云南两次中尺度对流雷暴系统演变和地闪特征  

Evolutions and Cloud-to-ground Lightning Features of Two Mesoscale Convective Thunder Storm Systems in Yunnan

作　　者：张腾飞[1] 尹丽云[1] 张杰 谢屹然[1] 朱莉[1] 

机构地区：[1]云南省气象台,昆明650034 [2]云南省气象信息中心,昆明650034

出　　处：《应用气象学报》2013年第2期207-218,共12页Journal of Applied Meteorological Science

基　　金：国家自然科学基金项目(41265001);云南省科技计划项目(2009CA014)

摘　　要：在利用NCEP/NCAR再分析资料诊断分析2010年9月21—23日中尺度对流雷暴系统形成的环流背景基础上,通过云南省闪电定位系统地闪监测资料和FY-2E卫星云图资料的同步叠加,分析两个中尺度雷暴系统的演变和地闪特征。结果表明:台风凡亚比(1011)西行减弱的热带低压为中尺度对流雷暴系统提供有利的暖湿和抬升动力环流背景,促使中尺度弧状对流云带、中尺度雷暴云团和中尺度对流复合体生成和发展。雷暴云团结构和地闪活动空间分布不均匀并随时间变化,且正、负地闪频数与云顶亮温(TBB)相关,当TBB降低和等值线密度变大,雷暴云团发展,低TBB中心偏于云团的前部云区,负地闪频数剧增;当TBB达最低值时,雷暴云团成熟,负地闪频数达峰值,正地闪出现;当TBB升高且等值线密度变小时,雷暴云团减弱,低TBB中心靠近云团中心,负地闪频数迅速减小,正地闪频数达到峰值;密集的负地闪出现在雷暴云团前部大的TBB梯度区和TBB不大于-56℃的低值中心附近,正地闪分散在TBB不大于-56℃的低值中心附近,偏于负地闪区域后部发生。The circulation background of mesoscale convective thunderstorm system is diagnostically analyzed from 21 September to 23 September in 2010 by NCEP/NCAR data, and the evolutions and cloud-to-ground lightning activity features of two mesoscale convective thunderstorm systems are analyzed by synchronous stack of lightning detection system observations and FY-2E satellite images. Results show that the advan-tageous circulation background conditions of high energy, high humidity, and lifting dynamism are also supplied for the mesoscale convective thunderstorm systems by the weakened thermal depression. Me- soscale arc convective cloud belts appears first, on which partial convective cloud clusters gradually develop to mesoscale storm cloud clusters and then run into mesoseale convective storm complexes moving to the west along the same route, leading to strong thunderstorm weather and frequent CG lightning activities on the way. The negative cloud-to-ground （negative CG） lightning is predominant compared to the positive cloud- to-ground （positive CG） lightning during the whole lifetime of a thunder cloud cluster. But not only the storm cloud cluster contracture and the CG lightning activity feature change with time, but also positive CG and negative CG lightning frequency is well related to the cloud top temperature, which is related to the three-negative-polar structure of thunder cloud over the lower latitude plateau of China. When the cloud top temperature TBB descends and TBB isoline density increases, the thunder cloud cluster develops gradually, the low TBB center locates to its foreside, and the negative CG lightning frequency leaps. When the TBB descends to the minimum, the thunder cloud cluster develops to the maturation, negative CG lightning frequency gets to an apex, and positive CG lightning begin to take place. When the Tt3B ascends and TBB isoline density decreases, the thunder cloud cluster weakens gradually, the low TBB center closes up its center, the negative CG lightning frequency decreas

关 键 词：云南 中尺度对流雷暴系统 地闪特征 

分 类 号：P427.32[天文地球—大气科学及气象学]