Initiative to explore uncertainty in Earth's Energy Imbalance calculations

The main question the World Climate Research Program (WCRP) Global Energy and Water Cycle Exchanges (GEWEX) Data and Analysis Panel (GDAP) was formed to address is "how sensitive is the Earth's climate to changes in radiative and other forcings?". This is a rather broad question - in fact multiple large scale questions. One initiative of the GDAP is quantifying and understanding the specific impacts of the Earth's Energy Imbalance (EEI) - the difference between incoming solar radiation and outgoing longwave radiation at the top of the atmosphere (TOA). Quantifying EEI is vital to understanding changes to the Earth's heat budget and where the heat is stored. There are observation systems for the incoming solar radiation as well as for the various major energy sinks within the Earth's system - atmosphere, land, ice, and oceans. There are quantifications for each of these energy sinks, often by multiple scientific teams around the world. Understanding the uncertainty of these quantifications in comparison with calculations (and uncertainties) of TOA incoming solar radiation is necessary for an understanding of the confidence in our quantification of EEI. Given that the ocean is by far the largest radiation sink (> 90% of the total), evaluating the uncertainty of ocean heat content (OHC) will be addressed first. There have been a number of scientific papers evaluating OHC uncertainty and comparing OHC to TOA net radiation, many concentrating on one particular OHC method. This initiative will examine uncertainties across OHC methods to provide a better comparison metric with TOA net radiation. Initial progress and further plans will be discussed.