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一次分散性暴雨中尺度对流系统发展特征

卢焕珍1,2孙晓磊1刘一玮1 孙建元1   

  1. 1.天津市气象台,天津300074;2.河北省气象与生态环境重点实验室,河北石家庄050021
  • 出版日期:2018-09-04 发布日期:2018-09-04
  • 作者简介:卢焕珍(1965— ),女,天津静海人,正研级高工,主要从事中尺度暴雨预报技术研究. E-mail:lu_hz12@sina.com。
  • 基金资助:

    天津市自然科学基金项目(17JCYBJC23600)、中国气象局预报员专项项目( CMAYBY2017-005)、河北省气象与生态环境重点实验室科研开放课题(Z201604Y)和国家自然科学基金项目(41575049)共同资助

The Development Characteristics of Meso-scale Convective System During a Disperse Heavy Rainfall Process

LU Huanzhen 1,2, SUN Xiaolei1, LIU Yiwei1, SUN Jianyuan1   

  1. 1. Tianjin Meteorological Observatory, Tianjin 300074, China;
    2. Key Laboratory of Meteorology and Ecological Environment of Hebei Province, Shijiazhuang 050021, China
  • Online:2018-09-04 Published:2018-09-04

摘要:

应用常规观测资料及加密自动站、卫星云图、多普勒雷达、风廓线雷达、雷达变分同化分析系统(VDRAS)资料,对2016年8月6日夜间天津一次漏报的分散性暴雨过程中尺度对流系统演变特征及其成因进行分析。结果表明:(1)副热带高压边缘暖湿气流,低空弱切变、东南急流及湿舌,弱对流抑制及北部冷空气南下为强降雨提供了有利的条件。(2)渤海西南部发展加强的中-β尺度对流系统北移,与其前侧触发的中-γ尺度对流单体合并加强,造成东南部局地强降雨;河北东北部中-β尺度对流系统南压造成东部局地强降雨;东部的线状对流系统前侧不断触发新的雷暴生成、并发展加强为先线状、后人字形中-β尺度对流系统,先稳定少动、后随移入北部地区的对流单体南压造成天津中南部、北部地区的强降雨。(3)海陆风辐合线形成的东南风-西北风辐合线,是造成前期渤海西南部对流系统发展加强的辐合系统;河北东北部对流系统前侧的冷性水平出流(东北气流)与海风(东南气流)形成的辐合线是造成天津东北部对流系统的辐合系统;天津东北部、东南部对流系统前侧的冷性水平出流(东北气流、东南气流)与环境冷空气(西北气流)形成的中尺度涡旋及两条相交辐合线是造成中南部人字形对流系统的辐合系统。(4)冷空气南压是从3000~4000 m高度转为偏北风开始的。

关键词: 暴雨, 中尺度对流系统, 形成机制

Abstract:

Based on conventional observation data, automatic weather station data, satellite data, Doppler radar data, wind profiling radar data and the Variational Doppler Radar Analysis System (VDRAS) data, the evolution characteristic of meso-scale convective system during a disperse heavy rain process in Tianjin in the night of August 6, 2016 was analyzed. The results were as follows:(1) The warm and moist air flow on the edge of subtropical high, weak shear, southeasterly jet stream and moist tongue in low level, weak convective inhibition, and the southward movement of the northern cold air provided favorable condition for the severe rainfall. (2) The developed and strengthened meso-β scale convective system in the southwest area of Bohai Sea moved northward, then merged with the meso-γ scale convective cells triggered in the front of the meso-β scale convective system and enhanced, leading to local heavy rainfall in the southeastern part of Tianjin. The local severe precipitation in the eastern part of Tianjin was caused by the southward movement of the meso-β scale convective system in the northeastern part of Hebei. In front of the convective system, new thunderstorms were triggered constantly and strengthened to a meso-β scale convective system with the shape of first line and then herringbone, which moved less first, and then moved southward with the convective cells moving into the northern region, resulting in heavy rainfall in the southern and northern parts of Tianjin. (3) The convergence line between southeast wind and northwest wind evolved from land and sea breeze convergence line, which was the convergence system, thus resulting in the development of the prophase convective system in the southwestern part of Bohai Sea. The convection over the northeast coast of Tianjin was caused by the convergence line, which was formed by the cold horizontal outflow (northeast wind) in the front of convective system in the northeastern part of Hebei and sea breeze (southeast wind). The herringbone convection system in the south-central region of Tianjin was caused by a mesoscale vortex and two convergence lines, which was formed by the cold horizontal outflow (northeast wind and southeast wind) in the front of convective system in the northeastern and southeastern Tianjin and environmental cold air (northwest wind). (4) Cold air moving southward started from the appearance of the northerly at a height of 3000-4000 m.

Key words: heavy rainfall, meso-scale convective system, forming mechanism

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