Comparison of Airborne Radar Altimeter and Ground-based Ku-band Radar Measurements on the Ice Cap Austfonna, Svalbard

We compare data from the European Space Agency´s (ESA) Airborne SAR/Interferometric Radar Altimeter System (ASIRAS) with ground-based Very High Bandwidth (VHB) stepped frequency radar measurements in the Ku-band. Using the VHB radar we have been able to pinpoint the major backscatter sources within the accumulation area. The ground-based and airborne waveforms show good agreement and we therefore find the ground-based measurements valuable for validation and interpretation of the airborne altimeter waveforms. The comparison shows that the surface and the Last year Summer Surface (LSS) can be tracked in the airborne data, but fails at lower elevations with snow depths less than _~1 m. For ground truth, i.e. snow depth, we use ground based radar profiles (800 MHz), snow pits, snow probing, and density retrieved from 7-12 m deep boreholes using a neutron probe.