Sensitivity of Bistatic Scattering to Soil Moisture and Surface Roughness of Bare Soils

The sensitivity of bistatic scattering coefficient s° to soil moisture (SMC) and surface roughness was investigated by means of model simulations of the incoherent scattered fields performed with the Advanced Integral Equation Model (AIEM) and the second order Small Perturbation Model (SPM). The study was performed by simulating scattering on the whole upper half space, for different values of incident angles. The achieved results, represented as maps of s° as a function of azimuth and zenith angles, were evaluated by means of a quality index which takes into consideration the effect of roughness on SMC measurement. The sensitivity analysis has pointed out that for measuring SMC a bistatic observation, by itself or combined with the monostatic one, can make appreciable improvements with respect to classical monostatic radar. Appendix A contains the AIEM formulas corrected for several typographical errors present in the specific literature