Scattering from a Target above Rough Sea Surface with Breaking Water Wave by an Iterative Analytic-Numerical Method

Two-dimensional (2D) electromagnetic scattering from a target above the sea with breaking water wave is studied by a multiregional iterative analytical-numerical method that combines the boundary integral method (BIM) and the Kirchhoff approximation (KA). Based on the “PiersonMoskowitz” (PM) sea surface and the LONGTANK breaking wave, a theoretical model of a target above the rough sea surface with breaking wave is built firstly in this paper. Unlike traditional sea surface, the multipath scattering between the crest of the breaking wave and the target cannot be accurately predicted based on KA alone. To improve the algorithm precision, a multiregional hybrid analytical-numerical method is proposed. In our multiregional model, the whole sea is divided into two subregions: the breaking wave and the PM sea surface. The scattering from the breaking wave and the object is well approximated by BIM, while the PM sea surfaces can be estimated very well by KA based on Fresnel theories. Taking the interaction between KA region and BIM region into account, an iterative system is developed which gives a quick convergence. The hybrid technique presented here is highly efficient in terms of computing memory, time consumed, and versatility.