江苏中部一次强对流天气的物理机制分析  

Mechanism analysis of a severe convection process in middle Jiangsu

作　　者：谢义明 解令运[2] 沙维茹 胡玉玲 徐莎莎 

机构地区：[1]扬州市气象局,江苏扬州225009 [2]江苏省气象局,南京210008

出　　处：《气象科学》2008年第2期212-216,共5页Journal of the Meteorological Sciences

基　　金：国家自然科学基金(40665001和40475017)

摘　　要：利用NCEP再分析资料、常规探测和多普勒雷达探测资料对2005年4月20日发生在江苏的一次龙卷强对流天气进行了分析,结果表明:此次强对流天气是发生在东北冷涡南压、高空风速异常偏大、温度场明显落后于高度场的环流背景下;高、低空三支急流的耦合为其提供动力上升条件;350 hPa高空急流显著加强引发低层锋区增强,加速低层锋区南压是其触发因素;低层的对流不稳定和中层的条件性对称不稳定叠加是其不稳定机制;而强的垂直风切变则使得强对流风暴得以维持和加强。多普勒雷达产品分析显示多普勒雷达是做好灾害性天气短时临近预报的最重要工具。NCAR/NCEP reanalyze data, meteorological routine data and Doppler radar data are used to analyze a severe convection process which took place in middle Jiangsu on 20 April,2005. The result shows that the favorable weather background is northeast cold vortex moving southward, abnormally large upper wind speed and obvious temperature advection. Coupling of three upper and low level jets supplies the dynamical condition. The strengthening of low level front and the speediness of front southward by the obvious accretion of the upper level jet at 350 hPa are trigger action. The cooperation of the low level convection instability and the middle level condition symmetry instability is the stability mechanism. The convection was strengthened and maintained by the strong vertical wind shear. The result of Doppler radar analysis indicates the Doppler radar data is the most important information for the shortterm forecasting.

关 键 词：强对流 急流对称不稳定 多普勒雷达 

分 类 号：P445[天文地球—大气科学及气象学]