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投稿时间:2020-12-10 修订日期:2021-07-14
投稿时间:2020-12-10 修订日期:2021-07-14
中文摘要: 利用常规观测、自动站、多普勒天气雷达以及美国环境预报中心的全球再分析资料,分析江苏2007—2018年间的台风龙卷活动时空分布特征、龙卷产生的环境条件及多普勒雷达关键特征,并与广东台风龙卷相应特征进行对比。结果表明:江苏台风龙卷与过去相比发生频次有所增加,主要集中在7—8月,且主要发生于午后的16—20时;比起广东台风龙卷多发生于台风登陆后的24 h以内,江苏台风龙卷多发生于登陆24 h之后,位于台风中心的东北象限,多集中于江淮中部以及西北部地区;低空急流输送充足的水汽和不稳定能量,为龙卷的发生提供了有利的环境条件,地面辐合线是龙卷发生发展的重要系统;江苏和广东龙卷均发生在对流不稳定能量不大、抬升凝结高度较低、深层(0~6 km)和低层(0~1 km)垂直风切变较大以及风暴相对螺旋度较大的环境下,但从均值来看,广东龙卷的对流有效位能和对流抑制能更小,抬升凝结高度更低,具有更大的深层(0~6 km)和低层(0~1 km)垂直风切变,且风暴相对螺旋度较小;江苏台风龙卷单体约有2/3伴随龙卷涡旋特征(TVS),产生强龙卷的雷暴单体生命期同时伴随有中气旋和TVS特征。当TVS的最低仰角速度差超过23 m·s-1时,更易产生强龙卷。与广东台风龙卷TVS关键特征量对比显示,江苏地区产生龙卷的TVS最低仰角速度差和最大切变值均偏小(最大切变值为广东的1/3)。
中文关键词: 台风龙卷,环境条件,雷达特征
Abstract:By using the conventional observation, automatic station, Doppler radar and FNL reanalysis data (1°×1°), this paper analyzes the spatial and temporal distribution characteristics, ambient conditions and radar key features of the typhoon-tornadoes in Jiangsu during the 2007-2018, and compares with the corresponding characteristics of typhoon-tornadoes in Guangdong. The analysis results indicate that the frequency of typhoon-tornadoes in Jiangsu has increased compared with the past, and the occurrence time of the tornadoes is concentrated in July and August from 16:00 BT to 20:00 BT. Jiangsu typhoon-tornadoes occur after typhoon landfall 24 hours later, different from Guangdong typhoon-tornadoes, which occur within 24 hours after typhoon makes landfall. A strong preference for tornado occurrence is in the northeast quadrant with respect to land-falling typhoon center. High risk areas of tornado occurrence in Jiangsu are concentrated in the central part of Jianghuai and Xuzhou. The low-level jet transports abundant water vapor and unstable energy, providing favorable ambient conditions for tornado, and the ground convergence line is an important system for tornado development. The common ambient conditions for Jiangsu and Guangdong tornadoes appear to be the low, strong deep-layer and low-level vertical wind shear and high storm relative helicity. The major difference between the Jiangsu and Guangdong tornado cases is that the Guangdong tornado has weaker convective available potential energy and convective inhibition and much lower lifting condensation level, but stronger deep-layer and low-level vertical wind shear. About 2/3 of typhoon tornadoes in Jiangsu accompany with tornadic vortex signature (TVS). The thunderstorm cells that produce strong tornadoes are associated with mesocyclone and TVS. Strong tornado is more likely to occur when the lowest level difference velocity of TVS exceeds 23 m·s-1. The lowest level difference velocity of tornado TVS in Jiangsu is weaker, and the maximum shear is smaller (1/3 of that in Guangdong).
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基金项目:国家重点研发计划(2018YFC1506103)、江苏省社会发展项目(BE2017776)、江苏省气象局面上项目(KM202007)、中国气象科学研究院基本科研业务费专项资金项目(2021Z003)共同资助
引用文本:
慕瑞琪,徐芬,孙康远,李峰,王易,2022.江苏台风龙卷环境条件与雷达关键特征分析[J].气象,48(2):190-202.
MU Ruiqi,XU Fen,SUN Kangyuan,LI Feng,WANG Yi,2022.Analysis of Environmental Conditions and Radar Key Features of Typhoon-Tornadoes in Jiangsu[J].Meteor Mon,48(2):190-202.
慕瑞琪,徐芬,孙康远,李峰,王易,2022.江苏台风龙卷环境条件与雷达关键特征分析[J].气象,48(2):190-202.
MU Ruiqi,XU Fen,SUN Kangyuan,LI Feng,WANG Yi,2022.Analysis of Environmental Conditions and Radar Key Features of Typhoon-Tornadoes in Jiangsu[J].Meteor Mon,48(2):190-202.