Improved resolution ice sheet mapping with satellite radar altimeters



The surface topography of ice sheets at scales of less than 50 km is intimately related to the rheology and dynamics of the ice and the topography of the bedrock. Satellite radar altimeters can provide surface topography, but current processing techniques limit the horizontal resolution to 5 km, while a proportion of dynamically related topography lies at scales smaller than this. However, the methods of seismic wavefield migration are applicable to radar altimeter echoes, and theory indicates that resolutions of the order of 500 m should be possible. Here we describe a comparison between a sequence of altimeter echoes recorded by the ERS-1 altimeter over Antarctica and the surface that results from the application of wavefield migration methods.