GPS掩星资料三维变分同化对台风模式预报的改进试验

本文尝试了GPSRO COSMIC资料在中尺度数值模式中的应用,利用COSMIC资料受云和降水影响较小,且有高数据精度、高垂直分辨率等优点,以改善模式初始场,进而提高预报准确度。模式采用中尺度气象模式WRF V3.0.1版本及其三维变分同化系统3DVAR,利用NCEP再分析资料、GTS资料和COSMIC资料对2009年第8号台风"莫拉克"登陆台湾岛前到登陆台湾岛的过程进行了模拟试验,并对温度、露点温度、对流有效位能等要素进行了诊断分析。试验结果表明:该项试验成功将COSMIC资料同化进模式,加深对"莫拉克"热力结构特征的了解,有效改善台风降水和路径预报,其中仅屏东县单点降水预报提高600 mm左右,24 h预报路径误差提高80 km以上。同时对提高台风强度预报起到积极作用。

The test of typhoon forescast improve by 3d variational assimilation of GPS occulation material

In recent years, along with the rapid development of atmospheric sounding technology, the application of a series of high spatial and temporal resolution unconventional data,such as GPS occulation refractive index,has compensated the shortages of Marine observation data. This paper presents the utility of GPSRO COSMIC material in meso-scale model. Cloud and precipation suffer less inpact on COSMIC,in addition COSMIC has high precision and high vertically resolution,so it could improve the initial field in model and then raise the prediction accuracy. With incorporated the meso-scale meterological model, V3.0.1 WRF,and 3d variational assimilation system(3DVAR), the MORAKOT landing process is simulated by using NCEP,GTS and COSMIC. Experiment results show: assimilation COSMIC could improve the rainstorm forecast in certain degree,and meanwhile through to the preliminarily discussion for each diagnosis quantity and different levels of wind field,it considers the assimilation data could play a certain indicate role for typhoon intensity,pathway and precipation by making better forecast results for the amount.