绵阳突发性大暴雨成因分析

Analysis of forming Mechanism of a Heavy Rain Event over Mianyang Region

在持续了一个月的阴雨天气、能量不足和大气层结稳定的条件下 ,绵阳市在2 0 0 1年 9月 19～ 2 0日突发了罕见的特大暴雨 ,并伴有强雷暴天气发生。利用天气学原理及过程前后的能量条件等对这次突发性大暴雨作了初步分析。

During 19-21 September of 2001, a rare heavy rain event was suddenly appeared and accompanied with powerful thunderstorm over Mianyang region. Under the condition of insufficient energy is not enough and stable atmospheric stratification after lasting a month with rainy weather. Its forming reasons using meteorology, NWF products, satellite image, and energy condition etc. are analyzed. It's considered that existence and stretch northwards of higher energy tongue with the type Ω in the low layer is a major reason for the heavy rainfall appeared suddenly. It is main energy of the suddenly arising rare torrential rain that releasing of latent heat energy for warm and wet flowing atmosphere climbing along could front face. The feedback speed up the low pressure grow, form the CISK(second unstable condition)mechanism. The article raise a point of view for movement′s energy accumulating, and attempt to explain the reason forming the suddenly arising torrential rain under condition of lower temperature and stable atmosphere.