Theoretical Study of Global Sensitivity Analysis of L-Band Radar Bistatic Scattering for Soil Moisture Retrieval
Theoretical Study of Global Sensitivity Analysis of L-Band Radar Bistatic Scattering for Soil Moisture Retrieval
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DOI：
10.1109/lgrs.2018.2858269
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发表时间：
2018-08
影响因子：
4.8
通讯作者：
J. Zeng;Kun Shan Chen
中科院分区：
文献类型：
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作者：
J. Zeng;Kun Shan Chen
本文利用全局灵敏度分析方法，即扩展傅立叶振幅灵敏度测试（EFAST）算法，探讨了l波段裸地土壤湿度检索的最佳双基地雷达配置。采用已建立的先进积分方程模型，模拟了涵盖大范围几何参数和地表条件的双基地散射的完整集。利用EFAST算法量化了雷达双基地信号对土壤湿度和表面粗糙度的敏感性，以及参数之间的相互作用。结果表明，在双基地散射中，VV偏振对土壤水分的敏感性明显高于HH偏振，特别是在大入射角时。对于VV偏振，随着入射角的增大，土壤水分的敏感区扩大并向前移动，特别是在小方位角散射角和大散射角时，成为土壤水分反演的理想配置。而对于HH极化，随着入射角的增大，敏感区逐渐向后移动，综合考虑敏感强度和参数相互作用效应，建议选取一个中间入射角（如40°）来反演土壤水分。
This letter explores the optimal bistatic radar configurations for bare soil moisture retrieval at L-band using a global sensitivity analysis method, the extended Fourier amplitude sensitivity test (EFAST) algorithm. Complete sets of bistatic scattering, covering a wide range of geometric parameters and ground surface conditions, are simulated by the well-established advanced integral equation model. The sensitivity of radar bistatic signals to soil moisture and surface roughness, and the interactions among the parameters are quantified using the EFAST algorithm. The results show that in bistatic scattering, VV polarization has notably higher sensitivity to soil moisture than HH polarization, particularly at large incident angles. For VV polarization, as incident angle increases, the sensitivity zone of soil moisture expands and shifts toward the forward direction, specifically at small azimuth scattering angles and large scattering angles, thereby becoming promising configurations for soil moisture retrieval. For HH polarization, in contrast, the sensitive zone gradually moves to the backward direction as incident angle increases, and an intermediate incident angle (e.g., 40°) is recommended for retrieving soil moisture by considering both sensitivity strength and parameter interaction effects.