两次下击暴流事件的多普勒天气雷达资料分析  

Analysis on Doppler weather radar of two downburst events

作　　者：杜文婷[1] 黄兴友[1] 黄铃光[1] 严洪梅 

机构地区：[1]南京信息工程大学,南京210044 [2]浙江省金华市气象局,金华321099

出　　处：《气象水文海洋仪器》2012年第4期11-16,共6页Meteorological,Hydrological and Marine Instruments

基　　金：国家自然科学基金重点基金项目"气象多普勒雷达测量近地面层大气折射率场的研究(40775029)"资助

摘　　要：利用盐城和合肥的多普勒雷达资料,分别对2003-06-06发生于安徽定远县境内的下击暴流和2007-07-25发生于江苏兴化市境内的下击暴流进行了研究分析。2003-06-06的一系列下击暴流是发生于静止型多单体风暴中,地面上存在辐合切变线,西南气流提供充足的水汽,使得下击暴流持续进行;2007-07-25的下击暴流是发生于弓状回波前部破裂的两个单体中,同时弓状回波前方的阵风锋上不断出现新生单体,对原风暴进行不断地补充,导致下击暴流连续产生。结果表明:(1)风暴单体顶高或强中心所在高度不断下降促使中层气流向下运动,引发地面下击暴流天气;(2)风暴单体与阵风锋相遇,有可能会产生下击暴流;(3)若风暴体垂直积分液态水含量(VIL)和风暴体雷达反射率因子极大值所在高度(CM)保持一个体扫(约6min)基本不变,表明风暴体已发展成熟,顶端即将崩溃、破碎,下击暴流即将产生,大约有6min的预警时间。Two downburst events in Anhui on June 6th,2003and in Jiangsu on July 25th,2007were analyzed respectively based on Doppler radar data collected from Hefei and Yancheng radar sites.A serial of severe storms are growing out of multicell storms,accompanied with a shear line on the ground and sufficient moisture is provided by southwesterly flow on June 6th,2003.Another severe storm is growing out of two new cells triggered by the crushed bow-echo storm,and sustained by new cells from the gust front in front of the bow-echo on July 25th,2007.The results show that the obvious dropping of reflectivity factor core or cell top can produce downward tilt airflows at middle levels in the storms,which can be used to issue the downburst warning ;a downburst may initiated if a storm encounters with a shear line ;if C-VIL（cell-vertical integrated liquid water content） and CM（centroid of mass） keep stable in 6min,a downburst will generate during the following VCP（vertical coverage pattern） collection with 6min warning.

关 键 词：下击暴流 切变线 VIL 多单体风暴 单体顶高 

分 类 号：TN958.2[电子电信—信号与信息处理]