ICE VELOCITY OBSERVATIONS AT GREENLAND’S JAKOBSHAVN GLACIER USING ERS-2 3-DAY REPEAT CAMPAIGN DATA

摘要

Investigations of short-term changes in ice flow have sofar been limited by a lack of fine temporal resolutionsatellite datasets. Here we explore the unique 3-daytime-series acquired by the recent ERS-2 3-day repeatcampaign to study ice dynamical processes atGreenland’s Jakobshavn glacier. Although we observe agradual velocity increase of up to 22 % at the lower partof the glacier in early summer, no significant trend inthe velocity evolution is found further upstream despitewidespread surface melting. Our results suggest that theobserved ice velocity fluctuations are not related toseasonal changes in the degree of basal ice lubrication;rather, they appear to be linked to changes in theglacier’s calving front position. Long-term acquisitionsof SAR data from satellites with a relatively short repeattime, such as the planned Sentinel-1 satelliteconstellation, are essential to obtain a betterunderstanding of glacier and ice sheet dynamics.