低纬高原地区一次大暴雨过程MβCS的数值模拟
投稿时间:2006-11-09  修订日期:2006-12-01  点此下载全文
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作者单位
朱莉 南京信息工程大学江苏省气象灾害重点实验室, 江苏, 南京, 210044
南京信息工程大学大气科学学院, 江苏, 南京, 210044 
丁治英 南京信息工程大学江苏省气象灾害重点实验室, 江苏, 南京, 210044
南京信息工程大学大气科学学院, 江苏, 南京, 210044 
基金项目:国家重点基础研究发展计划项目(2004CB418303;2004CB418304)
中文摘要:利用MM5(V3.6)模式对2003年6月低纬高原地区一次大暴雨过程进行了数值模拟和地形敏感性试验。分析表明:产生低纬高原暴雨的水汽在不同的层次来源不同,低层辐合和高层弱辐散是本次MβCS暴雨的触发因子;700~500hPa强相当位温梯度产生强不稳定能量的积累并迅速释放,高层增暖形成暖中心使高层等压面升高和500hPa有β中尺度气旋性扰动生成,从而导致低层辐合和高层辐散进一步加强;低纬高原地区MβCS的暖心结构维持时间较高原下游地区短,是MβCS生命史相对短,降水突发性强、强度大、历时短的主要原因。
中文关键词:暴雨MβCS  数值模拟  β中尺度扰动  地形敏感性试验  暖心结构
 
Numerical Simulation Research on β-Mesoscale Convective System (MβCS) of a Heavy Storm Rainfall Event in Low Latitude Plateau of China
Abstract:Mesoscale numerical model MM5(V3.6) is used to simulate a heavy storm rainfall event on 16th—17th June 2003 in the Low Latitude Plateau region of China,and orographic sensitivity experiment is also performed.Analysis indicates that the water vapour which contributes to the storm rainfall has different channels at different levels.Convergence on lower layers and weak divergence on upper layers is the factor which leads to the formation of storm rainfall of MβCS.Strong potential equivalent temperature gradients on 700—500 hPa levels accumulate and rapidly release intensive unstable energy,giving rise to the formation of upper level warm core and the lifting of isobaric surface,and the genesis of β-mesoscale cyclonic disturbance at 500 hPa.Then the lower level convergence and the upper level divergence strengthen further.The lifetime of warm core structure of MβCS in the Low Latitude Plateau region is shorter than that in downstream regions,which is the main reason why the lifetime of MβCS in the Low Latitude Plateau is relatively short and the precipitation intensively breaks out in a short time.
keywords:storm rainfall MβCS  numerical simulation  β-mesoscale disturbance  orographic sensitivity experiment  warm core structure
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