Energy Imbalance in the Sunlit Ocean Layer

November 12, 2025

Gael Forget

Hosted by Maria Rugenstein

Abstract

The sunlit ocean layer (SOL, above 200m depth) is where marine life is most abundant and critical climate feedbacks are enacted. Rapid warming of the SOL was underscored recently by unprecedented marine heat waves. Yet, SOL’s heat budget (HB) is not well understood, globally or regionally, as it remains difficult to estimate from observations alone. Here we resolve this issue using an ocean reanalysis and provide a simple operational definition of SOL’s energy imbalance (SOL-EI ), as the 10-year mean SOL-HB . This approach provides a new climate index that is useful not only at the global scale, but also to decipher mechanisms and the regional interplay of processes.

Bio & Interests: I work as a research scientist at the Massachusetts Institute of Technology (MIT) where I investigate oceanography and climate. As part of the Department of Earth, Atmospheric and Planetary Sciences, my work focuses on ocean modeling and the analysis of global ocean data sets such as Argo profile collections and satellite altimetry. Amongst other approaches, I carry out ocean state estimation using the MIT general circulation model to interpolate and interpret ocean observations. I also participate in the development of the MITgcm and in the NASA Sea Level Change Team activities. My scientific interests include: Ocean circulation and Climate variability; tracer transport and turbulent transformation processes; interaction of bio-geochemistry and physical processes; global cycles of heat, water, and carbon; observational statistics; forward and inverse modeling.