Soil moisture measurement and retrieval using Envisat ASAR imagery

High resolution data of the ASAR sensor aboard ESA´s Envisat satellite offers the opportunity for monitoring surface soil moisture at high spatial resolution with multi-polarization and multi-incidence capabilities. Using Integral Equation Model (IEM), we simulated the backscattering coefficients of C band SAR backscatter at different incidence angles and the alternating polarization mode, and analyzed the sensitivity to soil moisture. The algorithm of inferring surface soil moisture from radar backscatter is developed according to semi-empirical model from the results of simulation and sensitivity analysis. The soil moisture map are retrieved from ASAR backscatter measurements in Hetian, Xinjinag (37°15´N, 79°48´E) area, where are the arid and semi-arid area of west China. Accuracy in the retrieval of the surface moisture content from ASAR is compared to the spatially distributed ground truth. The results demonstrate the effects of soil moisture monitoring using multi-polarization multi-incidence ASAR data.