乌鲁木齐7·17暴雨的天气尺度与中尺度特征  

Synoptic Scale and Mesoscale Characteristics of 7·17 Urumqi Heavy Rainfall in 2007

作　　者：孔期 郑永光 陈春艳 

机构地区：[1]国家气象中心,北京100081 [2]新疆维吾尔自治区气象台,乌鲁木齐830002

出　　处：《应用气象学报》2011年第1期12-22,共11页Journal of Applied Meteorological Science

基　　金：国家自然科学基金项目(40875019);公益性行业(气象)科研专项(GYHY200906003;GYHY200906004)

摘　　要：新疆位于半干旱地区,2007年7月13—18日新疆沿天山一带多站出现暴雨。利用每分钟与小时降水资料、常规地面与高空观测资料、NCEP 1°×1°再分析资料、静止卫星云图资料与雷达资料进行分析,重点考察2007年7月16(?)17日乌鲁木齐暴雨过程(7·17暴雨)的天气尺度及中尺度特征,并与1996年同期暴雨过程以及我国东部暴雨过程进行对比。结果表明:该降水是一次大尺度斜压过程,中亚低涡是该暴雨过程的主要影响系统,但其位置、形态与强度均不同于1996年过程;干冷空气侵入加强了大气的对流性不稳定,对暴雨的加强和发展起重要作用;该暴雨过程的水汽主要来自于青藏高原东部—甘肃西部一线以及南疆北部;该暴雨过程中有明显的γ-中尺度对流雨团发生,径向速度辐合可能是γ-中尺度对流雨团的重要触发机制。Xinjiang is located in a semi-arid area,but a heavy rainfall event occurs unexpectedly along the Tianshan Mountains in Xinjiang during 13—18 July 2007.The circulation and the persistent mechanism of the low vortex as well as the mesoscale characteristics for the heavy rainfall in Urumqi during 16—17 July 2007 are analyzed and compared with one similar case in the same period of 1996,by use of the 1-hour and 1-minute precipitation data,geostationary satellite images,conventional surface and upper data,NCEP 1°×1°reanalysis data and the new generation Doppler radar data.The results are as follows：The heavy rainfall takes place under the favorable large-scale circumfluence.It is a large scale heavy rainfall which is related to the baroclinic disturbance.The central-Asian vortex is the major influential system,but the location, form and intensity are different from those of the cases in 1996.The atmospheric stratification turns unstable, but it is weaker comparing with the heavy rainfall in the eastern part of China.The characteristics of the stability are different during different rainfall periods,exhibiting the pattern of both stratiform and convective precipitation.The intrusion of the cold and dry air strengthens the instability of the atmosphere, and plays an important role for the heavy rainfall.The long maintenance of the vortex after the landing in Xinjiang is associated with the high PV anomaly（dry and cold air intrusion） in the upper-middle troposphere.Strong moisture convergence develops rapidly at lower level and the water mainly comes from the eastern part of the Tibetan Plateau,western part of Gansu Province and the north of the Southern Xinjiang Basin.The satellite and radar images show that there are obvious meso-γ-scale convective rainy cluster with characteristics of the echo pendency,vertical wind shear,but they are much weaker than those heavy rainfall systems in the east region of China.Radar radial base velocity products reveal that the mesoscale radial convergence may be the impor

关 键 词：新疆暴雨 中亚低涡 水汽输送 中尺度特征 

分 类 号：P458.121.1[天文地球—大气科学及气象学]