Dual-Polarimetry for Soil Moisture Inversion at X-Band

Dual-polarimetric, coherent (HH/VV) data of TerraSAR-X and TanDEM-X are used for soil moisture estimation under changing agricultural vegetation cover. Therefore a dual-polarimetric hybrid decomposition and inversion technique is developed including physically-based scattering models for soil (IEM) and vegetation (particle scattering model). The algorithm, applied on the dual-polarimetric X-band data, synthetically derives a cross-polarization channel for the quantification of the vegetation volume intensity within the decomposition. As a result soil moisture with an inversion rate of 50-69% can be mainly derived on bare and light vegetated soils in the beginning and in the end of the vegetation growth period at X-band. A reason for the heterogeneous inversion results with varying quality (RMSE between 6.3-19.5vol.%) might be also the selection of the best fitting vegetation volume type for appropriate removal of the vegetation scattering component before moisture inversion.