Effect of Ice Shelf Changes on Ice Sheet Volume Change in the Amundsen Sea Embayment, West Antarctica

Abstract

We derived elevation changes of the Geoscience Laser Altimeter System level-2 altimetry data from repeat tracks in the Amundsen Sea Embayment during 2004 to 2008. Then, we created four grid surfaces. Changes of ice shelf fronts in the study area were extracted from MODIS/Terra Calibrated Radiances Level-1B at 250-m resolution to analyze the relationship between ice shelf and ice sheet change. The results show the average volume change of the study area is about -92.8 km3/a. The obvious regions of the elevation decrease mainly located near the coastline, and the diversity of the ice volume loss corresponding to an elevation reduction exceeding 2 m was distinct between different periods. By analyzing the ice volume losses of the ice shelves and the large glaciers in the Amundsen Sea Embayment, we found the thinning of the ice shelf may result in the volume loss of the ice sheet, especially the thinning near the grounding line into which the glaciers flow. Because of this, the retreat of an ice shelf may cause the accelerated volume loss of the ice sheet, and the glacier buttressing ability of the fragmented ice shelf is weaker than that of unrifted or fractured large ice shelves.