中-β尺度对流单体造成局地特大暴雨分析——以02-07-04子长特大暴雨为例

Analysis of Local Extra-heavy Rainstorm by Meso-βScale Convective Monomer--Take the example of Zichang extra-heavy rainstorm on July 4, 2002

通过对2002-07-04T03-08发生在陕北子长特大暴雨过程的各种现象要素分析,认为,此次特大暴雨是由中-β尺度强对流云团产生,具有典型的对流单体形成、发展、消亡过程的特征。研究表明形成此次MCS主要特点云顶亮温较一般暴雨云团偏低,两单体在对流尺度内相互作用,一侧单体增伏变化为暴雨云团形成提供了使其发展的有利抬升机制、水汽资源和能量补充,为强对流单体形成暴雨云团提供了发展条件。并在此基础上分析了中-β尺度有利的环境场及其发展条件。特大暴雨发生在高低空冷暖空气相脱离的孤立系统中,大尺度环流长波槽后部弱上升气流是暴雨发生的大尺度背景场。

Through analysis of different phenomena in the process of rainstorm of Zichang in Norhern Shaanxi on July 4, 2002, this extra-heavy rainstorm is formed by meso-βscale strong convective cloud cluster, having the characteristics of the formation, development and disappearance of the typical convective monomer. Research shows that a strong convective monomer was formed through two convective monomers, and that extra-heavy rainstorm occurred in the isolated system of the separation between cold and hot air in high altitude, and that the weakness of the ending part of convection long wave large-scale circumfluence background against which rainstorm occurred.