黄先香,白兰强,炎利军,张泽宇,蔡康龙,植江玲. 2024. 热带气旋背景下广东龙卷气候特征和环境条件. 气象学报,82(3):319-339. DOI: 10.11676/qxxb2024.20230125
引用本文: 黄先香,白兰强,炎利军,张泽宇,蔡康龙,植江玲. 2024. 热带气旋背景下广东龙卷气候特征和环境条件. 气象学报,82(3):319-339. DOI: 10.11676/qxxb2024.20230125
Huang Xianxiang, Bai Lanqiang, Yan Lijun, Zhang Zeyu, Cai Kanglong, Zhi Jiangling. 2024. Climatic characteristics and environmental conditions of tornadoes in Guangdong under the background of tropical cyclones. Acta Meteorologica Sinica, 82(3):319-339. DOI: 10.11676/qxxb2024.20230125
Citation: Huang Xianxiang, Bai Lanqiang, Yan Lijun, Zhang Zeyu, Cai Kanglong, Zhi Jiangling. 2024. Climatic characteristics and environmental conditions of tornadoes in Guangdong under the background of tropical cyclones. Acta Meteorologica Sinica, 82(3):319-339. DOI: 10.11676/qxxb2024.20230125

热带气旋背景下广东龙卷气候特征和环境条件

Climatic characteristics and environmental conditions of tornadoes in Guangdong under the background of tropical cyclones

  • 摘要: 为研究热带气旋(简称TC)背景下广东龙卷发生的特征,利用《中国气象灾害大典》广东卷(1959—2000年)、广东省防灾减灾年鉴(2002—2022年)和近年来龙卷现场灾调记录等广东历史龙卷灾情数据和欧洲中期天气预报中心第5代大气再分析资料(ERA5),统计1961—2022年广东TC龙卷的时空分布、天气形势和环境条件,并对比分析了不同TC在相似路径下有/无龙卷及强/弱龙卷的关键热动力环境参数差异。结果表明:广东TC龙卷主要发生在珠江三角洲、雷州半岛和潮汕平原。TC龙卷占广东总龙卷数量的约42%,龙卷个数与影响广东的TC数量呈显著正相关;8月为TC龙卷最高发月份,14—18和06—10时(北京时)为日内高发时段。这些龙卷主要发生在TC的东北象限(或其前进方向的右后侧或深层环境风切变上切变区域);TC登陆后的2—18 h是龙卷发生的高发时段,龙卷生成时对应的TC强度主要为热带风暴和热带低压。TC背景下广东龙卷发生天气形势可分为偏南急流型和偏北急流型,两类天气型龙卷的生成位置均与超级单体复合参数(SCP)大值区和强龙卷指数(STP)大值区呈现较好的空间匹配关系。对比TC背景下龙卷/非龙卷及强/弱龙卷的环境条件,发现在TC中心的东北象限广东龙卷环境比非龙卷具有明显更大的夹卷对流有效位能(E-CAPE)和0—1 km 风暴相对螺旋度(SRH1)(差异均达95%置信度),E-CAPE和SRH1的组合能较好地指示TC引发龙卷的潜势;广东TC强龙卷的混合层对流有效位能(MLCAPE)和STP与美国TC强龙卷相当,但SRH1明显小于美国TC强龙卷,E-CAPE、0—6 km 风垂直切变(SHR6)、0—3 km风暴相对螺旋度(SRH3)和STP能较好地区分广东TC强、弱龙卷环境。对比TC背景下广东龙卷与江苏龙卷及冷涡背景下辽宁龙卷发现,广东TC龙卷CAPE均值约为江苏TC龙卷和辽宁冷涡龙卷的1/2,但广东TC龙卷具有明显更强的动力环境条件,其SRH1均值是冷涡背景下辽宁龙卷的2倍以上。上述结果有利于更好地认识TC背景下广东龙卷发生的环境条件,为TC龙卷潜势预报的开展提供依据。

     

    Abstract: To investigate the general characteristics of tornado occurrences within tropical cyclones (TCs) over Guangdong province, this study primarily analyzes the differences in some main thermodynamic and kinematic environmental indices between tornadic and non-tornadic TCs, and also the strongly and weakly tornadic TCs that have similar tracks during the period from 1961 to 2022. The analysis is conducted using the Full Collection of Meteorological Disasters in China (1959—2000), the Reports of Meteorological Disasters in Guangdong (2002—2022), and the ERA5 atmospheric reanalysis data. Results show that TC tornadoes in Guangdong are spatially concentrated over the Pearl River Delta, Leizhou peninsula and Chaoshan plain. TC tornado occurrences account for nearly 42% of all the tornado reports in Guangdong with a peak frequency in August, which is positively correlated with the number of TCs affecting Guangdong. On diurnal cycle, they are characterized by two diurnal peaks at 14:00—18:00 BT and 06:00—10:00 BT. Tornadoes mainly occur in the northeast quadrant of the TC center, the rear right sector relative to the TC’s movement, and the upper shear region relative to the deep-layer shear vector. The time window of 2—18 h after TC’s landfall is the tornado active period, during which the parent TCs are characterized by intensities of tropical storm and tropical depression. The dominant synoptic patterns can be classified into two types: The southerly jet and northerly jet on upper levels. The tornado locations associated with the two weather types agree well with the large-value areas of supercell composite parameters (SCP) and significant tornado parameters (STP). When comparing the environmental conditions between tornadic and non-tornadic TCs and between the TCs with strong and weak tornadoes, it is found that the tornadic environments are characterized by significantly larger values of entrainment convective available potential energy (E-CAPE) and 0—1 km storm relative helicity (SRH1) in the northeast quadrant of the TC center than those of non-tornadic TCs (at the 95% significance level). The combination of E-CAPE and SRH1 can better indicate the potential of tornadoes caused by TCs. The mixed layer CAPE (MLCAPE) and STP of Guangdong strong tornadoes in TCs are comparable to those of the strong tornadoes in the United States while SRH1 is significantly smaller. The E-CAPE, 0—6 km vertical wind shear (SHR6), 0—3 km storm relative helicity (SRH3), and STP can better distinguish strong and weak tornadic TC environments in Guangdong. Comparing the TC tornadoes between Guangdong and Jiangsu, as well as the Liaoning tornadoes under the cold vortex background, the average CAPE of Guangdong TC tornadoes is approximately half of that in Jiangsu and Liaoning. However, tornadoes in Guangdong have significantly stronger dynamic environmental conditions, with SRH1 more than twice that of the Liaoning tornadoes under the cold vortex background. These conclusions are conducive to better understanding of the environmental conditions of tornadoes in Guangdong under the TC background, and provide clues to potential forecasting on TC tornadoes.

     

/

返回文章
返回