 2799-2808, 10.1109/TVCG.2012.244.
Title: Living Liquid: Design and Evaluation of an Exploratory Visualization Tool for Museum Visitors
Type: Journal Article
Publication: IEEE Transactions on Visualization and Computer Graphics
Author(s): Ma, J.; Liao, I.; Kwan-Liu Ma; Frazier, J.
Year: 2012
Formatted Citation: Ma, J., I. Liao, Kwan-Liu Ma, and J. Frazier, 2012: Living Liquid: Design and Evaluation of an Exploratory Visualization Tool for Museum Visitors. IEEE Transactions on Visualization and Computer Graphics, 18(12), 2799-2808, doi:10.1109/TVCG.2012.244
Title: Determination of hydrological mass variations from GRACE data using the example of Siberian river systems
Type: Thesis
Publication:
Author(s): Scheller, Marita
Year: 2012
Formatted Citation: Scheller, M., 2012: Determination of hydrological mass variations from GRACE data using the example of Siberian river systems., 151 pp. https://d-nb.info/1068151382/34.
Abstract: The satellite mission GRACE (Gravity Recovery and Climate Experiment) observes the earth's gravity field on temporal scales of a few days to several weeks and spatial scales of a few hundred kilometers with high accuracy. A large part of the variations of the gravity field originate from hydrological mass changes on the continents. The dissertation discusses the determination of hydrological mass variations from GRACE for the Siberian water systems of the rivers Ob, Yenisey, Lena and Kolyma. The mass variations from GRACE data are combined with atmospheric data of the NCEP reanalysis to calculate the freshwater fluxes in the Arctic Ocean. The freshwater fluxes strongly influences the salinity and the oceanographic regime of the Arctic Ocean. In turn, the Arctic Ocean controls the global thermohaline circulation which is very important for the global climate. Because these large currents of the ocean influence the global climate, the changes of the freshwater fluxes in the Arctic Ocean are an important factor for the global climate change. The runoff can be measured pointwise with high temporal resolution, but measurements in the high latitudes are difficulty and expensive. Independent methods to measure the mass changes in the Arctic can help to determine the freshwater fluxes on large spatial scales, and contribute to understand the coupled and complex processes of the Arctic. Until present, the complex error structure of the GRACE data are not fully understand. The dissertation examines the errors and analysizes the leakage caused by the limited spectrum of the Stokes coefficients. A proposal for a solution will be discussed. The following steps are important: Expanding the GRACE data with adequate terms of degree one; Valuation of leakage errors because of the limited spectrum. Leakage due to oceanographic signals of the Arctic Ocean are small (< 1 %). Leakage errors due to signals on land produces relative errors of basin averages of 8-17 %. Beyond that, the largest errors are caused by the coefficients of higher degree. Filtering is an effective method to damp the error signals. In addition to the common filters described in the literature, a filter method, called composite filter, was created. Significant structures from hydrological models can be deteceted in the GRACE data without any other filtering. Only the residual signals should be filtered by using one of the common filters. In comparison to the common filters, the composite filter represents the signal strength, the signal structures, the amplitude and the phase of the saisonal signal on the continents much better. Combining hydrological mass variations from GRACE data with atmospheric data (for example the NCEP reanalysis) the runoff of the four Siberian river systems can be calcu- lated. The validation of the calculated runoff using observations leads to a good agreement (83 % for Yenisey and Lena). Furthermore, it is possible to combine the runoff of a river system with measurements of water level and salinity in the Arctic Ocean. The high runoff of the Lena river system in spring is visible in the water level changes in the Laptev sea.
Granskog, Mats A; Stedmon, Colin A; Dodd, Paul A; Amon, Rainer M W; Pavlov, Alexey K; de Steur, Laura; Hansen, Edmond (2012). Characteristics of colored dissolved organic matter (CDOM) in the Arctic outflow in the Fram Strait: Assessing the changes and fate of terrigenous CDOM in the Arctic Ocean, Journal of Geophysical Research: Oceans, C12 (117), 10.1029/2012JC008075.
Title: Characteristics of colored dissolved organic matter (CDOM) in the Arctic outflow in the Fram Strait: Assessing the changes and fate of terrigenous CDOM in the Arctic Ocean
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Granskog, Mats A; Stedmon, Colin A; Dodd, Paul A; Amon, Rainer M W; Pavlov, Alexey K; de Steur, Laura; Hansen, Edmond
Year: 2012
Formatted Citation: Granskog, M. A., C. A. Stedmon, P. A. Dodd, R. M. W. Amon, A. K. Pavlov, L. de Steur, and E. Hansen, 2012: Characteristics of colored dissolved organic matter (CDOM) in the Arctic outflow in the Fram Strait: Assessing the changes and fate of terrigenous CDOM in the Arctic Ocean. J. Geophys. Res. Ocean., 117(C12), doi:10.1029/2012JC008075
Abstract: Absorption coefficients of colored dissolved organic matter (CDOM) were measured together with salinity, δ18O, and inorganic nutrients across the Fram Strait. A pronounced CDOM absorption maximum between 30 and 120 m depth was associated with river and sea ice brine enriched water, characteristic of the Arctic mixed layer and upper halocline waters in the East Greenland Current (EGC). The lowest CDOM concentrations were found in the Atlantic inflow. We show that the salinity-CDOM relationship is not suitable for evaluating conservative mixing of CDOM. The strong correlation between meteoric water and CDOM is indicative of the riverine/terrigenous origin of CDOM in the EGC. Based on CDOM absorption in Polar Water and comparison with an Arctic river discharge weighted mean, we estimate that a 49-59% integrated loss of CDOM absorption across 250-600 nm has occurred. A preferential removal of absorption at longer wavelengths reflects the loss of high molecular weight material. In contrast, CDOM fluxes through the Fram Strait using September velocity fields from a high-resolution ocean-sea ice model indicate that the net southward transport of terrigenous CDOM through the Fram Strait equals up to 50% of the total riverine CDOM input; this suggests that the Fram Strait export is a major sink of CDOM. These contrasting results indicate that we have to constrain the (C)DOM budgets for the Arctic Ocean much better and examine uncertainties related to using tracers to assess conservative mixing in polar waters.
Keywords: 4207 Arctic and Antarctic oceanography, 4805 Biogeochemical cycles, 4806 Carbon cycling, 4808 Chemical tracers, 9315 Arctic region, Arctic Ocean, Fram Strait, absorption coefficient, and modelin, chromophoric dissolved organic matter, processes, river water, spectral slope coefficient
Condron, Alan; Winsor, Peter (2012). Meltwater routing and the Younger Dryas, Proceedings of the National Academy of Sciences, 49 (109), 19928-19933, 10.1073/pnas.1207381109.
Publication: Proceedings of the National Academy of Sciences
Author(s): Condron, Alan; Winsor, Peter
Year: 2012
Formatted Citation: Condron, A., and P. Winsor, 2012: Meltwater routing and the Younger Dryas. Proceedings of the National Academy of Sciences, 109(49), 19928-19933, doi:10.1073/pnas.1207381109
Abstract: The Younger Dryas-the last major cold episode on Earth-is generally considered to have been triggered by a meltwater flood into the North Atlantic. The prevailing hypothesis, proposed by Broecker et al. [1989 Nature 341:318-321] more than two decades ago, suggests that an abrupt rerouting of Lake Agassiz overflow through the Great Lakes and St. Lawrence Valley inhibited deep water formation in the subpolar North Atlantic and weakened the strength of the Atlantic Meridional Overturning Circulation (AMOC). More recently, Tarasov and Peltier [2005 Nature 435:662-665] showed that meltwater could have discharged into the Arctic Ocean via the Mackenzie Valley ∼4,000 km northwest of the St. Lawrence outlet. Here we use a sophisticated, high-resolution, ocean sea-ice model to study the delivery of meltwater from the two drainage outlets to the deep water formation regions in the North Atlantic. Unlike the hypothesis of Broecker et al., freshwater from the St. Lawrence Valley advects into the subtropical gyre ∼3,000 km south of the North Atlantic deep water formation regions and weakens the AMOC by <15%. In contrast, narrow coastal boundary currents efficiently deliver meltwater from the Mackenzie Valley to the deep water formation regions of the subpolar North Atlantic and weaken the AMOC by >30%. We conclude that meltwater discharge from the Arctic, rather than the St. Lawrence Valley, was more likely to have triggered the Younger Dryas cooling.
Title: Predicting habitat preferences for Anthometrina adriani (Echinodermata) on the East Antarctic continental shelf
Type: Journal Article
Publication: Marine Ecology Progress Series
Author(s): Hemery, LG; Galton-Fenzi, B; Améziane, N; Riddle, MJ; Rintoul, SR; Beaman, RJ; Post, AL; Eléaume, M
Year: 2011
Formatted Citation: Hemery, L., B. Galton-Fenzi, N. Améziane, M. Riddle, S. Rintoul, R. Beaman, A. Post, and M. Eléaume, 2011: Predicting habitat preferences for Anthometrina adriani (Echinodermata) on the East Antarctic continental shelf. Marine Ecology Progress Series, 441, 105-116, doi:10.3354/meps09330
Author(s): Williams, Richard G.; Follows, Michael J.
Year: 2011
Formatted Citation: Williams, R. G., and M. J. Follows, 2011: Ocean Dynamics and the Carbon Cycle. Cambridge University Press, Cambridge, 404 pp. doi:10.1017/CBO9780511977817.
Abstract: This textbook for advanced undergraduate and graduate students presents a multidisciplinary approach to understanding ocean circulation and how it drives and controls marine biogeochemistry and biological productivity at a global scale. Background chapters on ocean physics, chemistry and biology provide students with the tools to examine the range of large-scale physical and dynamic phenomena that control the ocean carbon cycle and its interaction with the atmosphere. Throughout the text observational data is integrated with basic physical theory to address cutting-edge research questions in ocean biogeochemistry. Simple theoretical models, data plots and schematic illustrations summarise key results and connect the physical theory to real observations. Advanced mathematics is provided in boxes and appendices where it can be drawn on to assist with the worked examples and homework exercises available online. Further reading lists for each chapter and a comprehensive glossary provide students and instructors with a complete learning package.
Keywords: Climatology and Climate Change, Earth and Environmental Sciences, Oceanography and Marine Science
Other URLs: http://ebooks.cambridge.org/ref/id/CBO9780511977817
Gennerich, Hans-Hermann; Villinger, Heinrich (2011). Deciphering the ocean bottom pressure variation in the Logatchev hydrothermal field at the eastern flank of the Mid-Atlantic Ridge, Geochemistry, Geophysics, Geosystems, 7 (12), 10.1029/2010GC003441.
Title: Deciphering the ocean bottom pressure variation in the Logatchev hydrothermal field at the eastern flank of the Mid-Atlantic Ridge
Type: Journal Article
Publication: Geochemistry, Geophysics, Geosystems
Author(s): Gennerich, Hans-Hermann; Villinger, Heinrich
Year: 2011
Formatted Citation: Gennerich, H., and H. Villinger, 2011: Deciphering the ocean bottom pressure variation in the Logatchev hydrothermal field at the eastern flank of the Mid-Atlantic Ridge. Geochemistry, Geophysics, Geosystems, 12(7), doi:10.1029/2010GC003441
Abstract: Ocean bottom pressure data from the Logatchev hydrothermal field (LHF) are presented and analyzed. The data were collected with two ocean bottom pressure meters (OBPs), constructed at the University of Bremen, that are capable of recording signals with frequencies up to 0.25 Hz. Over the long-term, a nearly 2.5 kPa (25 cm water column equivalent) pressure variation over 3.7 years is observed, which is consistent with uplift followed by subsidence, but cannot unequivocally be discerned from instrumental drift. Medium-term pressure variations are compared with satellite surface topography, satellite gravity, ocean modeling, and in situ data from an OBP 700 km away. It is shown that fluctuations in the oceanic mass distribution dominate the variations in this frequency range and that oceanic modeling and data from a 700 km distant OBP are positively correlated with the LHF bottom pressure time series. The short-term variations are dominated by microseisms originating from sea surface waves and pressure waves from earthquakes as can be shown by comparison with weather buoy and teleseismic data.
Mata, Aitor; Corchado, Juan M.; Tapia, Dante I. (2011). CROS: A Contingency Response multi-agent system for Oil Spills situations, Applied Soft Computing, 3 (11), 3147-3159, 10.1016/j.asoc.2010.12.017.
Title: CROS: A Contingency Response multi-agent system for Oil Spills situations
Type: Journal Article
Publication: Applied Soft Computing
Author(s): Mata, Aitor; Corchado, Juan M.; Tapia, Dante I.
Year: 2011
Formatted Citation: Mata, A., J. M. Corchado, and D. I. Tapia, 2011: CROS: A Contingency Response multi-agent system for Oil Spills situations. Applied Soft Computing, 11(3), 3147-3159, doi:10.1016/j.asoc.2010.12.017
Wang, Zeliang; Holloway, Greg; Hannah, Charles (2011). Effects of parameterized eddy stress on volume, heat, and freshwater transports through Fram Strait, Journal of Geophysical Research, C8 (116), C00D09, 10.1029/2010JC006871.
Title: Effects of parameterized eddy stress on volume, heat, and freshwater transports through Fram Strait
Type: Journal Article
Publication: Journal of Geophysical Research
Author(s): Wang, Zeliang; Holloway, Greg; Hannah, Charles
Year: 2011
Formatted Citation: Wang, Z., G. Holloway, and C. Hannah, 2011: Effects of parameterized eddy stress on volume, heat, and freshwater transports through Fram Strait. Journal of Geophysical Research, 116(C8), C00D09, doi:10.1029/2010JC006871
Abstract: Coarse-resolution models, such as those used in climate studies, often do not properly represent transports through narrow channels. We consider the climatically important transports of volume, heat, and freshwater through Fram Strait. A coarse grid (nominally 1°) global ocean model is seen to underrepresent exchanges. We test effects of eddy stress (Neptune) parameterization, finding strengthened volume exchanges both to and from the Arctic and increased mean northward heat transport while limiting southward freshwater export. Results are closer to observed transports and to results from fine-resolution models. This study finds that the effects of the eddy stress on temporal variations of transports are small.
Keywords: 4299 General or miscellaneous, Fram Strait, eddy stress, transports
Title: Modeling Diverse Communities of Marine Microbes
Type: Journal Article
Publication: Annual Review of Marine Science
Author(s): Follows, Michael J.; Dutkiewicz, Stephanie
Year: 2011
Formatted Citation: Follows, M. J., and S. Dutkiewicz, 2011: Modeling Diverse Communities of Marine Microbes. Annual Review of Marine Science, 3(1), 427-451, doi:10.1146/annurev-marine-120709-142848
Abstract: Biogeochemical cycles in the ocean are mediated by complex and diverse microbial communities. Over the past decade, marine ecosystem and biogeochemistry models have begun to address some of this diversity by resolving several groups of (mostly autotrophic) plankton, differentiated by biogeochemical function. Here, we review recent model approaches that are rooted in the notion that an even richer diversity is fundamental to the organization of marine microbial communities. These models begin to resolve, and address the significance of, diversity within functional groups. Seeded with diverse populations spanning prescribed regions of trait space, these simulations self-select community structure according to relative fitness in the virtual environment. Such models are suited to considering ecological questions, such as the regulation of patterns of biodiversity, and to simulating the response to changing environments. A key issue for all such models is the constraint of viable trait space and trade-offs. Size-structuring and mechanistic descriptions of energy and resource allocation at the individual level can rationalize these constraints.
Keywords: community structure, microbes, phytoplankton, traits
Title: Review of Oil Spill Trajectory Modelling in the Presence of Ice
Type: Report
Publication:
Author(s): Drozdowski, A.; Nudds, S.; Hannah, C. G.; Niu, H.; Peterson, I.; Perrie, W.
Year: 2011
Formatted Citation: Drozdowski, A., S. Nudds, C. G. Hannah, H. Niu, I. Peterson, and W. Perrie, 2011: Review of Oil Spill Trajectory Modelling in the Presence of Ice., Dartmouth, Nova Scotia, Canada, 90 pp. http://www.iob-bio.gc.ca/science/research-recherche/ocean/ice-glace/documents/drozdowski01.pdf.
Abstract: This report addresses marine oil spill trajectory modelling with a focus on the Arctic environment. The primary goals are a synthesis of the state-of-knowledge on oil spill trajectory modelling and the identification of the key gaps in this knowledge as it applies to the Canadian Arctic. The review addresses all the components of a comprehensive oil spill trajectory model including 1) a blowout plume model to determine the distribution of oil in the water column for spills that occur at depth, 2) models for the physical environmental forcing (wind, air temperature, precipitation, ocean currents, sea ice and waves); and 3) an oil fate-and-effects model to address weathering, evaporation, ice-oil interactions, and other details of the oil's interplay with the environment. Novel challenges presented by the Arctic environment include the presence of sea ice, sparse observations of ocean currents and limited ability to monitor the spill's evolution.
Yang, Qinghua; Liu, Yuping; Zhang, Zhanhai; Wu, Huizhen; Li, Qun; Xing, Jianyon (2011). A Preliminary Study of the Arctic Sea Ice Numerical Forecasting: Coupled Sea Ice-Ocean Modelling Experiments Based on MITgcm, Chinese Journal of Atmospheric Sciences, 3 (35), 473-482, 10.3878/j.issn.1006-9895.2011.03.08.
Formatted Citation: Yang, Q., Y. Liu, Z. Zhang, H. Wu, Q. Li, and J. Xing, 2011: A Preliminary Study of the Arctic Sea Ice Numerical Forecasting: Coupled Sea Ice-Ocean Modelling Experiments Based on MITgcm. Chinese Journal of Atmospheric Sciences, 35(3), 473-482, doi:10.3878/j.issn.1006-9895.2011.03.08
Abstract: Using the recently developed MITgcm (MIT General Circulation Model) sea ice-ocean coupling model, the NCEP (National Environmental Prediction Center) reanalyzed data for the atmospheric forcing field from January 1992 to December 2009. Numerical simulation of Arctic sea ice. The results show that this model can well simulate the Arctic sea ice season and interannual variation observed by satellite, and has a good numerical simulation ability of Arctic sea ice. Based on this, four sets of post-test studies were conducted on the two cases of Arctic sea ice ablation and growth in July and October 2009. The NCEP reanalyzed the climatic field and NCEPGFS (Global Forecast System) forecast data as atmospheric forcing fields, and adopted two different SSM/I (dedicated microwave imager) sea ice concentration initialization schemes. The comparison of forecast results with SSM/I, as well as forecasting skill analysis, shows that this model has short-term forecasting capabilities for Arctic sea ice. The difference in atmospheric forcing field is not significant for the improvement of sea ice forecasting, and the prediction of SSM/I sea ice concentration to reduce the initial error can better simulate the melting and growth of sea ice. In addition, the sea ice concentration of the model simulation is slightly higher, and the simulation ability of the sea ice freezing process is better than the ablation process.
Manizza, M; Follows, Michael J.; Dutkiewicz, Stephanie; Menemenlis, Dimitris; McClelland, J W; Hill, C N; Peterson, B J; Key, R M (2011). A model of the Arctic Ocean carbon cycle, Journal of Geophysical Research: Oceans, C12 (116), 10.1029/2011JC006998.
Publication: Journal of Geophysical Research: Oceans
Author(s): Manizza, M; Follows, Michael J.; Dutkiewicz, Stephanie; Menemenlis, Dimitris; McClelland, J W; Hill, C N; Peterson, B J; Key, R M
Year: 2011
Formatted Citation: Manizza, M., M. J. Follows, S. Dutkiewicz, D. Menemenlis, J. W. McClelland, C. N. Hill, B. J. Peterson, and R. M. Key, 2011: A model of the Arctic Ocean carbon cycle. J. Geophys. Res. Ocean., 116(C12), doi:10.1029/2011JC006998
Abstract: A three dimensional model of Arctic Ocean circulation and mixing, with a horizontal resolution of 18 km, is overlain by a biogeochemical model resolving the physical, chemical and biological transport and transformations of phosphorus, alkalinity, oxygen and carbon, including the air-sea exchange of dissolved gases and the riverine delivery of dissolved organic carbon. The model qualitatively captures the observed regional and seasonal trends in surface ocean PO4, dissolved inorganic carbon, total alkalinity, and pCO2. Integrated annually, over the basin, the model suggests a net annual uptake of 59 Tg C a−1, within the range of published estimates based on the extrapolation of local observations (20-199 Tg C a−1). This flux is attributable to the cooling (increasing solubility) of waters moving into the basin, mainly from the subpolar North Atlantic. The air-sea flux is regulated seasonally and regionally by sea-ice cover, which modulates both air-sea gas transfer and the photosynthetic production of organic matter, and by the delivery of riverine dissolved organic carbon (RDOC), which drive the regional contrasts in pCO2 between Eurasian and North American coastal waters. Integrated over the basin, the delivery and remineralization of RDOC reduces the net oceanic CO2 uptake by ∼10%.
Tulloch, Ross; Hill, Chris; Jahn, Oliver (2011). Possible Spreadings of Buoyant Plumes and Local Coastline Sensitivities Using Flow Syntheses From 1992 to 2007, Monitoring and Modeling the Deepwater Horizon Oil Spill: A Record-Breaking Enterprise, 245-255, 10.1029/2011GM001125.
Title: Possible Spreadings of Buoyant Plumes and Local Coastline Sensitivities Using Flow Syntheses From 1992 to 2007
Type: Book Section
Publication: Monitoring and Modeling the Deepwater Horizon Oil Spill: A Record-Breaking Enterprise
Author(s): Tulloch, Ross; Hill, Chris; Jahn, Oliver
Year: 2011
Formatted Citation: Tulloch, R., C. Hill, and O. Jahn, 2011: Possible Spreadings of Buoyant Plumes and Local Coastline Sensitivities Using Flow Syntheses From 1992 to 2007. Monitoring and Modeling the Deepwater Horizon Oil Spill: A Record-Breaking Enterprise, American Geophysical Union, 245-255, doi:10.1029/2011GM001125
Abstract: We present results from an ensemble of simulations where a buoyant dye is injected at the site of the Deepwater Horizon blowout from April 20 to July 15 of each year between 1992 and 2007. Ocean currents are taken from observationally constrained Estimating the Circulation and Climate of the Ocean Phase 2 (ECCO2) project state estimates spanning 1992 to 2007. Starting from this basis, we explore the utility of adjoint equations in allowing proactive evaluation of regional impact likelihood. Forward integrations are performed to assess the ensemble spread of the plume, the role of increased resolution of ocean eddies, and to compare spreading metrics using an Eulerian tracer and Lagrangian particles. Spreading statistics compare well with previous studies, and the Lagrangian and Eulerian approaches predict similar spread- ing rates, allowing some confidence in adjoint sensitivity analysis of the vulnerability of different local coastline regions to be conducted. Example adjoint calculations indicate that coastline of the Mississippi Delta is most sensitive to spills on the continental shelf off adjacent to Mississippi and Alabama, while Cape Hatteras, for example, is most sensitive to spills on the continental shelf from Delaware to South Carolina. Combined with accurate estimates of historical currents and winds, we argue that the adjoint approach we describe can be a useful regional planning and preparedness tool. Using the adjoint approach, local communities can proactively identify spill locations to which they are especially vulnerable, allowing for better preparedness and more efficient response to any future incidents.
Other URLs: http://ocean.mit.edu/~tulloch/Publications/tulloch_etalagu11.pdf
Davis, Xujing Jia; Rothstein, Lewis M; Dewar, William K; Menemenlis, Dimitris (2011). Numerical Investigations of Seasonal and Interannual Variability of North Pacific Subtropical Mode Water and Its Implications for Pacific Climate Variability, Journal of Climate, 11 (24), 2648-2665, 10.1175/2010JCLI3435.1.
Title: Numerical Investigations of Seasonal and Interannual Variability of North Pacific Subtropical Mode Water and Its Implications for Pacific Climate Variability
Type: Journal Article
Publication: Journal of Climate
Author(s): Davis, Xujing Jia; Rothstein, Lewis M; Dewar, William K; Menemenlis, Dimitris
Year: 2011
Formatted Citation: Davis, X. J., L. M. Rothstein, W. K. Dewar, and D. Menemenlis, 2011: Numerical Investigations of Seasonal and Interannual Variability of North Pacific Subtropical Mode Water and Its Implications for Pacific Climate Variability. J. Clim., 24(11), 2648-2665, doi:10.1175/2010JCLI3435.1
Abstract: North Pacific Subtropical Mode Water (NPSTMW) is an essential feature of the North Pacific subtropical gyre imparting significant influence on regional SST evolution on seasonal and longer time scales and, as such, is an important component of basin-scale North Pacific climate variability. This study examines the seasonal-to-interannual variability of NPSTMW, the physical processes responsible for this variability, and the connections between NPSTMW and basin-scale climate signals using an eddy-permitting 1979-2006 ocean simulation made available by the Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2). The monthly mean seasonal cycle of NPSTMW in the simulation exhibits three distinct phases: (i) formation during November-March, (ii) isolation during March-June, and (iii) dissipation during June-November-each corresponding to significant changes in upper-ocean structure. An interannual signal is also evident in NPSTMW volume and other characteristic properties with volume minima occurring in 1979, 1988, and 1999. This volume variability is correlated with the Pacific decadal oscillation (PDO) with zero time lag. Further analyses demonstrate the connection of NPSTMW to the basin-scale ocean circulation. With this, modulations of upper-ocean structure driven by the varying strength and position of the westerlies as well as the regional air-sea heat flux pattern are seen to contribute to the variability of NPSTMW volume on interannual time scales.
LI, Qun; WU, Huiding; Zhang, Lu (2011). Fine-scale simulation of the seasonal variations of sea ice cover in the Prydz bay, Antarctic, Acta Oceanologica Sinica, 5 (33), 32-38.
Title: Fine-scale simulation of the seasonal variations of sea ice cover in the Prydz bay, Antarctic
Type: Journal Article
Publication: Acta Oceanologica Sinica
Author(s): LI, Qun; WU, Huiding; Zhang, Lu
Year: 2011
Formatted Citation: LI, Q., H. WU, and L. Zhang, 2011: Fine-scale simulation of the seasonal variations of sea ice cover in the Prydz bay, Antarctic. Acta Oceanologica Sinica, 33(5), 32-38
Abstract:
Keywords:
ECCO Products Used: ECCO2;SeaIce
URL:
Other URLs:
DeVries, Tim; Primeau, François (2011). Dynamically and Observationally Constrained Estimates of Water-Mass Distributions and Ages in the Global Ocean, Journal of Physical Oceanography, 12 (41), 2381-2401, 10.1175/JPO-D-10-05011.1.
Title: Dynamically and Observationally Constrained Estimates of Water-Mass Distributions and Ages in the Global Ocean
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): DeVries, Tim; Primeau, François
Year: 2011
Formatted Citation: DeVries, T., and F. Primeau, 2011: Dynamically and Observationally Constrained Estimates of Water-Mass Distributions and Ages in the Global Ocean. Journal of Physical Oceanography, 41(12), 2381-2401, doi:10.1175/JPO-D-10-05011.1
Ivchenko, V. O.; Sidorenko, D.; Danilov, S.; Losch, M.; Schröter, J. (2011). Can sea surface height be used to estimate oceanic transport variability?, Geophysical Research Letters, 11 (38), 10.1029/2011GL047387.
Title: Can sea surface height be used to estimate oceanic transport variability?
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Ivchenko, V. O.; Sidorenko, D.; Danilov, S.; Losch, M.; Schröter, J.
Year: 2011
Formatted Citation: Ivchenko, V. O., D. Sidorenko, S. Danilov, M. Losch, and J. Schröter, 2011: Can sea surface height be used to estimate oceanic transport variability? Geophys. Res. Lett., 38(11), doi:10.1029/2011GL047387
Title: Cyclonic eddies formed at the Pacific tropical instability wave fronts
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Ubelmann, Clement; Fu, Lee-Lueng
Year: 2011
Formatted Citation: Ubelmann, C., and L. Fu, 2011: Cyclonic eddies formed at the Pacific tropical instability wave fronts. J. Geophys. Res. Ocean., 116(C12), doi:10.1029/2011JC007204
Abstract: Sea surface temperature images and surface drifter observations are compared to the results from a high-resolution numerical simulation to study the properties of cyclonic eddies generated at the density front of the tropical instability waves in the tropical Pacific Ocean. These cyclonic eddies, of which the diameter is about 30-100 km and the vertical extent is limited to the upper 100 m in depth, have physical characteristics similar to those of smaller submesoscale eddies at the midlatitudes according to the model. They have highly coherent structures below the surface, carrying cold and salty upwelled equatorial water probably rich in marine life. The stretching and tilting of the upper layer of the ocean provides the main mechanism responsible for the intense cyclonic vorticity of the eddies, involving complex evolution of the density field into occluded fronts.
Keywords: 4283 Water masses, 4520 Eddies and mesoscale processes, 4528 Fronts and jets, 4572 Upper ocean and mixed layer processes, TIW, eddy, front
Dorman, Jeffrey G. (2011). The Influence of Seasonal and Decadal Trends in Coastal Ocean Processes on the Population Biology of the krill species Euphausia pacifica: Results of a coupled ecosystem and individual based modeling study.
Title: The Influence of Seasonal and Decadal Trends in Coastal Ocean Processes on the Population Biology of the krill species Euphausia pacifica: Results of a coupled ecosystem and individual based modeling study
Type: Thesis
Publication:
Author(s): Dorman, Jeffrey G.
Year: 2011
Formatted Citation: Dorman, J. G., 2011: The Influence of Seasonal and Decadal Trends in Coastal Ocean Processes on the Population Biology of the krill species Euphausia pacifica: Results of a coupled ecosystem and individual based modeling study., 98 pp. https://escholarship.org/uc/item/5q8498kw.
Abstract: Krill of the California Current play a crucial role in the transfer of primary production up to many commercially important higher trophic levels. Understanding the short time scale (weeks to seasonal) and long time scale (decadal) variability in abundance, condition, and spatial patterns that results from changes in ocean conditions is critical if we hope to manage the fishery of any higher trophic levels from more than a single species approach. I have coupled a suite of models in an attempt to understand the impacts of changing ocean conditions on this important prey item. The coastal ocean was simulated with a commonly used oceanographic model (Regional Ocean Modeling System) coupled with an ecosystem model (Nutrient, Phytoplankton, Zooplankton, Detritus). The coastal ocean was simulated from Newport, OR to Point Conception, CA over an 18-year period (1991 - 2008). These model results were used to force a 3-dimensional individual based model (IBM) that was parameterized to represent the krill species Euphausia pacifica. Biological processes of the IBM (growth, life-stage progression, mortality, reproduction, vertical migration) were compared to laboratory data and field data under varying food and temperature conditions to understand how well the model can reproduced known biological rates and processes. The model performs well at simulating growth, life stage progression, and reproduction, as these are the areas from which there is an abundance of data from which to parameterize the model. Results from simulations of larval and adult populations indicated the greatest amount growth in both larval and adult populations was over the six- month period from April through October. Mortality was greatest for larvae during the winter (when food resources are typically lowest), but mortality was greatest for adults during summer due to offshore transport of individuals to regions of warmer surface waters and reduced food concentration. Condition of individuals and mortality of individuals correlated positively with the more productive phase of the Pacific Decadal Oscillation and the North Pacific Decadal Oscillation, providing evidence the impact of ocean basin scale atmospheric conditions on krill. The impacts of atmospheric forcing on E. pacifica are important factors that control the distribution, abundance and productivity of this important prey item for many commercially important fisheries of the West Coast of the United States.
Nguyen, An T; Menemenlis, Dimitris; Kwok, Ronald (2011). Arctic ice-ocean simulation with optimized model parameters: Approach and assessment, Journal of Geophysical Research: Oceans, C4 (116), 10.1029/2010JC006573.
Title: Arctic ice-ocean simulation with optimized model parameters: Approach and assessment
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Nguyen, An T; Menemenlis, Dimitris; Kwok, Ronald
Year: 2011
Formatted Citation: Nguyen, A. T., D. Menemenlis, and R. Kwok, 2011: Arctic ice-ocean simulation with optimized model parameters: Approach and assessment. J. Geophys. Res. Ocean., 116(C4), doi:10.1029/2010JC006573
Abstract: We present an optimized 1992-2008 coupled ice-ocean simulation of the Arctic Ocean. A Green's function approach adjusts a set of parameters for best model-data agreement. Overall, model-data differences are reduced by 45%. The optimized simulation reproduces the negative trends in ice extent in the satellite records. Volume and thickness distributions are comparable to those from the Ice, Cloud, and land Elevation Satellite (2003-2008). The upper cold halocline is consistent with observations in the western Arctic. The freshwater budget of the Arctic Ocean and volume/heat transports of Pacific and Atlantic waters across major passages are comparable with observation-based estimates. We note that the optimized parameters depend on the selected atmospheric forcing. The use of the 25 year Japanese reanalysis results in sea ice albedos that are consistent with field observations. Simulated Pacific Water enters the Bering Strait and flows off the Chukchi Shelf along four distinct channels. This water takes ∼5-10 years to exit the Arctic Ocean at the Canadian Arctic Archipelago, Nares, or Fram straits. Atlantic Water entering the Fram Strait flows eastward, merges with the St Ana Trough inflow, and splits into two branches at the southwest corner of the Makarov Basin. One branch flows along Lomonosov Ridge back to Fram Strait. The other enters the western Arctic, circulates cyclonically below the halocline, and exits mainly through the Nares and Fram straits. This work utilizes the record of available observations to obtain an Arctic Ocean simulation that is in agreement with observations both within and beyond the optimization period and that can be used for tracer and process studies.
Keywords: 1910 Data assimilation, 1952 Modeling, 4207 Arctic and Antarctic oceanography, 4283 Water masses, 4540 Ice mechanics and air/sea/ice exchange proces, Arctic, data, integration and fusion, model, ocean, optimization, sea ice
Condron, Alan; Winsor, Peter (2011). A subtropical fate awaited freshwater discharged from glacial Lake Agassiz, Geophysical Research Letters, 3 (38), 10.1029/2010GL046011.
Title: A subtropical fate awaited freshwater discharged from glacial Lake Agassiz
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Condron, Alan; Winsor, Peter
Year: 2011
Formatted Citation: Condron, A., and P. Winsor, 2011: A subtropical fate awaited freshwater discharged from glacial Lake Agassiz. Geophys. Res. Lett., 38(3), doi:10.1029/2010GL046011
Abstract: The 8.2 kyr event is the largest abrupt climatic change recorded in the last 10,000 years, and is widely hypothesized to have been triggered by the release of thousands of kilometers cubed of freshwater into the North Atlantic Ocean. Using a high-resolution (1/6°) global, ocean-ice circulation model we present an alternative view that freshwater discharged from glacial Lake Agassiz would have remained on the continental shelf as a narrow, buoyant, coastal current, and would have been transported south into the subtropical North Atlantic. The pathway we describe is in contrast to the conceptual idea that freshwater from this lake outburst spread over most of the sub-polar North Atlantic, and covered the deep, open-ocean, convection regions. This coastally confined freshwater pathway is consistent with the present-day routing of freshwater from Hudson Bay, as well as paleoceanographic evidence of this event. Using a coarse-resolution (2.6°) version of the same model, we demonstrate that the previously reported spreading of freshwater across the sub-polar North Atlantic results from the inability of numerical models of this resolution to accurately resolve narrow coastal flows, producing instead a diffuse circulation that advects freshwater away from the boundaries. To understand the climatic impact of freshwater released in the past or future (e.g. Greenland and Antarctica), the ocean needs to be modeled at a resolution sufficient to resolve the dynamics of narrow, coastal buoyant flows.
Kinney, Jaclyn Clement (2011). The Bering Sea : communication with the Western subarctic gyre, mesoscale activity, shelf-basin exchange, and the flow through Bering Strait.
Title: The Bering Sea : communication with the Western subarctic gyre, mesoscale activity, shelf-basin exchange, and the flow through Bering Strait
Type: Thesis
Publication:
Author(s): Kinney, Jaclyn Clement
Year: 2011
Formatted Citation: Kinney, J. C., 2011: The Bering Sea : communication with the Western subarctic gyre, mesoscale activity, shelf-basin exchange, and the flow through Bering Strait., 142 pp. http://hdl.handle.net/10945/10780.
Abstract: A 1/12th-degree, pan-Arctic ice-ocean numerical model is used to better understand the circulation and exchanges in the Bering Sea. Understanding the physical oceanography of the Bering Sea is significant for the U.S. Navy due to the expected increase in ship traffic and exploration of natural resources that will likely coincide with the ongoing retreat of sea ice in the Western Arctic. This model represents a large step forward in the ability to simulate the mesoscale eddies and meanders in the Alaskan Stream and the deep Bering Sea basin, which are shown to exert a strong control on the flow into and out of the western Aleutian Island passes. Model results show that upwelling of deep Bering Sea water, which is the primary source of nutrients for important ecosystems of the Bering, Chukchi, and Beaufort seas, is enhanced by the presence of cyclonic eddies in the vicinity of canyons along the slope. High values of eddy kinetic energy in Bering and Anadyr straits help explain the areas of high biological productivity located just downstream in the Chirikov Basin and north of Bering Strait. Model results show significant horizontal and vertical shear in the flow through Bering Strait, and indicate a need for more observations of the flow structure on a continuous basis.
Tulloch, Ross R.; Marshall, John; Hill, Chris; Smith, K Shafer (2011). Scales, Growth Rates, and Spectral Fluxes of Baroclinic Instability in the Ocean, Journal of Physical Oceanography, 6 (41), 1057-1076, 10.1175/2011JPO4404.1.
Title: Scales, Growth Rates, and Spectral Fluxes of Baroclinic Instability in the Ocean
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Tulloch, Ross R.; Marshall, John; Hill, Chris; Smith, K Shafer
Year: 2011
Formatted Citation: Tulloch, R. R., J. Marshall, C. Hill, and K. S. Smith, 2011: Scales, Growth Rates, and Spectral Fluxes of Baroclinic Instability in the Ocean. Journal of Physical Oceanography, 41(6), 1057-1076, doi:10.1175/2011JPO4404.1
Abstract: An observational, modeling, and theoretical study of the scales, growth rates, and spectral fluxes of baroclinic instability in the ocean is presented, permitting a discussion of the relation between the local instability scale; the first baroclinic deformation scale Rdef; and the equilibrated, observed eddy scale. The geography of the large-scale, meridional quasigeostrophic potential vorticity (QGPV) gradient is mapped out using a climatological atlas, and attention is drawn to asymmetries between midlatitude eastward currents and subtropical return flows, the latter of which has westward and eastward zonal velocity shears. A linear stability analysis of the climatology, under the "local approximation," yields the growth rates and scales of the fastest-growing modes. Fastest-growing modes on eastward-flowing currents, such as the Kuroshio and the Antarctic Circumpolar Current, have a scale somewhat larger (by a factor of about 2) than Rdef. They are rapidly growing (e folding in 1-3 weeks) and deep reaching, and they can be characterized by an interaction between interior QGPV gradients, with a zero crossing in the QGPV gradient at depth. In contrast, fastest-growing modes in the subtropical return flows (as well as much of the gyre interiors) have a scale smaller than Rdef (by a factor of between 0.5 and 1), grow more slowly (e-folding scale of several weeks), and owe their existence to the interaction of a positive surface QGPV gradient and a negative gradient beneath.These predictions of linear theory under the local approximation are then compared to observed eddy length scales and spectral fluxes using altimetric data. It is found that the scale of observed eddies is some 2-3 times larger than the instability scale, indicative of a modest growth in horizontal scale. No evidence of an inverse cascade over decades in scale is found. Outside of a tropical band, the eddy scale varies with latitude along with but somewhat less strongly than Rdef.Finally, exactly the same series of calculations is carried out on fields from an idealized global eddying model, enabling study in a more controlled setting. Broadly similar conclusions are reached, thus reinforcing inferences made from the data.
Dutkiewicz, Stephanie (2011). Driving ecosystem and biogeochemical models with optimal state estimates of the ocean circulation, CLIVAR Exchanges, 1 (9).
Title: Driving ecosystem and biogeochemical models with optimal state estimates of the ocean circulation
Type: Magazine Article
Publication: CLIVAR Exchanges
Author(s): Dutkiewicz, Stephanie
Year: 2011
Formatted Citation: Dutkiewicz, S., 2011: Driving ecosystem and biogeochemical models with optimal state estimates of the ocean circulation. CLIVAR Exchanges, 9(1) https://usclivar.org/sites/default/files/Variations-V9N1-1.pdf.
Ubelmann, Clement; Fu, Lee-Lueng (2011). Vorticity Structures in the Tropical Pacific from a Numerical Simulation, Journal of Physical Oceanography, 8 (41), 1455-1464, 10.1175/2011JPO4507.1.
Title: Vorticity Structures in the Tropical Pacific from a Numerical Simulation
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Ubelmann, Clement; Fu, Lee-Lueng
Year: 2011
Formatted Citation: Ubelmann, C., and L. Fu, 2011: Vorticity Structures in the Tropical Pacific from a Numerical Simulation. Journal of Physical Oceanography, 41(8), 1455-1464, doi:10.1175/2011JPO4507.1
Abstract: The small-scale variability of the tropical Pacific is studied with the simulations from a numerical model in terms of vorticity structures. A Lagrangian method based on the Okubo-Weiss parameter is used to identify the structures and track their main characteristics. Between 8°S and 8°N, the structure characteristics are spatially inhomogeneous compared to higher latitudes. They can be grouped into three categories: anticyclonic and cyclonic structures off the equator and the equatorial structures between 2°S and 2°N. They all have a strong annual cycle with maximum presence from September to March, except during strong El Niño years, when the number of structures becomes very low. Off the equator from 2° to 8°, the anticyclonic structures dominate, but with drastically different characteristics north and south of the equator. In the north, large nonlinear vortices develop (known as the tropical instability vortices) in phase with the 30-35-day oscillation related to an unstable first-meridional-mode Rossby waves. In the south, mostly fragmentary linear structures are present, with lower propagation speeds. The equatorial structures are mostly counterclockwise. The larger ones tend to be linear and are clearly associated with Yanai waves. The large majority of the cyclonic structures off the equator are also quite linear and smaller and less numerous than the anticyclonic structures. However, some of them are nonlinear with vorticity values higher than 2 times the Coriolis parameter.
van Sebille, Erik; Baringer, Molly O.; Johns, William E.; Meinen, Christopher S.; Beal, Lisa M.; de Jong, M. Femke; van Aken, Hendrik M. (2011). Propagation pathways of classical Labrador Sea water from its source region to 26°N, Journal of Geophysical Research, C12 (116), C12027, 10.1029/2011JC007171.
Title: Propagation pathways of classical Labrador Sea water from its source region to 26°N
Type: Journal Article
Publication: Journal of Geophysical Research
Author(s): van Sebille, Erik; Baringer, Molly O.; Johns, William E.; Meinen, Christopher S.; Beal, Lisa M.; de Jong, M. Femke; van Aken, Hendrik M.
Year: 2011
Formatted Citation: van Sebille, E., M. O. Baringer, W. E. Johns, C. S. Meinen, L. M. Beal, M. F. de Jong, and H. M. van Aken, 2011: Propagation pathways of classical Labrador Sea water from its source region to 26°N. Journal of Geophysical Research, 116(C12), C12027, doi:10.1029/2011JC007171
Holloway, Greg; Nguyen, An; Wang, Zeliang (2011). Oceans and ocean models as seen by current meters, Journal of Geophysical Research: Oceans, C8 (116), 10.1029/2011JC007044.
Formatted Citation: Holloway, G., A. Nguyen, and Z. Wang, 2011: Oceans and ocean models as seen by current meters. J. Geophys. Res. Ocean., 116(C8), doi:10.1029/2011JC007044
Abstract: From a collection at 18,588 current meter locations spanning 12,825 observation years, we examine ocean circulation in terms of topostrophy. We affirm previous indications of strongly positive topostrophy toward higher latitudes, and we consider variation with depth. We explore use of the current meter data set for evaluating models skills. This is illustrated from two models applied to Arctic Ocean circulation: (1) examining the influence of successive grid refinement in a high-resolution eddy-active model and (2) assessing skill in a coarse-resolution noneddying model for which effects of unresolved eddies are parameterized. We see that finer-grid eddy-active models achieve higher topostrophy and improved skill. We find that a coarse-grid noneddying model can be improved by parameterization.
Dorman, Jeffrey G.; Powell, Thomas M.; Sydeman, William J.; Bograd, Steven J. (2011). Advection and starvation cause krill (Euphausia pacifica) decreases in 2005 Northern California coastal populations: Implications from a model study, Geophysical Research Letters, 4 (38), 10.1029/2010GL046245.
Title: Advection and starvation cause krill (Euphausia pacifica) decreases in 2005 Northern California coastal populations: Implications from a model study
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Dorman, Jeffrey G.; Powell, Thomas M.; Sydeman, William J.; Bograd, Steven J.
Year: 2011
Formatted Citation: Dorman, J. G., T. M. Powell, W. J. Sydeman, and S. J. Bograd, 2011: Advection and starvation cause krill (Euphausia pacifica) decreases in 2005 Northern California coastal populations: Implications from a model study. Geophys. Res. Lett., 38(4), doi:10.1029/2010GL046245
Formatted Citation: Lee, T. and Coauthors, 2010: Ocean state estimation for climate research. Proceedings of OceanObs'09: Sustained Ocean Observations and Information for Society (Vol. 2), J. Hall, D. E. Harrison, and D. Stammer, Eds. ESA Publication WPP-306, Venice, Italy, 21-25 September 2009 doi:10.5270/OceanObs09.cwp.55.
Menemenlis, Dimitris; Zhang, Hong; Heimbach, P; Hill, Christopher N.; Campin, Jean-Michel; Forget, Gaël; Losch, Martin; Nguyen, A; Schodlok, M (2010). Global Ocean and Sea Ice State Estimation in the Presence of Eddies, Proceedings of OceanObs'09: Sustained Ocean Observations and Information for Society (Additional Contributions), 10.5270/OceanObs09.
Title: Global Ocean and Sea Ice State Estimation in the Presence of Eddies
Type: Conference Proceedings
Publication: Proceedings of OceanObs'09: Sustained Ocean Observations and Information for Society (Additional Contributions)
Author(s): Menemenlis, Dimitris; Zhang, Hong; Heimbach, P; Hill, Christopher N.; Campin, Jean-Michel; Forget, Gaël; Losch, Martin; Nguyen, A; Schodlok, M
Year: 2010
Formatted Citation: Menemenlis, D. and Coauthors, 2010: Global Ocean and Sea Ice State Estimation in the Presence of Eddies. Proceedings of OceanObs'09: Sustained Ocean Observations and Information for Society (Additional Contributions), J. Hall, D. E. Harrison, and D. Stammer, Eds. ESA Publication WPP-306, Venice, Italy doi:10.5270/OceanObs09.
Abstract: We aim to demonstrate the feasibility and utility of global, eddying ocean and sea ice state estimation. A first synthesis for the period 1992-2002 has been obtained using a Green's functions approach. Data constraints include hydrography, altimetry, gravity, drifter, and observations of sea-ice. Although the control space is small (~80 parameters), this first globalocean and sea ice data synthesis substantially reduces large-scale biases and drifts of the model relative to observations and to the baseline integration. A second synthesis is being obtained during the ARGO-rich period using the adjoint method, which permits a much larger number of control parameters to be estimated.
Volkov, Denis L.; Fu, Lee-Lueng; Lee, Tong (2010). Mechanisms of the meridional heat transport in the Southern Ocean, Ocean Dynamics, 4 (60), 791-801, 10.1007/s10236-010-0288-0.
Formatted Citation: Volkov, D. L., L. Fu, and T. Lee, 2010: Mechanisms of the meridional heat transport in the Southern Ocean. Ocean Dynamics, 60(4), 791-801, doi:10.1007/s10236-010-0288-0
Abstract: The Southern Ocean (SO) transports heat towards Antarctica and plays an important role in determining the heat budget of the Antarctic climate system. A global ocean data synthesis product at eddy-permitting resolution from the Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2) project is used to estimate the meridional heat transport (MHT) in the SO and to analyze its mechanisms. Despite the intense eddy activity, we demonstrate that most of the poleward MHT in the SO is due to the time-mean fields of the meridional velocity, V, and potential temperature, θ. This is because the mean circulation in the SO is not strictly zonal. The Antarctic Circumpolar Current carries warm waters from the region south of the Agulhas Retroflection to the lower latitudes of the Drake Passage and the Malvinas Current carries cold waters northward along the Argentinian shelf. Correlations between the time-varying fields of V and θ (defined as transient processes) significantly contribute to the horizontal-gyre heat transport, but not the overturning heat transport. In the highly energetic regions of the Agulhas Retroflection and the Brazil-Malvinas Confluence the contribution of the horizontal transient processes to the total MHT exceeds the contribution of the mean horizontal flow. We show that the southward total MHT is mainly maintained by the meridional excursion of the mean geostrophic horizontal shear flow (i.e., deviation from the zonal average) associated with the Antarctic Circumpolar Current that balances the equatorward MHT due to the Ekman transport and provides a net poleward MHT in the SO. The Indian sector of the SO serves as the main pathway for the poleward MHT.
Volkov, Denis L.; Fu, Lee-Lueng (2010). On the Reasons for the Formation and Variability of the Azores Current, Journal of Physical Oceanography, 10 (40), 2197-2220, 10.1175/2010JPO4326.1.
Title: On the Reasons for the Formation and Variability of the Azores Current
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Volkov, Denis L.; Fu, Lee-Lueng
Year: 2010
Formatted Citation: Volkov, D. L., and L. Fu, 2010: On the Reasons for the Formation and Variability of the Azores Current. Journal of Physical Oceanography, 40(10), 2197-2220, doi:10.1175/2010JPO4326.1
Abstract: Recent studies have shown that the formation of the well-defined, zonally oriented Azores Current may be the result of water mass transformation associated with the Mediterranean outflow in the Gulf of Cadiz. As the denser Mediterranean water descends down the continental slope, it entrains overlying North Atlantic Central Water. It is believed that the Azores Current then forms as part of the horizontal recirculating gyre generated through the β-plume mechanism. In this study, the authors further explore this hypothesis by performing a series of numerical experiments. These experiments are based on a high-resolution general circulation model that includes the Mediterranean Sea and that realistically simulates the water mass exchange through the Strait of Gibraltar and the transport and variability of the Azores Current. The authors show that the divergence of the relative vorticity flux and the planetary vorticity flux, associated with planetary waves, are the main factors determining the variability of the Azores Current. It is shown experimentally that the closure of the Strait of Gibraltar leads to a complete disappearance of the Azores Current. On the other hand, with the open Strait of Gibraltar, the Azores Current persists even when the wind forcing over the region is turned off. The atmospheric forcing is thus not responsible for the formation of the Azores Current, but it affects the variability of the current with a minor effect on its magnitude. Numerical experiments suggest that the strength and the variability of the Azores Current depend on the magnitude of the water mass exchange through the Strait of Gibraltar but not on its seasonal variability.
Mcguire, A.D.; Hayes, D.J.; Kicklighter, D.W.; Manizza, M.; Zhuang, Q.; Chen, M.; Follows, Michael J.; Gurney, K.R.; Mcclelland, J.W.; Melillo, J.M.; Peterson, B.J.; Prinn, R.G. (2010). An analysis of the carbon balance of the Arctic Basin from 1997 to 2006, Tellus B: Chemical and Physical Meteorology, 5 (62), 455-474, 10.1111/j.1600-0889.2010.00497.x.
Title: An analysis of the carbon balance of the Arctic Basin from 1997 to 2006
Type: Journal Article
Publication: Tellus B: Chemical and Physical Meteorology
Author(s): Mcguire, A.D.; Hayes, D.J.; Kicklighter, D.W.; Manizza, M.; Zhuang, Q.; Chen, M.; Follows, Michael J.; Gurney, K.R.; Mcclelland, J.W.; Melillo, J.M.; Peterson, B.J.; Prinn, R.G.
Year: 2010
Formatted Citation: Mcguire, A. and Coauthors, 2010: An analysis of the carbon balance of the Arctic Basin from 1997 to 2006. Tellus B: Chemical and Physical Meteorology, 62(5), 455-474, doi:10.1111/j.1600-0889.2010.00497.x
Scotti, Alberto (2010). Large eddy simulation in the ocean, International Journal of Computational Fluid Dynamics, 10 (24), 393-406, 10.1080/10618562.2010.522527.
Publication: International Journal of Computational Fluid Dynamics
Author(s): Scotti, Alberto
Year: 2010
Formatted Citation: Scotti, A., 2010: Large eddy simulation in the ocean. International Journal of Computational Fluid Dynamics, 24(10), 393-406, doi:10.1080/10618562.2010.522527
Heimbach, Patrick; Menemenlis, Dimitris; Losch, Martin; Campin, Jean-Michel; Hill, Chris (2010). On the formulation of sea-ice models. Part 2: Lessons from multi-year adjoint sea-ice export sensitivities through the Canadian Arctic Archipelago, Ocean Modelling, 1-2 (33), 145-158, 10.1016/j.ocemod.2010.02.002.
Title: On the formulation of sea-ice models. Part 2: Lessons from multi-year adjoint sea-ice export sensitivities through the Canadian Arctic Archipelago
Type: Journal Article
Publication: Ocean Modelling
Author(s): Heimbach, Patrick; Menemenlis, Dimitris; Losch, Martin; Campin, Jean-Michel; Hill, Chris
Year: 2010
Formatted Citation: Heimbach, P., D. Menemenlis, M. Losch, J. Campin, and C. Hill, 2010: On the formulation of sea-ice models. Part 2: Lessons from multi-year adjoint sea-ice export sensitivities through the Canadian Arctic Archipelago. Ocean Modelling, 33(1-2), 145-158, doi:10.1016/j.ocemod.2010.02.002
Abstract: The adjoint of an ocean general circulation model is at the heart of the ocean state estimation system of the Estimating the Circulation and Climate of the Ocean (ECCO) project. As part of an ongoing effort to extend ECCO to a coupled ocean/sea-ice estimation system, a dynamic and thermodynamic sea-ice model has been developed for the Massachusetts Institute of Technology general circulation model (MITgcm). One key requirement is the ability to generate, by means of automatic differentiation (AD), tangent linear (TLM) and adjoint (ADM) model code for the coupled MITgcm ocean/sea-ice system. This second part of a two-part paper describes aspects of the adjoint model. The adjoint ocean and sea-ice model is used to calculate transient sensitivities of solid (ice and snow) freshwater export through Lancaster Sound in the Canadian Arctic Archipelago (CAA). The adjoint state provides a complementary view of the dynamics. In particular, the transient, multi-year sensitivity patterns reflect dominant pathways and propagation timescales through the CAA as resolved by the model, thus shedding light on causal relationships, in the model, across the Archipelago. The computational cost of inferring such causal relationships from forward model diagnostics alone would be prohibitive. The role of the exact model trajectory around which the adjoint is calculated (and therefore of the exactness of the adjoint) is exposed through calculations using free-slip vs no-slip lateral boundary conditions. Effective ice thickness, sea surface temperature, and precipitation sensitivities, are discussed in detail as examples of the coupled sea-ice/ocean and atmospheric forcing control space. To test the reliability of the adjoint, finite-difference perturbation experiments were performed for each of these elements and the cost perturbations were compared to those "predicted" by the adjoint. Overall, remarkable qualitative and quantitative agreement is found. In particular, the adjoint correctly "predicts" a seasonal sign change in precipitation sensitivities. A physical mechanism for this sign change is presented. The availability of the coupled adjoint opens up the prospect for adjoint-based coupled ocean/sea-ice state estimation.
Keywords: Adjoint modeling, Canadian Arctic Archipelago, Coupled ocean and sea-ice model, Numerical sea-ice modeling, Sea-ice export, Sensitivities, State estimation, Viscous-plastic rheology
Dushaw, Brian D.; Au, Whitlow; Beszczynska-Möller, Agnieszka; Brainard, Rusty; Cornuelle, Bruce D; Duda, Tim; Dzieciuch, Matthew; Forbes, Andrew; Freitag, Lee; Gascard, Jean-Claude; Gavrilov, Alexander; Gould, John; Howe, Bruce; Jayne, Steven R; Johannessen, Ola M; Lynch, James F; Martin, David; Menemenlis, Dimitris; Mikhalevsky, Peter; Miller, James H; Moore, Sue E; Munk, Walter H; Nystuen, Jeff; Odom, Robert I; Orcutt, John; Rossby, Tom; Sagen, Hanne; Sandven, Stein; Simmen, Jeff; Skarsoulis, Emmanuel; Southall, Brandon; Stafford, Kate; Stephen, Ralph; Vigness-Raposa, Kathleen J; Vinogradov, Sergei; Wong, Kevin B; Worcester, Peter F; Wunsch, Carl (2010). A global ocean acoustic observing network, Proceedings of OceanObs'09: Sustained Ocean Observations and Information for Society (2), 10.5270/OceanObs09.cwp.25.
Title: A global ocean acoustic observing network
Type: Conference Proceedings
Publication: Proceedings of OceanObs'09: Sustained Ocean Observations and Information for Society
Author(s): Dushaw, Brian D.; Au, Whitlow; Beszczynska-Möller, Agnieszka; Brainard, Rusty; Cornuelle, Bruce D; Duda, Tim; Dzieciuch, Matthew; Forbes, Andrew; Freitag, Lee; Gascard, Jean-Claude; Gavrilov, Alexander; Gould, John; Howe, Bruce; Jayne, Steven R; Johannessen, Ola M; Lynch, James F; Martin, David; Menemenlis, Dimitris; Mikhalevsky, Peter; Miller, James H; Moore, Sue E; Munk, Walter H; Nystuen, Jeff; Odom, Robert I; Orcutt, John; Rossby, Tom; Sagen, Hanne; Sandven, Stein; Simmen, Jeff; Skarsoulis, Emmanuel; Southall, Brandon; Stafford, Kate; Stephen, Ralph; Vigness-Raposa, Kathleen J; Vinogradov, Sergei; Wong, Kevin B; Worcester, Peter F; Wunsch, Carl
Year: 2010
Formatted Citation: Dushaw, B. D. and Coauthors, 2010: A global ocean acoustic observing network. Proceedings of OceanObs'09: Sustained Ocean Observations and Information for Society, J. Hall, D. E. Harrison, and D. Stammer, Eds. ESA Publication WPP-306, Venice, Italy, 21-25 September 2009, 2 doi:10.5270/OceanObs09.cwp.25.
Abstract:
Keywords:
ECCO Products Used: ECCO-KFS;ECCO2
URL:
Other URLs:
Baruque, Bruno; Corchado, Emilio; Mata, Aitor; Corchado, Juan M. (2010). A forecasting solution to the oil spill problem based on a hybrid intelligent system, Information Sciences, 10 (180), 2029-2043, 10.1016/j.ins.2009.12.032.
Title: A forecasting solution to the oil spill problem based on a hybrid intelligent system
Type: Journal Article
Publication: Information Sciences
Author(s): Baruque, Bruno; Corchado, Emilio; Mata, Aitor; Corchado, Juan M.
Year: 2010
Formatted Citation: Baruque, B., E. Corchado, A. Mata, and J. M. Corchado, 2010: A forecasting solution to the oil spill problem based on a hybrid intelligent system. Information Sciences, 180(10), 2029-2043, doi:10.1016/j.ins.2009.12.032
Title: State estimation of the Labrador Sea with a coupled sea ice-ocean adjoint model
Type: Thesis
Publication:
Author(s): Fenty, Ian Gouverneur
Year: 2010
Formatted Citation: Fenty, I. G., 2010: State estimation of the Labrador Sea with a coupled sea ice-ocean adjoint model., Ph.D., 277 pp. http://hdl.handle.net/1721.1/59575.
Title: Organization based multiagent architecture for distributed environments
Type: Thesis
Publication:
Author(s): Mata Conde, Aitor
Year: 2010
Formatted Citation: Mata Conde, A., 2010: Organization based multiagent architecture for distributed environments., 355 pp. http://hdl.handle.net/10366/76526.
Abstract: Distributed environments represent a complex field in which applied solutions should be flexible and include significant adaptation capabilities. These environments are related to problems where multiple users and devices may interact, and where simple and local solutions could possibly generate good results, but may not be effective with regards to use and interaction. There are many techniques that can be employed to face this kind of problems, from CORBA to multi-agent systems, passing by web-services and SOA, among others. All those methodologies have their advantages and disadvantages that are properly analyzed in this documents, to finally explain the new architecture presented as a solution for distributed environment problems. The new architecture for solving complex solutions in distributed environments presented here is called OBaMADE: Organization Based Multiagent Architecture for Distributed Environments. It is a multiagent architecture based on the organizations of agents paradigm, where the agents in the architecture are structured into organizations to improve their organizational capabilities. The reasoning power of the architecture is based on the Case-Based Reasoning methology, being implemented in a internal organization that uses agents to create services to solve the external request made by the users. The OBaMADE architecture has been successfully applied to two different case studies where its prediction capabilities have been properly checked. Those case studies have showed optimistic results and, being complex systems, have demonstrated the abstraction and generalizations capabilities of the architecture. Nevertheless OBaMADE is intended to be able to solve much other kind of problems in distributed environments scenarios. It should be applied to other varieties of situations and to other knowledge fields to fully develop its potencial.
Lee, T; Awaji, T; Balmaseda, M; Ferry, N; Fujii, Y; Fukumori, I; Giese, B; Heimbach, P; Kohl, A; Masina, S; Remy, E; Rosati, A; Schodlok, M; Stammer, D; Weaver, A (2010). Consistency and fidelity of Indonesian-throughflow total volume transport estimated by 14 ocean data assimilation products, Dynamics of Atmospheres and Oceans, 2 (50), 201-223, 10.1016/J.Dynatmoce.2009.12.004.
Title: Consistency and fidelity of Indonesian-throughflow total volume transport estimated by 14 ocean data assimilation products
Formatted Citation: Lee, T. and Coauthors, 2010: Consistency and fidelity of Indonesian-throughflow total volume transport estimated by 14 ocean data assimilation products. Dynamics of Atmospheres and Oceans, 50(2), 201-223, doi:10.1016/J.Dynatmoce.2009.12.004
Abstract: Monthly averaged total volume transport of the Indonesian throughflow (ITF) estimated by 14 global ocean data assimilation (ODA) products that are decade to multi-decade long are compared among themselves and with observations from the INSTANT Program (2004-2006). The main goals of the comparisons are to examine the consistency and evaluate the skill of different ODA products in simulating ITF transport. The ensemble averaged, time-mean value of ODA estimates is 13.6 Sv (1 Sv = 10(6) m(3)/s) for the common 1993-2001 period and 13.9 Sv for the 2004-2006 INSTANT Program period. These values are close to the 15-Sv estimate derived from INSTANT observations. All hut one ODA time-mean estimate fall within the range of uncertainty of the INSTANT estimate. In terms of temporal variability, the scatter among different ODA estimates averaged over time is 1.7 Sv, which is substantially smaller than the magnitude of the temporal variability simulated by the ODA systems. Therefore, the overall "signal-to-noise" ratio for the ensemble estimates is larger than one. The best consistency among the products occurs on seasonal-to-interannual time scales, with generally stronger (weaker) ITF during boreal summer (winter) and during La Nina (El Nino) events. The scatter among different products for seasonal-to-interannual time scales is approximately 1 Sv. Despite the good consistency, systematic difference is found between most ODA products and the INSTANT observations. All but the highest-resolution (18 km) ODA product show a dominant annual cycle while the INSTANT estimate and the 18-km product exhibit a strong semi-annual signal. The coarse resolution is an important factor that limits the level of agreement between ODA and INSTANT estimates. Decadal signals with periods of 10-15 years are seen. The most conspicuous and consistent decadal change is a relatively sharp increase in ITF transport during 1993-2000 associated with the strengthening tropical Pacific trade wind. Most products do not show a weakening ITF after the mid-1970s' associated with the weakened Pacific trade wind. The scatter of ODA estimates is smaller after than before 1980, reflecting the impact of the enhanced observations after the 1980s. To assess the representativeness of using the average over a three-year period (e.g., the span of the INSTANT Program) to describe longer-term mean, we investigate the temporal variations of the three-year low-pass ODA estimates. The average variation is about 3.6 Sv, which is largely due to the increase of ITF transport from 1993 to 2000. However, the three-year average during the 2004-2006 INSTANT Program period is within 0.5 Sv of the long-term mean for the past few decades. (C) 2010 Elsevier B.V. All rights reserved.
Keywords: circulation model, climate system, gcm, global ocean, indonesian throughflow, interannual variability, north-atlantic, ocean data assimilation, pacific, temperature
Willis, Josh K (2010). Can in situ floats and satellite altimeters detect long-term changes in Atlantic Ocean overturning?, Geophysical Research Letters, 6 (37), 10.1029/2010GL042372.
Title: Can in situ floats and satellite altimeters detect long-term changes in Atlantic Ocean overturning?
Type: Journal Article
Publication: Geophysical Research Letters
Author(s): Willis, Josh K
Year: 2010
Formatted Citation: Willis, J. K., 2010: Can in situ floats and satellite altimeters detect long-term changes in Atlantic Ocean overturning? Geophys. Res. Lett., 37(6), doi:10.1029/2010GL042372
Abstract: Global warming has been predicted to slow the Atlantic Meridional Overturning Circulation (AMOC), resulting in significant regional climate impacts across the North Atlantic and beyond. Here, satellite observations of sea surface height (SSH) along with temperature, salinity and velocity from profiling floats are used to estimate changes in the northward-flowing, upper limb of the AMOC at latitudes around 41°N. The 2004 through 2006 mean overturning is found to be 15.5 ± 2.4 Sv (106 m3/s) with somewhat smaller seasonal and interannual variability than at lower latitudes. There is no significant trend in overturning strength between 2002 and 2009. Altimeter data, however, suggest an increase of 2.6 Sv since 1993, consistent with North Atlantic warming during this same period. Despite significant seasonal to interannual fluctuations, these observations demonstrate that substantial slowing of the AMOC did not occur during the past 7 years and is unlikely to have occurred in the past 2 decades.
Scharffenberg, Martin G. (2010). The Large-Scale Geostrophic Flow-Field and Eddy Variability as seen from the TOPEX/Poseidon and Jason-1 Tandem Mission.
Title: The Large-Scale Geostrophic Flow-Field and Eddy Variability as seen from the TOPEX/Poseidon and Jason-1 Tandem Mission
Type: Thesis
Publication:
Author(s): Scharffenberg, Martin G.
Year: 2010
Formatted Citation: Scharffenberg, M. G., 2010: The Large-Scale Geostrophic Flow-Field and Eddy Variability as seen from the TOPEX/Poseidon and Jason-1 Tandem Mission., 121 pp. http://ediss.sub.uni-hamburg.de/volltexte/2010/4625/.
Abstract: Geostrophic surface velocity anomalies are used to analyze the annual variations of the large-scale geostrophic currents and of the eddy kinetic energy (EKE) field of the ocean circulation. The underlying geostrophic currents were estimated from the Jason-1 - TOPEX/Poseidon (JTP) tandem altimetric sea surface height (SSH) measurements using the "parallel-track-approach" with a 6.2 km along-track resolution. However, due to the given separation of the tracks of the two satellites, only large mesoscale eddies are resolved by the tandem measurements. The analysis covers the entire 3-year period of the tandem mission (109 repeat cycles) from September, 2002, to September, 2005. The high resolution along-track availability of the geostrophic velocity estimates allows for a spacial mapping of all quantities on a 2 ◦ × 1 ◦ grid, resulting in a doubled mapping resolution. The ocean circulation is shown to have a slightly higher meridional variability by 10 to 20 % in mid lat- itudes, while in the tropics the EKE field is dominated by the variability of the mostly zonal current field which clarifies that in some regions it can be important to assume anisotropy. Very complex structures emerge in the ratio of EKE and mean kinetic energy (MKE). How- ever, the ratio is shown to be a lower bound estimate. The investigation of the seasonal flow changes reveals annual variations of all major current systems, particularly of the zonal flow-field in low latitudes. There, they lead to zonal jet-like structures on the annual cycle in the southern Pacific, Atlantic, and Indian Ocean. In mid and high latitudes, indications of a seasonally modulated strength of the Sverdrup circulation emerge from the analysis. Noticeable in mid- and high latitudes are large changes in the wind-driven barotropic cir- culation that are not represented in other altimetric velocity products. The EKE field also shows changes in its amplitude on the annual period. In low latitudes, these can be explained by seasonally modulated currents. The strongest signals appear in the Gulf of Tehuantepec close to the Central American continent and in the Great Whirl region. On the annual period (as well as for the 3-year mean EKE), the Indian Ocean is the most energetic basin. The frequency and wavenumber spectra are shown for both geostrophic velocity components and for the EKE on global and regional scales. New insights are obtained due to the sepa- rate consideration of both velocity components such as a slightly higher energy level for the meridional component in the frequency range below 100 days over the entire extra-tropical ocean. Furthermore, strikingly universal frequency-slopes are found for all extra-tropical regions, thought containing different power spectral densities (PSD). On the aliasing fre- quencies of the M 2 and S 2 tides, peaks exist in some regions on the continental shelves that suggest an insufficient correction of the tidal signal from the FES2004 tidal model. For the wavenumber spectra, the resolution of the tandem mission becomes evident for wave- lengths shorter than 100 - 200 km. Nevertheless, new features appear for longer wavelengths such as the steeper slope for the zonal velocity component compared to the meridional. Be- sides the differences between the velocity components, nearly equal slopes are found within the wavenumber spectra of all extra-tropical regions (excluding the meridional component of the low energy regions). The slopes of the EKE wavenumber spectra indicate that the surface quasi geostrophic (SQG) turbulence theory is a better explanation than the quasi geostrophic (QG) theory for the satellite data.
Ferrari, Raffaele; Wunsch, Carl (2010). The distribution of eddy kinetic and potential energies in the global ocean, Tellus A, 2 (62), 92-108, 10.1111/j.1600-0870.2009.00432.x.
Title: The distribution of eddy kinetic and potential energies in the global ocean
Type: Journal Article
Publication: Tellus A
Author(s): Ferrari, Raffaele; Wunsch, Carl
Year: 2010
Formatted Citation: Ferrari, R., and C. Wunsch, 2010: The distribution of eddy kinetic and potential energies in the global ocean. Tellus A, 62(2), 92-108, doi:10.1111/j.1600-0870.2009.00432.x
Abstract: Understanding of the major sources, sinks, and reservoirs of energy in the ocean is briefly updated in a diagram. The nature of the dominant kinetic energy reservoir, that of the balanced variablity, is then found to be indistinguishable in the observations from a sum of barotropic and first baroclinic ordinary quasi-geostrophic modes. Little supporting evidence is available to partition the spectra among forced motions and turbulent cascades, along with significant energy more consistent with weakly non-linear wave dynamics. Linear-response wind-forced motions appear to dominate the high frequency (but subinertial) mooring frequency spectra. Turbulent cascades appear to fill the high wavenumber spectra in altimetric data and numerical simulations. Progress on these issues is hindered by the difficulty in connecting the comparatively easily available frequency spectra with the variety of theoretically predicted wavenumber spectra.
Losch, Martin; Menemenlis, Dimitris; Campin, Jean-Michel; Heimbach, Patrick; Hill, Chris (2010). On the formulation of sea-ice models. Part 1: Effects of different solver implementations and parameterizations, Ocean Modelling, 1-2 (33), 129-144, 10.1016/j.ocemod.2009.12.008.
Title: On the formulation of sea-ice models. Part 1: Effects of different solver implementations and parameterizations
Type: Journal Article
Publication: Ocean Modelling
Author(s): Losch, Martin; Menemenlis, Dimitris; Campin, Jean-Michel; Heimbach, Patrick; Hill, Chris
Year: 2010
Formatted Citation: Losch, M., D. Menemenlis, J. Campin, P. Heimbach, and C. Hill, 2010: On the formulation of sea-ice models. Part 1: Effects of different solver implementations and parameterizations. Ocean Modelling, 33(1-2), 129-144, doi:10.1016/j.ocemod.2009.12.008
Abstract: This paper describes the sea ice component of the Massachusetts Institute of Technology general circulation model (MITgcm); it presents example Arctic and Antarctic results from a realistic, eddy-admitting, global ocean and sea ice configuration; and it compares B-grid and C-grid dynamic solvers and other numerical details of the parameterized dynamics and thermodynamics in a regional Arctic configuration. Ice mechanics follow a viscous-plastic rheology and the ice momentum equations are solved numerically using either line-successive-over-relaxation (LSOR) or elastic-viscous-plastic (EVP) dynamic models. Ice thermodynamics are represented using either a zero-heat-capacity formulation or a two-layer formulation that conserves enthalpy. The model includes prognostic variables for snow thickness and for sea ice salinity. The above sea ice model components were borrowed from current generation climate models but they were reformulated on an Arakawa C grid in order to match the MITgcm oceanic grid and they were modified in many ways to permit efficient and accurate automatic differentiation. Both stress tensor divergence and advective terms are discretized with the finite-volume method. The choice of the dynamic solver has a considerable effect on the solution; this effect can be larger than, for example, the choice of lateral boundary conditions, of ice rheology, and of ice-ocean stress coupling. The solutions obtained with different dynamic solvers typically differ by a few cm s−1 in ice drift speeds, 50 cm in ice thickness, and order 200 km3 yr−1 in freshwater (ice and snow) export out of the Arctic.
Keywords: Adjoint modeling, Canadian arctic archipelago, Coupled ocean and sea ice model, EVP, Numerical sea ice modeling, Sea-ice export, Sensitivities, State estimation, Viscous-plastic rheology
Title: Sea State Bias in Radar Altimetry Revisited
Type: Journal Article
Publication: Marine Geodesy
Author(s): Hausman, Jessica; Zlotnicki, Victor
Year: 2010
Formatted Citation: Hausman, J., and V. Zlotnicki, 2010: Sea State Bias in Radar Altimetry Revisited. Marine Geodesy, 33(sup1), 336-347, doi:10.1080/01490419.2010.487804
Abstract: Sea state bias (SSB) is calculated anew for each radar altimeter. The input data are sea surface height (h) differences, separated in time by at most one repeat cycle, or the difference between measured h and a time-mean sea surface, an approach called here "differences from the mean" (DFM). In order to release data to users soon, early estimates of SSB are computed from short time series. This work has three objectives: 1) show that the DFM approach introduces spurious values in the estimated SSB, 2) quantify the SSB error caused by short time series, and 3) estimate SSB for OSTM.
Title: A coupled regional Arctic sea ice-ocean model: Configuration and application
Type: Journal Article
Publication: Chinese Journal of Polar Research
Author(s): Li, Qun; Zhang, Lu; Wu, Huiding
Year: 2010
Formatted Citation: Li, Q., L. Zhang, and H. Wu, 2010: A coupled regional Arctic sea ice-ocean model: Configuration and application. Chinese Journal of Polar Research, 22(1), 79-89, http://journal.polar.org.cn/CN/article/downloadArticleFile.do?attachType=PDF&id=9971
Abstract: A regional sea ice ocean coupled model for the Arctic Ocean was developed. The coup led model was based on the MITgcm ocean circulation model and classical H ibler79 type two category thermodynam ics 2 dynam ics sea ice model. The sea ice dynam ics was considered based on Viscous 2 Plastic (VP) . The sea ice thermodynam ics was considered based on Winton three 2 lay 2 er models. A detailed configuration of coup led model has been introduced. Special attention has been paid to the model grid setup, subgrid paramerization, ice 2 ocean coup ling and open boundary treatm ent. The coup led model was then app lied and two test run examp les were p res 2 ented. The first model run was a clim atology sim ulation w ith ten years ( 1992 - 2002 ) averaged NCAR /NCEP reanalysis data as atm ospheric forcing. The second model run was a seasonal sim ulation for the period of 1992 - 2007. The atm ospheric forcing was daily NCAR /NCEP re 2 analysis. The clim atology sim ulation cap tured the general pattern of the sea ice thickness distri 2 bution of the A rctic, i. e. , the thickest sea ice is situated around the Canada A rchipelago and the north coast of the Greenland. For the second model run, the modeled Sep tember Sea ice extent anomaly from 1992 - 2007 was highly correlated w ith the observations, w ith a linear cor 2 relation coefficient of 0. 88. The m inim um of the A rctic sea ice area in the Sep tember of 2007 was unp recedented. The modeled sea ice area and extent for this m inim um was overestim ated relative to the observations. However, it cap tured the general pattern of the sea ice retreat.
Wunsch, Carl; Heimbach, Patrick; Ponte, Rui; Fukumori, Ichiro (2009). The Global General Circulation of the Ocean Estimated by the ECCO-Consortium, Oceanography, 2 (22), 88-103, 10.5670/oceanog.2009.41.
Formatted Citation: Wunsch, C., P. Heimbach, R. Ponte, and I. Fukumori, 2009: The Global General Circulation of the Ocean Estimated by the ECCO-Consortium. Oceanography, 22(2), 88-103, doi:10.5670/oceanog.2009.41
Abstract: Following on the heels of the World Ocean Circulation Experiment, the Estimating the Circulation and Climate of the Ocean (ECCO) consortium has been directed at making the best possible estimates of ocean circulation and its role in climate. ECCO is combining state-of-the-art ocean general circulation models. with the nearly complete global ocean data sets for 1992 to present. Solutions are now available that adequately fit almost all types of ocean observations and that are, simultaneously, consistent with the model. These solutions are being applied to understanding ocean variability, biological cycles, coastal physics, geodesy, and many other areas.
Keywords: adjoint, construction, meridional overturning circulation, model, satellite altimetry, sea, sensitivity, state estimation, variability, variational data assimilation
Title: Simulated Response of the Arctic Freshwater Budget to Extreme NAO Wind Forcing
Type: Journal Article
Publication: Journal of Climate
Author(s): Condron, Alan; Winsor, Peter; Hill, Chris; Menemenlis, Dimitris
Year: 2009
Formatted Citation: Condron, A., P. Winsor, C. Hill, and D. Menemenlis, 2009: Simulated Response of the Arctic Freshwater Budget to Extreme NAO Wind Forcing. J. Clim., 22(9), 2422-2437, doi:10.1175/2008JCLI2626.1
Abstract: The authors investigate the response of the Arctic Ocean freshwater budget to changes in the North Atlantic Oscillation (NAO) using a regional-ocean configuration of the Massachusetts Institute of Technology GCM (MITgcm) and carry out several different 10-yr and 30-yr integrations. At 1/6° (∼18 km) resolution the model resolves the major Arctic transport pathways, including Bering Strait and the Canadian Archipelago. Two main calculations are performed by repeating the wind fields of two contrasting NAO years in each run for the extreme negative and positive NAO phases of 1969 and 1989, respectively. These calculations are compared both with a control run and the compiled observationally based freshwater budget estimate of Serreze et al. The results show a clear response in the Arctic freshwater budget to NAO forcing, that is, repeat NAO negative wind forcing results in virtually all freshwater being retained in the Arctic, with the bulk of the freshwater content being pooled in the Beaufort gyre. In contrast, repeat NAO positive forcing accelerates the export of freshwater out of the Arctic to the North Atlantic, primarily via Fram Strait (∼900 km3 yr−1) and the Canadian Archipelago (∼500 km3 yr−1), with a total loss in freshwater storage of ∼13 000 km3 (15%) after 10 yr. The large increase in freshwater export through the Canadian Archipelago highlights the important role that this gateway plays in redistributing the freshwater of the Arctic to subpolar seas, by providing a direct pathway from the Arctic basin to the Labrador Sea, Gulf Stream system, and Atlantic Ocean. The authors discuss the sensitivity of the Arctic Ocean to long-term fixed extreme NAO states and show that the freshwater content of the Arctic is able to be restored to initial values from a depleted freshwater state after ∼20 yr.
Keywords: Arctic, Forcing, Freshwater, North Atlantic Oscillati
Mata, Aitor; Tapia, Dante I; González, Angélica; Pérez, Belén (2009). A Contingency Response Multi-agent System for Oil Spills, 7th International Conference on PAAMS'09, 274-283.
Title: A Contingency Response Multi-agent System for Oil Spills
Type: Conference Proceedings
Publication: 7th International Conference on PAAMS'09
Formatted Citation: Mata, A., D. I. Tapia, A. González, and B. Pérez, 2009: A Contingency Response Multi-agent System for Oil Spills. 7th International Conference on PAAMS'09, Springer-Verlag, Eds., Berlin, Heidelberg, 274-283 pp.
Abstract: This paper presents CROS, a contingency response multi-agent system for oil spills situations. The system makes use of a Case-Based Reasoning system which generates predic- tions to determine the probability of finding oil slicks in certain areas of the ocean. CBR uses past information to generate new solutions to the current problem. The system employs a distri- buted multi-agent architecture so that the main components of the system can be accessed remotely. Therefore, all functionalities can communicate in a distributed way, even from mo- bile devices. The core of the system is a group of deliberative agents acting as controllers and administrators for all functionalities. The system has been used to predict real oil spill situa- tions. Results have demonstrated that the system can accurately predict the presence of oil slicks in determined zones. It has been demonstrated that using a distributed architecture can enhance the overall performance of the system.
Other URLs: https://www.arcus.org/files/search/sea-ice-outlook/2009/06/pdf/pan-arctic/combined_contributions_junereport_maydata.pdf
Corchado, Juan Manuel; Mata, Aitor; Rodriguez, Sara (2009). OSM: A Multi-Agent System for Modeling and Monitoring the Evolution of Oil Slicks in Open Oceans, Advanced Agent-Based Environmental Management Systems, 91-117, 10.1007/978-3-7643-8900-0_5.
Title: OSM: A Multi-Agent System for Modeling and Monitoring the Evolution of Oil Slicks in Open Oceans
Type: Book Section
Publication: Advanced Agent-Based Environmental Management Systems
Author(s): Corchado, Juan Manuel; Mata, Aitor; Rodriguez, Sara
Year: 2009
Formatted Citation: Corchado, J. M., A. Mata, and S. Rodriguez, 2009: OSM: A Multi-Agent System for Modeling and Monitoring the Evolution of Oil Slicks in Open Oceans. Advanced Agent-Based Environmental Management Systems, Birkhäuser Basel, 91-117, doi:10.1007/978-3-7643-8900-0_5
Mata, Aitor; Corchado, Juan Manuel (2009). Forecasting the probability of finding oil slicks using a CBR system, Expert Systems with Applications, 4 (36), 8239-8246, 10.1016/j.eswa.2008.10.003.
Title: Forecasting the probability of finding oil slicks using a CBR system
Type: Journal Article
Publication: Expert Systems with Applications
Author(s): Mata, Aitor; Corchado, Juan Manuel
Year: 2009
Formatted Citation: Mata, A., and J. M. Corchado, 2009: Forecasting the probability of finding oil slicks using a CBR system. Expert Systems with Applications, 36(4), 8239-8246, doi:10.1016/j.eswa.2008.10.003
Manizza, M; Follows, Michael J.; Dutkiewicz, Stephanie; McClelland, J W; Menemenlis, Dimitris; Hill, C N; Townsend-Small, A; Peterson, B J (2009). Modeling transport and fate of riverine dissolved organic carbon in the Arctic Ocean, Global Biogeochemical Cycles, 4 (23), 10.1029/2008GB003396.
Title: Modeling transport and fate of riverine dissolved organic carbon in the Arctic Ocean
Type: Journal Article
Publication: Global Biogeochemical Cycles
Author(s): Manizza, M; Follows, Michael J.; Dutkiewicz, Stephanie; McClelland, J W; Menemenlis, Dimitris; Hill, C N; Townsend-Small, A; Peterson, B J
Year: 2009
Formatted Citation: Manizza, M., M. J. Follows, S. Dutkiewicz, J. W. McClelland, D. Menemenlis, C. N. Hill, A. Townsend-Small, and B. J. Peterson, 2009: Modeling transport and fate of riverine dissolved organic carbon in the Arctic Ocean. Global Biogeochemical Cycles, 23(4), doi:10.1029/2008GB003396
Abstract: The spatial distribution and fate of riverine dissolved organic carbon (DOC) in the Arctic may be significant for the regional carbon cycle but are difficult to fully characterize using the sparse observations alone. Numerical models of the circulation and biogeochemical cycles of the region can help to interpret and extrapolate the data and may ultimately be applied in global change sensitivity studies. Here we develop and explore a regional, three-dimensional model of the Arctic Ocean in which, for the first time, we explicitly represent the sources of riverine DOC with seasonal discharge based on climatological field estimates. Through a suite of numerical experiments, we explore the distribution of DOC-like tracers with realistic riverine sources and a simple linear decay to represent remineralization through microbial degradation. The model reproduces the slope of the DOC-salinity relationship observed in the eastern and western Arctic basins when the DOC tracer lifetime is about 10 years, consistent with published inferences from field data. The new empirical parameterization of riverine DOC and the regional circulation and biogeochemical model provide new tools for application in both regional and global change studies.
Keywords: 4572 Upper ocean and mixed layer processes, 4805 Biogeochemical cycles, 4806 Carbon cycling, 4808 Chemical tracers, Arctic Ocean, and modelin, biogeochemical processes, ocean circulation, processes
Nguyen, A T; Menemenlis, Dimitris; Kwok, R (2009). Improved modeling of the Arctic halocline with a subgrid-scale brine rejection parameterization, Journal of Geophysical Research: Oceans, C11 (114), 10.1029/2008JC005121.
Title: Improved modeling of the Arctic halocline with a subgrid-scale brine rejection parameterization
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Nguyen, A T; Menemenlis, Dimitris; Kwok, R
Year: 2009
Formatted Citation: Nguyen, A. T., D. Menemenlis, and R. Kwok, 2009: Improved modeling of the Arctic halocline with a subgrid-scale brine rejection parameterization. J. Geophys. Res. Ocean., 114(C11), doi:10.1029/2008JC005121
Abstract: The halocline in the Arctic Ocean plays an important role in regulating heat exchange at the bottom of the mixed layer and it has a direct effect on the ocean sea ice energy balance and sea ice mass balance. Modeling the halocline, however, remains a challenge in current state-of-the-art coupled ocean sea ice models including those that participated in the Arctic Ocean Model Intercomparison Project. In this study, we successfully reproduce a cold halocline in the Canada Basin by implementing a subgrid-scale brine rejection parameterization in an ocean general circulation model. The brine rejection scheme improves the solution by redistributing surface salts rejected during sea ice formation to their neutral buoyancy depths. The depths are based on salt plume physics and published laboratory and numerical experiments. Compared with hydrographic data from 1993 to 2004, distribution of most of the rejected salt to the bottom of the mixed layer seems to yield the lowest model-data misfits. We also show that the model's mixed layer depth is sensitive to the background diffusivity ν used in the k-profile parameterization vertical mixing scheme. A background diffusivity of 10−6 m2/s in combination with brine rejection scheme described herein yield the best simulation of the Arctic halocline.
Keywords: 4255 Numerical modeling, 4536 Hydrography and tracers, 4572 Upper ocean and mixed layer processes, 9315 Arctic region, brine rejection, halocline, model
Biswas, Rupak; Tu, Eugene L.; Van Dalsem, R. William (2009). Role of High-End Computing in Meeting NASA’s Science and Engineering Challenges, Computational Fluid Dynamics 2006, 14-28, 10.1007/978-3-540-92779-2_2.
Title: Role of High-End Computing in Meeting NASA’s Science and Engineering Challenges
Type: Book Section
Publication: Computational Fluid Dynamics 2006
Author(s): Biswas, Rupak; Tu, Eugene L.; Van Dalsem, R. William
Year: 2009
Formatted Citation: Biswas, R., E. L. Tu, and R. W. Van Dalsem, 2009: Role of High-End Computing in Meeting NASA's Science and Engineering Challenges. Computational Fluid Dynamics 2006, Springer Berlin Heidelberg, 14-28, doi:10.1007/978-3-540-92779-2_2
Abstract: High-end computing (HEC) has always played a major role in meeting the modeling and simulation needs of various NASA missions. Two years ago, NASA was on the verge of dramatically enhancing its HEC capability and capacity by significantly increasing its computational and storage resources. With the 10,240-processor Columbia supercomputer in production since Oc- tober 2004, HEC is having an even greater impact within the Agency and beyond. Advanced science and engineering simulations in space exploration, Shuttle operations, Earth sciences, and fundamental aeronautics research are occurring on Columbia, demonstrating its ability to accelerate NASA's ex- ploration vision. This paper describes how the integrated production environ- ment fostered at the NASA Advanced Supercomputing (NAS) facility at Ames Research Center is reducing design cycle times, accelerating scientific discov- ery, achieving rapid parametric analyses of multiple scenarios, and enhancing safety for several NASA missions. We focus on Columbia's impact on two key engineering and science disciplines: aerospace, and climate/weather. We also discuss future mission challenges and plans for NASA's next-generation HEC environment.
Fu, Lee-Lueng (2009). Pattern and velocity of propagation of the global ocean eddy variability, Journal of Geophysical Research, C11 (114), C11017, 10.1029/2009JC005349.
Title: Pattern and velocity of propagation of the global ocean eddy variability
Type: Journal Article
Publication: Journal of Geophysical Research
Author(s): Fu, Lee-Lueng
Year: 2009
Formatted Citation: Fu, L., 2009: Pattern and velocity of propagation of the global ocean eddy variability. Journal of Geophysical Research, 114(C11), C11017, doi:10.1029/2009JC005349
Abstract: Satellite altimeter data are used to study the characteristics of the horizontal propagation of eddy variability of the global oceans. Decade-long time series of sea surface height is analyzed for finding the maximum cross correlation with neighboring time series within a window of space and time lags. The space and time lags corresponding to the maximum correlation allow an estimate of the propagation velocity of the eddy variability that dominates the variance of sea surface height anomalies. The method cannot distinguish the various forms of eddy variability: isolated eddies and fronts, the meandering of ocean currents, or planetary waves. However, the results provide, at a given location of the global oceans, a uniquely determined propagation velocity that represents a time-averaged description of the tendency of the movement of the local eddy variability. The propagation velocity is highly inhomogeneous in space. Outside the equatorial zone, the zonal propagation is intrinsically westward, modified by ocean currents, which could reverse the zonal propagation to eastward in regions like the Gulf Stream and the Antarctic Circumpolar Current. At midlatitudes and high latitudes, the propagation pattern is highly affected by the path of ocean currents and the shape of bottom topography. At tropical latitudes, the meridional propagation is convergent toward the equator in the western basins and divergent away from the equator in the eastern basins. Comparison with the simulations of an eddy-permitting ocean general circulation model shows overall agreement, especially in the latitudinal variation of the zonal propagation velocity. The result suggests that the model has captured the essence of the dynamics governing the propagation of ocean eddy variability.
Formatted Citation: Galton-Fenzi, B. K., 2009: Modelling ice-shelf/ocean interaction., 151 pp. https://eprints.utas.edu.au/19882/1/whole_Galton-FenziBenjaminKeith2009_thesis.pdf.
Abstract: The effect of climate change on the mass balance of ice shelves and bottom water formation is investigated using a terrain-following three-dimensional numerical ocean model. The Regional Ocean Modeling System was modified to simulate the thermodynamic processes beneath ice shelves, including direct basal processes and frazil ice dynamics. Process-orientated studies of simplified ice-shelf-ocean cavities investigate the sensitivity of the melting/freezing to the various parametrisations which describe the internal physics of the models. The Amery Ice Shelf/ocean model is forced with tides, seasonal winds and relaxation to seasonal lateral boundary climatologies. The open ocean surface fluxes are modified by an imposed climatological sea-ice cover that includes the seasonal effect of polynyas. The circulation and basal melting and freezing show good agreement with glaciological and oceanographic observations that have been collected from beneath the Amery Ice Shelf via boreholes through the ice and in the adjacent area of Prydz Bay. Strong horizontal and thermohaline ("ice-pump") circulation is primarily driven by melting and refreezing of the ice shelf. The net basal melt rate is - 45 Gt year (- 0.7 m year -1 ), which represents 67 % of the total mass loss of the Amery Ice Shelf. The total amount of refreezing is - 5.3 Gt year -1 , of which 70 % is due to frazil accretion. The seasonal variability of the basal melt/freeze (up to ±1 m year -1 ) within 100 km of the open ocean is the same magnitude as the area-averaged melt rates. The annual averaged bottom water formation rates are r-1.2 Sv to the west of the Amery, in the vicinity of Cape Darnley. The Amery Ice Shelf/ocean model is used to investigate the sensitivity of the basal melt/freeze and bottom water formation to the inclusion of various physical mechanisms and changes in forcing. Direct comparison with glaciological observations shows that ice-shelf models that include frazil processes improve the simulated pattern of marine ice accretion. Simulations without ice-shelf/ocean thermodynamic processes overestimate bottom water formation by up to 2.8 times as much as simulations with ice-shelf/ocean thermodynamic processes, due to the missing buoyant freshwater from the melting ice shelf. Climate change sensitivity studies suggest that an ocean warming of 1°C above present day temperatures can potentially remove the Amery Ice Shelf in -500 years, solely due to increased basal melting, and can also lead to a significant decrease in the formation of bottom water. This research contributes to understanding how interaction between ice shelves and various forcing mechanisms can lead to changes in basal melt/freeze and dense water formation, which has major implications for the stability of ice shelves, sea level rise, and the salt budget of the global oceans.
Mata, Ai; Perez, B; Corchado, E; Bajo, J (2009). Organization based system for oceanographic monitoring, 2009 12th International Conference on Information Fusion, 968-975.
Title: Organization based system for oceanographic monitoring
Type: Conference Proceedings
Publication: 2009 12th International Conference on Information Fusion
Formatted Citation: Mata, A., B. Perez, E. Corchado, and J. Bajo, 2009: Organization based system for oceanographic monitoring. 2009 12th International Conference on Information Fusion, 968-975 pp.
Abstract: Objectives: Last years registered an increment in the number of endovascular procedures. Traditional carotid endoarterectomy (CEA) is the most performed surgical treatment for carotid stenosis. In symptomatic patients CEA reduces significantly absolute relative risk of stroke and death. In asymptomatic patients AHA guidelines recommend CEA for stenosis 60-99%, if the risk of peri-operative stroke or death is <3%. According to 2007 Clinical Expert Consensus Document Carotid Artery Stenting (CAS) should be used in patients at high-risk for CEA or into controlled trials and Cochrane Database of Systematic Reviews does not support a widespread change in clinical practice away from recommending CEA as the treatment of choice for suitable carotid artery stenosis. Methods: Large series about CEA, published in the last years, show a trend about a sensible reduction of neurologic complications or death, even below one percent. Several studies have been addressed to evaluate relative role of CEA and CAS. In carotid occlusive disease treatment SPACE and EVA-3S failed to demonstrate superiority of CAS vs. CEA. More studies are still enrolling patients but some of them, as WALLSTENT, SAPPHIRE, SPACE and EVA-3S, have been stopped for excessive complication rate in the CAS limb independently from patient subset and EDP stent. Results: Although the impact on stroke remains unestablished, results are consistent with a clinically important increase in stroke risk with CAS, an intervention that aims at reducing the risk of stroke 2 In a recent review of 32 studies comprising CAS and CEA, the incidence of any new Diffusion-Weighted Imaging lesion was significantly higher after CAS (37%) than after CEA (10%). After two years' follow-up SPACE trial showed as the rate of recurrent ipsilateral ischaemic strokes is similar for both treatment groups and the incidence of recurrent carotid stenosis is significantly higher after CAS. EVA 3S after four years' follow-up showed that cumulative probability of periprocedural stroke or death and non-procedural ipsilateral stroke was higher with CAS. After the periprocedural period, the risk of ipsilateral stroke was low and similar in both treatment groups. Open question regarding CEA still exist in particular about shunt, technique and anaesthesia. Conclusions: Today CEA is the best treatment until uncontroindicated. Current data, Cochrane and AHA support CAS procedures for TRIALS enrollment or for CEA contraindications. Indications both CEA or CAS should have the same criteria. For asymptomatic patients still remain debate in the choice of CEA, CAS or best medical treatment.
Veneziani, M.; Edwards, C. A.; Doyle, J. D.; Foley, D. (2009). A central California coastal ocean modeling study: 1. Forward model and the influence of realistic versus climatological forcing, Journal of Geophysical Research, C4 (114), C04015, 10.1029/2008JC004774.
Title: A central California coastal ocean modeling study: 1. Forward model and the influence of realistic versus climatological forcing
Type: Journal Article
Publication: Journal of Geophysical Research
Author(s): Veneziani, M.; Edwards, C. A.; Doyle, J. D.; Foley, D.
Year: 2009
Formatted Citation: Veneziani, M., C. A. Edwards, J. D. Doyle, and D. Foley, 2009: A central California coastal ocean modeling study: 1. Forward model and the influence of realistic versus climatological forcing. Journal of Geophysical Research, 114(C4), C04015, doi:10.1029/2008JC004774
Formatted Citation: Kwok, R., E. C. Hunke, W. Maslowski, D. Menemenlis, and J. Zhang, 2008: Variability of sea ice simulations assessed with RGPS kinematics. J. Geophys. Res. Ocean., 113(C11), doi:10.1029/2008JC004783
Abstract: Sea ice drift and deformation from coupled ice-ocean models are compared with high-resolution ice motion from the RADARSAT Geophysical Processor System (RGPS). In contrast to buoy drift, the density and extent of the RGPS coverage allows a more extensive assessment and understanding of model simulations at spatial scales from ∼10 km to near basin scales and from days to seasonal timescales. This work illustrates the strengths of the RGPS data set as a basis for examining model ice drift and its gradients. As it is not our intent to assess relative performance, we have selected four models with a range of attributes and grid resolution. Model fields are examined in terms of ice drift, export, deformation, deformation-related ice production, and spatial deformation patterns. Even though the models are capable of reproducing large-scale drift patterns, variability among model behavior is high. When compared to the RGPS kinematics, the characteristics shared by the models are (1) ice drift along coastal Alaska and Siberia is slower, (2) the skill in explaining the time series of regional divergence of the ice cover is poor, and (3) the deformation-related volume production is consistently lower. Attribution of some of these features to specific causes is beyond our current scope because of the complex interplay between model processes, parameters, and forcing. The present work suggests that high-resolution ice drift observations, like those from the RGPS, would be essential for future model developments, improvements, intercomparisons, and especially for evaluation of the small-scale behavior of models with finer grid spacing.
Campin, Jean-Michel; Marshall, J; Ferreira, D (2008). Sea ice-ocean coupling using a rescaled vertical coordinate z*, Ocean Modelling, 1-2 (24), 1-14, 10.1016/j.ocemod.2008.05.005.
Title: Sea ice-ocean coupling using a rescaled vertical coordinate z*
Type: Journal Article
Publication: Ocean Modelling
Author(s): Campin, Jean-Michel; Marshall, J; Ferreira, D
Year: 2008
Formatted Citation: Campin, J., J. Marshall, and D. Ferreira, 2008: Sea ice-ocean coupling using a rescaled vertical coordinate z*. Ocean Modelling, 24(1-2), 1-14, doi:10.1016/j.ocemod.2008.05.005
Abstract: Realistic representation of sea ice in ocean models involves the use of a non-linear free-surface, a real freshwater flux and observance of requisite conservation laws. We show here that these properties can be achieved in practice through use of a rescaled vertical coordinate "z*" in z-coordinate models that allows one to follow undulations in the free-surface under sea ice loading. In particular, the adoption of "z*" avoids the difficult issue of vanishing levels under thick ice. Details of the implementation within MITgcm are provided. A high resolution global ocean sea ice simulation illustrates the robustness of the z* formulation and reveals a source of oceanic variability associated with sea ice dynamics and ice-loading effects. The use of the z* coordinate allows one to achieve perfect conservation of fresh water, heat and salt, as shown in extended integration of coupled ocean sea ice atmospheric model. (C) 2008 Elsevier Ltd. All rights reserved.
Losch, Martin (2008). Modeling ice shelf cavities in a z coordinate ocean general circulation model, Journal of Geophysical Research, C8 (113), C08043, 10.1029/2007JC004368.
Title: Modeling ice shelf cavities in a z coordinate ocean general circulation model
Type: Journal Article
Publication: Journal of Geophysical Research
Author(s): Losch, Martin
Year: 2008
Formatted Citation: Losch, M., 2008: Modeling ice shelf cavities in a z coordinate ocean general circulation model. Journal of Geophysical Research, 113(C8), C08043, doi:10.1029/2007JC004368
Abstract: Processes at the ice shelf-ocean interface and in particular in ice shelf cavities around Antarctica have an observable effect on the solutions of basin scale to global coupled ice-ocean models. Despite this, these processes are not routinely represented in global ocean and climate models. It is shown that a new ice shelf cavity model for z coordinate models can reproduce results from an intercomparison project of earlier approaches with vertical σ or isopycnic coordinates. As a proof of concept, ice shelves are incorporated in a 100-year global integration of a z coordinate model. In this simulation, glacial meltwater can be traced as far as north as 15°S. The observed effects of processes in the ice shelf cavities agree with previous results from a σ coordinate model, notably the increase in sea ice thickness. However, melt rates are overestimated probably because the parameterization of basal melting does not suit the low resolution of this configuration.
Keywords: 1223 Ocean/Earth/atmosphere/hydrosphere/cryosphere, 4207 Arctic and Antarctic oceanography, 4255 Numerical modeling, 4532 General circulation, Ice shelf cavities, numerical ocean modeling, z coordinates
Other URLs: http://doi.wiley.com/10.1029/2007JC004368
Marshall, John; Plumb, R. Alan (2008). Atmosphere, Ocean and Climate Dynamics.
Title: Atmosphere, Ocean and Climate Dynamics
Type: Book
Publication:
Author(s): Marshall, John; Plumb, R. Alan
Year: 2008
Formatted Citation: Marshall, J., and R. A. Plumb, 2008: Atmosphere, Ocean and Climate Dynamics. Academic Press, 344 pp.
Abstract: For advanced undergraduate and beginning graduate students in atmospheric, oceanic, and climate science, Atmosphere, Ocean and Climate Dynamics is an introductory textbook on the circulations of the atmosphere and ocean and their interaction, with an emphasis on global scales. It will give students a good grasp of what the atmosphere and oceans look like on the large-scale and why they look that way. The role of the oceans in climate and paleoclimate is also discussed. The combination of observations, theory and accompanying illustrative laboratory experiments sets this text apart by making it accessible to students with no prior training in meteorology or oceanography.
Keywords:
ECCO Products Used: ECCO2
URL:
Other URLs:
Davis, Xujing Jia (2008). Numerical and theoretical investigations of North Pacific subtropical mode water with implications to Pacific climate variability.
Title: Numerical and theoretical investigations of North Pacific subtropical mode water with implications to Pacific climate variability
Type: Thesis
Publication:
Author(s): Davis, Xujing Jia
Year: 2008
Formatted Citation: Davis, X. J., 2008: Numerical and theoretical investigations of North Pacific subtropical mode water with implications to Pacific climate variability. https://digitalcommons.uri.edu/dissertations/AAI3328720/.
Abstract: An investigation using a combined numerical modeling and theoretical approach is followed to better resolve the role of Subtropical Mode Water (STMW) in the exchange of information between the atmosphere and the ocean linked to climate variability in the North Pacific Ocean. In this, a High resolution MIT General Circulation Model (MITgcm) simulation is analyzed to study the formation, isolation, dispersal of STMW and identify correlations between STMW variations and established climatic signals in the Pacific basin. During a 171-month time period (from January 1992 to March 2006), the seasonal variability is the dominant temporal variation observed. From climatological model fields, STMW exhibits distinct features in time and space. This can be seen more clearly by dividing the cycle into three distinct time periods: the formation, the isolation and the dissipation periods. In addition to seasonality there is also an interannual signal observed in STMW variability. This interannual variation pattern is connected closely to the climate shifts of North Pacific with further investigation showing that there is a high correlation between the STMW variability and the Pacific Decadal Oscillation index. To identify the mechanisms responsible for this interannual STMW variability, classical ocean thermocline theories are reviewed and STMW connections to large scale ocean circulation patterns are explored. A planetary geostrophic ocean model (PGOM) is employed as a theoretical platform for this purpose. Specifically, numerical PGOM experiments are performed to isolate and examine in further detail, the influence of variations of the large scale wind stress pattern and large scale air-sea heat flux on STMW variability. It may be gathered from these experiments that large scale wind stress patterns responsible for Ekman pumping are necessary for the generation of STMW in this ventilated thermocline scheme in the PGOM. Variability in this large scale wind stress is seen to affect the variability pattern of model STMW. Yet, results also indicate that the amplitude of seasonal and interannual variability of STMW volume is primarily dominated by the variability in the air-sea heat flux.
Volkov, Denis L.; Fu, Lee-Lueng (2008). The role of vorticity fluxes in the dynamics of the Zapiola Anticyclone, Journal of Geophysical Research: Oceans, C11 (113), 10.1029/2008JC004841.
Title: The role of vorticity fluxes in the dynamics of the Zapiola Anticyclone
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Volkov, Denis L.; Fu, Lee-Lueng
Year: 2008
Formatted Citation: Volkov, D. L., and L. Fu, 2008: The role of vorticity fluxes in the dynamics of the Zapiola Anticyclone. J. Geophys. Res. Ocean., 113(C11), doi:10.1029/2008JC004841
Abstract: The Argentine Basin in the South Atlantic Ocean is one of the most energetic regions in the ocean with complicated dynamics, which plays an important role in the global climate. A number of observations have discovered an intense anticyclonic gyre of barotropic circulation around the Zapiola Rise in the center of the basin. Theoretical studies have shown that the Zapiola Anticyclone represents an eddy-driven flow controlled by bottom friction. Recent advances in high-resolution global-ocean data syntheses, performed using NASA supercomputing facilities, provide realistic simulations of the circulation and the variability in the Argentine Basin. Using these simulations and satellite altimeter observations, we analyzed the vorticity balance of the Zapiola Anticyclone. Our results suggest the dominance of vorticity fluxes and the advection of the potential vorticity over a nonuniform bottom topography in determining the variability of the gyre, while the impact of the local wind stress is small. The divergence of the relative vorticity anomaly advection by eddies is found to be the most important contributor to the relative vorticity flux divergence influencing the variability of the Zapiola Anticyclone. Our results demonstrate that the relative vorticity influencing the variability of the anticyclone is mainly advected from the south where the northern branch of the Antarctic Circumpolar Current at the Subpolar Front is located.
Keywords: 4255 Numerical modeling, 4277 Time series experiments, 4512 Currents, 4520 Eddies and mesoscale processes, 4532 General circulation, Vorticity fluxes, Zapiola Anticyclone
Title: Can Large Eddy Simulation Techniques Improve Mesoscale Rich Ocean Models?
Type: Book Section
Publication: Ocean Modeling in an Eddying Regime
Author(s): Fox-Kemper, B; Menemenlis, Dimitris
Year: 2008
Formatted Citation: Fox-Kemper, B., and D. Menemenlis, 2008: Can Large Eddy Simulation Techniques Improve Mesoscale Rich Ocean Models?. Ocean Modeling in an Eddying Regime, American Geophysical Union, 319-337, doi:10.1029/177GM19
Abstract: This chapter contains sections titled: * Introduction * Nonlinear Viscosities and diffusivities * Filtering and Dynamical Adjustment * Summary and Discussion
Losch, Martin; Schröder, Michael; Hohn, Sönke; Völker, Christoph (2008). High-Resolution Modelling of Phytoplankton Distribution and Adaptation, John von Neumann Institute for Computing Symposium 2008 (39), 289-296.
Title: High-Resolution Modelling of Phytoplankton Distribution and Adaptation
Type: Conference Proceedings
Publication: John von Neumann Institute for Computing Symposium 2008
Author(s): Losch, Martin; Schröder, Michael; Hohn, Sönke; Völker, Christoph
Year: 2008
Formatted Citation: Losch, M., M. Schröder, S. Hohn, and C. Völker, 2008: High-Resolution Modelling of Phytoplankton Distribution and Adaptation. John von Neumann Institute for Computing Symposium 2008, 39, 289-296 pp.
Abstract: A state-of-the-art eddy-resolving ocean general circulation model has been coupled to a newly developed ecosystem and biogeochemical model that attempts to describe the physiology of phytoplankton cells, their adaptation to changing external conditions and the separate cycling of several phytoplankton nutrients (C, N, Si, Fe). In its initial state the advection of a large number of tracers in the model caused an increase in MPI-exchange costs that inhibited a good scaling behaviour with increasing number of processors used. This has been overcome by bundling the MPI exchange for all tracers. First results from the model show a much improved representation of small-scale biological features, e.g. along the axis of the Antarctic Circumpolar Current, a decoupling of the C and N cycles in nitrogen-limited subpolar gyres, and an increased Si:N ratio in iron-limited regions.
Keywords: Global ocean
ECCO Products Used: ECCO2
URL:
Other URLs:
Corchado, Juan Manuel; Mata, Aitor (2008). Predicting the Presence of Oil Slicks After an Oil Spill, Advances in Case-Based Reasoning, 573-586, 10.1007/978-3-540-85502-6_39.
Title: Predicting the Presence of Oil Slicks After an Oil Spill
Type: Book Section
Publication: Advances in Case-Based Reasoning
Author(s): Corchado, Juan Manuel; Mata, Aitor
Year: 2008
Formatted Citation: Corchado, J. M., and A. Mata, 2008: Predicting the Presence of Oil Slicks After an Oil Spill. Advances in Case-Based Reasoning, Springer Berlin Heidelberg, 573-586, doi:10.1007/978-3-540-85502-6_39
Formatted Citation: Volkov, D. L., T. Lee, and L. Fu, 2008: Eddy-induced meridional heat transport in the ocean. Geophys. Res. Lett., 35(20), doi:10.1029/2008GL035490
Abstract: A global ocean data synthesis product at eddy-permitting resolution from Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2) project are used to estimate the oceanic eddy heat transport. We show that in a number of locations the time-mean eddy heat transport constitutes a considerable portion of the total time-mean heat transport, in particular, in the tropics, in the Southern Ocean and in the Kuroshio Current. This research demonstrates that the variability of the eddy heat transport is a significant contributor to the variability of the total heat transport and globally it explains about 1/3 of its variance. Eddies are also found to explain a significant portion of the seasonal-interannual heat transport variance.
Keywords: 4215 Climate and interannual variability, 4255 Numerical modeling, 4520 Eddies and mesoscale processes, 4532 General circulation, eddy heat transport, oceanic heat transport
Haine, Thomas; Böning, Claus; Brandt, Peter; Fischer, Jürgen; Funk, Andreas; Kieke, Dagmar; Kvaleberg, Erik; Rhein, Monika; Visbeck, Martin (2008). North Atlantic Deep Water Formation in the Labrador Sea, Recirculation Through the Subpolar Gyre, and Discharge to the Subtropics, Arctic-Subarctic Ocean Fluxes, 653-701, 10.1007/978-1-4020-6774-7_28.
Formatted Citation: Haine, T. and Coauthors, 2008: North Atlantic Deep Water Formation in the Labrador Sea, Recirculation Through the Subpolar Gyre, and Discharge to the Subtropics. Arctic-Subarctic Ocean Fluxes, Springer Netherlands, 653-701, doi:10.1007/978-1-4020-6774-7_28
Menemenlis, Dimitris; Campin, Jean-Michel; Heimbach, Patrick; Hill, Christopher N.; Lee, Tong; Nguyen, An T.; Schodlok, Michael P.; Zhang, Hong (2008). ECCO2: High Resolution Global Ocean and Sea Ice Data Synthesis, Mercator Ocean Quarterly Newsletter (31), 13-21.
Title: ECCO2: High Resolution Global Ocean and Sea Ice Data Synthesis
Type: Journal Article
Publication: Mercator Ocean Quarterly Newsletter
Author(s): Menemenlis, Dimitris; Campin, Jean-Michel; Heimbach, Patrick; Hill, Christopher N.; Lee, Tong; Nguyen, An T.; Schodlok, Michael P.; Zhang, Hong
Year: 2008
Formatted Citation: Menemenlis, D., J. Campin, P. Heimbach, C. N. Hill, T. Lee, A. T. Nguyen, M. P. Schodlok, and H. Zhang, 2008: ECCO2: High Resolution Global Ocean and Sea Ice Data Synthesis. Mercator Ocean Quarterly Newsletter, 31, 13-21
Abstract:
Keywords:
ECCO Products Used: ECCO2;SeaIce
URL:
Other URLs:
Hill, Chris; Menemenlis, Dimitris; Ciotti, Bob; Henze, Chris (2007). Investigating Solution Convergence in a Global Ocean Model Using a 2048-Processor Cluster of Distributed Shared Memory Machines, Scientific Programming, 2 (15), 10.1155/2007/458463.
Title: Investigating Solution Convergence in a Global Ocean Model Using a 2048-Processor Cluster of Distributed Shared Memory Machines
Type: Journal Article
Publication: Scientific Programming
Author(s): Hill, Chris; Menemenlis, Dimitris; Ciotti, Bob; Henze, Chris
Year: 2007
Formatted Citation: Hill, C., D. Menemenlis, B. Ciotti, and C. Henze, 2007: Investigating Solution Convergence in a Global Ocean Model Using a 2048-Processor Cluster of Distributed Shared Memory Machines. Scientific Programming, 15(2), doi:10.1155/2007/458463
Köhl, A; Stammer, D; Cornuelle, B (2007). Interannual to Decadal Changes in the ECCO Global Synthesis, Journal of Physical Oceanography, 2 (37), 313-337, 10.1175/JPO3014.1.
Title: Interannual to Decadal Changes in the ECCO Global Synthesis
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Köhl, A; Stammer, D; Cornuelle, B
Year: 2007
Formatted Citation: Köhl, A., D. Stammer, and B. Cornuelle, 2007: Interannual to Decadal Changes in the ECCO Global Synthesis. Journal of Physical Oceanography, 37(2), 313-337, doi:10.1175/JPO3014.1
Abstract: An estimate of the time-varying global ocean circulation for the period 1992 - 2002 was obtained by combining most of the World Ocean Circulation Experiment ( WOCE) ocean datasets with a general circulation model on a 1 horizontal grid. The estimate exactly satisfies the model equations without artificial sources or sinks of momentum, heat, and freshwater. To bring the model into agreement with observations, its initial temperature and salinity conditions were permitted to change, as were the time-dependent surface fluxes of momentum, heat, and freshwater. The estimation of these "control variables" is largely consistent with accepted uncertainties in the hydrographic climatology and meteorological analyses. The estimated time-mean horizontal transports of volume, heat, and freshwater, which were largely underestimated in the previous 2 optimization performed by Stammer et al., have converged with time-independent estimates from box inversions over most parts of the World Ocean. Trends in the model's heat content are 7% larger than those reported by Levitus and correspond to a global net heat uptake of about 1.1 W m(-2) over the model domain. The associated model trend in sea surface height over the estimation period resembles the observations from Ocean Topography Experiment ( TOPEX)/Poseidon over most of the global ocean. Sea surface height changes in the model are primarily steric but show contributions from mass redistributions from the subpolar North Atlantic Ocean and the Southern Ocean to the subtropical Pacific Ocean gyres. Steric contributions are primarily temperature based but are partly compensated by salt variation. However, the North Atlantic and the Southern Ocean reveal a clear contribution of salt to large-scale sea level variations.
Title: Spatial Mapping of Time-Variable Errors in Jason-1 and TOPEX/Poseidon Sea Surface Height Measurements
Type: Journal Article
Publication: Journal of Atmospheric and Oceanic Technology
Author(s): Ponte, Rui M; Wunsch, Carl; Stammer, Detlef
Year: 2007
Formatted Citation: Ponte, R. M., C. Wunsch, and D. Stammer, 2007: Spatial Mapping of Time-Variable Errors in Jason-1 and TOPEX/Poseidon Sea Surface Height Measurements. Journal of Atmospheric and Oceanic Technology, 24(6), 1078-1085, doi:10.1175/JTECH2029.1
Abstract: Fitting ocean models to altimeter sea surface height (SSH) measurements requires knowledge of instrument noise (radar noise, sea state bias, path delay corrections, and orbit errors) and "representation" errors related to SSH signals (e.g., tidal or pressure driven) not computed in the models. Comparisons between the independent Ocean Topography Experiment (TOPEX)/Poseidon and Jason-1 altimetric missions when they were in identical orbits show that point by point the data are consistent within the mission specifications of about 3-cm rms, but large-scale dependences exist in the data differences, and these are both poorly known and capable of introducing major errors into oceanic state estimates. Here the authors focus on the time-variable component of the spatially dependent errors. The analysis reveals errors ranging from 2 cm in the Tropics to 4 cm at mid- and high latitudes and roughly consistent with a dependence of instrument noise on significant wave height. Analysis of the representation errors suggests that, over the deep ocean, uncertainties associated with the simplifying assumption of an inverted barometer response to pressure loading are larger than the remaining errors in modeling the large-scale tides. Over extensive regions, however, errors associated with eddy signals missing in coarse resolution models dominate. Obtaining a more quantitative estimate of the latter errors remains a challenge.
Forget, G; Wunsch, C (2007). Estimated global hydrographic variability, Journal of Physical Oceanography, 8 (37), 1997-2008, 10.1175/jpo3072.1.
Title: Estimated global hydrographic variability
Type: Journal Article
Publication: Journal of Physical Oceanography
Author(s): Forget, G; Wunsch, C
Year: 2007
Formatted Citation: Forget, G., and C. Wunsch, 2007: Estimated global hydrographic variability. Journal of Physical Oceanography, 37(8), 1997-2008, doi:10.1175/jpo3072.1
Abstract: An estimate is made of the three-dimensional global oceanic temperature and salinity variability, omitting the seasonal cycle, both as a major descriptive element of the ocean circulation and for use in the error estimates of state estimation. Historical erformance of GOhydrography, recent data from the World Ocean Circulation Experiment, and Argo profile data are all used. Root-mean-square vertical displacements in the upper 300 m of the ocean are generally smaller than 50 m, except in energetic boundary currents and in the North Atlantic subpolar gyre. Variability in temperature and salinity is strongly correlated below the top 100 m. Salinity contributions to sea surface height variability appear more significant at low latitudes than expected, possibly resulting from advective and diffusive processes. Results are generally consistent with altimetric variability under two simple kinematic hypotheses, and much of the observed structure coincides with known dynamical features. A large fraction of the sea surface height variability is consistent with the hypothesis of dominance of the first baroclinic mode.
Sachs, Julian P. (2007). Cooling of Northwest Atlantic slope waters during the Holocene, Geophysical Research Letters, 3 (34), L03609, 10.1029/2006GL028495.
Formatted Citation: Wunsch, C., and P. Heimbach, 2007: Practical global oceanic state estimation. Physica D: Nonlinear Phenomena, 230(1-2), 197-208, doi:10.1016/j.physd.2006.09.040
Abstract: The problem of oceanographic state estimation, by means of an ocean general circulation model (GCM) and a multitude of observations, is described and contrasted with the meteorological process of data assimilation. In practice, all such methods reduce, on the computer, to forms of least-squares. The global oceanographic problem is at the present time focussed primarily on smoothing, rather than forecasting, and the data types are unlike meteorological ones. As formulated in the consortium Estimating the Circulation and Climate of the Ocean (ECCO), an automatic differentiation tool is used to calculate the so-called adjoint code of the GCM, and the method of Lagrange multipliers used to render the problem one of unconstrained least squares minimization. Major problems today lie less with the numerical algorithms (least-squares problems can be solved by many means) than with the issues of data and model error. Results of ongoing calculations covering the period of the World Ocean Circulation Experiment, and including among other data, satellite altimetry from TOPEX/POSEIDON, Jason-1, ERS-1/2, ENVISAT, and GFO, a global array of profiling floats from the Argo program, and satellite gravity data from the GRACE mission, suggest that the solutions are now useful for scientific purposes. Both methodology and applications are developing in a number of different directions. (c) 2006 Elsevier B.V. All rights reserved.
Keywords: adjoint, adjoint method, assimilation, atlantic circulation, climate, construction, data assimilation, fitting dynamics, general-circulation model, method of lagrange multipliers, ocean circulation, satellite altimetry, sensitivity-analysis, state estimate
Title: Estimating the Circulation and Climate of the Ocean - The ECCO Consortia
Type: Magazine Article
Publication: U.S. CLIVAR Variations
Author(s): Heimbach, P; Wunsch, C
Year: 2007
Formatted Citation: Heimbach, P., and C. Wunsch, 2007: Estimating the Circulation and Climate of the Ocean - The ECCO Consortia. U.S. CLIVAR Variations, 5(3), 1-5 pp. https://www.usclivar.org/sites/default/files/Variations-V3N3.pdf.
Kwok, R.; Cunningham, G. F.; Zwally, H. J.; Yi, D. (2006). ICESat over Arctic sea ice: Interpretation of altimetric and reflectivity profiles, Journal of Geophysical Research, C6 (111), C06006, 10.1029/2005JC003175.
Title: ICESat over Arctic sea ice: Interpretation of altimetric and reflectivity profiles
Type: Journal Article
Publication: Journal of Geophysical Research
Author(s): Kwok, R.; Cunningham, G. F.; Zwally, H. J.; Yi, D.
Year: 2006
Formatted Citation: Kwok, R., G. F. Cunningham, H. J. Zwally, and D. Yi, 2006: ICESat over Arctic sea ice: Interpretation of altimetric and reflectivity profiles. Journal of Geophysical Research, 111(C6), C06006, doi:10.1029/2005JC003175
Abstract: We provide an assessment of the ICESat altimeter for studying the Arctic Ocean and examine the magnitude of the large- and small-scale expressions of geophysical processes embedded in the elevation profiles. This analysis includes data from six surveys. At the large scale the response of the ice-covered ocean to atmospheric loading is near ideal (i.e., approximately −1 cm/hPa). After removal of the inverted barometer effects and best available geoid the elevation signal is still dominated by unresolved geoid residuals (∼0.4 m) that can be seen in the similarity of the remaining spatial patterns. Seasonal differences in elevations over multiyear ice are consistent with snow depth climatology; the broad differential spatial patterns are indicative of interannual differences in multiyear ice coverage associated with advection. Patterns in the derived surface roughness fields correspond to the seasonal and perennial ice zones seen in QuikSCAT data. At the small scale, near-coincident RADARSAT imagery provides a spatial context for understanding the signature of the observed elevations, waveforms, and reflectivity, in particular, those associated with thin ice, open water, multiyear ice, and ridges. The precision of the elevation estimates measured over relatively flat sea ice, identified in synthetic aperture radar (SAR) imagery, is ∼2 cm. The unambiguous identification of ridged areas in coupled ICESat/RADARSAT analysis could be used to enhance the utility of SAR imagery for examining ridge distributions. Over a 20 day period we monitored the evolution of the reflectivity of a newly opened lead. The steep increase in reflectivity due to snow coverage suggests that dips in ICESat reflectivity are likely areas of thin ice and could serve as a basis for selection of tie points for use as sea level reference. Identification of these tie points is crucial for accurate estimation of sea ice freeboard.
Keywords: 0750 Sea ice, 0758 Remote sensing, 0762 Mass balance, 4207 Arctic and Antarctic oceanography, 4540 Ice mechanics and air/sea/ice exchange proces, Arctic Ocean, laser altimetry, sea ice thickness
Other URLs: http://doi.wiley.com/10.1029/2005JC003175
Heimbach, P; Ponte, R M; Evangelinos, C; Forget, G; Mazloff, M; Menemenlis, Dimitris; Vinogradov, S; Wunsch, C (2006). Combining Altimetric and All Other Data with a General Circulation Model, Proceedings of the 15 Years of Progress in Radar Altimetry Symposium (SP-614).
Title: Combining Altimetric and All Other Data with a General Circulation Model
Type: Book Section
Publication: Proceedings of the 15 Years of Progress in Radar Altimetry Symposium
Author(s): Heimbach, P; Ponte, R M; Evangelinos, C; Forget, G; Mazloff, M; Menemenlis, Dimitris; Vinogradov, S; Wunsch, C
Year: 2006
Formatted Citation: Heimbach, P., R. M. Ponte, C. Evangelinos, G. Forget, M. Mazloff, D. Menemenlis, S. Vinogradov, and C. Wunsch, 2006: Combining Altimetric and All Other Data with a General Circulation Model. Proceedings of the 15 Years of Progress in Radar Altimetry Symposium, ESA Special Publication SP-614, SP-614
Abstract:
Keywords:
ECCO Products Used: ECCO-V2;ECCO2
URL:
Other URLs:
Taft, James (2006). Scaling Methods and Results for Applicatiions Running on NASA’s 61 TFLOP Columbia System, 44th AIAA Aerospace Sciences Meeting and Exhibit, 10.2514/6.2006-85.
Title: Scaling Methods and Results for Applicatiions Running on NASA’s 61 TFLOP Columbia System
Type: Conference Proceedings
Publication: 44th AIAA Aerospace Sciences Meeting and Exhibit
Author(s): Taft, James
Year: 2006
Formatted Citation: Taft, J., 2006: Scaling Methods and Results for Applicatiions Running on NASA's 61 TFLOP Columbia System. 44th AIAA Aerospace Sciences Meeting and Exhibit American Institute of Aeronautics and Astronautics, Reston, Virigina doi:10.2514/6.2006-85.
Formatted Citation: Menemenlis, D. and Coauthors, 2005: NASA supercomputer improves prospects for ocean climate research. Eos, Transactions American Geophysical Union, 86(9), 89-96, doi:10.1029/2005EO090002
Abstract: Estimates of ocean circulation constrained by in situ and remotely sensed observations have become routinely available during the past five years, and they are being applied to myriad scientific and operational problems [Stammer et al., 2002]. Under the Global Ocean Data Assimilation Experiment (GODAE), several regional and global estimates have evolved for applications in climate research, seasonal forecasting, naval operations, marine safety, fisheries, the offshore oil industry coastal management, and other areas. This article reports on recent progress by one effort, the consortium for Estimating the Circulation and Climate of the Ocean (ECCO), toward a next-generation synthesis of ocean and sea-ice data that is global, that covers the full ocean depth, and that permits eddies.
Keywords: 4215 Climate and interannual variability, 4532 General circulation, 4540 Ice mechanics and air/sea/ice exchange proces
Menemenlis, Dimitris; Hill, C; Adcroft, Alistair J.; Campin, J; Cheng, B; Lee, T; Steele, M; Wang, O; Zhang, J (2005). Towards eddy permitting estimates of the global-ocean and sea-ice circulations, 8th Conference on Polar Meteorology and Oceanography, 1-6.
Title: Towards eddy permitting estimates of the global-ocean and sea-ice circulations
Type: Conference Proceedings
Publication: 8th Conference on Polar Meteorology and Oceanography
Author(s): Menemenlis, Dimitris; Hill, C; Adcroft, Alistair J.; Campin, J; Cheng, B; Lee, T; Steele, M; Wang, O; Zhang, J
Year: 2005
Formatted Citation: Menemenlis, D. and Coauthors, 2005: Towards eddy permitting estimates of the global-ocean and sea-ice circulations. 8th Conference on Polar Meteorology and Oceanography, 1-6 pp.
Abstract: Satellite and in-situ observations are now routinely combined with numerical models in order to estimate the time-evolving oceanic circulation and to address a wide variety of operational and research problems. For climate dynamics analysis, what is required is a synthesis of all available observations over the last several decades with the best possible numerical model. Rigorous low-resolution estimates of ocean circulation are already possible using the existing data base and modeling capability. But these low-resolution estimates lack the ability to resolve many small-scale oceanic processes, for example, flow over narrow sills, western boundary currents, regions of deep convection, and eddies, that are important both for climate studies and for operational applications. I will discuss four recent advances that bring rigorous eddy-permitting estimates of the global ocean and sea-ice circulations within reach: 1) the configuration of an efficient eddy-permitting global-ocean and sea-ice model that achieves a throughput approaching ten years of model integration per day of computation, 2) the demonstration that boundary conditions estimated at coarse resolution have some skill when applied to an eddy-permitting model, 3) the development of an inexpensive yet effective methodology for calibrating model parameters and for blending estimates from different solutions and data products, and 4) a hierarchical Kalman filter that can estimate model uncertainties commensurate with available degrees of freedom in observations and the model. This is a contribution of the consortium for Estimating the Circulation and Climate of the Ocean (ECCO) and of the Arctic Sea-ice Ocean Reanalysis (ASOR) project.
Glazman, Roman E; Golubev, Yury N (2005). Variability of the ocean-induced magnetic field predicted at sea surface and at satellite altitudes, Journal of Geophysical Research: Oceans, C12 (110), 10.1029/2005JC002926.
Title: Variability of the ocean-induced magnetic field predicted at sea surface and at satellite altitudes
Type: Journal Article
Publication: Journal of Geophysical Research: Oceans
Author(s): Glazman, Roman E; Golubev, Yury N
Year: 2005
Formatted Citation: Glazman, R. E., and Y. N. Golubev, 2005: Variability of the ocean-induced magnetic field predicted at sea surface and at satellite altitudes. J. Geophys. Res. Ocean., 110(C12), doi:10.1029/2005JC002926
Abstract: Spatial and temporal variability of the magnetic field component induced by ocean circulation is investigated on the basis of a standard thin-shell approximation of electro- and magneto-static equations. Well-known difficulties of numerical solution of the governing equations are resolved by reducing the problem to an equation for the electric field potential, Φ, as opposed to a more conventional approach focused on the vertical jump, ψ, of the magnetic field potential across a combined ocean/marine-sediment-layer spherical shell. The present formulation permits using more realistic input data on ocean currents and ultimately yields much greater (by at least an order of magnitude) values of the magnetic field at sea surface than predicted in earlier studies. Such large values are comparable to, and in some cases exceed, magnetic field variations caused by lithospheric and ionospheric sources on monthly to interannual timescales. At the 400-km altitude (of CHAMP satellite), the field attains 6 nT. The model predictions show favorable comparisons with some in situ measurements as well as with Challenging Minisatellite Payload (CHAMP) satellite magnetometer data.
Keywords: 0619 Electromagnetic theory, 0689 Wave propagation, 1517 Magnetic anomalies: modeling and interpretati, 1545 Spatial variations: all harmonics and anomali, 4275 Remote sensing and electromagnetic processes, Earth's magnetic field, ocean induction, ocean remote sensing
Žuvela-Aloise, Maja (2005). Modelling of the Indonesian Throughflow on glacial-interglacial time-scales.
Title: Modelling of the Indonesian Throughflow on glacial-interglacial time-scales
Type: Thesis
Publication:
Author(s): Žuvela-Aloise, Maja
Year: 2005
Formatted Citation: Žuvela-Aloise, M., 2005: Modelling of the Indonesian Throughflow on glacial-interglacial time-scales, December
Abstract: The Indonesian Throughflow transports warm and fresh Pacific waters into the Indian Ocean and is a major tropical pathway of the global thermohaline circulation. An important paleoclimatic question is to what extent lowered sea level at the Last Glacial Maximum effected the Indonesian Throughflow by restricting the gateways aperture. In this study, a regional dynamics of the Indonesian Throughflow are analysed for present- day and Last Glacial Maximum conditions. The focus of the study is on the impact of changes in Indonesian Gateways configuration on ocean circulation and distribution of marine organisms. A high resolution regional ocean model with seasonal forcing is used to simulate mean climatic circulation through the Indonesian Gateways. During the Last Glacial Maximum, both bathymetry and climate conditions were different. Relative importance of individual effects is investigated by separately testing the sensitivity of the ITF volume and heat transport to the sea level lowering and to the glacial climate conditions. The closure of the main passages is expected to reduce mean ITF transport during the glacial period. However, model results show that reduction in the glacial sea level of 120 m does not seem to be sufficient to severely block the flow within the Makassar Strait as the main passage of the Throughflow. An important impact of topographic changes is found in the vertical profile of the flow. Reduction in sill depth and absence of low buoyancy surface waters due to the exposure of shelf area lead to intensification of surface flow within Makassar Strait. Moreover, the seasonality of the surface flow is changed compared to the present-day. Both effects might have significant impact on the heat transport towards the Indian Ocean. A strong impact of individual passages on ITF profile and seasonal variability emphasis the role of Indonesian Gateways on modulating the water masses exchange between the Pacific and the Indian Ocean. However, the intensity of the Throughflow seems to be highly dependant on the boundary conditions. Glacial climate conditions lead to reduction in ITF transport which might be related to several factors out of scope of regional dynamics. Such factors could include glacial changes in wind stress over Pacific, changes in density gradient between Pacific and Indian Ocean or overall El- Niño conditions over the tropical Pacific. In addition, by calculating Lagrangian trajectories, main pathways, velocities of propagation and probabilities of exchange of marine biota between the Pacific and the Indian Ocean can be assessed. The developed patterns of distribution can be in the future compared with sedimentological evidence from the region.
Keywords:
ECCO Products Used: ECCO-KFS;ECCO-V0;ECCO2
URL:
Other URLs:
Adcroft, Alistair J.; Hill, Chris; Campin, Jean-Michael; Marshall, John; Heimbach, Patrick (2004). Overview of the formulation and numerics of the MITgcm, Proceedings of the ECMWF seminar series on Numerical Methods Recent developments in numerical methods for atmosphere and ocean modelling, 139-149.
Title: Overview of the formulation and numerics of the MITgcm
Type: Conference Proceedings
Publication: Proceedings of the ECMWF seminar series on Numerical Methods Recent developments in numerical methods for atmosphere and ocean modelling
Author(s): Adcroft, Alistair J.; Hill, Chris; Campin, Jean-Michael; Marshall, John; Heimbach, Patrick
Year: 2004
Formatted Citation: Adcroft, A. J., C. Hill, J. Campin, J. Marshall, and P. Heimbach, 2004: Overview of the formulation and numerics of the MITgcm. Proceedings of the ECMWF seminar series on Numerical Methods Recent developments in numerical methods for atmosphere and ocean modelling, 139-149 pp. http://www.gfdl.noaa.gov/~aja/papers/ECMWF2004-Adcroft.pdf.
Abstract: The MIT general circulation model (MITgcm) is a widely portable circulation model designed for study of a wide range of scales in both the ocean and atmosphere. The model is rooted in the incompressible Navier-Stokes equations and can include the non-hydrostatic terms that are important in mixing processes. In the hydrostatic limit, an isomorphism between height based-coordinates and pressure based-coordinates allows the same dynamical kernel to drive an atmospheric model. The model uses finite volume methods and orthogonal curvilinear coordinates in the horizontal that can accommodate novel spherical grids such as that based on the conformally expanded spherical cube. An adjoint of the model is maintained using automatic differentiation.
