Abstract

o date InSAR obvservations of ice flow have used pairs or triplets of observations from both ascending and descending satellite orbits. Employing the surface parallel flow assumption together with a digital elevation model (DEM) has been the only means to derive three dimensional ice flow. We present a new method of deriving 3-D flow from InSAR observations alone, by using multiple crossing orbits close to the South Pole, as acquired during the left-looking Radarsat Antarctic Mapping Project (RAMP) in the fall of 1997. We present the 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.