2006年春季内蒙古久旱转雨过程分析  

Characteristic analysis of prolonged drought turning to rain in Inner Mongolia in spring 2006

作　　者：韩经纬 吴学宏 宋桂英 丁晓华 李大光 

机构地区：[1]内蒙古气象台,呼和浩特010051 [2]内蒙古自治区乌海市气象局,内蒙古乌海016000

出　　处：《气象科学》2009年第2期235-240,共6页Journal of the Meteorological Sciences

基　　金：国家自然科学基金项目(40765006);中国气象局新技术应用项目(CMATG2006Y08)

摘　　要：应用T213数值预报产品资料和基本气象资料,对发生在2006年5月11日内蒙古春季的久旱转雨天气过程进行了气候背景、天气成因和转折性特征的分析。分析表明,青藏高原低槽的建立与中纬度低槽的叠加是此次久旱转雨过程大尺度环流调整的转折性信号,西南急流的建立、水汽的长距离输送和偏东方向水汽的垂直叠加是转折性降水最重要的条件。东亚地区中纬度40°N低槽对转折性降水的作用主要体现为动力作用,而青藏高原低槽主要体现在对西南气流的加强和水汽的远距离输送。高层正涡度由南向北的输送,使中纬度低槽进一步加深,垂直运动上升区自西向东的输送主要发生在低层东风切变中。辐散场在垂直方向上形成了较好的抽吸效应,使低层动力辐合作用进一步加强。有利的动力、热力条件叠加成为此次转折性降水的又一重要原因。Abstract T213 numerical prediction productions and basic observations have been used to diagnose and analyze the climatic background, weather factors and course characteristics of one prolonged drought turning to rain in Inner Mongolia on May 11,2006. The analysis indicates that the establishment of Qing- hai-Xizang Plateau low trough and supperposition of middle latitude low trough is the turning signal of the large scale circulation adjustment in the process. The most important factors of sinuous precipitation are west-south jet stream founding, long distance vapor transportation and east inclining vapor conveyance and combination. The 40 °N low trough in East Asia played an role in dynamics. The function of Qinghai-Xizang Plateau low trough are enhancing the west-south stream and carrying vapor for long distance. The positive vortex transfer from south to north deepens the middle latitude trough. The movement of vertical rising area from south to north mainly happens in east wind shear at low level. Divergence field acted as a pump in vertical direction. It enhances the convergence at low level. Another important factor of sinuous precipitation is combination of advantageous dynamical conditions with thermodynamic ones.

关 键 词：久旱转雨 转折性特征 长距离水汽输送 物理量诊断 

分 类 号：P458.121[天文地球—大气科学及气象学]