Comparison of Greenland ice sheet topography measured by TOPSAR and airborne laser altimetry

A digital elevation model (DEM) produced from airborne interferometric synt hetic aperture radar (TOPSAR) data of a 5 km x 65 km region of the Greenlan d Ice Sheet is compared with multiple airborne laser altimeter profiles of the same surface TOPSAR-derived elevation values were calculated on a 10 m x 10 m grid, Surface topography at wavelengths greater than one kilometer i s accurately reproduced. A planar adjustment of -8 m with along-track and c ross-track tilts of 0.17 and 2.4 m/km, respectively, is required to match t he two elevation data sets, Residual noise of the TOPSAR data at subkilomet er wavelengths is less than two meters, This study underscores the need for independent elevation data for controlling TOPSAR elevation surveys.