海浪波谱仪微波散射模型

【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。

Sea Surface Scattering Model for SWIM

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.