西北区东部一次大暴雨过程的湿位涡诊断与数值模拟  

Numerical Simulation and Moist Potential Vorticity Diagnostic Analyses of a Heavy Rain Process in Eastern Part of Northwest China

作　　者：任余龙[1] 寿绍文[1] 李耀辉[2] 

机构地区：[1]南京信息工程大学气象灾害和环境变化重点实验室,江苏南京210044 [2]中国气象局兰州干旱气象研究所,甘肃兰州730020

出　　处：《高原气象》2007年第2期344-352,共9页Plateau Meteorology

基　　金：国家自然科学基金项目(40405009;4057022;40205008);江苏省气象局科技开发项目(200406);江苏省气象灾害重点实验室项目(KLME050201);国家重点基础研究发展规划项目(2004CB418301);江苏省自然科学基金项目(BK2005141)共同资助

摘　　要：利用绝热、无摩擦大气湿位涡守衡理论和NCEP（1°×1°）再分析资料，对我国西北区东部2005年7月1～2日大暴雨过程进行了分析。结果表明：700hPa上副热带高压西侧强西南气流北上，在西北区东部与东移南压的西北冷空气形成强辐合，是造成西北区东部这次强降水的主要影响系统。在700hPa等压面上湿位涡与辐合区域相对应的是，在西北区东部存在一个湿位涡正压项MPV1的正值区和湿位涡斜压项MPV2的负值区域，它们准确地指示了辐合区的范围及变化，暴雨出现在辐合区中或MPV1和MPV2的等值线密集区边缘上；对流层高低层正值MPV1可以指示对流稳定的冷空气的变化，而对流稳定度小的暖湿气流表现为小的正值（高层）或负值（低层），等值线密集带指示了降水的后界。用模式输出的高时空分辨率资料诊断暴雨发生期间各个暴雨中心的等熵面结构，表明用湿位涡理论可以很好地解释这次暴雨发生的局地特征。Diagnoses was made on a heavy rain which occured in the eastern part of northwest China during 1～2 July 2005 by using NCEP data（1°× 1°, 6 h intervals） and the MPV theory. The result show that a convergent region in the eastern part of northwest China, formed by the west-south flow of the western part of subtropical ridge and the north cold air, was responsible for the heavy rain. In relation to the convergent region over 700 hPa, there exist a positive area of MPV1 and a negative area of MPV2. They indicate the range and variation of convergent region. The heavy rain was emerged on the edge of intensive region of MPV1 and MPV2. In other place, the positive MPV1 both over upper and low levels indicate the variation of the cold air, while the moist flow with convective instability appears small positive （high） or negative area（low）. The intensive belt of the contour point out the back edge of the raining area. In order to discover the messcale structure of the heavy rain, MM5V3.6 was used to simulate this process, then diagnoses shows that the was made on the structure local character of the heavy of isentropic surface rain can be explained in each center of heavy propertly by using rain. The result MPV theory.

关 键 词：西北区东部 湿位涡 中尺度数值模拟 等熵面分析 

分 类 号：P458.121.1[天文地球—大气科学及气象学]