In order to evaluate a potential calibration target for spaceborne L-band radiometer systems, a 350 × 350 km area near the Concordia station on the East Antarctica plateau was mapped by an airborne L-band radiometer. Unexpectedly, the area showed significant brightness temperature spatial variations, well correlated with bedrock topography, hence ice thickness. Using SMOS data over a poorly known part of Antarctica, ice thickness in this area has been assessed, and an existing bedrock map has been improved.