李彩玲1, 蔡康龙1, 黄先香2, 植江玲1, 陈志芳3, 麦文强3
Genetic analysis of a strong downburst in Guilin
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投稿时间:2019-11-05    修订日期:2020-12-28
中文摘要: 2019年3月21日广西桂林市临桂区发生一次极端大风天气过程(简称 “3?21” 临桂大风),当天21:13临桂观测站录得最大阵风60.3 m?s-1(17级)。通过风灾现场调查判断这是强度为EF2级的微下击暴流过程。应用常规观测资料以及加密自动气象站、 探空、多普勒雷达等资料,分析了“3?21”临桂大风过程的环流背景与影响系统,基于雷达和观测资料探讨了其形成原因。结果表明:(1)低层暖湿气流活跃,中层显著干层,强的低层垂直风切变是大风发生的有利条件,地面中尺度辐合线、冷锋南压为其提供了触发机制;(2)“3?21” 临桂大风由2个超级单体风暴合并加强造成,在下击暴流发生前,风暴单体最强反射率因子核心高度(HGT)超过6km,有中等强度中气旋伴随,中层径向辐合明显,辐合值达36 m?s-1;当反射率因子减弱、风暴顶高下降、HGT下降时,下击暴流发生;当HGT剧降,一个体扫间隔下降3.5 km,17级极端大风发生,低层0.5°仰角在强中气旋的出流区观测到强的径向辐散,辐散值达27 m?s-1;中气旋有最强切变加强,底高迅速下降到1 km以下等特征。(3)本次下击暴流发生与极端强降水和冰雹的拖曳作用有密切关系,冰雹和雨水粒子的拖曳和融化蒸发作用使下击暴流加强。当1 min雨强>3 mm,风速超过12级,1 min雨强>6 mm,出现17级极大风速。
Abstract:An extreme gale event, hereinafter referred to as“3.21 Lingui gale event”, occurred in Lingui, Guangxi on 21 March 2019, Maximum gust of 60.3 m?s-1 (level 17) was recorded at the Lingui Observatory at 21:13. Based on the results of the wind damage survey with video and meteorological data, this paper presents that the high wind damage was caused by a strong microburst. Using data from conventional meteorological observations, intensive automatic weather station, radiosonde, Doppler weather radar, we have analyzed the environmental conditions and influencing systems of the“3.21 Lingui gale event”, with special emphasis on analyzing its cause based radar data and observational data. Results are as follows.(1) The “3.21 Lingui gale event” occurred under some favorable conditions such as Low-level warm and humid air flow is active, Mid-level significant dry layer and strong low-level vertical wind shear, and it is triggered by the development of convergence line at ground level and cold front.(2) “3.21 Lingui gale event” is caused by 2 in 1 supercell, Before the downburst occurs, the supercell develops to the most powerful stage, the maximum reflectivity core height (HGT) is more than 6 km, there is a medium intensity of the mesocyclone accompanied by the MARC value of 36 m?s-1. When the downbursts occurs ,reflectivity factor begins to weaken, the storm top drops high, HGT drops. when HGT drops sharply, a body sweep interval drops by 3.5 km, 17 thumps occur, and the low level 0.5 degrees elevation is observed in the high-altitude region of the cyclone, with a high radial dispersion value of 27 m?s-1, Mesocyclone has the strongest shear strengthening, the bottom high height rapidly dropped to less than 1km and other characteristics. (3) The occurrence of downburst is closely related to the dragging effect of extreme heavy precipitation and hail, When 1min rain strength of 3 mm, wind speed of more than 12 levels, 1min rain strong 6 mm, 17 degrees of extreme wind speed.
文章编号:201911050392     中图分类号:    文献标志码:
李彩玲,蔡康龙,黄先香,植江玲,陈志芳,麦文强,0.Genetic analysis of a strong downburst in Guilin[J].Meteor Mon,():-.
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