C波段极化合成孔径雷达海面后向散射特性及风场反演研究

项目名称： C波段极化合成孔径雷达海面后向散射特性及风场反演研究

项目编号： No.41306186

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 天文学、地球科学

项目作者： 张毅

作者单位： 国家卫星海洋应用中心

项目金额： 26万元

中文摘要： 准确获取风向信息是合成孔径雷达(SAR)风场反演的难点，极化SAR 包含目标物更加丰富的信息使独立SAR风场反演成为可能，为此必须深入研究极化SAR海面后向散射随风场的变化特性。定量化地分析同极化后向散射系数、交叉极化后向散射系数以及极化相关后向散射系数在不同风速、风向、入射角下的变化特征是本项目研究的重点，并以此为基础开展C波段极化SAR风场反演算法研究，提出利用C波段极化SAR观测数据中同极化后向散射系数及由同极化与交叉极化后向散射信号所获得的相关极化后向散射系数协同进行海面风场反演的方法。本项目从C波段极化SAR单视复数据获取同极化和极化相关后向散射系数，利用最大似然估计以及空间滤波等方法获得海面风矢量,与以往SAR风场反演方法相比，本项目完全由C波段极化SAR数据本身获得风矢量，不依赖于外部风向信息，最终反演结果与微波散射计、浮标观测以及数值预报模式风场进行对比分析和真实性检验。

中文关键词： 极化合成孔径雷达；海面风场反演；极化相关后向散射系数；；

英文摘要： Coastal wind is strongly influenced by topology and the discontinuity between land and sea surface. Wind assessment from remote sensing in coastal regions thus remains challenging. Space-borne scatterometer does not provide any information about the coastal wind field, as the coarse spatial resolution hampers the radar backscattering. Synthetic aperture radar (SAR) with a high spatial resolution and all-weather observation ability has become one of the most important ways for ocean surface wind observation, especially in the coastal area. Conventional wind field retrievals from SAR, however, always need wind direction as initial information, such as from numerical weather prediction models (NWP) which may not match the time when SAR image is acquired. The polarimetric observations of SAR make the independent wind retrieval from SAR images become reality. In this project, the relationship between C-band polarimetric SAR backscattering and ocean wind field will be quantitatively analysed and a new method of using co-polarization backscattering coefficients from polarimetric SAR observations up to polarimetric correlation backscattering coefficients which are acquired from the conjugate product of co-polarization backscatter, and cross-polarization backscatter is proposed to obtain the coastal wind field. Co-polari

英文关键词： polarimetric synthetic aperture radar；ocean wind field retrieval；polarimetric correlation backscattering coefficien；；