干旱气象

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2016年7月湖南一次极端持续性暴雨成因分析

周慧1,2蔡荣辉1尹冬德2周莉1   

  1. (1.湖南省气象台,湖南长沙410018 ;2.湖南省气象防灾减灾重点实验室,
    湖南长沙410018;3.湖南省益阳市气象局,湖南益阳423000)
  • 出版日期:2018-03-05 发布日期:2018-03-05
  • 通讯作者: 蔡荣辉,男,高工. E-mail:54622813@qq.com。
  • 作者简介:周慧(1973—),女,正研级高工,主要从事天气预报和数值预报方面的研究. E-mail:514446798@qq.com。
  • 基金资助:

    中国气象局预报员专项(CMAYBY2018-049)和中国气象局气象关键技术与集成面上项目(CMAGJ2014M36)共同资助

Causes Analysis of an Extreme Persistent Rainstrom in Hunan Province in July 2016

ZHOU Hui1, CAI Ronghui1, YING Dongde2, ZHOU Li1   

  1. (1. Hunan Meteorological Observatory, Changsha 410018, China;2. Key Laboratory
     of Hunan Meteorological Disaster Prevention and Reduction, Changsha 410018, China;
    3. Yiyang Meteorological Bureau of Hunan Province, Yiyang 423000, Hunan, China)
  • Online:2018-03-05 Published:2018-03-05

摘要:

利用NCEP(1°×1°)逐6 h再分析资料、FY-2E卫星云图和常德多普勒天气雷达资料,结合HYSPLIT (hybrid single-particle lagrangian integrated trajectory v4.9)气流轨迹扩散模式对2016年7月1—5日湘中以北一次罕见的持续性暴雨过程进行综合分析。结果表明:(1)中纬度高空槽的东移、带状分布且稳定少动的副热带高压为中低层西南低涡不断生成发展及“人”字型切变线的维持提供了有利的环流条件;(2)低空、超低空西南急流异常旺盛,并稳定维持5 d,强降水发生时850 hPa逐6 h区域 (27°N—29°N、110°E—114°E)平均风速增大,可作为强降水预报中重要参考指标;(3)线状排列的多个中-β尺度对流单体不断长大、互相合并,发展成积雨云团,稳定维持在湘中以北一带;(4)模拟气团输送路径的结果显示,低层的水汽主要从南海向北输送到湘中以北;中层水汽从孟加拉湾以偏西南路径为主向湘中以北输送;高层水汽沿着西风带向湘中以北输送。

关键词: 持续性暴雨, 西南急流, 中尺度对流系统, 水汽输送通道

Abstract:

Based on 6-hourly NCEP/NCAR reanalysis data, FY-2E satellite cloud images and Changde Doppler radar data, combined with HYSPLIT (hybrid single-particle lagrangian integrated trajectory v4.9) model, a comprehensive analysis of an extreme persistent rainstorm process in the north of central Hunan during July 1-5 2016 was conducted. The results were as follows: (1) The trough moving eastward and the subtropical high pressure maintaining stablely provide the favorable conditions for the formation and development of southwest low vortex and the “人” font shear line. (2) The southwest jet in low level was unusually strong and remained stablely for 5 days. When heavy rainstorm happened, 6-hourly regional mean wind speed on 850 hPa increased over 27°N—29°N,110°E—114°E .That may be used in the forecasting of heavy rainfall. (3) The meso-β scale convective cells arranged in a linear pattern continued to grow and merge with each other to form a cumulonimbus cloud and remained stablely in the north of central Hunan. (4) 120 h backward air flow trajectory results using HYSPLITV4.9  model showed that low level water vapor mainly came from the South China Sea, in the middle and upper level it was from Bay of Bengal and transported along the southwesterly flow to the precipitation zone, while in the upper level it was transported along the westerly belt to the precipitation zone.

Key words: persistent rainstorm, southwest jet, meso-scale convective system, vapor transport channel

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