一次致雹超级单体结构特征分析
投稿时间:2017-10-19  修订日期:2018-03-15  点此下载全文
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王易 中国气象局 交通气象重点开放实验室, 江苏 南京 210008
江苏省气象台, 江苏 南京 210008 
 
徐芬 中国气象局 交通气象重点开放实验室, 江苏 南京 210008
江苏省气象科学研究所, 江苏 南京 210008 
xufen1130@tom.com 
吴海英 中国气象局 交通气象重点开放实验室, 江苏 南京 210008
江苏省气象台, 江苏 南京 210008 
 
基金项目:国家重点研发计划"重大自然灾害"专项(2018YFC1506103);气象预报业务关键技术发展专项(YBGJXM(2019)02-07);江苏省科技厅项目(BE2015731;BE2017776);江苏省气象局科研重点项目(KZ201704);北极阁开放研究基金(NJCAR2018MS02)
中文摘要:利用常规观测资料、多普勒雷达资料,对发生在徐州地区的一次冰雹天气的环流背景、降雹超级单体结构特征进行了分析。结果表明,此次强对流发生在前倾槽背景下,500 hPa高空槽东移过程中其后部冷空气南下,叠置在低层槽前西南暖湿急流之上,促进了大气层结不稳定发展。产生冰雹的对流风暴具有明显的超级单体结构特征,风暴中伴有旋转强烈的中气旋,持续时间约30 min,且最大切变高度都在0℃层高度以上。进一步分析发现,中气旋旋转速度中心和切变值中心均位于中高层,风暴中的旋转趋于向上发展,旋转强度在中高层有明显的跃升,且冰雹出现前后,位于风暴内中高层的旋转经历了尺度减小、旋转加剧的变化,风暴中的旋转导致风暴呈现出有界弱回波区和强回波悬垂结构特征。此外,尽管此次冰雹过程的垂直累积液态水含量(Vertically Integrated Liquid,下文简称VIL)值较小,但可以看到VIL值在冰雹发生前后有明显的跃增现象,这一现象对判断小冰雹的发生有一定的指示意义。
中文关键词:冰雹  超级单体  雷达回波特征  中气旋
 
Structure characteristics analysis of a supercell hailstorm
Abstract:In this study,based on routine weather and Doppler weather radar data,the characteristics of the synoptic circulation background and structure characteristics of the supercell hailstorm which had occurred in Xuzhou are analyzed.The results show that this event had a forward-tilting structure,namely the upper-level trough moved from west to east at 500 hPa,and the cold air moved toward the south interface with the low-level jet,which was favorable to the formation of an unstable stratification structure.The convective storm that caused the hail had a typical supercell structure,and a strong rotation mesocyclone.The mesocyclone lasted nearly 30 minutes,and the max shear level of the mesocyclone was continuously higher than the 0℃ thermal level.Further research found that the max values of the rotational velocity and azimuthal shear of the mesocyclone were in the middle and upper levels,the rotation of the storm tended to expand upward,and the rotation had an abrupt increase in middle and upper levels.The rotation in the middle and upper levels of the storm underwent a process of decreasing in size,and the rotation intensified before and after the hail occurred,while the rotation in the storm led to the characteristics of suspended high strong echo and prominent bounded weak echo.In addition,the vertically integrated liquid (VIL) was much lower in this hail event,yet the vertically integrated liquid (VIL) underwent an abrupt increase before and after the hail occurred.This phenomenon can help us to judge the occurrence of small hail in the future.
keywords:hail  supercell  characteristics of radar echo  mesocyclone
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