Meeting Documents

Leading Dynamical Processes of Global Marine Heatwaves

Abstract

Marine heatwaves (MHWs) have emerged as a very active area of research due to the devastating impacts of these events on marine ecosystems across different trophic levels. Yet, a clear understanding of the local drivers of these extreme ocean conditions is still limited at a global scale. Observations of the terms needed to constrain ocean heat budgets are very sparse, many ocean reanalysis products may have limitations due to the non-conservative nature of the data assimilation procedure used, while the fidelity of climate models in simulating MHWs is still unclear.

In this study, we make use of Argo floats observations and the Estimating the Circulation and Climate of the Ocean (ECCO) state estimate to evaluate local drivers of global MHWs both at the surface and in the subsurface. ECCO assimilates observations using the adjoint methodology, which optimizes the system trajectory given the observational constraints in a conservative fashion, making it an ideal product for the estimation of heat budgets. The representation of MHWs in ECCO, especially in the subsurface, is validated through the comparison with a new Argo climatology that also includes uncertainty estimates.

The findings from our study have significant implications for understanding the key factors driving MHWs on a global scale. A more complete understanding of MHWs and their drivers is crucial for predicting their development, duration, intensity and decline, to ultimately inform the development of mitigation and adaptation strategies in support of coastal communities.