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气象:2007,33(12):31-38
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一次大暴雨过程中低空急流演变与强降水的关系
(1.南京大学大气科学系,210093;2.辽宁省营口市气象;3.中国气象局培训中心)
Mesoscale Structure and Evolution of the Low level Jet and Its Relationship with the Heavy Rainfall During a Torrential Rain Process
(1.Atmospheric Sciences Department, Nanjing University, 210093;2. Yingkou Meteorological Office, Liaoning Province;3.Training Center, CMA)
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投稿时间:2007-05-17    修订日期:2007-08-16
中文摘要: 利用营口新一代天气雷达提供的每6分钟一次的风廓线资料,详细分析了2006年6月29日辽宁 省西部大暴雨过程中强降雨时段的低空风场结构。得出:此次强降水天气的发生与低空急流 的迅速加强和向下扩展相对应,短时大暴雨发生前低空西南急流提前2小时左右开始有动量 快速下传,当20m·s-1的急流中心下传到≤1km超低空,1.2~2.1km低空出现24m·s-1东南急流,有利于产生短时大暴雨;说明低空脉动及向地面扩展程度与短时强降水之 间关系密切。低空急流到达测站上空不一定立即产生强降水,有时会滞后1~2个小时,强降 水或强烈天气的发生都存在着一定的动量下传,引起低空扰动加强,同时低空急流的强度和 伸展高度,以及动量下传的能量大小,都直接制约着强降水的强弱。低空急流指数增大的程 度和降水量的强度呈正比关系,低空急流指数不仅可以说明低空急流的脉动以及向地面扩展 程度与中小尺度的强降水存在密切的关系,同时对强降水的出现以及雨强的大小有一定的预 示作用。
中文关键词: 大暴雨  风廓线  低空急流
Abstract:Using the data of the wind profile delivered every six minutes by the new genera tion of weather radar of Yingkou,the detailed analysis is made for the low lev el wind field structure duringthe heavy rain periods of torrential rains on 29 June 2006 in the w est of Liaoning Province. The conclusion is as follows: The incidence of the heavy rain is corresponding to the rapid strengthening of l ow level jet and its downward expansion. The southwest low level jet in advan ce of two hours before the short term heavy rain starts to move downward rapidl y . The fluctuation in the low level and its degree of expansion towards the grou nd has a close relation to the strong short term rainfall. The low level jet w ill not certainly immediately cause a strong rainfall when it arrives at the sta tion,sometimes this process will be delayed one or two hours. The emergence of the strong rainfall or the strong weather has definite momentum transmission. It strengthens the low level disturbance and the strength of low level jet. The extended height and the magnitude of the momentum transmission restrict directly the strength of the strong rainfall. The degree of increase in the low level j et index (I) and the intensity of rainfall has a direct proportional relationsh ip. Index (I) not only indicates that the fluctuation of low level jet and the intensity of ground expansion have a close relationship with the strong rainfall of meso scale,but also indicates the occurrence of strong rainfall a nd the magnitude of rainfall intensity.
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基金项目:“中国气象局气象新技术推广项目‘强灾害性天气预警技术的研究及其推广 应用’的研究。课题编号:CMATG2007M10”
引用文本:
金巍,曲岩,姚秀萍,黄素文,2007.一次大暴雨过程中低空急流演变与强降水的关系[J].气象,33(12):31-38.
Jin Wei,Qu Yan,Yao Xiuping,Huang Suwen,2007.Mesoscale Structure and Evolution of the Low level Jet and Its Relationship with the Heavy Rainfall During a Torrential Rain Process[J].Meteor Mon,33(12):31-38.