海洋粗糙面全极化电磁散射特性研究

针对基于几何光学-微扰法(GO-SPM)的传统双尺度模型对截断波数敏感的问题，该文建立了一种基于几何光学-小斜率近似(GO-SSA)的改进双尺度模型。该模型将小尺度部分的微扰法替换为一阶小斜率近似，并改进镜向分量的几何光学解。仿真表明该方法在获取传统双尺度精度的同时，不需要考虑截断波数的选取问题。针对Elfouhaily海浪谱模型的特点，简化GO-SSA积分形式。最后采用GO-SSA对以Elfouhaily海浪谱建模的海表面的单双站极化散射特性进行了仿真分析。发现双站极化散射中，粗糙表面的斜率调制导致交叉极化出现了异于传统模型的分布。同时在全空域的双站极化散射仿真中，发现所有的极化方式在方位向内均存在极小值。该极小值的大小与环境参数密切相关，在环境参数反演方面具有应用潜力。

Research on the Full Polarimetric Electromagnetic Scattering Characteristics of Ocean Rough Surface

Considering the fact that the classical two scale model which is based on the Geometrical Optics-Small Perturbation Method (GO-SPM) is sensitive to the cut-off wave number, a two scale model derived from the Geometrical Optics-Small Slope Approximation (GO-SSA) is established. In this model, the SPM in the classical two scale model is replaced by the first order Small Slope Approximation (SSA1). At the same time, the solution of geometrical optics for specular contribution is modified. The simulations show that GO-SSA can get the same accuracy as GO-SPM while do not need to consider the choice of cut-off wave number. The integral equation of GO-SSA is simplified based on the characteristics of Elfouhaily wave spectrum. At last, the full polarimetric scattering characteristics of Elfouhaily ocean model in monostatic and bistatic cases are simulated and analyzed. It can be found that the results of cross polarization present an interesting distribution with variation of angles which is different from classical models. In the three-dimensional results of bistatic scattering, the scattered direction with minimum value always exists in every polarization form. The value of the scattering power in this direction has relationship with the parameters of the environment, which has a potential application to the parameter inversion.