Journal of Arid Meteorology

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Analysis on Multi-scale Characteristics of a Torrential Rainstorm in Liaoning Province on 16 August 2013

  

  1. 1. Meteorological Disaster Monitoring and Early Warning Centre of Liaoning Province, Shenyang 110166, China;
    2. Weather Modification Office of Liaoning Province, Shenyang 110166, China
  • Online:2017-04-30 Published:2017-04-30

“8·16”辽宁特大暴雨多尺度特征分析

  

  1. 1.辽宁省气象灾害监测预警中心,辽宁 沈阳 110166;
    2.辽宁省人工影响天气办公室,辽宁 沈阳 110166
  • 通讯作者: 蒋大凯. E-mail:jdkjyt@126.com
  • 作者简介:杨磊(1987- ),男,工程师,主要从事短时天气预报预警方面研究. E-mail:yanglei_nuist@163.com
  • 基金资助:

    2014年度辽宁省气象部门“添翼”人才奖励基金、辽宁省气象局科研项目(201508)、强对流天气物理量特征研究与雷达三维风场反演项目和气象关键技术集成与应用项目(CMAGJ2015M15)及中国气象局预报员专项(CMAYBY2017-015)共同资助

Abstract:

Based on conventional observation data, unconventional observation data from regional automatic weather stations, Doppler and wind-profiler radar as well as ground-based GPS, and NCEP reanalysis data with 1°×1° spatial resolution, the multi-scale convective characteristics of a torrential rainstorm on 16 August 2013 in Qingyuan county of Liaoning Province were analyzed. The results show that the low vortex shear line and low pressure in Northeast China were the dominant dynamic systems during the rainstorm process. The difference of pseudo-equivalent potential temperature between 700 hPa and ground was 43 K, which indicated the strong instablility of atmospheric stratification. The specific humidity on 850 hPa over most areas of Liaoning Province reached 14 g·kg-1, the vapor convergence was obvious in high specific humidity region, and the atmospheric precipitable water over Shenyang from GPS was 55 mm, so the vapor condition in the process was abundant. Five radar echoes went through Qingyuan region in turn, and formed “train effect”, which caused the heavy rainfall. The surface convergence line triggered new convective cells, and the intensity of wind fields in two sides of the convergence line affected the moving direction and speed of new convective cells. Moreover, the enhancement of southwesterly winds at middle and low levels was beneficial to improve the instability and moisture conditions. In addition, the intersection between the cold air in cold pool caused by short-time strong rainfall and the surrounding warm airflow might trigger new convective cells. Under the influence of terrain, the microphysical interaction in the process of merging between the meso-β scale cloud cluster and α cloud system might play an important role to produce the strong rainfall.

Key words: torrential rainstorm, radar echo, multi-scale characteristics, train effect, surface convergence line

摘要:

利用常规观测资料和区域自动气象站、多普勒雷达、风廓线雷达、地基GPS水汽观测仪等非常规观测资料以及NCEP(1°×1°)再分析资料,对辽宁省清原县2013年8月16日特大暴雨过程的多尺度对流系统特征进行分析。结果表明:低涡切变线和东北低压是本次暴雨过程的主要影响系统。700 hPa与地面之间假相当位温差达43 K,表明大气强烈的对流性不稳定结构。850 hPa辽宁大部分地区比湿达14 g·kg-1,比湿大值区存在明显的水汽通量辐合,沈阳站监测到的大气可降水量达55 mm,可见本次过程水汽充沛。5次雷达回波依次经过清原地区形成“列车效应”,导致该地区特大暴雨。地面辐合线触发的对流单体受其两侧风场的强弱影响,中低层西南风的加强有利于加大新生单体的垂直风切变和水汽条件。短时强降水导致的冷池与其周边暖气流交汇可能触发新的对流单体。在地形影响下,中-β尺度云团和α云系合并过程中的微物理作用可能是导致强降水的主要原因之一。

关键词: 暴雨, 雷达回波, 多尺度特征, 列车效应, 地面辐合线

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