Improved elevation-change measurement of the southern Greenland ice sheet from satellite radar altimetry

摘要

A new analysis of Seasat and Geosat satellite radar altimeter measurements over the Greenland ice sheet was performed to determine surface elevation change. The new analysis includes twice as many measurements and has 50% greater spatial coverage than the authors' previous study. In addition, a precise global ocean reference network created from four years of Topex/Poseidon altimeter data is used to obtain improved estimates of altimeter orbit errors and measurement system biases. The results show that the average elevation change of the southern Greenland ice sheet above 2000 m from 1978 to 1988 is not significantly different than zero. This contradicts earlier and even more recent studies that reported positive ice sheet growth rates and suggested increased precipitation due to a warmer polar climate.