Soil Parameter Retrievals Over Bare Agricultural Fields Using Multiangular RADARSAT-2 Dataset

摘要

The objective of this study is to evaluate the potential of multiangular SAR data at C-band for soil parameters’ discrimination over bare agricultural fields. In order to exploit the incidence angle diversity to enhance the soil parameter retrievals, the conventional multiangular roughness descriptor ΔHH formulated originally as the backscattering difference between two specific incidence angles is adapted to take into account a general incidence angle effect. Moreover, a new angular coherence SAR descriptor γHH is proposed by using a pair of low and high incidence angle SAR data. The adapted ΔHH and the proposed γHH are applied to the RADARSAT-2 data with three different incidence angles. The results indicate that the proposed γHH is more sensitive to surface roughness than the adapted ΔHH. Thus, the γHH is selected to retrieve the surface roughness, and then the retrieved surface roughness is substituted into a low incidence angle data to retrieve the soil moisture. The RMSE of 6.1–8.5 m3/m3 is obtained for soil moisture retrieval.