Roughness determination from multi-angular ASAR Wide Swath mode observations for soil moisture retrieval over the Tibetan Plateau

Multi-angular ASAR WS mode data sets are used for the estimation of the Integral Equation Method surface scattering model surface roughness parameterization. The ASAR WS data sets selected for the roughness estimation are collected during the cold and dry winter of the western part of the Tibetan Plateau. The estimated surface roughness is subsequently assumed to be constant for the retrieval of soil moisture. The retrievals are validated using the in-situ measurements from the Tibetan Plateau Soil Moisture/Temperature Observatory (Tibet-Obs), which demonstrated a positive and biased agreement of the retrievals with the measurements.