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邓意学, 肖天贵, 汤志亚, 史朝. 2022: 2020年7月22日淮北地区两次龙卷过程的环境背景和雷达特征的对比分析. 暴雨灾害, 41(3): 266-275. DOI: 10.3969/j.issn.1004-9045.2022.03.003
引用本文: 邓意学, 肖天贵, 汤志亚, 史朝. 2022: 2020年7月22日淮北地区两次龙卷过程的环境背景和雷达特征的对比分析. 暴雨灾害, 41(3): 266-275. DOI: 10.3969/j.issn.1004-9045.2022.03.003
DENG Yixue, XIAO Tiangui, TANG Zhiya, SHI Zhao. 2022: Comparative analysis of environmental background and radar characteristics of two tornadoes in Huaibei area on 22 July 2020. Torrential Rain and Disasters, 41(3): 266-275. DOI: 10.3969/j.issn.1004-9045.2022.03.003
Citation: DENG Yixue, XIAO Tiangui, TANG Zhiya, SHI Zhao. 2022: Comparative analysis of environmental background and radar characteristics of two tornadoes in Huaibei area on 22 July 2020. Torrential Rain and Disasters, 41(3): 266-275. DOI: 10.3969/j.issn.1004-9045.2022.03.003

2020年7月22日淮北地区两次龙卷过程的环境背景和雷达特征的对比分析

Comparative analysis of environmental background and radar characteristics of two tornadoes in Huaibei area on 22 July 2020

  • 摘要: 2020年7月22日, 安徽宿州和苏北宿迁、连云港、盐城三市先后出现了龙卷天气过程。利用ERA-5(0.25°×0.25°)逐小时再分析资料和雷达回波资料对龙卷发生的天气背景、环境条件和雷达特征进行分析并简单对比, 结果表明: (1)两次龙卷过程都发生在有利于发生强对流的梅雨期环流背景下, 龙卷发生地位于副高边缘且500 hPa上存在西风槽东移, 700 hPa和850 hPa上低涡切变明显, 中低空西南急流强盛且不断输送水汽。(2)环境条件的相同点表现在具有强的0-6 km垂直风切变和0-1 km垂直风切变, 龙卷发生地处于0-3 km风暴相对螺旋度(SRH)高值中心左侧的高梯度区域, 同时位于能量-螺旋度指数(EHI)的高值中心附近, 梅雨锋前上升运动强烈且低层假相当位温θse值较大, 不同点为两次过程的对流有效位能(CAPE)值存在明显的差异。(3)雷达特征表明, 两次龙卷均由准线状对流雨带南端的超级单体所引发, 并具有明显的中气旋特征, 其中宿州龙卷的钩状回波特征明显, 而苏北龙卷具有明显的入流缺口、有界弱回波区和悬垂回波特征。

     

    Abstract: On 22 July 2020, tornadoes occurred successively in Suzhou, Anhui and Suqian, Lianyungang and Yancheng in Northern Jiangsu. Era-5 (0.25°×0.25°) hourly reanalysis data and radar echo data are used to analyze and compare the weather background, environmental conditions and radar characteristics of the tornadoes. The results indicated that: (1) the two tornadoes occurred under the circulation background of Meiyu period which is conducive to strong convection. Tornado places is located at the edge of the subtropical high. The westerly trough moves eastward on 500 hPa, and the low vortex shear at 700 hPa and 850 hPa is significant. The southwest jet at medium and low altitude is strong and continuously transports water vapor. (2) The similarities of environmental conditions are as follows: strong 0-6 km vertical wind shear and 0-1 km vertical wind shear. The tornado occurred in the high gradient area on the left of the high value center of 0-3 km storm relative helicity Srh, and near the high value center of energy helicity index Ehi. The ascending motion in front of the Meiyu front is strong and the low-level pseudo equivalent potential temperature θse value is large. The difference is only obvious in the Cape value of the two processes. (3) The radar characteristics show that the two tornadoes are caused by the supercell at the south end of the linear convective rain belt, and have obvious mesocyclone characteristics. The hook echo characteristics of the Suzhou tornado are obvious. The northern Jiangsu tornado has obvious inflow gap, bounded weak echo area and suspended echo characteristics.

     

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