Satellite gravimetry and altimetry combined with in-situ ocean temperature profiles enable to close the Earth energy budget and track yearly global energy anomalies from top of the atmosphere to the ocean

More than 90% of the excess energy entering the Earth system due to increased greenhouse gas concentrations is stored in the ocean within just a few years. This ocean heat storage has helped limit surface warming and modulate Earth’s radiative response, thereby influencing the global energy budget. Understanding Ocean Heat Content (OHC), including its temporal and spatial variations, is crucial for grasping global energy dynamics and constraining climate change projections.

Geodetic observations from satellite gravimetry (GRACE and GRACE-FO) and satellite altimetry enable to estimate OHC through thermal expansion, derived from sea level rise corrected for changes in ocean mass. This geodetic approach provides broad coverage and high resolution but faces challenges in resolving interannual variability. In particular, it cannot determine the depth at which heat is stored, introducing ambiguity when converting thermal expansion into OHC anomalies.

This work introduces a new OHC product that, for the first time, combines in-situ, altimetric, and gravimetric data using an inverse method. The inclusion of in-situ ARGO data helps constrain the vertical distribution of heat down to 2000 m, addressing ambiguities in the geodetic approach. By optimizing the residuals between in-situ and geodetic OHC and applying objective mapping techniques, the method produces consistent OHC fields along with associated uncertainty estimates.

The new product is validated against existing in-situ datasets. Its derivative—Ocean Heat Uptake (OHU)—is compared with CERES radiation budget data to assess the closure of the Earth’s energy balance over the ocean. The comparison shows that the ocean energy budget is closed from the top of the atmosphere (TOA) to 2000 m depth on an annual basis, with a residual of approximately 0.3 W/m² (1σ). This implies that energy anomalies greater than 0.3 W/m² can be tracked within the ocean system between TOA and 2000 m depth thanks to their signature on the Earth deformation.