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“0706”周口龙卷现场调查和可预警性综合分析
张一平1,2,3, 牛淑贞1, 郑世林1, 张宁1, 王建忠1, 刘莹莹1
(1.河南省农业气象保障与应用技术重点实验室;2.河南省气象局;3.河南省气象台)
Investigation of “0706” tornado in Zhoukou and General Analysis of Warning Practicability
ZHANG Yiping1,2,3, NIU Shuzhen1, ZHENG Shilin1, ZHANG Ning1, WANG Jianzhong1, LIU Yingying1
(1.Key Laboratory of Agrometeorological Safeguard Application Technique,CMA;2.Henan Provincial Meteorological Bureau;3.Henan Provincial Meteorological Observatory)
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投稿时间:2018-03-26    修订日期:2019-05-10
中文摘要: 2017年7月6日,周口出现了局地龙卷致灾强对流天气,地面龙卷灾害主要出现在西华和淮阳两县交界处长约4.5-5km、宽约100-150m的地带,雷达监测和现场灾情具有显著中-γ尺度涡旋特征。通过人工现场调查、拍摄视频、媒体图片并结合新一代天气雷达观测等综合分析,确定周口局地龙卷整体为EF1级,最强达到EF2级。本文从预报预警灾害天气的实际业务出发,利用常规高空地面、区域加密自动站、新一代天气雷达以及风云2G实时分析资料,综合分析了周口局地龙卷的环境条件和可预警性。结果表明:(1)本次龙卷发生在中纬度低槽东移和副热带高压边缘西南暖湿气流共同影响的环流形势下,高空分流辐散和低空急流发展的配置为暴雨、局地龙卷提供了有利的天气尺度动力条件,龙卷由强降水冷出流和东部暖湿环境之间形成辐合线上的气旋性辐合诱发产生,地面自动站温度、露点和能量梯度大值带偏暖湿的正涡度中心附近是龙卷可能发生的区域。(2) 08时阜阳探空资料分析大气处于较强的条件不稳定状态,对流有效位能1712J/kg(14时温度、露点订正后为3182J/kg),K指数42℃,SWEAT指数312,SI为-4.5℃;大气可降水量在65mm左右;抬升凝结高度很低,位于959.2hPa处;0-1km在10m/s或以上。大的热力不稳定和低层垂直风切变及低的抬升凝结高度为小尺度龙卷的发生提供了环境条件。(3)卫星云图上,龙卷发生在大尺度暖区云带前部,云顶亮温低至-72℃,对流发展非常旺盛。闪电监测龙卷位于闪电密集区东侧。卫星云图和闪电加密探测资料中发展旺盛的深对流云和闪电密集区附近是龙卷发生的高危区。(4)雷达回波图上,龙卷发生在东北西南向暴雨回波带前沿的块状强回波处,尽管中气旋和TVS的出现并不一定代表地面一定有龙卷发生,但实时业务中可以作为预警龙卷非常可靠的线索。根据中气旋、龙卷涡旋特征的持续、移动特点可对局地龙卷提前预警。旋转速度迅速加强、高度下降预示龙卷将影响到地面。以上结论可作为今后黄淮平原监测预警龙卷的参考依据。
Abstract:A tornado occurred in Zhoukou on 6 July 2017 and caused severe weather, and the disaster is mainly on a region of 4.5-5 km long and 100-150 m wide where is between Xihua and Huaiyang. The γ mesoscale vortex characteristic was notable on the scene of radar monitoring and disaster area. A general analysis was made by means of manual investigation, video shooting and media pictures with a combination of Doppler weather radar monitoring, the rank of the tornado was EF1and EF2 when strongest. Basing on actual works about disastrous weather forecasting and warning, the circumstance and early warning practicability of tornado in Zhoukou was analyzed using high, surface, auto station data, Doppler weather radars and FY-2G satellite data. The result shows that: (1) the tornado process was influenced by the mid-latitude trough moving eastward and the warm and moist southwest airflow on the edge of subtropical high. Coordination of divergent bypass upper-level airflow and lower-level jet offer heavy rain and tornado a favorable synoptic scale dynamic condition, the tornado was induced and produced by the cyclonical convergent airflow on the convergence line lies between cold heavy rainfall outflow and warm and moist east circumstance, the plus vortex center on the big region of surface temperature, dew-point temperature and energy gradient maybe where tornado can occur. Fuyang sounding data at 08:00 AM shows a strong conditional instable air when CAPE is 1712 J·kg-1 (3182 J·kg-1 corrected with surface temperature and dew point temperature at 14:00 PM), K index is 42 ℃, SWEAT index is 312 and PW is 65 mm. The LCL is at a very low height of 959.2 hPa, 0-1 km wind shear is 10 m·s-1 or above, what offers a profitable circumstance conditions for tornado. (3) On satellite cloud pictures, tornado occurred at the front of warm cloud bands whose TBB was under -72 ℃, where convective clouds developed vigorously. Lightning monitor result showed the tornado was on the east side of the dense flashes area. Deep convective clouds and dense flash area is the high-risk region of tornado. (4) On radar echo pictures, the tornado occurred at the massive echo region on the front of northeast-southwest heavy rain echo banks. The occurrence of mesocyclone and TVS did not imply the tornado should happen but can be a reliable clue for tornado warning. Rotating velocity enhanced and felled indicating the tornado would come to ground. The results above could be the reference on tornado monitoring and warning of huanghuai plain.
文章编号:201803260134     中图分类号:    文献标志码:
基金项目:中国气象局预报员专项(CMAYBY2018-044)、中国气象局气象关键技术集成与应用面上项目( CMAGJ2015M36)和河南省强对流创新团队共同资助
引用文本:
张一平,牛淑贞,郑世林,张宁,王建忠,刘莹莹,0.[en_title][J].Meteor Mon,():-.
ZHANG Yiping,NIU Shuzhen,ZHENG Shilin,ZHANG Ning,WANG Jianzhong,LIU Yingying,0.Investigation of “0706” tornado in Zhoukou and General Analysis of Warning Practicability[J].Meteor Mon,():-.