Antarctic ice-shelf thickness changes from CryoSat-2 SARIn mode measurements: Assessment and comparison with IceBridge and ICESat

Ice-shelf thickness changes are of critical importance for understanding the stability of the Antarctic ice-sheet because they restrain the seaward flow of grounded glaciers. In this study, we find that neither backscatter nor leading-edge width contained in the least-squares fitting model can improve the accuracy of ice-shelf thickness change estimations from CryoSat-2, which is validated by comparing the CryoSat-2-derived elevation changes from least-squares fitting models with different combinations of waveform parameters against the Operation IceBridge ATM L4 data. Using the model without backscatter and leading-edge width to infer the thickness changes in Antarctic ice shelves from CryoSat-2, we find that the most significant thinning signals are mainly concentrated on the ice shelves along the Amundsen Sea coast, such as Getz, whose thickness variations are dominated by ocean-driven basal melting. This phenomenon has also been confirmed by the ICESat results. Overall, the Antarctic ice shelves volume changed on average by –0.34 ± 66.36 km3 yr−1 during the period from July 2010 to December 2016.