Estimation of soil moisture with L-band multi-polarization radar

Through analyses of the model simulated database, we developed a technique to estimate surface soil moisture under HYDROS radar sensor (L-band multi-polarizations and 40degrees incidence) configuration. This technique includes two steps. First, it decomposes the total backscattering signals into two components - the surface scattering components (the bare surface backscattering signals attenuated by the overlaying vegetation layer) and the sum of the direct volume scattering components and surface-volume interaction components at different polarizations. From the model simulated data-base, our decomposition technique works quit is-ell in estimation of the surface scattering components with RMSEs of 0.12, 0.25, and 0.55 dB for W, HH, and VH polarizations, respectively. Then, we use the decomposed surface back-scattering signals to estimate the soil moisture and the combined surface roughness and vegetation attenuation correction factors with all three polarizations.