基于FY-3B微波成像仪的海面风速反演

风云三号B星微波成像仪的10.65、18.7、23.8和36.5 GHz频点对海表面粗糙度和介电特性比较敏感,能够用于海面地球物理参数的反演。为获得一种适用于全球大部分海域的海面风速反演算法,利用快速辐射传输模式和再分析大气廓线库模拟微波成像仪海面微波辐射特性,在此基础上建立了半经验反演算式,并利用浮标现场测量数据及WindSat全极化辐射计风速产品对半经验算法和经验算法分别进行了验证和对比。另外,通过分析风向对风速反演的影响,借助AT BV-TBH模型,尝试利用查找表算法对风向造成的晴空区域风速反演偏差进行初步校正。校正风向误差后,反演风速与浮标风速的均方根误差为0.9775 m/s。

Sea Surface Wind Speed Retrieval based on FY-3B Microwave Imager

FY-3B MWRI uses the 10.65,18.7,23.8 and 36.5 GHz microwave brightness temperatures which are sensitive to ocean surface roughness and dielectric properties,to retrieve sea surface geophysical parameters.In order to obtain an algorithm for global use,the microwave radiation is emitted from the wind\|roughed ocean surface and measured by MWRI,which is simulated by the JCSDA Community Radiative Transfer Model CRTM and the ECMWF sampled databases of 60-level atmosphere profiles.Based on this simulation,a semi\|empirical algorithm is established.The in\|situ buoy measurements and WindSat wind speed production are used to validate the semi\|empirical algorithm.Furthermore,the retrieval error caused by the wind direction relative to the radiometer azimuth is analyzed.RMS/ATBV-TBH look-up-table is made to correct the relative wind direction error.After the relative wind direction error correction,the rms accuracy is reduced to 0.9775 m/s.