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气象:2017,43(6):745-755
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柳州“4·09”致灾冰雹的超级单体风暴过程分析
覃靖,潘海,刘蕾
(广西壮族自治区柳州市气象局,柳州 545001)
Analysis of Supercell Storm Leading to Disastrous Hail in Liuzhou on 9 April 2016
QIN Jing,PAN Hai,LIU Lei
(Liuzhou Meteorological Office of Guangxi, Liuzhou 545001)
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投稿时间:2016-05-31    修订日期:2017-04-20
中文摘要: 利用柳州和桂林天气雷达(SB)资料和相关实况资料,对2016年4月9日夜间柳州一次强雹暴天气的环境条件和雷达回波结构演变特征进行了详细分析。结果表明:(1)雹暴发生在低层热低压发展,中层有冷温槽发展东移,高层有急流的背景下。地面干线和中尺度辐合线触发的对流云团在不稳定层结和较强的深层垂直风切变作用下发展为超级单体。(2)超级单体的低层反射率因子呈现出明显的钩状回波或倒“V”型入流缺口。反射率因子垂直剖面呈现出典型的有界弱回波区、回波悬垂和回波墙。最大的回波强度出现在沿着回波墙的一个竖直的狭长区域,其值达到65 dBz。相应的中低层径向速度图呈现出一个强中气旋,旋转速度达到24 m·s-1。该中气旋的发展和维持使得超级单体风暴发展并维持。(3)得出大冰雹临近预警的雷达参数量化指标:最大反射率因子达到60 dBz,中等强度以上中气旋,VIL值和VIL密度分别达到60 kg·m-2和5.0 g·m-3,50 dBz以上强回波区伸展到-30℃层高度以上。
Abstract:Based on the Doppler weather radar data of Liuzhou and Guilin, and the conventional upper air and surface observation data, this paper analyzes the environmental condition and radar echo structure of the severe hailstorm which occurred in Liuzhou on 9 April 2016. The results show that: (1) The background responsible for the hailstorm includes intense heating up of the surface which led to the development of thermal depression in the lower atmosphere, the developing eastward cold temperature trough in the mid level, and an upper level jet stream above the convective location. The convective clouds triggered by surface dryline and the mesoscale convergence line evolved into supercells under the influence of the unstable stratification and significant vertical wind shear. (2) The low level reflectivity of the supercell showed a typical hook echo or inverted V notch. Along the inflow direction and through the strongest echo, the reflectivity showed typical BWER, overhanging echo and echo wall. The strongest echo was within a vertical narrow zone along the echo wall and the value got to 65 dBz. The corresponding radial velocity in the lower atmosphere had a strong mesocyclone with rotation speed reaching 24 m·s-1. The development and maintenance of mesocyclone made the supercell storm develop and maintain. (3) Maximum reflectivity reaches 60 dBz, strong echo over 50 dBz extending to the height of -30℃ layer, VIL value over 60 kg·m-2 and VIL density over 5.0 g·m-3, mesocyclone in moderate or severe intensity can be taken as the early warning indicator of severe hail.
文章编号:     中图分类号:P458    文献标志码:
基金项目:柳州市气象局自立项目(柳气科201602)资助
引用文本:
覃靖,潘海,刘蕾.柳州“4·09”致灾冰雹的超级单体风暴过程分析[J].气象,2017,43(6):745-755.
QIN Jing,PAN Hai,LIU Lei.Analysis of Supercell Storm Leading to Disastrous Hail in Liuzhou on 9 April 2016[J].METEOROLOGICAL MONTHLY,2017,43(6):745-755.