Radio echo sounding in the Shirase Glacier drainage basin

Abstract

Airborne radio echo sounding was carried out in order to measure the thickness of the ice sheet in the Shirase Glacier drainage basin. From the analysis of the result obtained, the bedrock topography was estimated and it was found that the elevation of the bedrock in the upstream area of the basin was about 500-1000m higher than sea level as predicted by preliminary works. The investigation of the echo strength reflected from the bedrock indicates that the echo in the main part of the ice flow in the basin is stronger than in the edge part. Since the strengthening of echo intensity is caused by the existence of water, the strong echo observed in the main part supports an assumption proposed from the thinning of the ice sheet that the main part of the base of the basin is wet and the ice sheet is sliding on the bedrock.