Quantitative retrieval of soil moisture content and surface roughness from multipolarized radar observations of bare soil surfaces

A semiempirical polarimetric backscattering model for bare soil surfaces is inverted directly to retrieve both the volumetric soil moisture content M_v and the rms surface height s from multipolarized radar observations. The rms surface height s and the moisture content M_v can be read from inversion diagrams using the measurements of the cross-polarized backscattering coefficient σ_vh⁰ and the copolarized ratio p(=σ_hh⁰/σ_vv⁰). Otherwise, the surface parameters can be estimated simply by solving two equations (σ_vh⁰ and p) in two unknowns (M_v and s). The inversion technique has been applied to the polarimetric backscattering coefficients measured by ground-based polarimetric scatterometers and the Jet Propulsion Laboratory airborne synthetic aperture radar. A good agreement was observed between the values of surface parameters (the rms height s, roughness parameter ks, and the volumetric soil moisture content M_v) estimated by the inversion technique and those measured in situ.