夏季东天山中段一次强对流天气过程的数值模拟分析
投稿时间: 2016-10-31  最后修改时间: 2016-10-31  点此下载全文
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作者单位E-mail
连钰 云南省气象台 ylian_nuist@163.com 
杨军 南京信息工程大学中国气象局气溶胶-云-降水重点开放实验室  
基金项目:天山云水资源潜力评估与增雨雪技术开发应用
中文摘要:利用常规气象观测资料、区域自动站观测资料和FY-2D卫星逐时TBB资料,使用WRF中尺度数值模式,对2011年夏季发生在东天山中段一次强对流天气过程进行数值模拟和诊断分析,研究了天山特殊地形对降水过程的动力结构、水汽输送和云降水微物理机制的影响。结果表明:西风气流东移时受东天山的阻挡,气流从东天山南北两侧绕流,北侧急流经博尔塔拉谷地越过北天山西段后,急流右侧气流反气旋转向形成北支气流;南侧急流遇吐鲁番地区反气旋系统阻挡而转向北进形成南支气流。两支气流受地形动力抬升在东天山中段北坡汇合,为此区域局地强对流降水的形成和发展提供动力条件,北支气流为主要的水汽供应源。高空西南气流引导的冰相云系与低层局地对流云在东天山中段北坡结合,分别持续提供冰晶和云水,促使云微物理过程发展旺盛,致使局地暴雨过程产生。
中文关键词:强对流降水,WRF中尺度模式,数值模拟,云降水微物理机制
 
A Numerical Study of a Severe Convective Precipitation Process over the Middle Section of Eastern Tianshan Mountains in Summer
Abstract:By using the data from ordinary observations, automatic weather stations and FY-2D TBB data, as well as Weather Research & Forecast (WRF) model, a severe convective precipitation process in the summer of 2011 over the middle section of eastern Tianshan Mountains has been simulated and analyzed. This research aims to explore the dynamical structure, transport of water vapor and microphysical mechanism affecting by Tianshan Mountains’ topography. The results indicate that East Tianshan Mountains blocked one airflow moving towards east, making flow going around East Tianshan Mountains from its north and south slope. Northern stream which flowed through Bortala Valley turned right after climbing over the west section of north Tianshan Mountains, forming the north sub-flow; Southern stream turned to north after blocked by the anti-cyclone system over Turfan Depression, forming the south sub-flow. These two sub-flows converged over the north slope of mid-section of east Tianshan Mountains after dynamic lifting, providing driving force for the formation and development of the local convective precipitation. Among these two flows, the north sub-flow was the main source of water vapor. High level southwest airflow drove ice clouds along and merged with low level deep convections, continuously providing icicles and cloud water and boosting the microphysical processes in the clouds, which eventually led to local heavy rainfall .
keywords:severe convective precipitation, WRF model, numerical simulation, microphysical mechanism
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