粗糙海面电磁散射的小斜率近似方法

Electromagnetic scattering from rough sea surface using small slope approximation

利用小斜率近似方法研究了粗糙海面的电磁散射特性,推导了极坐标下小斜率近似方法的双站散射系数计算公式。基于Elfouhaily海谱模型,计算了海面的散射系数,将得到的理论计算结果和实验数据及考虑和不考虑遮蔽效应的基尔霍夫近似结果进行了对比。讨论了不同极化状态下小斜率近似方法的后向散射系数随入射波频率和风速的变化关系。结果表明,在后向散射情况下,理论计算结果和实验数据吻合很好;在双站散射情况下,在大散射角时小斜率近似的结果更为准确;无论是何种极化,后向散射系数均随入射波频率和风速的增大而增大。

The small slope approximation method is used to investigate the electromagnetic scattering properties of rough sea surface, and the bistatic scattering coefficient of the small slope approximation is derived in the polar coordinates. Based on the spectral model of Elfouhaily, the scattering coefficient of sea surface is calculated, and the theoretical results are compared with the experimental data and Kirchhoff approximation with or without shadowing effect considered. The dependence of the backscattering coefficient of the small slope approximation on the incident wave frequency and the wind speed in different polarization conditions is discussed. The results show that the theoretical results are consistent with the experimental data in backscattering case. In the case of the bistatic scattering, the result of the small slope approximation is accurate, especially for large scattering angle. The backscattering coefficient increases with increasing of the incident wave frequency and the wind speed in both horizontal and vertical polarization.