造成湖南暴雨的三个登陆热带气旋数值试验

Numerical experiments of three landfall tropical cyclons causing rainstorms in Hunan

"圣帕"(0709)、"碧利斯"(0604)和"格美"(0605)是近两年给湖南省造成严重灾害影响的三个台风。本文利用GRAPES2.5模式对3个登陆福建热带气旋进行了数值模拟分析,利用模式输出的1h基本物理量计算湿位涡。结果表明:湿位涡对台风特大暴雨的预报有指示意义,湿位涡绝对值随着暴雨的增强而增大,7月15日05—08时之间暴雨增幅最大,为113 mm/3 h,而湿位涡值也相应出现了最大的增幅120 PVU,此后两者又一致地逐渐减弱。

Bilis （0604）, Kaemi （0605） and Sepat （0709） have the serious disaster effect on Hunan province. Numerical experiments were conducted on three landfall tropical cyclones （TCs） by use of mesoscale model （GRAPES2.5）. Verified against observations, the tracks and detailed mesoscale precipitation distributions were well reproduced. Based on reliable outputs of lh factor, the moist potential vortieity （MPV） was analyzed. It is found that MPV is an evident predictor of heavy rains, the corresponding relation between the negative center of MPV and heavy rain area was better, and the absolute value variation of MPV had positive correlation to the intensitiy of one hour precipitation, during 05：00 - 08, July 15,113mm/3h,while MPV reaches its maximum of 120 PVU, followed by consistent weakening of them both.