Refinement of the X and Ku band dual-polarization scatterometer snow water equivalent retrieval algorithm

Abstract

Snow water equivalent is an important parameter for natural science studies. One promising sensor configuration for quantitative snow water equivalent remote sensing is the X and Ku band dual-polarization SAR, such as the CoreH2O mission. The retrieval algorithm of terrestrial snow water equivalent from this sensor configuration suffers two major problems which are the decomposition of volume and surface backscattering, and the calibration of snow grain size effect. In previous study, we proposed a preliminary algorithm for snow water equivalent retrieval using X and Ku band dual-polarization radar. In the meantime, in the past years there has been progress in both ground experiment techniques and electromagnetic scattering modeling of snow cover. This enables us to make a further refinement and improvement of the retrieval algorithm based on the new experimental data and newly developed electromagnetic scattering models. In this study, we propose a refined version snow water equivalent inversion algorithm based on X and Ku band dual-polarization radar. The volume backscattering of snow is decomposed using the depolarization ratio, and the single scattering albedo and the optical depth is retrieved by the dual-frequency volume backscattering signal. Then the snow water equivalent is retrieved using the absorption part of the optical depth. The retrieval algorithm is tested using the Nosrex experiment carried out in Finland.