摘要
利用WSR-98D多普勒天气雷达和闪电定位资料分析了2003年7月8日发生在安徽省无为县境内的一次龙卷过程。此次龙卷产生于低空急流左侧,动力、热力条件均为较有利的大尺度环境,多普勒雷达回波分析发现,龙卷起源于中高层向低层发展的中-γ尺度气旋中。闪电定位资料分析表明,龙卷发生前10min闪电活动开始频繁,龙卷出现后负地闪明显加大,且龙卷闪电存在于雷暴的发展后期、成熟和消亡阶段。此次龙卷的一些基本特征与通常结论有所不同,(1)雷达反射率因子小于通常结论;(2)龙卷风暴发展高度不是很高,回波顶高仅6～9km,类似于普通雷暴;(3)闪电活动中以负地闪为主,正地闪较少,并未出现正地闪一度占主导地位的现象。
In this paper,a tornado case,which occurred in Wuwei,Anhui Province in Jul. 8 2003,is analyzed by using the WSR-98D Doppler Radar data and the Lightning Location data.The tornado took place on the left-hand side of a low-level jet,and the large scale background environment dynamically and thermally are favorable to the genese of tornado.From the analysis of the Doppler radar echoes,we found that the tornado was born in a mesoscale(γ-scale)cyclone,which developed from the middle level to low level.The analysis of the lightning location data shows that about 10 minutes before the tornado took place,the lightning rate increased distinctly,and after the occurance of the tornado it fell down and the negative ground flashes were obviously increased.Furthermore,tornado lightning existed in the most lifetime of the thunderstorm.In this paper,some observation facts of the tornado are different from some classical theories.Firstly,radar reflectivity factor is not as strong as the classical result.Secondly,the height of the radar echo of the tornadic thunderstorm is only about 6～9 km as high as the common thunderstorm.Thirdly,in the tornado case,the negative ground flashes are more than the positive ground flashes,which is different from the classical theory that the fraction of tornadic storm is dominated by frequent positive ground flashes.
出处
《南京气象学院学报》
CSCD
北大核心
2004年第5期587-594,共8页
Journal of Nanjing Institute of Meteorology
基金
国家重点基础研究发展规划项目(G1998040909)
国家自然科学基金资助项目(40333027)
关键词
多普勒天气雷达
闪电定位
龙卷
doppler weather radar
lightning location
tornado
