Scattering properties of a statistically rough interface inside a multilayered medium

In this paper, electromagnetic wave scattering from a slightly rough interf ace inside a stratified medium is considered. A three-layer model for the m edium is chosen, which allows us to investigate both possible cases of the medium's stratification: above and below the rough interface. It also is a simple but realistic model for the ground, in which the upper layer is thou ght to be vegetation or snow, while the middle layer and the homogeneous ha lf-space below it represent the ground itself. The vegetation-ground interf ace is considered to be rough with statistically homogeneous corrugation, w hile the two other interfaces are flat. The backscatter coefficients for ve rtically and horizontally polarized waves are found in the framework of the small perturbation method combined with the Green function formalism. Such an approach allows one to consider arbitrary layers and, in this respect, go far beyond the radiative transfer theory. The influence of the stratific ation of the medium above and below the rough interface on the scattered fi eld is analyzed numerically. Qualitatively new angular and frequency depend encies of backscattering are found. It is shown that in the case of small o hmic losses stratification of a medium can cause the deviation of backscatt ering up to 20 dB.