Driving Stresses in the Antarctic Ice Sheet

Abstract

Radio echo-soundings obtained during joint programmes of the US National Science Foundation (NSF), the Scott Polar Research Institute (SPRI), and the Technical University of Denmark (TUD) have provided sufficient data of good quality to map driving stress over approximately one half of the Antarctic ice sheet. Computerized averaging of data over 1 degree of latitude squares has largely eliminated local effects of longitudinal stress variations on surface slope. Methods of data handling are outlined. Variations in driving stresses between different regions are discussed in relation to the balancing restraining forces. These are primarily related to ice velocity and thickness, bedrock topography, the presence of basal water and possibly to the development of easy-glide fabric in the ice mass, to the temperature of basal ice layers, and to the excess hydrostatic pressure in areas where ice rests on bedrock well below sea-level.