对引发密云泥石流的局地暴雨的分析和诊断  

ANALYSIS AND DIAGNOSIS OF A LOCAL HEAVY RAIN IN MIYUN COUNTY, BEIJING

作　　者：王迎春[1] 钱婷婷[2] 郑永光[2] 陶祖钰[2] 

机构地区：[1]北京城市气象研究所,北京100089 [2]北京大学物理学院大气科学系,暴雨监测和预测实验室北京100871

出　　处：《应用气象学报》2003年第3期277-286,共10页Journal of Applied Meteorological Science

基　　金：北京市科学技术委员会奥运重大项目H0 2 0 62 0 1 90 0 91;国家自然科学基金重点项目 40 2 3 3 0 3 6的资助。

摘　　要：20 0 2年 8月 1日晚北京东北部密云县发生了降雨量达到 2 80 .2mm的局地短历时特大暴雨 ,并引发了洪水和泥石流。卫星云图分析表明 ,它是由一个中 β尺度对流系统在北京北部山区停留造成的。TBB图的等值线密集区和上冲云顶对暴雨落区有指示意义。大尺度环流诊断表明 ,暴雨前一天存在较深厚的下沉运动 ,其伴随的逆温层抑制对流的发生 ,使不稳定能量得以积累。各种稳定参数的计算结果证实了这一能量的积累过程。暴雨当天 ,下沉运动转为微弱的上升运动 ,使对流的发生成为可能。大尺度水汽场的诊断表明 ,北京处在西太平洋副热带高压边缘的高温高湿气流的控制下 ,有很强的水汽输送。地面中尺度分析表明 ,中尺度低压和辐合线是对流的触发系统 ,北京地区北部处于中尺度低压东部暖湿气流的辐合区中 ,在有利的地形条件下使密云县西部山区产生了局地特大暴雨。Miyun, the northeast county of Beijing, had a local and short time heavy rain on 1 August, 2002. The amount of precipitation reached 280.2 mm and the rain caused a mud rock flow and flood fatality. Satellite cloud pictures show that this rain was triggered by a meso β convective system which settled in the northern mountain area. The dense isoline region of TBB and the up rushing cloud top indicate the rainfall area. The large scale circulation shows that there was sinking motion, accompanying an inversion layer which restrained the convection and favored the accumulation of instable energy. During the rain process, the conversion from sinking to ascending made the convection possible. The large scale analysis of water vapor indicates that there was abundant water vapor from the northwest of the subtropical high to Beijing. The result of surface mesoscale analysis shows that the mesoscale low and the convergence line are trigger factors for a meso β convective system, and that the high humidity and high temperature airflow is in favorable of the local heavy rains.

关 键 词：密云泥石流 局地暴雨 中尺度对流系统 天气过程分析 大尺度环流诊断 

分 类 号：P458.121.1[天文地球—大气科学及气象学] P642.23