基于SAR子孔径分解的海表面二维流场反演  

Two-dimensional sea surface current field inversion based on SAR sub-aperture decomposition

作　　者：张佳辉 苗洪利[1] 杨忠昊 刘昆池 Zhang Jiahui;Miao Hongi;Yang Zhonghao;Liu Kunchi(College of Physics and Optoelectronic Engineering,Faculty of Information Science Engineering,Ocean University of China,Qingdao 266100,China)

机构地区：[1]中国海洋大学信息科学与工程学部物理与光电工程学院,山东青岛266100

出　　处：《海洋学报》2023年第8期24-30,共7页

基　　金：国家自然科学重点基金(62031005);山东省自然科学基金(ZR2020MD097)。

摘　　要：对Radarsat-2和Sentinel-1A分别观测的两个海域的单景SAR图像进行子孔径分解,各自得到不同方位角上的两幅SAR子孔径图像。使用多普勒质心频移法分别对不同方位角的两幅SAR图像进行海流反演,并进行海流矢量合成,采用经过时空匹配的HYCOM模式数据对反演结果进行检验,结果表明:Radarsat-2观测的SAR图像分解的两幅子孔径SAR图像矢量合成后的海流与HYCOM模式数据相比,速度均方根值为0.09m/s,相关系数为0.64;方向均方根值为10.49°,相关系数为0.78。Sen-tinel-1A观测的SAR图像分解的两幅子孔径SAR图像矢量合成后的海流与HYCOM模式数据相比,速度均方根值为0.06m/s,相关系数为0.82;方向均方根值为2.85°,相关系数为0.86。由此可见,基于单景SAR分解的两幅子孔径SAR图像可以有效反演二维海流。其反演精度与雷达视向和真实海流矢量的方向有关,二者的角度越小,反演海流矢量的精度越高。Two single-scene SAR images observed by Radarsat-2 and Sentinel-1A were decomposed to obtain a pair of SAR sub-aperture images at different azimuth-angles,respectively.Doppler centroid anomaly method was used to invert the sea surface current of two sub-aperture images with different azimuth angles.The current field was obtained by vector synthesis.The inversion results were verified by the HYCOM model data with spatio-tem-poral matching.The results show that the root mean square(RMS)of the current velocity between the synthesized result by two sub-aperture images of Radarsat-2 and the HYCOM model data is 0.09 m/s,and the correlation coeffi-cient is 0.64.The RMS of current direction is 10.49°and the correlation coefficient is 0.78 of this group data.As for the results of the Sentinel-1A image,the RMS of the current velocity is 0.06 m/s,and the correlation coefficient is 0.82.The RMS of the current direction is 2.85°,and the correlation coefficient is 0.86.It can be seen that the two-dimensional ocean currents field can be effectively inverted based on the two sub-aperture SAR images that decom-posed from single-scene SAR image.The inversion accuracy is related to the relative direction of the radar’s look-ing direction and the real current vector.The inversion accuracy of the sea surface current field can be higher when the relative angle is small.

关 键 词：SAR 子孔径 多普勒质心异常 二维流场 HYCOM 

分 类 号：P714.1[天文地球—海洋科学] P731.21