Geodetic Variables

The ocean is a key factor in determining and understanding the geodetic properties (geometric shape, orientation in space, and gravity field) of the Earth. For example, changes in the oceanic mass field can have important effects on crustal loading. Knowledge of the mean ocean surface circulation and dynamic topography can help determine the marine geoid and the gravity field. And variability in both ocean currents and bottom pressure can affect the Earth's orientation in space. ECCO products make it possible to calculate geodetically relevant quantities such as the ocean angular momentum and center of mass.

Effects of ocean tides are not included in any of these geodetic variables. In addition, all quantities except those based on V4r4 do not consider surface atmospheric pressure effects. For V4r4, two sets are provided based on sea level with and without the inverted barometer signal removed. Similarly, effects of net freshwater flux into the ocean, related to barystatic sea level, are only considered in the latest releases (V4r3, V4r4), for which two sets are provided based on values with and without those effects included. Some variables are provided hourly but variability at periods shorter than 12 hours are not expected to be realistic.

Download the data using the button. Clicking on the icon will take you to Google Drive* instead. A description of each dataset is included in each data file, and as a preview using the "view metadata" button. Variables here are derived from a subset of ECCO products to facilitate geodetic studies.

Data: International Earth Rotation & Reference Systems Service
Acronyms: CoM: Center-of-Mass; FWF: Freshwater Flux; IB: Inverted Barometer; OAM: Oceanic Angular Momentum; OBP: Ocean Bottom Pressure

Global Oceanic Angular Momentum (OAM) & Excitation Functions

File	Status	Ocean Model	Date Span	Resolution	Contents
ECCO_v4r4_noIBremoved_noFWF.oam		MITgcm	Jan 1992 – Dec 2017	1 hour	OAM (w/o FWF; no IB signal removed)
File name: ECCO_v4r4_noIBremoved_noFWF.oam File contents: Global oceanic angular momentum mass and motion terms, and total ocean mass (includes effects of sea ice); mass term based on full sea level with no inverted barometer (IB) signal removed File units: kg-m2/s for OAM, kg for mass Contact: Rui Ponte ([email protected]) References: Forget et al. 2015, doi:10.5194/gmd-8-3071-2015 Fukumori et al. 2019, https://www.ecco-group.org/docs/v4r4_synopsis.pdf Quinn et al. 2019, doi:10.1093/gji/ggy452 Temporal domain: January 1992 through December 2017 Temporal resolution: hourly Number of data records: 210359 Ocean model: ECCO Version 4 release 4 (based on MITgcm) Horizontal domain: Global Horizontal resolution: Variable spacing ranging from 22 km to 111 km (see Forget et al. 2015, section 2) Vertical resolution: 50 levels ranging in thickness from 10 m at surface to 460 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Does not include mass effects from net real freshwater flux Ocean model forcing: 6-hourly ERA-Interim values adjusted by optimization (see Forget et al. 2015, section 3.5); atmospheric surface pressure included but not adjusted by optimization (see Fukumori et al. 2019) Data assimilated: sea level altimetry, in situ temperature/salinity, satellite SST/SSS, bottom pressure, sea-ice concentration (see Fukumori et al. 2019) Notes: The mean has been removed from the tabulated OAM and mass values. The mean OAM mass term (kg-m2/s; x,y,z) = 1.35446093E+29 1.04770776E+29 2.92757161E+30 The mean OAM motion term (kg-m**2/s; x,y,z) = -9.05105808E+23 9.38062199E+23 1.18721691E+25 The mean total ocean mass (kg) = 1.37371282E+21
ECCO_v4r4_noIBremoved_yesFWF.oam		MITgcm	Jan 1992 – Dec 2017	1 hour	OAM (with FWF; no IB signal removed)
File name: ECCO_v4r4_noIBremoved_yesFWF.oam File contents: Global oceanic angular momentum mass and motion terms, and total ocean mass (includes effects of sea ice); mass term based on full sea level with no inverted barometer (IB) signal removed File units: kg-m2/s for OAM, kg for mass Contact: Rui Ponte ([email protected]) References: Forget et al. 2015, doi:10.5194/gmd-8-3071-2015 Fukumori et al. 2019, https://www.ecco-group.org/docs/v4r4_synopsis.pdf Quinn et al. 2019, doi:10.1093/gji/ggy452 Temporal domain: January 1992 through December 2017 Temporal resolution: hourly Number of data records: 227903 Ocean model: ECCO Version 4 release 4 (based on MITgcm) Horizontal domain: Global Horizontal resolution: Variable spacing ranging from 22 km to 111 km (see Forget et al. 2015, section 2) Vertical resolution: 50 levels ranging in thickness from 10 m at surface to 460 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Includes mass effects from net real freshwater flux Ocean model forcing: 6-hourly ERA-Interim values adjusted by optimization (see Forget et al. 2015, section 3.5); atmospheric surface pressure included but not adjusted by optimization (see Fukumori et al. 2019) Data assimilated: sea level altimetry, in situ temperature/salinity, satellite SST/SSS, bottom pressure, sea-ice concentration (see Fukumori et al. 2019) Notes: The mean has been removed from the tabulated OAM and mass values. The mean OAM mass term (kg-m2/s; x,y,z) = 1.35448687E+29 1.04774548E+29 2.92768328E+30 The mean OAM motion term (kg-m**2/s; x,y,z) = -9.05105808E+23 9.38062199E+23 1.18721691E+25 The mean total ocean mass (kg) = 1.37376730E+21
ECCO_v4r4_IBremoved_yesFWF.oam		MITgcm	Jan 1992 – Dec 2017	1 hour	OAM (with FWF; IB signal removed)
File name: ECCO_v4r4_IBremoved_yesFWF.oam File contents: Global oceanic angular momentum mass and motion terms, and total ocean mass (includes effects of sea ice); mass term based on sea level with inverted barometer (IB) signal removed File units: kg-m2/s for OAM, kg for mass Contact: Rui Ponte ([email protected]) References: Forget et al. 2015, doi:10.5194/gmd-8-3071-2015 Fukumori et al. 2019, https://www.ecco-group.org/docs/v4r4_synopsis.pdf Quinn et al. 2019, doi:10.1093/gji/ggy452 Temporal domain: January 1992 through December 2017 Temporal resolution: hourly Number of data records: 227903 Ocean model: ECCO Version 4 release 4 (based on MITgcm) Horizontal domain: Global Horizontal resolution: Variable spacing ranging from 22 km to 111 km (see Forget et al. 2015, section 2) Vertical resolution: 50 levels ranging in thickness from 10 m at surface to 460 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Includes mass effects from net real freshwater flux Ocean model forcing: 6-hourly ERA-Interim values adjusted by optimization (see Forget et al. 2015, section 3.5); atmospheric surface pressure included but not adjusted by optimization (see Fukumori et al. 2019) Data assimilated: sea level altimetry, in situ temperature/salinity, satellite SST/SSS, bottom pressure, sea-ice concentration (see Fukumori et al. 2019) Notes: The mean has been removed from the tabulated OAM and mass values. The mean OAM mass term (kg-m2/s; x,y,z) = 1.35449608E+29 1.04775850E+29 2.92769749E+30 The mean OAM motion term (kg-m**2/s; x,y,z) = -9.05105808E+23 9.38062199E+23 1.18721691E+25 The mean total ocean mass (kg) = 1.37376730E+21
ECCO_v4r4_IBremoved_noFWF.oam		MITgcm	Jan 1992 – Dec 2017	1 hour	OAM (w/o FWF; IB signal removed)
File name: ECCO_v4r4_IBremoved_noFWF.oam File contents: Global oceanic angular momentum mass and motion terms, and total ocean mass (includes effects of sea ice); mass term based on sea level with inverted barometer (IB) signal removed File units: kg-m2/s for OAM, kg for mass Contact: Rui Ponte ([email protected]) References: Forget et al. 2015, doi:10.5194/gmd-8-3071-2015 Fukumori et al. 2019, https://www.ecco-group.org/docs/v4r4_synopsis.pdf Quinn et al. 2019, doi:10.1093/gji/ggy452 Temporal domain: January 1992 through December 2017 Temporal resolution: hourly Number of data records: 210359 Ocean model: ECCO Version 4 release 4 (based on MITgcm) Horizontal domain: Global Horizontal resolution: Variable spacing ranging from 22 km to 111 km (see Forget et al. 2015, section 2) Vertical resolution: 50 levels ranging in thickness from 10 m at surface to 460 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Does not include mass effects from net real freshwater flux Ocean model forcing: 6-hourly ERA-Interim values adjusted by optimization (see Forget et al. 2015, section 3.5); atmospheric surface pressure included but not adjusted by optimization (see Fukumori et al. 2019) Data assimilated: sea level altimetry, in situ temperature/salinity, satellite SST/SSS, bottom pressure, sea-ice concentration (see Fukumori et al. 2019) Notes: The mean has been removed from the tabulated OAM and mass values. The mean OAM mass term (kg-m2/s; x,y,z) = 1.35447015E+29 1.04772078E+29 2.92758581E+30 The mean OAM motion term (kg-m**2/s; x,y,z) = -9.05105808E+23 9.38062199E+23 1.18721691E+25 The mean total ocean mass (kg) = 1.37371282E+21
ECCO_v4r3_yesFWF.oam	deprecated (see ECCO_v4r4_yesFWF.oam)	MITgcm	Jan 1992 – Dec 2015	1 hour	OAM (with FWF)
File name: ECCO_v4r3_yesFWF.oam File contents: Global oceanic angular momentum mass and motion terms, and total ocean mass (includes effects of sea ice) File units: kg-m2/s for OAM, kg for mass Contact: Rui Ponte ([email protected]) References: Forget et al. 2015, doi:10.5194/gmd-8-3071-2015 Fukumori et al. 2018, https://www.ecco-group.org/docs/v4r3_data.pdf Quinn et al. 2019, doi:10.1093/gji/ggy452 Temporal domain: January 1992 through December 2015 Temporal resolution: hourly Number of data records: 210359 Ocean model: ECCO Version 4 release 3 (based on MITgcm) Horizontal domain: Global Horizontal resolution: Variable spacing ranging from 22 km to 111 km (see Forget et al. 2015, section 2) Vertical resolution: 50 levels ranging in thickness from 10 m at surface to 460 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Includes mass effects from net real freshwater flux Ocean model forcing: 6-hourly ERA-Interim values adjusted by optimization (see Forget et al. 2015, section 3.5); no pressure forcing used Data assimilated: sea level altimetry, in situ temperature/salinity, satellite SST/SSS, bottom pressure, sea-ice concentration (see Fukumori et al. 2018) Notes: The mean has been removed from the tabulated OAM and mass values. The mean OAM mass term (kg-m2/s; x,y,z) = 1.35449653E+29 1.04775649E+29 2.92768012E+30 The mean OAM motion term (kg-m**2/s; x,y,z) = -9.24763218E+23 9.03408559E+23 1.17821483E+25 The mean total ocean mass (kg) = 1.37375920E+21
ECCO_v4r3_noFWF.oam	deprecated (see ECCO_v4r4_noFWF.oam)	MITgcm	Jan 1992 – Dec 2015	1 hour	OAM (w/o FWF)
File name: ECCO_v4r3_noFWF.oam File contents: Global oceanic angular momentum mass and motion terms, and total ocean mass (includes effects of sea ice) File units: kg-m2/s for OAM, kg for mass Contact: Rui Ponte ([email protected]) References: Forget et al. 2015, doi:10.5194/gmd-8-3071-2015 Fukumori et al. 2018, https://www.ecco-group.org/docs/v4r3_data.pdf Quinn et al. 2019, doi:10.1093/gji/ggy452 Temporal domain: January 1992 through December 2015 Temporal resolution: hourly Number of data records: 210359 Ocean model: ECCO Version 4 release 3 (based on MITgcm) Horizontal domain: Global Horizontal resolution: Variable spacing ranging from 22 km to 111 km (see Forget et al. 2015, section 2) Vertical resolution: 50 levels ranging in thickness from 10 m at surface to 460 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Does not include mass effects from net real freshwater flux Ocean model forcing: 6-hourly ERA-Interim values adjusted by optimization (see Forget et al. 2015, section 3.5); no pressure forcing used Data assimilated: sea level altimetry, in situ temperature/salinity, satellite SST/SSS, bottom pressure, sea-ice concentration (see Fukumori et al. 2018) Notes: The mean has been removed from the tabulated OAM and mass values. The mean OAM mass term (kg-m2/s; x,y,z) = 1.35447445E+29 1.04772438E+29 2.92758505E+30 The mean OAM motion term (kg-m**2/s; x,y,z) = -9.24763218E+23 9.03408559E+23 1.17821483E+25 The mean total ocean mass (kg) = 1.37371282E+21
ECCO_kf080i.chi		MITgcm	Jan 1993 – Mar 2020	1 day	excitation
File name: ECCO_kf080i.chi File contents: Global oceanic excitation functions (mass and motion terms) File units: milliarcseconds (mas) for chi-x and chi-y, milliseconds (ms) for lod Contact: Richard Gross, [email protected] References: Gross et al., Atmospheric and Oceanic Excitation of Decadal-Scale Earth Orientation Variations, J. Geophys. Res., 110(B09405), 2005 Gross, R.S., An Improved Empirical Model for the Effect of Long-Period Ocean Tides on Polar Motion, J. Geodesy, 83, 635-644, doi:10.1007/s00190-008-0277-y, 2009 Temporal domain: January 1993 through March 2020 Temporal resolution: 1-day averages Number of data records: 9950 Ocean model: ECCO (based on MITgcm) Horizontal domain: 80 degrees South to 80 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure : None Data assimilated: Altimetric measurements of sea surface height and XBT data Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated excitation values. The mean chi mass term (mas,mas,ms; chi-x,chi-y,lod) = 1.64265610E+06 1.24061090E+06 3.69504088E+04 The mean chi motion term (mas,mas,ms; chi-x,chi-y,lod) = -1.83484961E+01 1.09989517E+01 1.58559979E-01 The oceanic excitation functions have been computed from the oceanic angular momenta by Equations (4) and (6) of Gross et al. (2005). The tidal contamination present in previous versions of the ECCO/JPL data assimilative ocean models (e.g., kf049f,kf066b) is not present in this model. For a discussion of this problem see Gross (2009). A problem with assimilating altimetric data in kf080 has been fixed here.
ECCO_kf080i.oam		MITgcm	Jan 1993 – Mar 2020	1 day	OAM
File name: ECCO_kf080i.oam File contents: Global oceanic angular momentum mass and motion terms File units: kg-m2/s Contact: Richard Gross, [email protected] Reference:Gross, R.S., An Improved Empirical Model for the Effect of Long-Period Ocean Tides on Polar Motion, J. Geodesy, 83, 635-644, doi:10.1007/s00190-008-0277-y, 2009 Temporal domain: January 1993 through March 2020 Temporal resolution: 1-day averages Number of data records: 9950 Ocean model: ECCO (based on MITgcm) Horizontal domain: 80 degrees South to 80 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure: None Data assimilated: Altimetric measurements of sea surface height and XBT data Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated OAM values. The mean OAM mass term (kg-m2/s; x,y,z) = 1.35566427E+29 1.02386121E+29 2.93882227E+30 The mean OAM motion term (kg-m**2/s; x,y,z) = -1.05158282E+24 6.30368206E+23 9.53387493E+24 The tidal contamination present in previous versions of the ECCO/JPL data assimilative ocean models (e.g., kf049f,kf066b) is not present in this model. For a discussion of this problem see Gross (2009). A problem with assimilating altimetric data in kf080 has been fixed here.
ECCO_kf079.chi		MITgcm	Jan 1993 – Mar 2020	1 day	excitation
File name: ECCO_kf079.chi File contents: Global oceanic excitation functions (mass and motion terms) File units: milliarcseconds (mas) for chi-x and chi-y, milliseconds (ms) for lod Contact: Richard Gross, [email protected] References: Gross et al., Atmospheric and Oceanic Excitation of Decadal-Scale Earth Orientation Variations, J. Geophys. Res., 110(B09405), 2005 Gross, R.S., An Improved Empirical Model for the Effect of Long-Period Ocean Tides on Polar Motion, J. Geodesy, 83, 635-644, doi:10.1007/s00190-008-0277-y, 2009 Temporal domain: January 1993 through March 2020 Temporal resolution: 1-day averages Number of data records: 9950 Ocean model: ECCO (based on MITgcm) Horizontal domain: 80 degrees South to 80 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure: None Data assimilated: None Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated excitation values. The mean chi mass term (mas,mas,ms; chi-x,chi-y,lod) = 1.64265621E+06 1.24061209E+06 3.69504053E+04 The mean chi motion term (mas,mas,ms; chi-x,chi-y,lod) = -1.73992836E+01 1.11507929E+01 1.55578087E-01 The oceanic excitation functions have been computed from the oceanic angular momenta by Equations (4) and (6) of Gross et al. (2005). The tidal contamination present in previous versions of the ECCO/JPL data assimilative ocean models (e.g., kf049f,kf066b) is not present in this model. For a discussion of this problem see Gross (2009).
ECCO_kf079.oam		MITgcm	Jan 1993 – Mar 2020	1 day	OAM
File name: ECCO_kf079.oam File contents: Global oceanic angular momentum mass and motion terms File units: kg-m2/s Contact: Richard Gross, [email protected] Reference: Gross, R.S., An Improved Empirical Model for the Effect of Long-Period Ocean Tides on Polar Motion, J. Geodesy, 83, 635-644, doi:10.1007/s00190-008-0277-y, 2009 Temporal domain: January 1993 through March 2020 Temporal resolution: 1-day averages Number of data records: 9950 Ocean model: ECCO (based on MITgcm) Horizontal domain: 80 degrees South to 80 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure: None Data assimilated: None Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated OAM values. The mean OAM mass term (kg-m2/s; x,y,z) = 1.35566436E+29 1.02386220E+29 2.93882199E+30 The mean OAM motion term (kg-m**2/s; x,y,z) = -9.97181873E+23 6.39070483E+23 9.35458007E+24 The tidal contamination present in previous versions of the ECCO/JPL data assimilative ocean models (e.g., kf049f,kf066b) is not present in this model. For a discussion of this problem see Gross (2009).
ECCO_kf066b.chi	deprecated (see kf080i.chi)	MITgcm	Jan 1993 – Dec 2008	1 day	excitation
File name: ECCO_kf066b.chi File contents: Global oceanic excitation functions (mass and motion terms) File units: milliarcseconds (mas) for chi-x and chi-y, milliseconds (ms) for lod Contact: Richard Gross, [email protected] References: Gross et al., Atmospheric and Oceanic Excitation of Decadal-Scale Earth Orientation Variations, J. Geophys. Res., 110(B09405), 2005 Gross, R.S., An Improved Empirical Model for the Effect of Long-Period Ocean Tides on Polar Motion, J. Geodesy, 83, 635-644, doi:10.1007/s00190-008-0277-y, 2009 Temporal domain: January 1993 through December 2008 Temporal resolution: 1-day averages Number of data records: 5843 Ocean model: ECCO (based on MITgcm) Horizontal domain: 80 degrees South to 80 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure: None Data assimilated: Altimetric measurements of sea surface height and XBT data Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated excitation values. The mean chi mass term (mas,mas,ms; chi-x,chi-y,lod) = 1.64265514E+06 1.24061214E+06 3.69504039E+04 The mean chi motion term (mas,mas,ms; chi-x,chi-y,lod) = -1.83880749E+01 1.12574774E+01 1.60703930E-01 The oceanic excitation functions have been computed from the oceanic angular momenta by Equations (4) and (6) of Gross et al. (2005).
ECCO_kf066b.oam	deprecated (see kf080i.oam)	MITgcm	Jan 1993 – Dec 2008	1 day	OAM
File name: ECCO_kf066b.oam File contents: Global oceanic angular momentum mass and motion terms File units: kg-m2/s Contact: Richard Gross, [email protected] Reference: Gross, R.S., An Improved Empirical Model for the Effect of Long-Period Ocean Tides on Polar Motion, J. Geodesy, 83, 635-644, doi:10.1007/s00190-008-0277-y, 2009 Temporal domain: January 1993 through December 2008 Temporal resolution: 1-day averages Number of data records: 5843 Ocean model: ECCO (based on MITgcm) Horizontal domain: 80 degrees South to 80 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure: None Data assimilated: Altimetric measurements of sea surface height and XBT data Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated OAM values. The mean OAM mass term (kg-m2/s; x,y,z) = 1.35566348E+29 1.02386224E+29 2.93882188E+30 The mean OAM motion term (kg-m**2/s; x,y,z) = -1.05385115E+24 6.45184748E+23 9.66278610E+24
ECCO_kf066a2.chi	deprecated (see kf079.chi)	MITgcm	Jan 1993 – Dec 2008	1 day	excitation
File name: ECCO_kf066a2.chi File contents: Global oceanic excitation functions (mass and motion terms) File units: milliarcseconds (mas) for chi-x and chi-y, milliseconds (ms) for lod Contact: Richard Gross, [email protected] References: Gross et al., Atmospheric and Oceanic Excitation of Decadal-Scale Earth Orientation Variations, J. Geophys. Res., 110(B09405), 2005 Gross, R.S., An Improved Empirical Model for the Effect of Long-Period Ocean Tides on Polar Motion, J. Geodesy, 83, 635-644, doi:10.1007/s00190-008-0277-y, 2009 Temporal domain: January 1993 through December 2008 Temporal resolution: 1-day averages Number of data records: 5843 Ocean model: ECCO (based on MITgcm) Horizontal domain: 80 degrees South to 80 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure: None Data assimilated: None Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated excitation values. The mean chi mass term (mas,mas,ms; chi-x,chi-y,lod) = 1.64265523E+06 1.24061168E+06 3.69504039E+04 The mean chi motion term (mas,mas,ms; chi-x,chi-y,lod) = -1.81207064E+01 1.11877709E+01 1.60432264E-01 The oceanic excitation functions have been computed from the oceanic angular momenta by Equations (4) and (6) of Gross et al. (2005).
ECCO_kf066a2.oam	deprecated (see kf079.oam)	MITgcm	Jan 1993 – Dec 2008	1 day	OAM
File name: ECCO_kf066a2.oam File contents: Global oceanic angular momentum mass and motion terms File units: kg-m2/s Contact: Richard Gross, [email protected] Reference: Gross, R.S., An Improved Empirical Model for the Effect of Long-Period Ocean Tides on Polar Motion, J. Geodesy, 83, 635-644, doi:10.1007/s00190-008-0277-y, 2009 Temporal domain: January 1993 through December 2008 Temporal resolution: 1-day averages Number of data records: 5843 Ocean model: ECCO (based on MITgcm) Horizontal domain: 80 degrees South to 80 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure: None Data assimilated: None Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated OAM values. The mean OAM mass term (kg-m2/s; x,y,z) = 1.35566355E+29 1.02386186E+29 2.93882188E+30 The mean OAM motion term (kg-m**2/s; x,y,z) = -1.03852781E+24 6.41189749E+23 9.64645142E+24
ECCO_kf049f.oam	deprecated (see kf080i.oam)	MITgcm	Jan 1993 – Mar 2006	1 day	OAM
File name: ECCO_kf049f.oam File contents: Global oceanic angular momentum mass and motion terms File units: kg-m2/s Contact: Richard Gross, [email protected] Reference: Gross et al., Atmospheric and Oceanic Excitation of Decadal-Scale Earth Orientation Variations, J. Geophys. Res., 110(B09405), 2005 Temporal domain: January 1993 through March 2006 Temporal resolution: 1-day averages Number of data records: 4837 Ocean model: ECCO (based on MITgcm) Horizontal domain: 74 degrees South to 74 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated mass term corrected for volume changes due to steric effects?: Yes Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure: None Data assimilated: Altimetric measurements of sea surface height and XBT data Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated OAM values. The mean OAM mass term (kg-m2/s; x,y,z) = 1.35566307E+29 1.02386255E+29 2.93882176E+30 The mean OAM motion term (kg-m**2/s; x,y,z) = -1.05341480E+24 6.12099499E+23 9.85063101E+24

Oceanic Center-of-Mass

File	Status	Ocean Model	Date Span	Resolution	Contents
ECCO_v4r4_yesFWF.cm		MITgcm	Jan 1992 – Dec 2017	1 hour	CoM (with FWF)
File name: ECCO_v4r4_yesFWF.cm File contents: oceanic center-of-mass (COM), and total ocean mass (includes effects of sea ice) File units: meters for COM, kg for mass Contact: Rui Ponte ([email protected]) References: Forget et al. 2015, doi:10.5194/gmd-8-3071-2015 Fukumori et al. 2019, https://www.ecco-group.org/docs/v4r4_synopsis.pdf Quinn et al. 2019, doi:10.1093/gji/ggy452 Temporal domain: January 1992 through December 2017 Temporal resolution: hourly Number of data records: 227903 Ocean model: ECCO Version 4 release 4 (based on MITgcm) Horizontal domain: Global Horizontal resolution: Variable spacing ranging from 22 km to 111 km (see Forget et al. 2015, section 2) Vertical resolution: 50 levels ranging in thickness from 10 m at surface to 460 m at depth Boussinesq model?: Yes Tabulated COM corrected for volume changes due to steric effects?: Yes Includes mass effects from net real freshwater flux Ocean model forcing: 6-hourly ERA-Interim values adjusted by optimization (see Forget et al. 2015, section 3.5); atmospheric surface pressure included but not adjusted by the optimization (see Fukumori et al. 2019) Data assimilated: sea level altimetry, in situ temperature/salinity, satellite SST/SSS, bottom pressure, sea-ice concentration (see Fukumori et al. 2019) Notes: The mean has been removed from the tabulated COM and mass values. The mean COM (meters; x,y,z) = -7.63696350E+05 -4.66355056E+05 -8.75387015E+05 The mean total ocean mass (kg) = 1.37376730E+21 This ocean mass can be used to convert the COM values given here to geocenter values.
ECCO_v4r4_noFWF.cm		MITgcm	Jan 1992 – Dec 2017	1 hour	CoM (w/o FWF)
File name: ECCO_v4r4_noFWF.cm File contents: oceanic center-of-mass (COM), and total ocean mass (includes effects of sea ice) File units: meters for COM, kg for mass Contact: Rui Ponte ([email protected]) References: Forget et al. 2015, doi:10.5194/gmd-8-3071-2015 Fukumori et al. 2019, https://www.ecco-group.org/docs/v4r4_synopsis.pdf Quinn et al. 2019, doi:10.1093/gji/ggy452 Temporal domain: January 1992 through December 2017 Temporal resolution: hourly Number of data records: 227903 Ocean model: ECCO Version 4 release 4 (based on MITgcm) Horizontal domain: Global Horizontal resolution: Variable spacing ranging from 22 km to 111 km (see Forget et al. 2015, section 2) Vertical resolution: 50 levels ranging in thickness from 10 m at surface to 460 m at depth Boussinesq model?: Yes Tabulated COM corrected for volume changes due to steric effects?: Yes Does not include mass effects from net real freshwater flux Ocean model forcing: 6-hourly ERA-Interim values adjusted by optimization (see Forget et al. 2015, section 3.5); atmospheric surface pressure included but not adjusted by optmization (see Fukumori et al. 2019) Data assimilated: sea level altimetry, in situ temperature/salinity, satellite SST/SSS, bottom pressure, sea-ice concentration (see Fukumori et al. 2019) Notes: The mean has been removed from the tabulated COM and mass values. The mean COM (meters; x,y,z) = -7.63703879E+05 -4.66360672E+05 -8.75396018E+05 The mean total ocean mass (kg) = 1.37371282E+21 This ocean mass can be used to convert the COM values given here to geocenter values.
ECCO_v4r3_yesFWF.cm	deprecated (see ECCO_v4r4_yesFWF.cm)	MITgcm	Jan 1992 – Dec 2015	1 hour	CoM (with FWF)
File name: ECCO_v4r3_yesFWF.cm File contents: oceanic center-of-mass (COM), and total ocean mass (includes effects of sea ice) File units: meters for COM, kg for mass Contact: Rui Ponte ([email protected]) References: Forget et al. 2015, doi:10.5194/gmd-8-3071-2015 Fukumori et al. 2018, https://www.ecco-group.org/docs/v4r3_data.pdf Quinn et al. 2019, doi:10.1093/gji/ggy452 Temporal domain: January 1992 through December 2015 Temporal resolution: hourly Number of data records: 210359 Ocean model: ECCO Version 4 release 3 (based on MITgcm) Horizontal domain: Global Horizontal resolution: Variable spacing ranging from 22 km to 111 km (see Forget et al. 2015, section 2) Vertical resolution: 50 levels ranging in thickness from 10 m at surface to 460 m at depth Boussinesq model?: Yes Tabulated COM corrected for volume changes due to steric effects?: Yes Includes mass effects from net real freshwater flux Ocean model forcing: 6-hourly ERA-Interim values adjusted by optimization (see Forget et al. 2015, section 3.5); no pressure forcing used Data assimilated: sea level altimetry, in situ temperature/salinity, satellite SST/SSS, bottom pressure, sea-ice concentration (see Fukumori et al. 2018) Notes: The mean has been removed from the tabulated COM and mass values. The mean COM (meters; x,y,z) = -7.63692443E+05 -4.66366138E+05 -8.75353737E+05 The mean total ocean mass (kg) = 1.37375920E+21 This ocean mass can be used to convert the COM values given here to geocenter values.
ECCO_v4r3_noFWF.cm	deprecated (see ECCO_v4r4_noFWF.cm)	MITgcm	Jan 1992 – Dec 2015	1 hour	CoM (w/o FWF)
File name: ECCO_v4r3_noFWF.cm File contents: oceanic center-of-mass (COM), and total ocean mass (includes effects of sea ice) File units: meters for COM, kg for mass Contact: Rui Ponte ([email protected]) References: Forget et al. 2015, doi:10.5194/gmd-8-3071-2015 Fukumori et al. 2018, https://www.ecco-group.org/docs/v4r3_data.pdf Quinn et al. 2019, doi:10.1093/gji/ggy452 Temporal domain: January 1992 through December 2015 Temporal resolution: hourly Number of data records: 210359 Ocean model: ECCO Version 4 release 3 (based on MITgcm) Horizontal domain: Global Horizontal resolution: Variable spacing ranging from 22 km to 111 km (see Forget et al. 2015, section 2) Vertical resolution: 50 levels ranging in thickness from 10 m at surface to 460 m at depth Boussinesq model?: Yes Tabulated COM corrected for volume changes due to steric effects?: Yes Does not include mass effects from net real freshwater flux Ocean model forcing: 6-hourly ERA-Interim values adjusted by optimization (see Forget et al. 2015, section 3.5); no pressure forcing used Data assimilated: sea level altimetry, in situ temperature/salinity, satellite SST/SSS, bottom pressure, sea-ice concentration (see Fukumori et al. 2018) Notes: The mean has been removed from the tabulated COM and mass values. The mean COM (meters; x,y,z) = -7.63698852E+05 -4.66370919E+05 -8.75361400E+05 The mean total ocean mass (kg) = 1.37371282E+21 This ocean mass can be used to convert the COM values given here to geocenter values.
ECCO_kf080i.cm		MITgcm	Jan 1993 – Mar 2020	1 day	CoM
File name: ECCO_kf080i.cm File contents: oceanic center-of-mass (COM) File units: meters Contact: Richard Gross, [email protected] References: Gross, R.S., An Improved Empirical Model for the Effect of Long-Period Ocean Tides on Polar Motion, J. Geodesy, 83, 635-644, doi:10.1007/s00190-008-0277-y, 2009 Temporal domain: January 1993 through March 2020 Temporal resolution: 1-day averages Number of data records: 9950 Ocean model: ECCO (based on MITgcm) Horizontal domain: 80 degrees South to 80 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated COM corrected for volume changes due to steric effects?: No (correction is negligibly small, being 6 orders of magnitude smaller than the COM variations) Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure: None Data assimilated: Altimetric measurements of sea surface height and XBT data Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated COM values. The mean oceanic COM (m; x,y,z) = -7.65137016E+05 -4.69378616E+05 -9.60916152E+05 The mass of the ocean model is 1.366125999072050E+021 kg. This ocean mass can be used to convert the COM values given here to geocenter values. The tidal contamination present in previous versions of the ECCO/JPL data assimilative ocean models (e.g., kf049f,kf066b) is not present in this model. For a discussion of this problem see Gross (2009). A problem with assimilating altimetric data in kf080 has been fixed here.
ECCO_kf079.cm		MITgcm	Jan 1993 – Mar 2020	1 day	CoM
File name: ECCO_kf079.cm File contents: oceanic center-of-mass (COM) File units: meters Contact: Richard Gross, [email protected] References: Gross, R.S., An Improved Empirical Model for the Effect of Long-Period Ocean Tides on Polar Motion, J. Geodesy, 83, 635-644, doi:10.1007/s00190-008-0277-y, 2009 Temporal domain: January 1993 through March 2020 Temporal resolution: 1-day averages Number of data records: 9950 Ocean model: ECCO (based on MITgcm) Horizontal domain: 80 degrees South to 80 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated COM corrected for volume changes due to steric effects?: No (correction is negligibly small, being 6 orders of magnitude smaller than the COM variations) Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure: None Data assimilated: None Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated COM values. The mean oceanic COM (m; x,y,z) = -7.65134890E+05 -4.69377674E+05 -9.60916455E+05 The mass of the ocean model is 1.366126000458376E+21 kg. This ocean mass can be used to convert the COM values given here to geocenter values. The tidal contamination present in previous versions of the ECCO/JPL data assimilative ocean models (e.g., kf049f,kf066b) is not present in this model. For a discussion of this problem see Gross (2009).
ECCO_kf066b.cm	deprecated (see kf080i.cm)	MITgcm	Jan 1993 – Dec 2008	1 day	CoM
File name: ECCO_kf066b.cm File contents: oceanic center-of-mass (COM) File units: meters Contact: Richard Gross, [email protected] Temporal domain: January 1993 through December 2008 Temporal resolution: 1-day averages Number of data records: 5843 Ocean model: ECCO (based on MITgcm) Horizontal domain: 80 degrees South to 80 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated COM corrected for volume changes due to steric effects?: No (correction is negligibly small, being 6 orders of magnitude smaller than the COM variations) Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure: None Data assimilated: Altimetric measurements of sea surface height and XBT data Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated COM values. The mean oceanic COM (m; x,y,z) = -7.65133304E+05 -4.69377652E+05 -9.60916615E+05 The mass of the ocean model is 1.366125999072050E+21 kg. This ocean mass can be used to convert the COM values given here to geocenter values.
ECCO_kf066a2.cm	deprecated (see kf079.cm)	MITgcm	Jan 1993 – Dec 2008	1 day	CoM
File name: ECCO_kf066a2.cm File contents: oceanic center-of-mass (COM) File units: meters Contact: Richard Gross, [email protected] Temporal domain: January 1993 through December 2008 Temporal resolution: 1-day averages Number of data records: 5843 Ocean model: ECCO (based on MITgcm) Horizontal domain: 80 degrees South to 80 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated COM corrected for volume changes due to steric effects?: No (correction is negligibly small, being 6 orders of magnitude smaller than the COM variations) Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure: None Data assimilated: None Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated COM values. The mean oceanic COM (m; x,y,z) = -7.65133398E+05 -4.69378126E+05 -9.60916615E+05 The mass of the ocean model is 1.366126000458376E+21 kg. This ocean mass can be used to convert the COM values given here to geocenter values.
ECCO_kf049f.cm	deprecated (see kf080i.cm)	MITgcm	Jan 1993 – Mar 2006	1 day	CoM
File name: ECCO_kf049f.cm File contents: oceanic center-of-mass (COM) File units: meters Contact: Richard Gross, [email protected] Temporal domain: January 1993 through March 2006 Temporal resolution: 1-day averages Number of data records: 4837 Ocean model: ECCO (based on MITgcm) Horizontal domain: 74 degrees South to 74 degrees North latitude Horizontal resolution: 1/3 degree at equator to 1 degree at high latitudes by 1 degree longitude Vertical resolution: 46 levels ranging in thickness from 10 m at surface to 400 m at depth Boussinesq model?: Yes Tabulated COM corrected for volume changes due to steric effects?: No (correction is negligibly small, being 6 orders of magnitude smaller than the COM variations) Ocean model forcing: Surface wind stress: 12-hour NCEP/NCAR reanalysis Surface heat flux: Daily NCEP/NCAR reanalysis Surface freshwater flux: Daily NCEP/NCAR reanalysis (freshening only) Surface pressure: None Data assimilated: Altimetric measurements of sea surface height and XBT data Notes: The tabulated date corresponds to the midpoint of the 1-day-long averaging interval. The mean has been removed from the tabulated COM values. The mean oceanic COM (m; x,y,z) = -7.65133134E+05 -4.69378457E+05 -9.60916344E+05 The mass of the ocean model is 1.3661260089537554E+21 kg. This ocean mass can be used to convert the COM values given here to geocenter values.

Ocean-Bottom Pressure

File	Ocean Model	Date Span	Resolution	Contents
ECCO v4-r4 OBPNOPAB	MITgcm	Jan 1992 – Dec 2017	1 day	OBP
ECCO Version 4: Fourth Release (1992-2017) [ECCO v4-r4] [https://ecco.jpl.nasa.gov/drive/files/Version4/Release4/] This directory contains the "ECCO version 4, release 4" daily mean outputs: README: This file OBP: Ocean Bottom Pressure adjusted with global steric height change (m). OBP includes the effect of air-pressure forcing. To compare with GRACE data that has the global mean of air-pressure removed, one needs to use OBPNOPAB, which is part of the v4r4 product. OBPNOPAB: OBP with Global Mean Air-Pressure Removed (m). OBPNOPAB can be compared against GRACE data that has the global mean of air-pressure removed. SALT: Salinity (psu) sIceLoad: SEAICE loading (kg/m^2) SIarea: SEAICE fractional ice-covered area [0 to 1] (m^2/m^2) SIheff: SEAICE effective ice thickness (m) SIhsnow: SEAICE effective snow thickness (m) SSH: Surface Height Anomaly adjusted with global steric height change and sea-ice load (m). SSH is the sum of the dynamic SSH (SSHDYN) and the inverted barometer SSH (SSHIB). SSHDYN, not SSH, should be compared with the IB corrected altimetry data. SSH, SSHDYN, and SSHIB are all part of the v4r4 product. SSHDYN: Dynamic SSH (SSH-SSHIB) (m) SSHIB: Inverted Barometer SSH (m) THETA: Potential Temperature (degC) Each directory contains daily tiled netCDF files for a particular variable and year. The tiled netCDF file is such that a global field is split into 13 tiles with each tile for one 90x90 subdomain of ECCO v4 native grid. References Fukumori, I., O. Wang, I. Fenty, G. Forget, P. Heimbach, and R. M. Ponte, 2017: ECCO Version 4 Release 3, http://hdl.handle.net/1721.1/110380, doi:1721.1/110380. Available at https://ecco.jpl.nasa.gov/drive/files/Version4/Release3/doc/v4r3_estimation_synopsis.pdf Forget, G., J.-M. 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. Geoscientific Model Development, 8, 3071-3104, doi:10.5194/gmd-8-3071-2015 Software Fukumori, I., O. Wang, I. Fenty, G. Forget, P. Heimbach, and R. M. Ponte, 2019: ECCO Version 4 Release 4. Available at https://ecco.jpl.nasa.gov/drive/files/Version4/Release4/doc/v4r4_synopsis.pdf The ECCO v4-r4 files were produced using the 'checkpoint66g' versions of the general circulation model (MITgcm and ECCO v4 settings), Python analysis package (ECCOv4-py), and Matlab analysis toolboxes (gcmfaces and MITprof). These software versions are available at http://mitgcm.org/download/other_checkpoints/, https://github.com/ECCO-GROUP/ECCOv4-py, and https://github.com/MITgcm/gcmfaces. Contact Us: [email protected] (please subscribe via http://mailman.mit.edu/mailman/listinfo/ecco-support) README file revision history: README file creation: Ou Wang [2019/08/30]
ECCO v4-r4 OBP	MITgcm	Jan 1992 – Dec 2017	1 day	OBP
ECCO Version 4: Fourth Release (1992-2017) [ECCO v4-r4] [https://ecco.jpl.nasa.gov/drive/files/Version4/Release4/] This directory contains the "ECCO version 4, release 4" daily mean outputs: README: This file OBP: Ocean Bottom Pressure adjusted with global steric height change (m). OBP includes the effect of air-pressure forcing. To compare with GRACE data that has the global mean of air-pressure removed, one needs to use OBPNOPAB, which is part of the v4r4 product. OBPNOPAB: OBP with Global Mean Air-Pressure Removed (m). OBPNOPAB can be compared against GRACE data that has the global mean of air-pressure removed. SALT: Salinity (psu) sIceLoad: SEAICE loading (kg/m^2) SIarea: SEAICE fractional ice-covered area [0 to 1] (m^2/m^2) SIheff: SEAICE effective ice thickness (m) SIhsnow: SEAICE effective snow thickness (m) SSH: Surface Height Anomaly adjusted with global steric height change and sea-ice load (m). SSH is the sum of the dynamic SSH (SSHDYN) and the inverted barometer SSH (SSHIB). SSHDYN, not SSH, should be compared with the IB corrected altimetry data. SSH, SSHDYN, and SSHIB are all part of the v4r4 product. SSHDYN: Dynamic SSH (SSH-SSHIB) (m) SSHIB: Inverted Barometer SSH (m) THETA: Potential Temperature (degC) Each directory contains daily tiled netCDF files for a particular variable and year. The tiled netCDF file is such that a global field is split into 13 tiles with each tile for one 90x90 subdomain of ECCO v4 native grid. References Fukumori, I., O. Wang, I. Fenty, G. Forget, P. Heimbach, and R. M. Ponte, 2017: ECCO Version 4 Release 3, http://hdl.handle.net/1721.1/110380, doi:1721.1/110380. Available at https://ecco.jpl.nasa.gov/drive/files/Version4/Release3/doc/v4r3_estimation_synopsis.pdf Forget, G., J.-M. 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. Geoscientific Model Development, 8, 3071-3104, doi:10.5194/gmd-8-3071-2015 Software Fukumori, I., O. Wang, I. Fenty, G. Forget, P. Heimbach, and R. M. Ponte, 2019: ECCO Version 4 Release 4. Available at https://ecco.jpl.nasa.gov/drive/files/Version4/Release4/doc/v4r4_synopsis.pdf The ECCO v4-r4 files were produced using the 'checkpoint66g' versions of the general circulation model (MITgcm and ECCO v4 settings), Python analysis package (ECCOv4-py), and Matlab analysis toolboxes (gcmfaces and MITprof). These software versions are available at http://mitgcm.org/download/other_checkpoints/, https://github.com/ECCO-GROUP/ECCOv4-py, and https://github.com/MITgcm/gcmfaces. Contact Us: [email protected] (please subscribe via http://mailman.mit.edu/mailman/listinfo/ecco-support) README file revision history: README file creation: Ou Wang [2019/08/30]
ECCO_kf080i.obp	MITgcm	Jan 1993 – present	1 day	OBP
DESCRIPTION OF FILES Near Real-Time Analyses KalmanFilter (kf080): Kalman filter analysis Smoother (dr080): RTS smoother analysis Simulation (kf079): Simulation with no data assimilated Directory Structure Model results are archived first by year and then by quarter of the year. For instance, 1995 of run dr080 will be in directory dr080_1995. Inside the directory for a given year, there are four subdirectories corresponding to the four quarters of the year: n10day_01_09, n10day_10_18, n10day_19_27, and n10day_28_37. For instance, n10day_10_18 contains the results of the 10th to 18th 10-day period of the year, i.e., day 90 to day 180 of year 1995. Note n10day_28_37 contains results for day 270 to day 370 which is the 5th day of the following year for non-leap years (4th day for leap years.) The 37th 10-day mean is an average from year-day 360 to 370. File Naming Convention Each subdirectory for a particular quarter of a particular year contains both time-averaged fields and instantaneous fields. Naming convention of the files is illustrated by the following examples: Uave_08_08.02160_04320_240.cdf U: Variable name (Zonal velocity) ave: Time-averaged field. If no "ave", the field is an instantaneous field. 08_08: The run was conducted by using 8 by 8 tiled layout. 02160_04320: time span from time step 2160 to 4320. The model uses 1-hour time step. So the time span is from day 90 to day 180. 240: The time interval in time steps between time records. For time-averaged fields, the time interval is also the length in time steps of average period. For 1-hour time step, 240 time steps is 10-day. H_08_08.02160_04320_012.cdf H: Variable name (Sea level). Since there is no "ave" following "H", the field is an instantaneous field. 08_08: The run was conducted by using 8 by 8 tiled layout. 02160_04320: Time span from time step 2160 to 4320. The model has 1-hour time step. So the time span is from day 90 to day 180. 012: The time interval of in time steps between records. The 12 time steps is 12-hour for 1-hour time step. Variables available (File prefixes) 10-day average fields Save: Salinity (PSU) Tave: Temperature (degC) Uave: Zonal (east-west) velocity (m/s) Vave: Meridional (north-south) velocity (m/s) Wave: Vertical velocity (m/s) Have: Sea level (m) 12-hourly instantaneous fields H: Sea level (m) OBP: Ocean bottom pressure (newton/meter^2) OBPano: Ocean bottom pressure anomaly relative to the 1993-2009 time-mean of kf079 OBP (newton/meter^2) Hourly instantaneous fields SBO_DIAG.data: The core products of the IERS Special Bureau for the Oceans. The files are in direct access format with 11 variables per time record pertaining to earth rotation of that year. time: seconds from the beginning of the year oceanic angular momentum due to currents x-dir: kg m^2/s oceanic angular momentum due to currents y-dir: kg m^2/s oceanic angular momentum due to currents z-dir: kg m^2/s oceanic angular momentum due to pressure x-dir: kg m^2/s oceanic angular momentum due to pressure y-dir: kg m^2/s oceanic angular momentum due to pressure z-dir: kg m^2/s mass: kg center-of-mass of oceans x-dir: meter, where the x-dir is from the center of the Earth to 0E center-of-mass of oceans y-dir: meter, where the y-dir is from the center of the Earth to 90E center-of-mass of oceans z-dir: meter, where the z-dir is along the Earth's rotation axis SBO_DIAG.meta: meta data for SBO_DIAG.data TS tendencies (30-day average fields) EPrelaxAve: Surface relaxation of surface salt flux (psu/sec) gs: Prefix for terms in the salinity budget (psu/sec) gt: Prefix for terms in the temperature budget (degree/sec) Extave: External forcing (includes penetrative components) Iceave: Forcing due to seaice formation KFave: Forcing corresponding to Kalman filter corrections KPPave: Forcing due to KPP mixing Relaxave: Forcing due to surface relaxation Uave: Forcing due to U advection Vave: Forcing due to V advection Wave: Forcing due to W advection Xdiffave: Forcing due to zonal diffusion Ydiffave: Forcing due to meridional diffusion ZdiffGMave: Forcing due to vertical component of GM diffusion Zdiffave: Forcing due to implicit or explicit vertical diffusion Temporally integrating each component and summing them together equal the temporal variation of T & S; these estimates are instantaneous values as opposed to time-averages as in Tave and Save files listed above. The 13th record of each year in the files corresponds to tendency averages over the remaining 5 (6 for leap year) days of each year. Advective tendencies, Uave, Vave, Wave, above are in flux form, viz., d(uT)/dx, etc. Advective tendencies in gradient form ( u dT/dx ) are also available in a separate directory (NON_MOTO). Differences between these two forms of tendencies and their physical significances are described in Lee et al (2004). The advective tendencies of volume mean temperature and salinity used in referencing the advective flux form tendencies in the "external form" of the TS budgets, described in Lee et al (2004), can be evaluated from the 10-day average fields (Tave, Save, Uave, Vave, Wave) listed elsewhere. See, for instance, Kim et al (2007) for an example of such computation. Forcing The forcing data are based on NCEP Reanalysis. When NCEP Reanalysis data are not available, NECP Operational data are used for ust, vtr, and tmp and the 1980-2000 mean NCEP Reanalysis for e-p, qnet, and sw. e-p: Evaporation minus Precipitation min runoff (kg/m^2/s). Positive to increase S. qnet: Surface heat flux (latent+sensible+longwave) entering the top layer (W/m^2). Positive to increase T. sw: Penetrating short wave radiation (W/m^2). Positive to increase T. tmp: Sea surface temperature (deg C). ustr: Zonal wind stress (N/m^2). vstr: Meridional wind stress (N/m^2). The files are direct access binary files written in tiled-format used in corresponding model integrations. References Kim, S.-B., T. Lee, I. Fukumori, 2007. Mechanisms controlling the interannual variation of mixed layer temperature averaged over the NINO3 region. J. Clim., 20, 3822-3843. Lee, T., I. Fukumori and B. Tang, 2004. Temperature advection: internal versus external processes, J. Phys. Oceanogr., 34, 1936-1944.

*ECCO Drive requires a NASA Earthdata Account for access.