Flow variations of the Antarctic ice sheet from comparison of modern and historical satellite data

Since 1962, high quality satellite images of Antarctica have been acquired. The earliest images, from the Corona Program, have only recently become available to the science community. They reveal a rich variety of details about the ice sheet, ice shelves, grounding lines, and rocky areas. The most recent high-resolution images covering all of Antarctica were collected by the Canadian Radarsat-1 in September and October of 1997. That activity, a collaboration between NASA and the Canadian Space Agency, has resulted in the first, complete, high resolution SAR mapping of the Antarctic. The Radarsat images are also spectacular and graphically portray Antarctic ice streams, outlet glaciers, calving margins, and mountains. This paper examines how different Antarctic flow regimes have changed over the 35-year interval between Corona and Radarsat. Study areas focus on the Ross Ice Shelf and Crary Ice Rise. The comparison reveals dramatic variations in ice flow, particularly around Crary Ice Rise-an area of long standing glaciological interest because of its potential for retarding upstream flow