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干旱区地理 ›› 2019, Vol. 42 ›› Issue (4): 724-734.doi: 10.12118/j.issn.1000-6060.2019.04.03

• 气候与水文 • 上一篇    下一篇

中亚低涡背景下一次短时强降水过程MCS成因分析

李建刚1,2，姜彩莲3，张云惠4，李如琦4，杨莲梅1,2   

  1. 1 中亚大气科学研究中心，新疆乌鲁木齐830002；2 中国气象局乌鲁木齐沙漠气象研究所，新疆乌鲁木齐830002;3 新疆五家渠市气象局，新疆五家渠831300；4 新疆气象台，新疆乌鲁木齐 830002
  • 收稿日期:2018-12-05 修回日期:2019-03-25 出版日期:2019-07-25 发布日期:2019-07-24
  • 作者简介:李建刚（1978-），男，新疆石河子人，副研究员，主要从事短时天气预报和灾害性天气研究. E-mail:shzljg_qxj@163.com
  • 基金资助:
    中国沙漠气象科学研究基金（SQJ2014008）；中央级公益性科研院所基本科研业务费专项资金项目（IDM2017003；IDM2016001）

Causal analysis of MCS in a short time severe precipitation process  under the background of Central Asia vortex

LI Jiangang1,2,JIANG Cailian3,ZHANG Yunhui4,LI Ruqi4,YANG Lianmei1,2   

  1. 1 Center of Central Asian Atmospheric Science Research,Urumqi 830002,Xinjiang,China;2 Institute of Desert Meteorology,CMA,Urumqi 830002,Xinjiang,China;3 Wujiaqu Meteorology Bureau,Wujiaqu 831300,Xinjiang,China;4 Xinjiang Meteorological Observatory,Urumqi 830002,Xinjiang,China
  • Received:2018-12-05 Revised:2019-03-25 Online:2019-07-25 Published:2019-07-24

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摘要： 为了深入了解天山山区中尺度对流系统（MCS）的触发和变化，对发生在新疆伊犁河谷一次中亚低涡背景下的短时强降水过程MCS成因进行了分析。通过利用自动站小时降水数据分析得出此次降水时空分布特征，并基于FY-2G卫星TBB产品、多普勒天气雷达数据对MCS的云图和雷达特征进行分析，得出该地区中-β尺度MCS(MβCS)具有明显的夜发性和后向传播特征，且分别在山区、平原上空发展和增强并长时间维持，雷达图上强回波带、逆风区和超低空急流的持续出现说明局地对流增强。此外，选取代表站雨强与对应TBB、雷达回波进行分析，发现强降水时段雨强的空间分布与TBB梯度大小成正比，时间分布与回波顶高和垂直液态含水量成正比。利用探空、地面风场以及ERAInterim再分析资料对MCS形成的大尺度环流背景和中尺度特征进行分析，得出深厚中亚低涡前部局地对流活动的加强触发MCS的生成，中低层多通道水汽输送和局地长时间水汽辐合、大气不稳定层结、中低层的风场辐合和垂直切变、高低层θse梯度增大以及低层暖平流增强为MCS的发展和维持提供了动热力和水汽条件。

关键词: 中亚低涡, MCS, 短时强降水

Abstract: In order to understand the triggering and developing mechanism of Mesoscale Convective System (MCS) in the Tianshan Mountains,the causes of MCS in a short-time severe precipitation process under the background of Central Asian vortex in the Ili Valley of Xinjiang,China were analyzed deeply.Based on the hourly precipitation data,the temporal spatial distribution characteristics of the precipitation were obtained.The cloud pattern and radar characteristics of MCS were analyzed according to FY-2G satellite TBB products and Doppler weather radar data.The results indicated that MβCS in this area had obvious characteristics of nocturnal and backward propagation,being formed over the mountain areas and developed,enhanced and retained for a long time period over the plain areas.The continuous occurrence of strong echo zone,adverse wind region and ultralow level jet on the radar map illustrated the enhancement of local convection.Moreover,the rainfall intensity of representative stations was analyzed with corresponding TBB and radar echo,which showed that the spatial and temporal distribution of rainfall intensity was proportional to the TBB gradient,ET and VIL respectively.Using sounding,surface wind field and ERA-Interim reanalysis data,the largescale circulation background and mesoscale characteristics of MCS was analyzed,which concluded that enhanced local convective activity triggered the formation of MCS in the front of deep Central Asian vortex,and the multi-channel water vapor transport and long-time water vapor convergence in the middle and low levels,the atmospheric instability stratification,and convergence and vertical shear of wind field in the low and middle levels,the increase of θse between the upper and lower level and the enhancement of warm advection in the lower level provided better dynamic,thermal conditions and water vapor for the development and retainment of MCS.

Key words: CentralAsia vortex, MCS, shorttime severe precipitation