一次副高控制下暴雨过程的数值模拟和诊断分析

Numerical Simulation and Development Mechanism Analysis of Heavy Rain Process in North of Henan Province

利用NCEP再分析资料和实时观测资料,用中尺度数值模式MM5对2007-08-25豫北暴雨过程进行了数值模拟.结果表明:这次暴雨过程水汽主要辐合在700 hPa以下;低层强辐合区配合高层强辐散区才能触发暴雨天气的爆发,250 hPa附近的辐散区对暴雨的贡献更大;干层携带高层冷空气的下沉逼迫作用,促进了对流层在垂直方向的深厚发展;在低空新生成的热力正环流的生消对暴雨的加强和维持起着重要作用.

This paper presents results of simulations for a case of heavy rain that occurred in august 2007 over north of Henna province using the fifth generation Penn state/NCAR mesoscale model（MMS）. The model result recaptures the major observed features of these events as well as the associated mesoscale system. The moisture was centralized under 700 hPa. The disposition of the lower-level convergence and upper-level divergence was very favorable for the generation and development of the heavy rain. The cold air from dry-level was very favorable the accumulation of unstable energy in low level;the evolution of direct circulation was important to heavy rain.