降雨对SAR风场反演的影响及校正  

The correction of rain effect on SAR wind field retrieval

作　　者：余水[1,2] 杨劲松[2] 贺双颜[1] 贺治国[1] 任林[2] 郑罡[2] 

机构地区：[1]浙江大学海洋学院,浙江舟山316021 [2]国家海洋局第二海洋研究所卫星海洋环境动力学国家重点实验室,浙江杭州310012

出　　处：《海洋学报》2017年第9期40-50,共11页

基　　金：国家自然科学基金(41321004;41306191;41306192;41406203;41676167);国家863项目(2013AA09A505);中国科技部-欧洲空间局合作"龙计划"四期项目(32249);全球变化与海气相互作用专项国际合作项目(GASI-IPOVAI-04)

摘　　要：合成孔径雷达(Synthetic Aperture Radar,SAR)在风场反演中发挥着重要的作用,但由于受到降雨的影响,海面风场的反演精度会随之下降。本文利用Radarsat-2SAR观测数据,准同步降雨数据和再分析风场资料对2014年台风"威马逊"外围风场受降雨影响的情况进行了分析,建立了雨致海表阻尼后向散射系数受降雨强度,入射角等因素影响的拟合模型,并对降雨引起的信号衰减,后向体散射进行了评估。实验发现雨致海表面阻尼作用抑制风致海面波的影响十分明显,且降雨造成的信号衰减随降雨强度和入射角的增大而增加,雨滴产生的后向体散射和雨致海表阻尼作用造成的后向散射系数变化随降雨强度的增大而增加,随入射角的增大而减小。实例表明本文建立的模型能够有效改善降雨条件下SAR风场的反演精度。Synthetic Aperture Radar （SAR） plays an important role in typhoon wind field retrieval, but due to theinfluence of the rainfall on the radar signal, the inversion precision of sea surface wind field will decline. In this pa- per, we analysis the rain effect to the 2014 typhoon Rammasun by using RADARSAT-2 SAR data, quasi-synchro- nous rainfall data and reanalysis data. The damping from rainfall to the water surface is simulated by rain rate and incident angle. Rain-induced attenuation and raindrop volumetric scattering was also evaluated. It is found that the rain effect to the sea surface perturbation is much complex than the other two factors, and the signal attenuation increases with the increases of rainfall and incident angle, raindrop volumetric scattering and rain-iaduced sea sur- face damping increase with the increase of rainfall, but with the decrease of incident angle. The experimental re- suits also indicate that the model can improve the SAR wind measurement accuracy under rainfall conditions.

关 键 词：SAR 风场反演 降雨影响 校正 

分 类 号：TN957.52[电子电信—信号与信息处理] P444[电子电信—信息与通信工程]