Reconciling Observations of Global Sea Level Rise with Changes in the Earth's Energy Balance

Ocean warming and the thermal expansion of seawater account for a sizable portion of global sea-level rise during the past two decades. The rate of ocean warming, however, carries additional climatic significance because the vast majority of any excess heat trapped in the Earth's climate system winds up warming the oceans. Thus in addition to the implications for sea level rise, ocean warming rates also provide a measure of the net radiative balance of the Earth as a whole. Despite its importance, the historical record of global ocean warming still contains large uncertainties. Prior to global deployment of the Argo array in about 2005, the historical record of ocean warming is dominated by data from eXpendable BathyThermographs (XBTs), which are known to contain sizable systematic errors. Global ocean warming during the transition period between XBT and Argo data therefore remains highly uncertain. In this study, we consider observations from the Clouds and the Earth's Radiant Energy System (CERES) instruments to assess the Earth's net radiation balance from 2000 to 2010. These observations provide an important constraint on ocean warming rates during the critical period from 2003 to 2005 when ocean temperature observations transitioned from XBT to Argo data. Observations of the net change in ocean mass from GRACE, as well as the net change in total sea level rise from altimetry will also be used to constrain ocean warming rates during this period. Given these constraints, we will assess the validity of different corrections for XBT biases and will assess both the global sea level budget and energy balance during the first decade of the 2000s.