Polarization degradation in the sea surface environment

The problem of electromagnetic scattering from a randomly rough surface is analyzed using the Kirchhoff approximation (stationary phase, scalar approximation), the small perturbation model and the two-scales models. A first major new consideration in this paper is study of the domain of validity of the Kirchhoff and small-perturbation rough surface scattering models (in the bistatic case). Comparisons between the numerical calculations and the models are made for various of the surface rms height and correlation length both normalized to the incident wave number (denoted by k/spl sigma/ and kL, respectively). By using these two parameters to form a two-dimensional space, the approximate regions of validity are then established. The second major new consideration is the development of the composite model in the bistatic case. One application is made in the ocean surface case.