The azimuth cutoff wavelength of synthetic aperture radar (SAR) is an important parameter for retrieval of sea surface wind and wave. Earlier studies have fully demonstrated the substantial dependence of azimuth cutoff wavelength on polarization, but the present studies only focus on horizontal and vertical (H-V) linear polarization bases [horizontal-horizontal (HH), horizontal-vertical (HV)/vertical-horizontal (VH), and vertical-vertical (VV)] without considering the effects of other polarization bases (e.g., linear rotated, circular, and elliptical polarization). Benefiting from the quad-polarization advantage of GaoFen-3 SAR wave mode data and the support of polarization basis transformation theory, this study used 4648 SAR data to study the correlation between cutoff wavelength and wind and wave parameters (e.g., significant wave height and wind speed) under different polarization bases and analyzed the variation of correlation coefficient caused by polarization basis change. Finally, the results were applied to evaluate the performance of wind and wave parameters retrieval. The results of the study show that the azimuth cutoff is strongly dependent on the polarization state of the electromagnetic wave. The azimuth cutoff wavelength under the elliptical polarization bases has a higher correlation with wind and wave than that under H-V linear, circular, and linear rotated polarization bases. Using the azimuth cutoff wavelength of the elliptical polarization bases can significantly improve the retrieval accuracy of wind and wave parameters. This study shall enhance the capabilities of polarized SAR systems to precisely derive more ocean surface properties. The result implies that polarization basis is an important factor that must be considered in future ocean SAR studies.

中文翻译：

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偏振基础对使用 GF-3 SAR 图像方位角截止估计风浪参数的影响


合成孔径雷达(SAR)方位截止波长是海面风浪反演的重要参数。早期的研究已经充分证明了方位角截止波长对偏振的实质性依赖性，但目前的研究仅集中在水平和垂直（HV）线性偏振基础上[水平-水平（HH）、水平-垂直（HV）/垂直-水平（ VH）和垂直-垂直（VV）]，而不考虑其他偏振基础（例如线性旋转、圆形和椭圆偏振）的影响。受益于高分三号SAR波模数据的四偏振优势以及偏振基变换理论的支持，本研究利用4648个SAR数据研究截止波长与风浪参数（如有效波高、风浪等）的相关性。速度）在不同偏振基下，分析了偏振基变化引起的相关系数的变化。最后，将结果应用于评估风浪参数反演的性能。研究结果表明，方位截止强烈依赖于电磁波的偏振态。椭圆偏振基下的方位截止波长与风波的相关性高于高压线偏振、圆偏振和线旋转偏振基下的方位截止波长。利用椭圆偏振基的方位截止波长可以显着提高风浪参数的反演精度。这项研究将增强偏振SAR系统精确获取更多海洋表面特性的能力。 结果表明，偏振基础是未来海洋SAR研究中必须考虑的重要因素。