Re-Estimation of the Greenland Ice Sheet Changes from ICESat Measurements with Slope Correction

Abstract

The Greenland ice sheet, the second largest glacier in the world after the Antarctic ice sheet, is losing its mass significantly since the 21st century. Although Ice, Cloud, and land Elevation Satellite (ICESat) has been successfully applied to detect changes in the elevation of the Greenland ice sheet since its launch in 2003, there are larger uncertainty to retrieve the glacier height in the altimetry data processing. In this paper, we use repeat-tracks method with slope correction to re-process ICESat data from 2003–2008 and estimate the mass changes of Greenland ice sheet. The elevation change results varies from about −2 m/yr up to 1.5 m/yr. The well-pronounced height decrease are clearly visible in the catchment area of J akobshavn Isbrae glacier (north-western), the Helheim and Kangerdlugssuaq glaciers (south-eastern), where the elevation change rate reaches a remarkable amount of more than −2 m/yr. The elevation change rate is around zero in the northern area of the Greenland ice sheet. The elevation change rates in most of the inland arears are slightly positive with about 0.02m/yr, indicating that there are small amount of ice mass accumulation. The volume change rate of the whole Greenland ice sheet is −237.65km3/yr by the repeat-track plane fitting method from the ICESat elevation measurements. The volume change rate of the whole Greenland ice sheet is −198.54km3/r by the repeat-track with slope correction, which has a good agreement with GRACE measurements.