The Influence of the Finite Size of the Illuminated Area
on Electromagnetic Scattering from Surfaces with and Without Slicks
Alla I. Timchenko
In this paper, the problem of scattering from sea surface with and without oil slicks is investigated taking the finite size of the illuminated area into account. A model of an inhomogeneous random rough surface with finite size of the scattering area is considered. To apply the results for a broad range of the random surface spectrum, an approach is developed which extends the range of validity beyond that of small perturbation theory. The general expression obtained for the scattering cross section takes into account a modulation of the rough surface by long surface waves. Analytical and numerical studies of the scattering cross section are provided to investigate the role of different mechanisms of scattering from various parts of the surface spectrum, and of diffraction caused by the finite size of the area. It is shown that the area size may affect the normalized scattering cross section in the case of the surface with a slick. Possibilities to explain the features of the suppression of the backscattering by oil slicks 238 Timchenko, Serebryannikov, and Schünemann are discussed. Furthermore, a way to distinguish between different scattering mechanisms is suggested.