影响广西北部的两次系列龙卷形成机制及预警分析

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• 英文论文题名：Analysis of Formation Mechanism and Forewarning of Two Tornadoes over Northern Guangxi Province
• 论文作者：李向红 ; 胡静 ; 伍静 ; 刘锋 ; 郑传新
• 英文论文作者：LI Xianghong ; LIU Feng ; HU Jing ; WANG Juan ; ZHENG Chuanxin ; LIU Feng
• 年：2017
• 作者机构：桂林市气象局;柳州市气象局;
• 论文关键词：龙卷 ; 触发机制 ; 雷达产品特征 ; 预警
• 英文论文关键词：tornado ; formation mechanism ; radar signature ; forewarning
• 会议召开时间：2017-09-27
• 会议录名称：第34届中国气象学会年会 S1 灾害天气监测、分析与预报
• 语种：中文
• 分类号：P445
• 学会代码：ZGQX
• 会议名称：第34届中国气象学会年会
• 会议地点：中国河南郑州
• 主办单位：中国气象学会
• 学会名称：中国气象学会
• 页数：14
• 文件大小：2272k
• 原文格式：D
• 会议级别：全国

摘要

利用桂林和柳州雷达资料分析了2013年4月17日和2015年5月10日发生在桂林、柳州的龙卷天气形势及雷达产品特征,及其预警的可能性分析,表明:0417过程影响范围比0510过程大,持续时间更长。两次龙卷都发生于低压带中,0417过程的触发机制是边界层的小低涡,0510过程触发机制是低层切变。两次过程都有低层高温高湿的特征。龙卷中气旋的入流与出流并不平衡,径向风切变最大达到36m/s,有别于冰雹中气旋。反射率剖面显示在龙卷的初生到最强阶段,反射率剖面具有钩子的特征,可见在龙卷发生的同时伴有冰雹。地面大风增强时,反射率增强,反射率剖面显示钩子不明显,有强反射率核心下降特征,可见下击暴流相伴随。径向速度剖面显示,在低层千米以下有辐合3,在6千米有辐散,同时表现为倾斜。两过程都存在提前预警困难的问题,通过对温度对数压力图的订正,将预测未来几小次龙卷时湿对流有效位能的增幅,尽力提前预警龙卷,同时,通过对雷达产品的分析达到对龙卷临近预报的时间尽可能提前。
Based on the Guilin Doppler weather radar and Liuzhou Doppler weather radar data, the tornadoes occurred in Guilin and Liuzhou,Guangxi province on 17 April 2013 and 10 May 2015 are analyzed in detail. The results are summarized as follows. The influence area of the 0417 tornado is wider than that of the 0510 tornado, lasting more time. The two tornadoes both occurred in the low pressure zone. The triggering mechanism of the 0417 process is a small vortex in boundary layer. The trigger mechanism of the 0510 process is a low-level shear. There are high temperature and humidity characteristics at lower-level in these two processes. Synoptic background of this two tornadoes are similar. The inflow and outflow within middle cyclone of the tornadoes is imbalanced, radial wind shear is about 36m/s, different form that of hail. In the primary stages to the strongest stage of tornadoes, the reflectivity cross section shows hook-shaped echo feature, accompanied by the hail. When the ground wind enhance, the reflectivity enhance also. At the same time the cross section of reflectivity show the hook is not obvious. The strong reflectivity core descends vertically, accompanied by the downbursts. Radial velocity cross section shows convergence below 3 km and divergence at 6 km, having the characteristics of tilting. The two tornado processes are both difficult to bring forward the warning. By revising the T-logp diagram, forecast the increase of moist CAPE in the next few hours to advance the tornado warning, meanwhile, tornado nowcasting could be advanced through the analysis of radar products.

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