Temporal changes in crevasses in the middle Slessor Glacier, Coats Land, East Antarctica through SAR data analysis

Abstract

Mosaic processing of SAR images by ERS 1/2 AMI revealed the detailed topography within a large valley (middle Slessor Glacier) in Coats Land, East Antarctica, showing oval and feather-shaped features that correspond to precipitous cliffs and accumulated crevasses, respectively. Time-series analysis of SAR intensity images acquired on six dates within the period October 1991 to August 2000 revealed the following topographic changes over time: (1) the feather-shaped feature moved down the slope at a rate of about 100 m/year; and (2) the extent of crevasse areas increased with time, both at the northern end of the feather-shaped feature and at the northeastern tip of the oval feature, with the increasing rates being much larger in the case of the feather-shaped feature. High increase ratios were generally correlated with a rapid increase in wintertime temperature within a short period of about 2 weeks: the relationship was approximated by an exponential function. Furthermore, we interpreted that the occurrence of a fault in the subglacial topography may have led to the initiation of ice fractures and a subsequent concentration of crevasses at the end of the feather-shaped feature.