Bistatic reflection and transmission of electromagnetic scattering by rough surfaces with large heights and slopes

Abstract

In this paper, we study the electromagnetic scattering properties of 2-D rough surface with large slope and large height. The ridges on the surface have heights of about 20cm. In microwave remote sensing of land, these heights are larger than wavelength. By using a tapered incident wave, the surface fields are solved by using numerical solution of Maxwell equations. Method of Moment (MOM) is used to solve the surface integral equations and rooftop basis function and Galerkin's method are used. The bistatic reflection and transmission are then calculated from the surface fields. Then the reflectivity from sastrugi over layered snow is calculated by solving multilayer radiative transfer (RT) equation with bistatic reflection and transmission coefficients as the boundary condition. We compare the electromagnetic scattering properties between Sastrugi rough surface and smooth surface. We show in this paper that for the sastrugi case, transmission angle can be larger than incident angle when incident from air to snow. This results in total internal reflection when the second layer of snow beneath sastrugi has a smaller permissivity and larger reflectivity than smooth surface.