Cross-polarization geophysical model function for C-band radar backscattering from the ocean surface and wind speed retrieval
Cross-polarization geophysical model function for C-band radar backscattering from the ocean surface and wind speed retrieval
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DOI：
10.1002/2014jc010439
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发表时间：
2015-02-01
影响因子：
3.6
通讯作者：
Shen, Hui
中科院分区：
文献类型：
--
作者：
Hwang, Paul A.;Stoffelen, Ad;Shen, Hui
来自海洋表面的交叉极化 (cross-pol) 雷达后向散射截面 (VH) 的风速灵敏度随着风速的增大而增加。与共极化（copol：VV 或 HH）海面回波相比，VH 的信号饱和问题（如果存在）会在更高的风速下发生。这些特性使 VH 成为监测恶劣天气时比 VV 或 HH 更好的选择。结合合成孔径雷达 (SAR) 的高空间分辨率，利用 VH 进行飓风反演的发展正在迅速推进。本文描述了一种跨极化 C 波段雷达后向散射地球物理模型函数 (GMF)，其在可用数据集中的整个风速范围（高达 56 m/s）中具有入射角依赖性。 GMF 源自具有 300 公里和 500 公里测绘带的 RADARSAT-2 (R2) 双极化 (dual-pol) ScanSAR 模式。所提出的 GMF 与其他已发布的算法进行了比较。结果表明，用所提出的 GMF 模拟的 VH 截面和反演的风速与测量结果吻合较好。通过仔细处理噪声，VH 反演的风速可能会扩展到温和或中等条件。 VH 中非布拉格贡献的较高部分可用于表面波破碎分析。
The wind speed sensitivity of cross-polarization (cross-pol) radar backscattering cross section (VH) from the ocean surface increases toward high winds. The signal saturation problem of VH, if it exists, occurs at a much higher wind speed compared to the copolarization (copol: VV or HH) sea returns. These properties make VH a better choice over VV or HH for monitoring severe weather. Combined with high spatial resolution of the synthetic aperture radar (SAR), the development of hurricane wind retrieval using VH is advancing rapidly. This paper describes a cross-pol C-band radar backscattering geophysical model function (GMF) with incidence angle dependence for the full wind speed range in the available data sets (up to 56 m/s). The GMF is derived from RADARSAT-2 (R2) dual-polarization (dual-pol) ScanSAR modes with 300 and 500 km swaths. The proposed GMF is compared to other published algorithms. The result shows that the simulated VH cross section and the retrieved wind speed with the proposed GMF is in better agreement with measurements. With careful treatment of noise, the VH-retrieved wind speeds may extend to mild or moderate conditions. The higher fraction of non-Bragg contribution in VH can be exploited for analysis of surface wave breaking.