西北东部一次大暴雨数值模拟及中尺度分析  

Numerical simulation and meso-scale analysis on heavy rain occurred in eastern part of northwest China

作　　者：任余龙[1] 寿绍文[2] 

机构地区：[1]中国气象局兰州干旱气象研究所甘肃省防灾减灾重点实验室,兰州730020 [2]南京信息工程大学大气科学学院,南京210044

出　　处：《气象科学》2008年第3期316-321,共6页Journal of the Meteorological Sciences

基　　金：国家自然科学基金项目(40405009、40575022、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)

摘　　要：2005年7月1—2日,西北东部出现一次造成严重灾害的大暴雨天气过程(本文简称为"050702"暴雨),利用NCEP(1°×1°)资料分析表明,副热带高压边缘偏南和西南气流北上,与西北冷空气在西北区东部形成辐合区造成了此次暴雨的发生,此次暴雨的水汽来源于中国南海和孟加拉湾。本文用非静力中尺度模式MM5V3.6成功模拟出此次过程,对暴雨中心冷暖平流、辐合层及水汽通量散度等暴雨因子的中尺度结构与强降水的关系进行了研究。结果表明:(1)降水强度和对流层中层冷平流有很好的相关,随着冷平流的增强,降水强度也迅速增大;暖平流对降水强度起到维持的作用;(2)在降水达最强时段,对流层中出现低层强辐合,高层辐散的结构;(3)在降水达最强时段,对流层中低层水汽辐合的达到最强,表明水汽通量散度场和降水有较好的对应关系。A disastrous rainstorm occurred in the eastern part of Northwest China during 1--2 July, 2005. Analysis by NCEP data with 1°×1° shows that the rainstorm was formed by the west-south flow of the western part of subtropical ridge and the north cold air. The moisture came from south China sea and Bengal. Based on numerical simulation of the rainstorm using MM5V3.6 meso-scale model, this paper an- alysed the relation between the rainfall intensity and such factors of rainstorm as meso-scale structure of temperature advector, convergence field and moisture flux divergence. The result shows that ： （ 1 ） there exists a good relation between the rainfall intensity and middle level cold temperature advector. With the boost up of cold temperature advector, the rainfall intensity augments quickly. Warm advector helps maintain the rainfall intensity; （2） during the maximum the rainfall intensity , there are convergence at the lower level and divergence at upper level in the troposphere; （3） during the maximum rainfall intensity, the strongest convergence of moisture flux appears at the middle and lower levels, which shows that a favorable relation exists between the moist flux field and the precipitation.

关 键 词：大暴雨 数值模拟 中尺度结构 

分 类 号：P426.62[天文地球—大气科学及气象学]