Constraining the Global Ocean Heat Content Through Assimilation of CERES-Derived TOA Energy Imbalance Estimates

The Earth's energy imbalance (EEI) is stored in the oceans for the most part. Thus, estimates of its variability can be ingested in ocean retrospective analyses to constrain the global ocean heat budget. Here we propose a scheme to assimilate top of the atmosphere global radiation imbalance estimates from Clouds and the Earth's Radiant Energy System (CERES) in a coarse-resolution variational ocean reanalysis system (2000-2014). The methodology proves able to shape the heat content tendencies according to the EEI estimates, without compromising the reanalysis accuracy. Spurious variability and underestimation (overestimation) present in experiments with in situ (no) data assimilation disappear when EEI data are assimilated. The warming hiatus present without the assimilation of EEI data is mitigated, inducing ocean warming at depths below 1,500 m and slightly larger in the Southern Hemisphere, in accordance with recent studies. Furthermore, the methodology may be applied to Earth System reanalyses and climate simulations to realistically constrain the global energy budget.