摘要
根据1899-2009年北半球月平均海平面气压场资料,计算近111年来东亚夏季风强度指数,分析了东亚夏季风的年代际及年际变化特征。结果表明,20世纪20年代东亚夏季风达最强,80年代中期以后东亚夏季风强度一直呈减弱趋势,其中21世纪初达最弱。Morlet小波分析发现,东亚夏季风年代际及年际变化中存在准10年和准2年显著性周期。我国东部降水的年际变化与东亚夏季风的强度变化密切相关,强（弱）东亚夏季风年份,长江中下游地区降水量比常年偏少（偏多）;而华北地区降水量比常年偏多（偏少）。东亚夏季风减弱是造成20世纪80年代中期以后华北地区干旱少雨,长江中下游地区洪涝多雨的一个重要原因。
Based on the monthly average SLP data in the Northern Hemisphere from 1899 to 2009,the intensity index of the East Asian summer monsoon（EASM） was calculated,and its interannual variation and interdecadal variation have been investigated.The results showed that the EASM was most intense during 1920s,while it became weak in middle 1980s and in early 21st century,the intensity achieved the weakest.Morlet wavelet analysis showed that there were quasi decennial and quasi biennial periods in interannual variation and interdecadal variation of EASM.In addition,the interannual variation of precipitation over East China was closely related to intensity variation of East Asian summer monsoon.It was found that the precipitation over the middle and lower reaches of the Yangtze River was fewer（abundant） than that of normal year,while the precipitation over North China was more abundant（meager） than normal year during strong（weak） EASM years.The decrease of East Asian summer monsoon intensity was one of important reasons of the meager precipitation over North China and the abundant precipitation over the middle and lower reaches of the Yangtze River after middle 1980s.
出处
《安徽农业科学》
CAS
北大核心
2011年第4期2007-2011,共5页
Journal of Anhui Agricultural Sciences
基金
国家科技支撑计划项目(2009BAC51B03)
江苏省"六大人才高峰"项目(2005)
关键词
东亚夏季风
变异
中国降水
East Asian summer monsoon
Variation
Precipitation over China
