MAPPING TIDE-WATER GLACIER DYNAMICS IN EAST GREENLAND USING LANDSAT DATA

Landsat multispectral scanner and thematic mapper images were co-registered for the Kangerdlugssuaq Fjord region in East Greenland and were used to map glacier drainage-basin areas, changes in the positions of tide-water glacier termini and to estimate surface velocities of the larger tide-water glaciers. Statistics were compiled to document distance and area changes to glacier termini. The methodologies del eloped in this study are broadly applicable to the investigation of tide-water glaciers in other areas. The number of images available for consecutive years and the accuracy with which images are co-registered are key factors that influence the degree to which regional glacier dynamics can be characterized using remotely sensed data. Three domains of glacier state were interpreted: net increase in terminus area in the southern part of the study area, net loss of terminus area for glaciers in upper Kangerdlugssuaq Fjord and a slight loss of glacier terminus area northward from Ryberg Fjord. Local increases in the concentrations of drifting icebergs in the fjords coincide with the observed extension of glacier termini positions. Ice-surface velocity estimates were derived for several glaciers using automated image cross-correlation techniques. The velocity determined for Kangerdlugssuaq Gletscher is approximately 5.0 km a(-1) and that for Kong Christian IV Gletscher is 0.9 km a(-1). The continuous 5.0 km a presence of icebergs and brash ice in front of these glaciers indicates sustained rates of ice-front calving.