粤东一次台风外围龙卷天气过程分析
Analysis of a Tornado Process in Eastern Guangdong at the Periphery of a Typhoon
陈婉玲 1郑瑶娜 2李兆明3
作者信息
- 1. 揭阳市气象局,广东揭阳 522000
- 2. 揭阳市气象局,广东揭阳 522000;揭阳市突发事件预警信息发布中心,广东揭阳 522000
- 3. 佛山市龙卷风研究中心/中国气象局龙卷风重点开放实验室/粤港澳大湾区气象研究院,广东佛山 528000
- 折叠
摘要
为了了解2117号台风"狮子山"外围环流影响时,揭阳市揭东区出现EF2级强龙卷风的原因,利用ERA5再分析资料、常规气象观测资料和汕头S波段多普勒天气雷达观测等数据对该次龙卷风过程进行分析.结果表明:该次龙卷风出现在台风"狮子山"和副热带高压之间的东南急流中,并伴有暖湿能量和水汽的持续输送;龙卷风发生在台风登陆前,距离台风中心约725 km,台风强度为热带风暴级;低的抬升凝结高度和较强的0～1 km垂直风切变以及较大的风暴相对螺旋度有利于龙卷母体风暴的发生发展;龙卷风影响前近地面存在明显的辐合线北移,龙卷风发生于辐合中心;龙卷风过境时,路径附近的自动站出现风速骤增和风向突变,并伴随气温下降,但仅其路径西南侧出现短时强降水;从雷达特征上可以看到,龙卷母体风暴存在低层入流缺口、中层回波悬垂特征,并具有较典型的台风龙卷母体风暴的低质心特征;TVS持续两个体扫,对龙卷预警有一定的提前量.
Abstract
In order to explore the cause of an EF2-strong tornado in Jiedong District of Jieyang City un-der the influence of the peripheral circulation of Typhoon Lionrock(2117),the tornado process was analyzed by the ERA5 reanalysis data,conventional meteorological observation data and S-band Doppler weather radar observation data in Shantou.The results show that the tornado appeared in the southeast jet stream between Typhoon Lionrock and the subtropical high,accompanied by the continuous transport of energy and water va-por.About 725 km away from the typhoon center,the tornado occurred before the typhoon landed at the in-tensity of tropical storm.The low uplift condensation height,strong 0-1 km vertical wind shear and large storm relative helicity were conducive to the occurrence of and development of the tornado parent storm.Be-fore the tornado,a convergence line near the ground moved north obviously,and the tornado occurred at the convergence center.When the tornado passed through,the wind speed and direction had a sudden change as observed by automatic weather stations near the path,along with a temperature drop,but the short-term heavy precipitation only appeared on the southwest side of the path.It can be seen from the radar character-istics that the tornado parent storm was characterized by a low-level inflow gap and a middle-level overhang echo,and had a low mass core typical of typhoon-induced tornado parent storm.Two continuous volumetric scans of tornadic vortex signature(TVS)can be used to warn of tornadoes in certain amount of advance.
关键词
天气学/台风龙卷/环境条件/雷达特征/台风"狮子山"/粤东Key words
synoptics/typhoon-related tornado/environmental conditions/radar characteristics/Ty-phoon Lionrock/eastern Guangdong引用本文复制引用
出版年
2024
NETL
NSTL
万方数据