The rough sea surface covered by an organic film will cause attenuation of capillarity waves,which implies that the organic films play an important role in rough sea surface processes.We focus on a one-dimensional(1D)rough sea surface with the Pierson-Moskowitz(PM)spectrum distributed to the homogeneous insoluble organic slicks.First,the impact of the organic film on the PM surface spectrum is presented,as well as that of the correlation length,the rms height and slope of the rough sea surface.The damping effect of the organic film changes the physical parameters of the rough sea surface.For example,the organic film will reduce the rms height and slopee of the rough sea surface,which results in the attenuation of the high-frequency components of the PM spectrum leading to modification of the surface PM spectrum.Then,the influence of the organic film on the electromagnetic(EM)scattering coefficients from PM rough sea surface covered by the organic film is investigated and discussed in detail,compared with the clean PM rough sea surface through the method of moments.
An iterative strategy combining Kirchhoff approximation （KA） method is presented in this paper to study the interactions between KA is applied to study scattering from underlying rough surfaces with the hybrid finite element-boundary integral （FE-BI） the inhomogeneous object and the underlying rough surface. whereas FE-BI deals with scattering from the above target. Both two methods use updated excitation sources. Huygens equivalence principle and an iterative strategy are employed to consider the multi-scattering effects. This hybrid FE-BI-KA scheme is an improved and generalized version of previous hybrid Kirchhoff approximation-method of moments （KA-MoM）. This newly presented hybrid method has the following advantages： （1） the feasibility of modeling multi-scale scattering problems （large scale underlying surface and small scale target）; （2） low memory requirement as in hybrid KA-MoM; （3） the ability to deal with scattering from inhomogeneous （including coated or layered） scatterers above rough surfaces. The numerical results are given to evaluate the accuracy of the multi-hybrid technique; the computing time and memory requirements consumed in specific numerical simulation of FE-BI-KA are compared with those of MoM. The convergence performance is analyzed by studying the iteration number variation caused by related parameters. Then bistatic scattering from inhomogeneous object of different configurations above dielectric Gaussian rough surface is calculated and the influences of dielectric compositions and surface roughness on the scattering pattern are discussed.
