1880—2010年中国东部夏季降水年代际变化特征
投稿时间:2016-01-01  修订日期:2016-01-28  点此下载全文
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任永建 南京信息工程大学 大气科学学院, 江苏 南京 210044
中国气象局 国家气候中心, 北京 100081
武汉区域气候中心, 湖北 武汉 430074 
renyj@nuist.edu.cn 
宋连春 中国气象局 国家气候中心, 北京 100081  
肖莺 武汉区域气候中心, 湖北 武汉 430074  
基金项目:湖北省气象局重点项目(2015Z03);国家自然科学基金青年科学基金项目(41405077)
中文摘要:利用1880-2010年中国东部66站夏季降水数据,开展夏季长序列降水的年代际变化特征研究。结果表明,中国东部夏季降水年代际变化特征显著,华北、江淮和华南地区存在明显的差异。经验正交分解结果表明,偶极型(“-+”和“+-”)和三极型(“+-+”和“-+-”)分布是中国东部夏季的两种主要降水模态。夏季500 hPa高度场年代际分量与同期太平洋SST典型相关分析(BP-CCA)得出,太平洋年代际振荡(PDO,Pacific Decadal Oscillation)正位相可以激发出负的PJ型遥相关波列,导致长江中下游地区降水偏多,华北降水偏少;反之亦然。同时,通过滑动相关分析发现,中国东部不同区域的夏季降水对PDO不同位相的响应特征存在差异。
中文关键词:年代际变化  夏季降水  中国东部  太平洋年代际  振荡
 
Interdecadal change of summer precipitation in eastern China during 1880——2010
Abstract:The interdecadal variability of precipitation in eastern China is studied based on data from 66 meteorological stations for the period 1880-2010.Combined with the summer Pacific Decadal Oscillation (PDO) during 1900-2010 and NCEP/NCAR data for the period 1961-2010,summer precipitation in eastern China is analyzed corresponding to the different phases of the PDO,and the possible underlying physical mechanism is discussed.In order to resolve the spatial distribution differences,empirical orthogonal function (EOF) analysis is carried out on the summer precipitation in the near 130-year period.Conventional synthesis analysis,the t-test of statistical significance,and sliding correlation analysis are also used.Decadal features are obtained using Fourier filtering,which filtered out less than 10 years.The work presented in this paper is useful in improving our understanding of the decadal characteristics of summer precipitation in eastern China,especially in the context of promoting the forecasting ability of summer precipitation.The results show that the interdecadal variability of precipitation in eastern China is significant,with obvious differences in North China,the Jianghuai region,and South China.Three change-points occur in North China (in the early 1920s,1940s and early 1970s),four in the Jianghuai region (in the early 1920s,1940,late 1950s and 1970s),and three in South China (in the late 1900s,1940s and early 1970s).A dipole (negative-positive or positive-negative) and tripole (negative-positive-negative or positive-negative-positive) distribution are the two main modes of summer precipitation in eastern China,as determined by EOF analysis.In 1929-1944 (positive PDO),summer rainfall in eastern China presents a negative-positive dipole distribution,which indicates the main rain belt to be located in South China,with the negative anomaly in the Jianghuai basin.During 1945-1977 (negative PDO),the meridional distribution of summer rainfall in eastern China is characterized by a positive-negative-positive tripole pattern,with the main rain belt in North China and South China.In another positive phase of the PDO (1978-2005),the spatial structure of precipitation follows a negative-positive dipole distribution-opposite to that of the previous positive PDO phase-with the main rain belt in eastern China located in the Jianghuai region and the negative anomaly in North China and South China.We also find through sliding correlation analysis that summer precipitation in different areas of eastern China show response characteristics according to the different phases of the PDO.It is apparent that the location of the main rain belt is not only affected by the phase of the PDO,but also by the main circulation system (e.g.the western Pacific subtropical high,East Asia teleconnection and East Asia blocking high).The interdecadal components of the 500-hPa height field and Pacific SST in the summer,via canonical correlation analysis,indicates that the positive phase of the PDO can trigger a negative wave train of the Pacific-Japan teleconnection.This negative teleconnection wave train can lead to more precipitation over the middle and lower reaches of the Yangtze river,less precipitation over North China,and vice versa.
keywords:interdecadal variability  summer precipitation  eastern China  PDO
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