A Generalized Anisotropic Power-Law Roughness Spectrum and Its Applications to Radar Backscattering from Soil Surfaces

Abstract

We present a generalized power-law roughness spectrum to account for the spatial anisotropy. For completeness, both the correlation anisotropy and the scaling anisotropy are included. The spatial anisotropy is essential to correctly interpret the radar scattering from an agriculture field where both plow and sow practice. The dependence of the backscattering coefficient on the correlation anisotropy and the scaling anisotropy is investigated through a model simulation. Drastic change of backscattering strength is observed due to the anisotropy. The correlation anisotropy and the scaling anisotropy generate similar backscattering angular behavior, implying that in the context of spatial anisotropy, merely using correlation length in scattering modeling is insufficient. Equivalently, the correlation length retrieved from the backscattering coefficients perhaps is not unique. A fair use of the generalized anisotropic power-law roughness spectrum in conjunction with the scattering model is illustrated by comparing the backscattering coefficients with experimental measurements.