Ground-based multi-channel synthetic-aperture radar for mapping the ice-bed interface

An 8-channel ground-based radar has been developed and used to image the ice-bed interface under the icesheet near Summit Camp, Greenland. This radar, which chirps from 120 to 300 MHz, was developed to demonstrate the feasibility of using radar to characterize the basal conditions (topography, roughness, and presence of liquid water) thus enabling improved modeling of ice-sheet dynamics. Using a basal contour map from the dataset processed in depth-sounding mode to establish the elevation level, the data were SAR processed to produce 15-look images with 30-m resolution. A SAR mosaic covering a 6.25-km by 25-km area reveals for the first time regions of relative roughness as well as a wide, smooth valley beneath the 3.2-km thick ice sheet.