Sensitivity of radar backscattering to soil surface parameters: a comparison between theoretical analysis and experimental evidence

The understanding of the sensitivity of radar backscattering to surface parameters is essential in applying microwave remote sensing to the retrieval of geo- and bio-physical parameters. A theoretical model, the integral equation model, is used to investigate the sensitivity of radar backscattering to soil surface parameters. This model is first tested against a dataset retrieved under well controlled conditions at the European Microwave Signature Laboratory, Joint Research Centre, Ispra, Italy. Then the surface roughness parameters are normalised with respect to wavelength and incidence angle to improve insight into the sensitivity of radar observations to surface roughness. In this way the roughness space can be subdivided in two regions where surface slope controls the dependency of the signal to roughness.