基于外部风向初始信息的SAR影像海面风场反演研究

Ocean Wind Retrieval from Synthetic Aperture Radar Images based on External Initial Wind Direction

首先利用SeaWinds散射计风向作为初始信息进行SAR(Synthetic Aperture Radar)影像海面风场反演,在对SAR影像进行了噪声剔除、辐射定标、极化转换等处理后获得VV极化下各分辨单元的后向散射系数,结合地球物理模式函数获取风速并显示输出海面风场的分布情况。在此基础上,尝试利用WRF(Weather Research Forecast)数值预报模式风向作为初始场从SAR影像中反演风速信息,将结果与之前以散射计风向作为初始信息得到的反演结果进行对比,验证实验方法的正确性,高分辨率数值预报模式风向结合SAR影像将是未来业务化近岸海面风场反演的发展趋势。

Firstly,wind direction from Seawinds scatterometer was used as the initial wind direction for the wind field retrieval from synthetic aperture radar images,which includes the process of noise removal,radiometric calibration,polarization conversion,acquisition of normalized radar backscatter coefficient and ocean wind field retrieval and display by using geophysical model function.Secondly,wind direction form numerical weather prediction（NWP） model WRF（Weather Research Forecast） was used as the initial wind direction to get the wind field from SAR images.Comparison of results form the two ways were made to validate our methods.Combination of high resolution NWP wind direction and SAR images will be the trends of operational coastal wind field retrieval in the future,a useful try was carried out in this paper.