| 辽宁省温带气旋龙卷的环境参数特征 |
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| 引用本文： | 白华,袁潮,潘晓,杨磊,李得勤.辽宁省温带气旋龙卷的环境参数特征[J].应用气象学报,2023,34(1):104-116. |
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| 作者姓名： | 白华 袁潮 潘晓 杨磊 李得勤 |
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| 作者单位： | 1.中国气象局沈阳大气环境研究所，沈阳 110166 |
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| 摘 要： | 利用欧洲中期天气预报中心ERA5再分析数据, 统计1979—2020年辽宁省42个温带气旋龙卷环境背景和物理量参数特征, 结果表明:辽宁省温带气旋龙卷多发于温带气旋中心的西南、东南象限, 与冷锋前暖区相对应, 主要分布在辽河平原中西部及渤海湾沿岸, 强龙卷(EF2及以上级别)占比为28.6%。风暴相对螺旋度和对流有效位能的大值区出现在气旋西南—东南象限, 呈带状分布, 龙卷风暴主要分布于风暴相对螺旋度大值区西北侧、对流有效位能大值区的顶端的强梯度区附近。强龙卷参数最大值达0.7, 其大值区与EF2及以上级别龙卷相对应。地面冷锋和干线是温带气旋龙卷的关键触发系统, 对比近气旋中心和冷锋尾部湿度垂直分布, 后者所表现的高层强干侵入导致风暴产生更强的冷池, 过强的下沉气流可能是龙卷产生的不利因素。温带气旋龙卷多分布于高空急流左侧气流的分流区内, 对应高空强辐散区。0~3 km垂直温度递减率大值区与气旋中心附近的弱龙卷高发区有较好对应关系。
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| 关 键 词： | 龙卷 温带气旋 环境参数 辽宁省 |
| 收稿时间： | 2022-07-27 |
Environmental Characteristics of Extratropical Cyclone Tornadoes in Liaoning |
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| Institution: | 1.Institute of Atmospheric Environment, China Meteorological Administration, Shenyang 1101662.Shenyang Meteorological Bureau of Liaoning, Shenyang 1100683.College of Agronomy, Shenyang Agricultural University, Shenyang 1108664.Kangping Meteorological Bureau of Liaoning, Shenyang 1105005.Panjin Meteorological Bureau of Liaoning, Panjin 1240106.Liaoning Warning Center of Meteorological Disaster Monitoring, Shenyang 110166 |
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| Abstract: | Liaoning is one of the active regions for tornadoes in China, and the generation of a considerable number of tornadoes is associated with extratropical cyclones. In order to improve the understanding of environmental background and physical parameter characteristics, 42 extratropical cyclone tornadoes in Liaoning from 1979 to 2020 are statistically analyzed. The study is based on the reanalysis data of ERA5(ECMWF Reanalysis V5), combining with records of China Meteorological Disaster Classic and China Meteorological Disaster Yearbook. Results show that extratropical cyclone tornadoes are mainly distributed in the central and western Liaohe Plain and along the coast of the Bohai Bay. Significant tornadoes(EF2 and above) account for 28.6% of all extratropical cyclone tornadoes.Extratropical cyclone tornadoes occur mostly in the southwest and southeast quadrants of extratropical cyclones, corresponding to the warm area before the cold front. The high-value area of the storm relative helicity and convective available potential energy(CAPE) appear in the southwest-southeast quadrant of the extratropical cyclones, with a belt-like distribution. Extratropical cyclone tornadoes are mainly distributed within 1° of latitude in the northwest of the large-value area of storm relative helicity and the strong gradient area at the top of the large-value area of CAPE. The strong tornado parameter(STP) center is located near the -2° of longitude distance and -5° of latitude distance from the center of tornadic extratropical cyclones, and the maximum value is above 0.7. The large value area of STP corresponds to the high-incidence area of EF2 and above extratropical cyclone tornadoes. The cold front and dry line in the surface are the key trigger of extratropical cyclone tornadoes, and the induced tornadoes are mainly distributed near the warm ridge of temperature field and the top of the tongue of humidity field. Comparing the vertical distribution of humidity near the center of tornadic extratropical cyclones and the tail of the cold front, the strong cold pool caused by the strong high-level dry intrusion can generate excessively strong downdraft, which may be an unfavorable factor for tornado formation. Extratropical cyclone tornadoes are mostly distributed in the distributary area of the left air flow of the upper-level jet, corresponding to the strong upper-level divergence area. The large value area of 0-3 km vertical temperature lapse rate has a good correspondence with the high incidence area of weak tornadoes near the center of extratropical cyclones. |
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