Simulation of Microwave Backscattering from Sea Surface Using an Improved Two-Scale Model

The two-scale model (TSM) has been frequently used in the study of EM (electromagnetic) scattering from rough surface due to its simple and practical merit. However, for microwave scattering from sea surface, it cannot provide accurate predictions for hh (horizontal) polarization. To overcome this problem, an improved version of the TSM (ITSM) which can be better used for predicting microwave scattering from sea surface is proposed in this paper. In the ITSM, we propose to use two cutoff parameters to separate sea surface roughness. For k
_w
<;k
_cs
, the KA-SP (Kirchhoff approximation-stationary phase approximation) rather than KA-GO (Kirchhoff approximation-geometric optics approximation) is employed to simulate the specular scattering component. For k
_w
>k
_cb
, the SPM modulated by tilts of large-scale waves is employed to simulate the Bragg scattering component. The values of k
_cs
and k
_cb
are chosen according to the validity conditions of the KA and the SPM. The numerical comparisons illustrate that the ITSM performs better than the TSM and the SSA-1, especially in the prediction of hh polarized scattering coefficient.