CAJ | 학술논문

针对基于散射计地球物理模型函数的机载合成孔径雷达(SAR)海面风场反演中存在的风向获取依赖于图像风条纹或数值预报、散射计数据和浮标等背景场资料,风向与SAR图像时空分辨率不匹配,进而影响机载SAR海面风场反演精度等问题,本文根据机载SAR对海探测特点,研究一种适用于C波段机载SAR的海面风场反演新方法.利用SAR图像距离向不同入射角的后向散射系数,依据地球物理模型构造最小代价函数,通过代价函数的求解直接从机载SAR数据同时反演出海面风速和风向.利用论文提出的海面风场反演方法分别对仿真SAR数据和实测C波段机载SAR数据进行风向、风速的反演误差分析及试验验证.研究结果表明,该方法适用于机载SAR海面风场反演,可不依赖背景风向直接反演出精度较高的风速和风向;雷达后向散射系数误差是决定海面风速、风向反演精度的关键因素,辐射定标精度越高则反演误差越小;海面风速反演误差随着风速的提高而增大,当海面风速大于18 m/s时,风速反演误差显著增加,而海面风向的反演误差与风速无明显关系.
침대기우산사계지구물리모형함수적궤재합성공경뢰체(SAR)해면풍장반연중존재적풍향획취의뢰우도상풍조문혹수치예보、산사계수거화부표등배경장자료,풍향여SAR도상시공분변솔불필배,진이영향궤재SAR해면풍장반연정도등문제,본문근거궤재SAR대해탐측특점,연구일충괄용우C파단궤재SAR적해면풍장반연신방법.이용SAR도상거리향불동입사각적후향산사계수,의거지구물리모형구조최소대개함수,통과대개함수적구해직접종궤재SAR수거동시반연출해면풍속화풍향.이용논문제출적해면풍장반연방법분별대방진SAR수거화실측C파단궤재SAR수거진행풍향、풍속적반연오차분석급시험험증.연구결과표명,해방법괄용우궤재SAR해면풍장반연,가불의뢰배경풍향직접반연출정도교고적풍속화풍향;뢰체후향산사계수오차시결정해면풍속、풍향반연정도적관건인소,복사정표정도월고칙반연오차월소;해면풍속반연오차수착풍속적제고이증대,당해면풍속대우18 m/s시,풍속반연오차현저증가,이해면풍향적반연오차여풍속무명현관계.
@@@@Wind direction retrieval depending on other background sources, e.g., the visible wind-induced streaks, numerical weather predic-tion model data, scatterometer data and buoy data is the key problem existing in the ocean wind field retrieval using airborne synthetic aperture radar (SAR) data based on geophysical model function which influences the wind speed and direction retrieval accuracies. To solve this problem, a new ocean wind field retrieval method is proposed, with which the wind speed and direction are estimated simultaneously through using the normalized radar cross sections corresponding to different incidence angles and geophysical model function according to the sounding characteristics of airborne SAR. To evaluate the ocean wind field retrieval errors and effects, the simulated data and C band airborne SAR data are used to obtain the wind speed and direction by the proposed method. The verification results show that the wind field retrieval method is suited to retrieve highly accurate wind speed and direction from airborne SAR sounding data without other background sources. The major error can be explained by the insufficient accuracy in calibration of the NRCS for wind speed and wind direction retrieval. The wind speed error increases with the value of speed increasing and at high wind speeds exceeding 18 m/s the error increases distinctly. The value of wind speed has no obvious influence on wind direction retrieval accuracy.