海浪波谱仪微波散射模型

Sea Surface Scattering Model for SWIM

【目的】建立与观测数据相符的海浪波谱仪（SWIM）散射模型。【方法】利用Kirchhoff近似以及准镜面散射理论,建立从海浪方向谱映射到海浪波谱仪后向散射截面（σ°）的散射模型,并利用热带降雨测量卫星（TRMM）所搭载的降雨雷达（PR）提供的低入射角下的后向散射截面数据,对模型进行检验。【结果】准镜面散射模型结合高阶Gram-Charlier级数型海表斜率概率密度函数,模拟的雷达后向散射截面与入射角的关系在降雨雷达的0∽18°入射角范围内与实测数据一致。【结论】海浪波谱仪的信号散射可利用准镜面散射模型结合高阶Gram-Charlier级数型海表斜率概率密度函数来描述。

【Objective】A sea surface scattering model was established in order to agree well with measurement data for SWIM（Surface Waves Investigation and Monitoring）.【Methods】The forward transfer function from sea surface directional wave spectrum to normalized radar cross section（NRCS,σ°）was developed based on Kirchhoff approximation and quasi-specular reflection theory.Precipitation radar（PR）on the Tropical Rainfall Mapping Mission（TRMM）provides NRCS at low incidence angles.The model is tested using measurements from PR.【Results】By using the quasi-specular scattering theory,combined with Gram-Charlier expansion of probability density function of wave slopes to the forth order,the modeled NRCS agrees well with radar measurements from nadir to 18°.【Conclusion】For SWIM,the sea surface scattering can be presented by quasi-specular scattering theory,combined with Gram-Charlier expansion of probability density function of wave slopes to the forth order.