Abstract

Two mapping campaigns of the Antarctic Ice Sheet have been completed using the Radarsat-1 SAR. The first Radarsat Antarctic Mapping Project (RAMP) acquired data over a 30-day period in the fall of 1997 providing a static "snapshot" of the entire ice sheet. Since Radarsat-1 has a 24-day orbit cycle, repeat-pass interferometric SAR (InSAR) data were also acquired for large portions if the ice sheet, permitting ice surface velocities to be derived. Crossing InSAR swaths close to the South Pole have provided the first opportunity to study surface velocity using multiple look directions, rather than the conventional two (ascending and descending) look directions. This has permitted us to derive ice velocities for all three dimensions without the need for a surface parallel flow assumption. We present our technique and compare our three dimensional results to conventional ascending/descending surface parallel flow assumption results, particularly in regard to vertical ice motion. Our study is centered on Ice Stream A, West Antarctica, giving us an insight into the implications for ice sheet and ice stream velocity mapping.