台风Rananim数值模拟试验及其结构特征分析

利用非静力平衡中尺度数值模式MM5(V3)对2004年第14号台风Rananim进行了数值模拟试验,对路径、移速、降水量和暴雨时空分布等方面的对比验证表明,MM5模式对台风Rananim的模拟是比较成功的。在模拟效果较好的基础上,利用高分辨的模拟结果,分析了Rananim登陆前后两阶段的动力和热力特征,包括水平环流、温湿结构、涡度、散度等基本动、热力因子的时空结构特征,发现登陆后低层水汽输送的非对称分布与降水落区有较好对应关系,水汽输送通过影响台风的热力结构来影响台风的强度,致使物理量在垂直方向的伸展高度比台风登陆前要明显降低,并且在量值上也更小一些。

Numerical Simulation Experiments and Structural Characteristic Analysis of Typhoon Rananim

A numerical experiment is conducted on typhoon Rananim(0414) by use of the PSU/NCAR non-hydrostatic mesoscale model(MM5) and verified against observations;the track,speed,and detailed mesoscale precipitation distributions are well reproduced.Based on the successful simulation of the typhoon process,the characteristics of the typhoon before and after the landfalling are analyzed in circulation patterns and dynamical and thermodynamic structures such as horizontal circulation,temperature/humidity structure,vorticity,divergence,etc.It is found that the distribution of rainfall is related to the asymmetric distribution of moisture transportation,which affects the thermodynamic structure of the typhoon to a great extent.In vertical direction,the extension of physical elements is not only low in height but also small in amount.