Investigation on Electromagnetic Scattering from Dynamic Sea Surfaces Covered by Natural Sea Slicks

A model of dynamic nonlinear sea surfaces damped by natural sea slicks is presented. Lombardini et al. model is adopted for predicting the hydrodynamic damping of sea surfaces in the presence of natural sea slicks, and "choppy wave model" (CWM) nonlinear sea surface is utilized for describing the nonlinear interactions between ocean waves. On this basis, the influence of sea slicks' damping on Doppler spectrum of backscattered echoes from contaminated sea surface is investigated by comparison with that from clean sea surfaces. Numerical simulation shows a narrowing of the Doppler spectrum of contaminated sea surfaces compared to that of clean sea. In addition, it is also indicated that the Doppler shift in slicks can decrease or increase, depending on incidence angles.