Elevation Changes of LAS, East Antarctica, Derived From ICESat and CryoSat-2 Altimetric Data

Abstract:

Understanding of mass changes of the Antarctic ice sheet is essential for sea level rise study. A research effort has been made to estimate elevation mass changes at Lambert Glacier-Amery Ice Shelf System (LAS), East Antarctica using ICESat data of 2004-2008 and Cryosat-2 data of 2010-2015. A repeat-tack processing method that includes a trend and the first order terrain terms is applied to repeat-track points of all ICESat Campaigns of 2004-2008. The estimated change rate in LAS from 2004-2008 is 3.14±4.13 Gt yr^-1. At the basin level, two basins show a combined positive trend of 8.16±2.96 Gt yr^-1 while other four basins a combined negative trend of -5.39±6.04 Gt yr^-1. Cryosat-2 altimeter works in three modes with the “synthetic aperture interferometer mode” (SARIn) and “low-resolution mode” (LRM) in LAS. Our data coverage is from 2010 to 2015. Cryosat-2 ground tracks do not maintain repeated points. We further divide the entire area into a grid of 5km by 5km. Then we estimate the elevation change rate in each grid cell using a least-squares fitting model with a trend and a second order polynomial. We found that the quality of the estimates is correlated with slopes of cells. The progress of the CryoSat-2 data processing result as well as the analysis with the existing ICESat result will be presented. An integrated model of both ICESat and CryoSat-2 data processing will be developed.