Combining Differential SAR Interferometry and Copolar Phase Differences for Snow Water Equivalent Estimation

The amount of water in a snow pack can be described by the snow water equivalent (SWE). SWE is a crucial parameter for hydrological models, for example, for flood predictions. Previous studies have shown that the interferometric phase between two repeat-pass synthetic aperture radar (SAR) measurements can be used to determine the change in SWE. However, a limitation of this method is phase wraps. To overcome this, the copolar phase difference (CPD) between the VV and HH channel can be used, which has been proven to be related to the depth of freshly accumulated snow. This study proposes an approach to incorporate the information on the fresh snow accumulation from the CPD into the interferometric SWE retrieval algorithm. The aim is to detect and correct interferometric phase wraps. The first results using airborne SAR data indicate that including the CPD improves the accuracy of the SWE retrieval.