The knowledge of snow pack properties and its temporal and spatial variability are of importance for the interpretation of backscattered signals in the microwave region. For example, forthcoming radar altimetric satellite missions, like ESA's CRYOSAT, aim at improved measurements of both ice surface height and surface height fluctuation, which is especially needed at the margins of the continental ice sheets where the topography is more complex. However, a change in surface height does not imply a mass imbalance, as snow and ice density may change. Spaceborne scatterometers provide valuable information on backscattering characteristics at low spatial but high temporal resolution. In addition, the surface is illuminated at different viewing angles during a single overflight. Previous studies demonstrated that anisotropies in the scatterometer signal are related to surface features like sastrugis, which also cause anomalies in the altimeter signal.This investigation focuses on the area between the German Neumayer base (70°39'S, 08°15'W) at the ice shelf Ekströmisen and the drilling site for the EPICA (European Project on Ice Coring in Antarctica) ice core at Kohnen station (75°S, 0°W, 2850m a.s.l.) in Dronning Maud Land. The backscattering properties in Ku band at vertical and horizontal polarization from two satellite borne scatterometers are compared at several sites to snow pack properties such as accumulation rate and grain size. In addition, SAR (Synthetic Aperture Radar) images with high spatial resolution are compared to long term accumulation rates around Kohnen station, which are derived by means of ice penetrating radar and firn cores.Differences in the backscattering signatures reflect the variable pattern in the snow morphology, although the relation is not straightforward. The normalized backscattering cross section is classified to localize those areas, where additional field measurements should be conducted to obtain an improved understanding of backscattering and snowpack properties. The signature study provides additional information for a better understanding of signals like radar altimeter and high resolution SAR.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL1-Processes and interactions in the polar climate system