Characterisation of oriented volumes in glacier ice and extinction inversion with 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 the estimation of ice extinctions through the modelling of Pol-InSAR coherences as a combination of a surface contribution from the snow-ice interface and a volume response from an oriented particle cloud. Separation of the ground and volume contributions is obtained using a novel decomposition of the polarimetric covariance matrix which allows for preferential particle orientations and accounts for the influence of the dielectric constants of ice and snow. 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.