河南长葛南席一次龙卷成因分析及雷达预警初探  

Analysis on the causes of a tornado in Nanxi,Changge of Henan province and the preliminary study on radar warning

作　　者：王红燕 王东平 牛淑贞[2] 张晓鹏 侯凯 胡彩菊 

机构地区：[1]河南省许昌市气象局,许昌461000 [2]河南省气象局,郑州450003 [3]河南省长葛市气象局,长葛461500

出　　处：《暴雨灾害》2013年第3期256-262,共7页Torrential Rain and Disasters

基　　金：公益性行业(气象)科研专项(GYHY201306016;GYHY200906010);河南省重点科技攻关计划项目(112102310033)

摘　　要：利用常规气象资料、四要素自动气象站和多普勒天气雷达资料,对发生在2010年7月19日05时30分左右长葛东部南席镇一次罕见龙卷天气成因进行分析,初步探讨如何应用多普勒天气雷达对类似强对流天气进行有效预警。结果表明:此次龙卷天气发生在中空急流与中低层辐合、高层辐散相互配置的有利环境背景下,中低空露点锋和强湿度梯度带为龙卷产生提供触发机制,龙卷产生于干、湿空气交界并靠近湿区一侧;龙卷发生前中气旋表现出较低的底高、逐渐变小的最强切变高度、降低的顶高、较小的方位角方向直径和较强的垂直风切变等特征,初步总结出识别龙卷的雷达探测中气旋预警指标。Using conventional meteorological data, four elements automatic weather station data and Doppler radar data, a rare tornado pro- eess occurring on July 19, 2010 at the Nanxi town, in the eastern Changge was analyzed. In the paper, the application of Doppler radar for ef- fective early warning the similar strong convective weather was discussed preliminarily. The results indicate that the tornado was caused by fa- vorable circulation background, which produced by the coupled of middle level jets and convergence at middle and low layers, and divergence at high layer. The dew point front at middle and low layers and the zone of strong moisture gradient were the trigger mechanism of tornado. The tornado is generated in the moist air and close to the moist gradient area. Characteristics of this process are the lower height of meso-cyclone echo base, the height of severely shear and echo top descended, less azimuth direction and strong vertical wind shear ere before the occur- rence of tornado. And the meso-cyclone indicator using tornado radar detection was summarized.

关 键 词：龙卷 露点锋 强湿度梯度带 中气旋 雷达预警 

分 类 号：P445.1[天文地球—大气科学及气象学]