Within ESA’s CryoSat-2 calibration and validation program (CryoVEx) an airborne campaign was carried out in the blue ice area in the vicinity of Schirmacher oasis, Dronning Maud Land, Antarctica in 2008. POLAR 5, the Alfred-Wegener-Institute’s research aircraft, carried the ESA airborne Ku-band SAR interferometric radar altimeter (ASIRAS) and a laser scanner during the CryoVEx campaign. In the blue ice area, partly covered with snow patches, a dense grid of 30 km x 40 km with a line spacing of 1 km was measured. Here, we present results of the comparisons of the final SAR processed ASIRAS elevations with the laser scanner elevation model. We will show the influence of snow patches on and the accuracy of the ASIRAS derived surface elevations by using the laser scanner DEM as reference. Furthermore, the derived Ku-band penetration depths and the thickness of the snow patches, derived from the ASIRAS data, are compared with the radar backscatter of a TerraSAR-X scene, acquired at the same time when the campaign took place. Our results show that Ku-band radar penetrates through the snow, while the snow patches do not affect the derived ASIRAS surface elevations. In contrast the radar backscatter of TerraSAR-X shows a strong correlation of the thickness of the snow patches. The results of this study highlight the need of careful waveform processing/re-tracking and though will contribute to improved CryoSat-2 elevation products.