Extinction estimation over land ice using long-wavelength Pol-InSAR

Abstract

In recent years there has been increased interest in using SAR to study and monitor glaciers and ice sheets for glaciological and climate change research. This paper describes for the first time the estimation of ice extinction through the modelling of Pol-InSAR coherences as a combination of a surface contribution from the snow-ice interface and a volume response. Separation of the ground and volume contributions is obtained through decomposition of the polarimetric coherency matrix. Both model-based Freeman 2- and 3-component and eigenvector decompositions are examined. Ground-to-volume scattering ratios derived from polarimetry are used in conjunction with Pol-InSAR interferometric coherences to invert the extinction of the ice layer. Validation is performed with airborne Pol-InSAR data at L- and P-band collected using DLR's E-SAR system over the Austfonna ice cap in Svalbard, Norway as part of the ICESAR campaign.