Polarimetric Decomposition of L-Band PolSAR Backscattering Over the Austfonna Ice-Cap

Abstract

Over the last 30 years, the use of airborne and satellite remote sensing techniques has revolutionized glaciology through unequaled improvements in the scale and in the temporal and spatial resolutions of cryospheric observations. In this sense, the introduction of Synthetic Aperture Radars (SARs) likely represents the greatest advance for glaciological applications. This paper describes a novel polarimetric scattering model to interpret polarimetric SAR (PolSAR) measurements of glaciers and ice sheets. Different scattering components are considered according to the specific glacier facies, in order to infer physical parameters of the ice volume. Total backscatter is modelled as the incoherent sum of eventual surface and volume contributions. A new component is introduced to describe differential propagation effects related to firn anisotropy, which is able to interpret polarization phase differences. The developed model is used to perform a polarimetric decomposition of L-band PolSAR data collected by the E-SAR sensor of the German Aerospace Center (DLR) over the Austfonna ice cap, Svalbard, Norway, as part of the ICESAR2007 campaign. Decomposition results are consistent with the information provided by a set of ground measurements about the subsurface structure of the study area and confirm the need of dedicated scattering models for the different glacier zones.