天宫二号成像高度计海洋内波特征及振幅反演  

Features of the Internal Wave Observed by TG2-InIRA and Amplitude Retrieval

作　　者：安潇楠 张云华 董晓 Xiaonan AN;Yunhua ZHANG;Xiao DONG(CAS Key Laboratory of Microwave Remote Sensing,National Space Science Center,Beijing 100190,China;University of Chinese Academy of Science,Beijing 100049,China)

机构地区：[1]中国科学院国家空间科学中心中国科学院微波遥感重点实验室,北京100190 [2]中国科学院大学,北京100049

出　　处：《遥感技术与应用》2024年第5期1141-1150,共10页Remote Sensing Technology and Application

基　　金：国家重点研发计划项目(2016YFC1401004)。

摘　　要：海洋内波是一种重要的中尺度海洋现象,星载合成孔径雷达(SAR)是其常用的观测手段之一。2016年发射的天宫二号干涉成像高度计(TG2-InIRA)第一次以1°~8°小入射对海洋进行干涉成像观测,以实现宽刈幅海面高度测量,目前尚无针对该入射角范围的内波成像模型开展研究的报道。基于TG2-InIRA图像建立了小入射角海洋内波一维成像模型,利用该模型对海洋内波成像特征进行了仿真分析,并采用变分模态分解(VMD)方法对内波参数进行反演。为验证模型及反演方法的正确性,利用TG2-InIRA和Sentinel-1 SAR间隔4 h 13 min对同一内波获取的雷达图像进行了亮暗条纹对比和内波参数反演实验。实验结果表明:TG2-InIRA海洋内波条纹的亮暗顺序与Sentinel-1 SAR的相反,所得到内波特征宽度和振幅的反演结果相对偏差分别为8.14%和15.62%,并且均表现出沿传播方向宽度由小到大、振幅由大到小的变化,符合内波传播的规律,从而展示了TG2-InIRA对内波的探测能力。对TG2-InIRA和Sentinel-1在南海区域分别获取的40幅和19幅内波图像的统计分析表明,大于80%的实际图像中内波条纹亮暗顺序与SAR相反,与所建立的模型和仿真结果一致。Ocean internal wave is an important mesoscale ocean phenomenon.Spaceborne synthetic aperture radar(SAR)is one of the commonly used observation methods.Tiangong-2 interferometric imaging altimeter(TG2-InIRA)launched in 2016 is a new microwave sensor for ocean observation,which observes the sea surface at small incidence angles of 1°~8°,and the internal wave imaging model applicable to such range of incidence angles has not been reported before.An internal wave imaging model is established based on TG2-InIRA images,and the imaging characteristics of ocean internal waves at small incident angles are analyzed by one-dimensional simulation.The internal wave parameters were retrieved by Variational Mode Decomposition(VMD),and the SAR image for the same internal wave obtained by Sentinel-14 hours and 13 minutes later was used for comparison and validation.The results show that the light and dark sequence of the observed internal wave by TG2-InIRA is opposite to that by Sentinel-1 SAR,and the relative differences between the retrieved widths and amplitudes from TG2-InIRA and Sentinel-1 SAR images are about 8.14%and 15.62%,respectively,and their variations are accorded with the variation law for the internal wave propagation,and thus,the detection ability of internal wave is demonstrated.The statistical analysis results from 40 and 19 internal wave images obtained by TG2-InIRA and Sentinel-1 SAR in the South China Sea region respectively show that over 80%of the actual images have the opposite light and dark stripes,which is consistent with the established model and simulation conclusions.

关 键 词：海洋内波 内波振幅 天宫二号干涉成像高度计(TG2-InIRA) 小入射角 准镜面散射 

分 类 号：TP722.6[自动化与计算机技术—检测技术与自动化装置]