摘要
利用1951-2006年6-8月NCEP/NCAR的500hPa高度场、850hPa高度场和风场、降水率和海平面气压以及全国600多站的降水量资料,选择东亚—西太平洋地区(10o-80oN,70o-180oE)经9点高通滤波、EOF分析、合成分析和其它统计诊断手段,研究了东亚夏季风的年际变化及其与环流和降水的关系,得到如下的结论:1.东亚—西太平洋地区海平面气压存在着蒙古低压和西太平洋高压之间纬向的偶极子振荡型(APD),APD指数可以作为东亚夏季风强度指数;2.东亚—西太平洋地区500hPa高度距平EOF的第一模态具有明显经向东亚遥相关型特征(EAP)。EAP指数也可以作为东亚夏季风强度指数。3.APD指数与500hPa(或850hPa)的东亚遥相关型关系密切。APD指数和EAP指数存在明显的反相关关系,它们之间的相关系数为-0.23,已超过了10%显著检验;4.APD指数和EAP指数都和我国汛期降水、东亚—西太平洋降水率关系密切,超过5%显著性的相关区主要在长江流域以南地区至日本南部海面一带,前者为正相关,后者为负相关。
Using NCEP/NCAR reanalysis geopotential height and winds at 500 hPa and 850 hPa, precipitation rate, sea level pressure （SLP）, as well as the observed precipitation from more than 600 stations in China in June-August from 1951 to 2006 and focusing on the East Asia-West Pacific region （10°-80°N, 70°-180°E）, interannual variation of East Asian summer monsoon （EASM） and the relationship with atmospheric circulation and rainfall are studied by means of statistical diagnose methods, such as 9 points high-pass filter, empirical orthogonal function （EOF） analysis, composite analysis etc. Some conclusions can be drawn as below： （1） From the EOF analysis result of SLP in the East Asia-West Pacific region, a zonal dipole oscillation mode between Mongolia cyclone and West Pacific anticyclone （APD） can be found and the APD index can act as an intensity index of EASM. （2） The EOF-1 of anomalies of geopotential height at 500 hPa show an obvious meridional East Asia remote correlation mode （EAP） and EAP index also can be seen as an intensity index of EASM. （3） The result of composite analysis to the years with high/low APD index reveals that APD index is closely correlated with EAP at 500 hPa/850 hPa. The correlation coefficient between APD index and EAP index is -0.23, which can pass the significant test at confidence level 0.1. （4） Both APD index and EAP index are closely correlated with rainfall in the flood season in China and precipitation rate in the East Asia-West Pacific region. The significant correlation areas at confidence level 0.05 are mainly located in the scope from the land south of the Yangtze River valley to the sea south to Japan, and the former/latter is positive/negative, respectively.
出处
《地理学报》
EI
CSCD
北大核心
2008年第7期751-760,共10页
Acta Geographica Sinica
基金
科技部国际科技合作项目(2007DFB20210)
国家自然科学基金项目(90502003)
中日政府间JICA渠道技术合作项目“中日气象灾害合作研究中心”~~
关键词
夏季风
东亚—西太平洋偶极子
东亚遥相关型
降水
summer monsoon
East Asia-West Pacific dipole
East Asia remote correlation mode
rainfall
