An Improved Facet-Based TSM for Electromagnetic Scattering From Ocean Surface

An improved facet-based model derived from a two-scale model (TSM) is proposed to evaluate the scattering strength of an electrically large ocean surface. In this model, a slope cutoff probability distribution function is introduced into geometrical optics to deal with the specular scattering of an individual facet. This modification allows us to approximate the rough surface with a large facet size without disrupting the accuracy of scattering evaluation. In addition, considering the sensitivity of the classical TSM to the cutoff wavenumber, the cutoff-invariant TSM is used into the facet-based model. Finally, our numerical results show that the facet-based model can obtain the comparable accuracy with the statistical models regardless of facet size and cutoff wavenumber. Due to the advantages of simplicity and efficiency, this model is of high applicable value for the synthetic aperture radar imaging.