Refined Structural Evolution Analysis of a Tornado
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摘要: 利用上海南汇WSR-88D和江苏南通CINRAD-SAD型S波段型双偏振雷达资料、雷达协同观测试验中的向化X波段双偏振雷达(CINRAD-XAD)连续垂直观测资料、ERA5再分析资料和常规观测资料,对2023年6月10日的南通龙卷过程进行深入分析。结果表明:(1)此次龙卷过程发生在东北冷涡南落的背景下,整体呈高空前倾槽的配置,为一次较典型的高空冷平流强迫型风雹天气,且此过程前期有能量累积,环境场指数利于龙卷发生;(2)该龙卷过程时段内,南汇及南通雷达0.5 °仰角平面位置扫描(Plan Position Indicator, PPI)显示有较典型的钩状回波、中气旋、差分反射率(ZDR)弧、龙卷碎片特征(Tornadic Debris Signature, TDS)等龙卷特征因子,配合区域自动站风场可见较明显的前侧下沉气流(Forward Flank Downdraft, FFD)和后侧下沉气流(Rear Flank Downdraft, RFD)阵风锋;(3)向化X波段双偏振雷达针对龙卷母体进行了长达20 min的连续距离高度扫描(Range Height Indicator, RHI)观测,精细地刻画了ZDR柱、风暴顶辐散以及降雹区等特征,并捕捉到龙卷多次触地的过程;(4)结合S波段和X波段雷达的精细化观测数据和环境场特征凝练了此类西风带龙卷形成的垂直和水平概念模型及其对应的双偏振雷达特征,解释了此类西风带龙卷的形成机理。Abstract: The study conducts a comprehensive analysis of the tornado in Nantong on 10 June, 2023, using data from Nanhui WSR-88D radar, Nantong CINRAD-SAD S-band dual-polarization radar, collaborative vertical observations from the CINRAD-XAD X-band dual-polarization radar, ERA5 reanalysis data, and conventional observational data. The results showed that: (1) The tornado took place under the background of a northeast cold vortex, with the overall configuration characterized by an upper-level forward-tilted trough, indicating a typical high-altitude cold advection-forced wind and hail weather system. Prior to the event, the energy accumulated and environmental indices were favorable for a tornado's formation. (2) During this event, Plan Position Indicator (PPI), which was at a 0.5 ° elevation angle from both the Nanhui and Nantong radars, revealed typical tornado characteristics such as hook echoes, mesocyclones, differential reflectivity (ZDR) arcs, and Tornadic Debris Signatures (TDS). Meanwhile, the gust fronts of forward flank downdrafts (FFD) and rear flank downdrafts (RFD) were recognized in combination with the regional automatic weather stations. (3) The CINRAD-XAD X-band dual-polarization radar's conducted continuous Range Height Indicator (RHI) scans for 20 minutes on the tornado parent storm, meticulously capturing features such as ZDR columns, storm top divergence, and hail zones. It also successfully documented multiple ground touches in this event. (4) By integrating the high-resolution observational data from both S-band radar PPI scan and the X-band RHI scan, the study develops vertical and horizontal conceptual models of tornado formation within the westerlies. It also illustrates the typical dualpolarization radar characteristics, making it clear to understand the formation mechanisms of such westerly belt tornadoes.
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Key words:
- tornado /
- evolution and dissipation /
- fine structure /
- formation mechanism
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表 1 龙卷近风暴环境特征参数
要素 08时(宝山实况探空) 16时(龙卷位置西侧ERA5) MUCAPE/(J·kg-1) 1 688 2 798 0~1 km风暴螺旋度/(m2·s-2) 49 49 0~3 km风暴螺旋度/(m2·s-2) 21 90 0~1 km风切变/(m·s-1) 4 4 0~3 km风切变/(m·s-1) 2 10 0~6 km风切变/(m·s-1) 15 21 DCAPE/(J·kg-1) 1 498 981 850~500 hPa温度递减率/(℃·km-1) 7.0 7.5 0~3 km温度递减率/(℃·km-1) 6.7 7.5 固定层STP 0.3 0.6 超级单体指数SCP 0.0 3.8 冰雹指数SHIP 0.5 1.2 -
[1] 范雯杰, 俞小鼎. 中国龙卷的时空分布特征[J]. 气象, 2015, 41(7): 793-805. [2] 郑永光, 周康辉, 盛杰, 等. 强对流天气监测预报预警技术进展[J]. 应用气象学报, 2015, 26(6): 641-657. [3] 白兰强, 孟智勇, SUEKI K, 等. 中国热带气旋龙卷的气候统计特征(2006~2018)[J]. 中国科学: 地球科学, 2020, 50(5): 619-634. [4] 李峰, 李柏, 唐晓文, 等. 近20年美国龙卷探测研究进展--对我国龙卷风研究的启示[J]. 气象, 2020, 46(2): 245-256. [5] 黄先香, 炎利军, 顾伯辉, 等. 广东一次超级单体强龙卷的形成环境和观测特征分析[J]. 热带气象学报, 2021, 37(5-6): 721-732. [6] 戴建华, 王国荣, 龚剑, 等. 梅雨锋中尺度涡旋内微型超级单体龙卷的形成研究[J]. 热带气象学报, 2021, 37(5-6): 693-709. [7] 俞小鼎, 赵娟, 范雯杰. 中国龙卷的时空分布与关键环境参数特征[J]. 热带气象学报, 2021, 37(5-6): 681-692. [8] 才奎志, 姚秀萍, 孙晓巍, 等. 冷涡背景下辽宁龙卷气候特征和环境条件[J]. 气象学报, 2022, 80(1): 82-92. [9] 徐芬, 郑媛媛, 孙康远. 江苏龙卷时空分布及风暴形态特征[J]. 气象, 2021, 47(5): 517-528. [10] 俞小鼎, 郑永光. 中国当代强对流天气研究与业务进展[J]. 气象学报, 2020, 78(3): 391-418. [11] PALMER R D, BODINE D, KUMJIAN M, et al. Observations of the 10 May 2010 tornado outbreak using OU-PRIME: Potential for new science with high-resolution polarimetric radar[J]. Bull Amer Meteor Soc, 2020, 92(7): 871-891. [12] BODINE D J, KUMJIAN M R, PALMER R D, et al. Tornado damage estimation using polarimetric radar[J]. Wea Forecasting, 2013, 28(1): 139-158. [13] RYZHKOV A V, SCHUUR T J, BURGESS D W, et al. Polarimetric tornado detection[J]. J Appl Meteor Climatol, 2005, 44(5): 557-570. [14] 黄先香, 俞小鼎, 炎利军, 等. 1804号台风"艾云尼"龙卷分析[J]. 气象学报, 2019, 77(4): 645-661. [15] KUMJIAN M R, KHAIN A P, BENMOSHE N, et al. The anatomy and physics of ZDR columns: Investigating a polarimetric radar signature with a spectral bin microphysical model[J]. J Appl Meteor Climatol, 2014, 53(7): 1 820-1 843. [16] ILOTOVIZ E, KHAIN A, RYZHKOV A V, et al. Relationship between aerosols, hail microphysics, and ZDR columns[J]. J Atmos Sci, 2018, 75(6): 1 755-1 781. [17] 刁秀广, 杨传凤, 张骞, 等. 二次长寿命超级单体风暴参数与ZDR柱演变特征分析[J]. 高原气象, 2021, 40(3): 580-589. [18] KIKUCHI H, SUEZAWA T, USHIO T, et al. Initial observations for precipitation cores with X-band dual polarized phased array weather radar[J]. IEEE Trans Geosci Remote Sens, 2020, 58(5): 3 657-3 666. [19] 王磊, 王啸华, 李杨, 等. 2020年江苏高邮EF2级龙卷多尺度特征分析和预警思考[J]. 气象, 2023, 49(3): 291-303. [20] 慕瑞琪, 吴海英, 李杨, 等. 2020年7月22日苏北地区EF2~EF3级龙卷天气分析[J]. 热带气象学报, 2021, 37(5-6): 759-769. [21] 何建新, 李学华, 徐梓欣, 等. X波段天气雷达组网扫描策略及协同控制技术研究[J]. 气象科技进展, 2021, 11(4): 82-88. [22] BHARADWAJ N, CHANDRASEKAR V, JUNYENT F. Signal processing system for the CASA Integrated Project I radars[J]. J Atmos Oceanic Technol, 2010, 27(9): 1 440-1 460. [23] 吴翀, 刘黎平, 吴海涛. 多部X波段天气雷达测量偏差分布及组网拼图结果分析[J]. 高原气象, 2016, 35(3): 823-833. [24] 许爱华, 孙继松, 许东蓓, 等. 中国中东部强对流天气的天气形势分类和基本要素配置特征[J]. 气象, 2014, 40(4): 400-411. [25] ANDERSON-FREY A K, RICHARDSON Y P, DEAN A R, et al. Near-storm environments of outbreak and isolated tornadoes[J]. Wea Forecasting, 2018, 33(5): 1 397-1 412. [26] BLUMBERG W G, HALBERT K T, SUPINIE T A, et al. SHARPpy: An open-source sounding analysis toolkit for the atmospheric sciences [J]. Bull Amer Meteor Soc, 2017, 98(8): 1 625-1 636. [27] 慕瑞琪, 徐芬, 孙康远, 等. 江苏台风龙卷环境条件与雷达关键特征分析[J]. 气象, 2022, 48(2): 190-202. [28] 曾明剑, 吴海英, 王晓峰, 等. 梅雨期龙卷环境条件与典型龙卷对流风暴结构特征分析[J]. 气象, 2016, 42(3): 280-293. [29] RYZHKOV A V. The impact of beam broadening on the quality of radar polarimetric data[J]. J Atmos Oceanic Technol, 2007, 24(5): 729-744. -