影响北京夏季降水异常的大尺度环流特征  

Large Scale Circulation Characteristics Influencing Summer Precipitation in Beijing

作　　者：何敏[1] 林建[2] 韩荣青[1] 

机构地区：[1]国家气候中心,北京100081 [2]国家气象中心

出　　处：《气象》2007年第6期89-95,共7页Meteorological Monthly

基　　金：北京市自然科学基金"副热带高压中短期变异对北京夏季降水影响的机理研究"(资助号:8042021)

摘　　要：利用1951—2004年500hPa高度场、副高特征量及北京降水量资料,采用相关和合成分析方法,研究了夏季北半球500hPa环流异常与北京旱涝的关系。结果表明:北京夏季降水与副高强度和位置的关系比较复杂,中高纬与副热带环流特征的各种配置会对北京夏季降水产生不同的影响。欧亚中高纬环流出现欧亚—太平洋遥相关型,华北上空持续受高压控制;北京及附近地区处在西高东低的形势下,持续受西北下沉气流控制是北京夏季少雨的有利环流条件。北京及附近地区位于低压槽区或处在东高西低的下游“阻塞”形势,是北京夏季多雨的基本环流条件。研究的结果为北京地区夏季旱涝预测提供了环流背景。With correlation and resultant analysis methods, the climate aspects between the tendencies of drought and flood in Beijing and the abnormities of 500hPa circulations are analyzed, by using the data of 500hPa height fields, subtropical high character fields and Beijing＇s precipitation. The results show that the strength and the position of the subtropical ridge are not remarkably associated with the summer precipitation in Beijing, while the flow pattern collocations between the mid-high latitudes and the subtropics are. The drought summers of Beijing were associated with the tele-connection pattern over Eurasian continent mid-high latitude （EUP pattern）. In those years, anticyclone circulation prevails in Northern China with ridge to the western side of Beijing. Beijing and near by regions are controlled by Northwest descending flow. On the other hand, a block high pressure in the down stream side of Beijing is the basic circulation characteristics for plentiful precipitation summers of Beijing. In those years, Beijing and near by regions are controlled by Southwest ascending flow in front of trough. These results provide some knowledge on large scale circulation background for seasonal prediction of summer precipitation tendency in Beijing.

关 键 词：夏季 降水 副高 中高纬环流 

分 类 号：P458.121[天文地球—大气科学及气象学]