Low-grazing-angle (LGA) sea-spike backscattering from plunging breaker crests
Low-grazing-angle (LGA) sea-spike backscattering from plunging breaker crests
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DOI：
10.1109/36.992830
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发表时间：
2002-08
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影响因子：
--
通讯作者：
J. West
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文献类型：
--
作者：
J. West
低掠射角（LGA）微波后向散射从一系列的波剖面代表的时间演变的一个暴跌破碎机水波的数值计算和模型预测进行了比较。波的波峰区域被隔离，以消除产生干扰的大规模多次背反射路径。水平极化后向散射（HH）显着超过在垂直极化（VV）在破碎过程中，尽管缺乏多径。现有的散射模型与一些启发式的修正被施加到配置文件，以确定占主导地位的散射机制。使用扩展几何光学（EGO）方法从单次散射预测大的HH-VV比。使用衍射几何理论的修改，将反向散射随波陡度的初始上升预测为波峰表面曲率拐点的衍射。计算结果表明，LGA的后向散射破碎波峰是非常复杂的，即使在没有多径和简单的光学为基础的模型，处理波峰的横截面在两个偏振相等将是不准确的。
The low-grazing-angle (LGA) microwave backscattering from a series of wave profiles representing the time evolution of a plunging breaker water wave is numerically calculated and compared with modeled predictions. The crest regions of the waves are isolated to remove large-scale multiple back-reflection paths that give interference. The horizontally polarized backscatter (HH) significantly exceeds that at vertical polarization (VV) during the breaking, despite the lack of multipath. Existing scattering models with some heuristic corrections are applied to the profiles to identify the dominant scattering mechanisms. The large HH-to-VV ratio is predicted from single scattering using an extended geometrical optics (EGO) approach. The initial rise in the backscatter as the wave steepens is predicted as diffraction from inflection points in the surface curvature at the crest using a modification of the geometrical theory of diffraction. The calculations show that the LGA backscattering from breaking wave crests is very complicated even in the absence of multipath and simple optically based models that treat the crest cross sections as equal at the two polarizations will be inaccurate.