Measurement of Surface Deformation of the Greenland Ice Sheet by Satellite Tracking

Abstract

Seven Magnavox MX1502 satellite receivers were used during the summers of 1980 and 1981 to obtain the coordinates of 22 stations in three locations on the Greenland ice sheet. Two of the receivers were located at stationary sites on the west coast of Greenland for both seasons. This allowed the short-arc method to be used to obtain relative coordinates with high precision. The stations were located at about 65° N, and positions on the ice sheet were obtained with formal accuracies of better than 0.20 m. From the coordinates, the station velocities, ice-sheet slopes, baseline lengths (between the stations) and strain-rates were calculated. Our results show that the two stations just to the east of the ice crest are not moving in the expected direction (north-east) but are moving in a direction slightly west of north. Hence, the positions of the ice crest and the ice divide do not coincide. The other stations are moving approximately as expected. No major velocity differences between, neighboring flow lines are apparent. The magnitudes of the maximum strain and the velocities increase away from the ice divide and with increasing slope.