Comparison of Antarctic Basin Scale Mass Change from GRACE/GOCE and CryoSat-2
Monday, 15 December 2014: 2:55 PM
When data of the GRACE satellite gravity mission are combined with those of the satellite gravity gradiometer mission GOCE, it can be shown that trends in ice mass balance can be resolved at basin scale for the Amundsen Sea Sector in West Antarctica. We will extend our analysis to the complete Antarctic continent, paying special attention to unavoidable leakage effects between basins, and glacial isotactic adjustment and its uncertainty. In addition, it is known that the gravitational flattening coefficient is better determined from satellite laser ranging (SLR) than from GRACE. The GRACE C20 coefficients are therefore routinely replaced by those from SLR. We will show that an alternative SLR time series, using tracking data to more satellites, may give ice mass trend differences of 10 – 15 Gt/yr (in the order of 13% of the total signal) compared with the commonly applied SLR time series. With data of the CryoSat-2 radar altimeter mission Antarctic ice sheet elevation changes can be determined, which can be converted to mass changes. GRACE/GOCE and CryoSat-2 ice mass trends will be compared and the possible cause of differences will be discussed.