0418号台风艾莉暴雨成因分析

Diagnostic Analysis and Numerical Simulation of Typhoon Aili Rainstorm

利用MM5数值模拟的输出资料和常规资料对2004年8月25—26日台风艾莉造成福建省特大暴雨的物理成因进行了研究。结果表明,台风转向西南横穿福建全省是造成大范围暴雨的关键,而台风外围风场不对称分布是台风转向的原因之一。台风暴雨区位于对流有效位能(CAPE)高值区、总风暴相对螺旋度中心、对流层低层湿非地转Q矢量散度辐合辐散交界处。敏感性数值试验表明地形对垂直运动有明显影响,并且影响暴雨强度及分布。

Based on PSU/NCAR＇ s mesoscale model MM5 （V3.7）, the typhoon Aili rainstorm event is investigated. The results show that the anisomerous distribution of wind field is one of reasons causing Typhoon turning. The center of rainstorm is in the high value area of Convective Available Potentional Energy （CAPE）, the center of Storm Relative Helicity （SRH）, and the common boundary of positive and negative Q-vecter divergence. The sensitive numerical experiments are also conducted. It is concluded that terrain have significant impacts on vertical motion, intensity and distribution of heavy rainfall