“6.23”北京对流暴雨中尺度环境时空演变特征及影响因子分析  

On the evolution of mesoscale environment and influential factors of the heavy rainfall in Beijing on 23 June 2011

作　　者：章丽娜[1] 王秀明[1] 熊秋芬[1] 俞小鼎[1] 

机构地区：[1]中国气象局气象干部培训学院,北京100081

出　　处：《暴雨灾害》2014年第1期1-9,共9页Torrential Rain and Disasters

基　　金：国家自然科学基金(41005002;41175043);南京信息工程大学气象灾害教育部重点实验室开放课题(KLME1311);全国强对流预报专家团队项目

摘　　要：综合使用北京14时加密探空、常规观测资料、高时空分辨率资料等，针对2011年6月23日北京对流暴雨过程，采用基于构成要素的方法（“配料法”），分析了暴雨发生前2～12 h北京中尺度环境的时空演变特征并探讨了变化原因，重点讨论了北京周围地区物理过程如何使得北京午后局地的中尺度环境更有利于对流暴雨的产生。结果表明：（1）在低层湿度平流（偏南水汽输送加强）和温度平流（出现温度直减率大值区和逆温）的共同作用下，北京午后的水汽在逆温层之下的低层积聚。（2）由于热力条件呈现出不均匀分布的特征，午后北京山前和城区具有最有利的水汽条件和不稳定条件。（3）早晨生成于河北西北地区的对流系统在东南移动过程中加强，16时强阵风出流下山后与北京平原地区的偏南气流形成强烈辐合抬升，最强辐合恰好位于山前水汽和不稳定条件最有利地区。同时午后北京地区的垂直风切变加强，因此对流系统下山后增强，致洪对流暴雨发生。（4）河北西北部的平流过程对北京的午后探空特征影响显著，张家口早晨的探空特征对北京午后探空的变化具有很好的指示意义。Based on 14：00 BT sounding data, conventional observation data, and high resolution data, the spatial and temporal evolution of the mesoscale environment 2-12 hours prior to the event are analyzed for the storm produced heavy rainfall in Beijing on June 23, 2011 using ingredients based forecasting methodology. The associated physical processes are also discussed. The results are as follows：1） Influenced by low level moisture advection （low level southeasterly wind continuously transports moisture） and thermal advection （warm and cold advections attribute to high lapse rate and inversion）, moisture is accumulated at low levels;2） Because of the inhomogeneous distribution of thermal pa-rameters, the most unstable and moist regions are confined to the foothill and urban area of Beijing;3） The convection initiated at the north-western part of Hebei Province strengthens when it moves toward southeast. Cold mesoscale high and strong outflow are then formed. When the strong outflow moves down from the mountains at about 16：00 BT, it converges with the moist southerly and forms a strong uplift. The strongest convergence is formed in the most unstable and moist region. Meanwhile, vertical wind shear in the Beijing area strengthens in the afternoon. The convective system strengthens when it moves down from the mountains causing the heavy rainfall event;4） Since the Beijing sounding is influenced by the advections from northwestern part of Hebei Province, the morning sounding in Zhangjiakou is a good indictor for the variation of Beijing sounding in the afternoon.

关 键 词：对流暴雨 短时预报 配料法 中尺度环境 探空分析 

分 类 号：P458.121.1[天文地球—大气科学及气象学]