Seasonal, interannual, and long-term elevation change of the East Antarctic ice sheet from satellite radar altimetry

Abstract

Surface elevation measurements from the Seasat (1978) and Geosat (1985-88) satellite altimeters are analyzed for the East Antarctic Ice Sheet (EAIS) from 66-72/spl deg/S and 30-150/spl deg/E. The authors examined seasonal and interannual variations in surface elevation using the first two years of the Geosat-ERM dataset (Nov. 1986 to Nov. 1988). In general, the amplitude of the seasonal signal is /spl plusmn/5 cm. In addition, there is no clear periodicity in the seasonal signal as has been observed in Greenland altimeter data. Interannual variations were determined by dividing each year of the Geosat-ERM data into four 3-month seasons. The results show year-to-year variations of about /spl plusmn/3 cm. Long-term elevation change estimates from 1978-88 were measured by comparing surface elevations from the Seasat and Geosat datasets. The results show that the rate of elevation change, in general, varies spatially from -10 to +10 cm/yr. A spatial average of more than 250,000 elevation-change measurements over an area of 1.8 million km/sup 2/ yields a -3.1/spl plusmn/0.95 cm/yr rate of elevation change.