Monday 22 August 2005

GP1 - PLENARY SESSION
0800-0930 hours

002
Estimating heat storage from a combination of satellite altimetry and GRACE data
Chambers, Don¹
1 University of Texas - Center For Space Research, Austin, USA
Author email: chambers@csr.utexas.edu
Theoretically, the GRACE mission should observe sea level variations related to non-steric ocean mass changes, while satellite altimeters observe the total sea level (SL) variation, which are a combination of steric and non-steric signals. Thus, one can subtract the ocean mass variations observed by GRACE from the total sea level observed by satellite altimeters (provided the mass variations are expressed in equivalent water level) in order to determine steric SL variations. Since steric sea level variations are predominantly caused by changes in ocean heat storage, one can relate steric sea level to heat storage. This is useful for combining with data from direct temperature profiles, or as a measure of heat storage variation where there are no direct observations. In practice, however, there are subtle corrections that need to be applied to either the GRACE or altimeter data in order to reconcile the two data sets. If this is not done properly, the resulting combination will be wrong. Here we will describe how to properly combine GRACE and altimetry, noting the important corrections that need to be applied to each, and the conversion from steric sea level to heat storage. We demonstrate the accuracy by comparing results to those obtained from mean seasonal temperature profiles from the World Ocean Atlas 2001 (WOA01) climatology, as well as real monthly profiles from 2002 to 2004.G41000-1200 hours

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