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首先获取覆盖浙江省近海215景长时间序列多模式ASAR Level 1B数据,对获取的ASAR数据进行几何校正、辐射定标、极化比转化、噪声剔除后,将所有的影像统一重采样得到1km×1km分辨单元的后向散射系数影像,尝试利用CCMP风向作为SAR风速反演地球物理模式函数的风向初始场,对比目前国际上最常用的3种模式函数CMOD4、CMOD-IFR2和CMOD5的风速反演效果,将反演得到风速分别与CCMP插值风速和现场观测气象站点的风速进行对比,结果表明CCMP风向数据可作为SAR风速反演的风向初始场,其中结合CMOD4模式函数能够得到较高精度的反演风速,由于CCMP数据有效时间长、覆盖范围广、易于获取,因此联合CCMP风向有利于SAR近海风场反演的业务化应用。
Firstly, the long time series multi-mode ASAR Level 1B data covering the 215 scenes in the coastal area of Zhejiang Province were obtained. After geometric correction, radiation calibration, polarization ratio conversion and noise elimination, all images were uniformly resampled to obtain 1km × 1km resolution unit, we try to use CCMP wind direction as wind direction initial field of wind speed inversion geophysical model function. Compared with the wind speed inversion of CMOD4, CMOD-IFR2 and CMOD5, which are the most commonly used three kinds of mode functions in the world at present, The results show that the CCMP wind direction data can be used as the wind direction initial field for the wind speed inversion of SAR, and the combination of the CMOD4 mode function and the wind speed of the CCMP interpolation wind speed can be obtained. As the CCMP data is available for a long time and has a wide coverage and easy access, the combined CCMP wind direction is conducive to the operational application of the wind field inversion of SAR.