Soil Moisture Retrieval from Temporal Series of Palsar Scansar Data

The availability of dense temporal series of SAR acquisitions from space platforms makes possible the use of change detection techniques to monitor near-surface soil moisture content globally. The rational of this method is that temporal changes of surface roughness, canopy structure and vegetation biomass occur at longer temporal scales than soil moisture changes, excluding periods of cultivation. Therefore, variations in surface backscatter observed with a short repeat cycle are expected to reflect mainly changes in soil moisture, since other parameters affecting radar backscatter can be considered fairly constant. A soil moisture retrieval algorithm based on change detection has recently been developed and tested making use of either Cor L-band SAR data collected by the E-SAR airborne system [1]. The study demonstrated that:  low incidence angles (e.g. 20°-35°) and HH polarization are generally better suited to mv retrieval than VV polarization and higher incidence angles;  at L-band, it is feasible to retrieve soil moisture content, underlying a broad range of agricultural crops, with an accuracy between 5% and 6%.