摘要
利用NCEP/NCAR再分析资料和我国160站地表面气温和降水的观测资料,首先采用旋转经验正交函数(REOF)方法定义了冬季欧亚遥相关型(EU),并计算了冬季的欧亚遥相关型指数(EU指数),在此基础上分析了欧亚遥相关型的时间和空间变化特征,并进一步研究了与欧亚遥相关型异常相联系的东亚冬季风系统变化以及我国冬季气温和降水的异常。针对欧亚遥相关型的分析结果表明,在欧亚大陆上空,大气内部存在与EU相联系的波列从北大西洋传播到乌拉尔山以东的欧亚大陆地区。在时间变化上,冬季EU以为年际变率为主,年代际变化的分量不明显,其显著周期表现为2～4年。当冬季EU处于正位相时,与之相关联的东亚大气环流异常表现为:东亚地区高空的急流增强、东亚大槽加深,导致东亚冬季风偏强,东亚地区温度偏低,从而使得我国东部降温、降水减少;反之,当冬季EU处于负位相时,我国东部增温、降水增加。
Based on the monthly mean NCEP/NCAR reanalysis dataset and the surface air temperature and precipi- tation data from 160 China stations, the interannual variations of winter Eurasian teleconnection pattern （ELI） and its possible influence on the climate in China are investigated. Wavelet analysis reveals that the significant periods of Eurasian teleconnection pattern index （EU index） are 2 - 4 years. The result suggests that the interannual variation of the ELI is dominant, whereas the interdecadal component is weak. In a winter with positive EU phase, the East Asian westerly jet stream at 200 hPa tends to be enhanced and the East Asian trough at 500 hPa becomes stronger. In the meantime, there are the surface northerly anomalies in East Asia which lead to a cooling condition over there. The opposite situations tend to occur in a negative EU winter. Hence, during the boreal winter the cooling and less precipitation are likely to occur in most of eastern China associated with a positive phase of EU.
出处
《大气科学》
CSCD
北大核心
2012年第2期423-432,共10页
Chinese Journal of Atmospheric Sciences
基金
国家重点基础研究发展规划项目2010CB428603
国家自然科学基金资助项目41025017
40921160379
关键词
欧亚遥相关型
气候异常
东亚冬季风
Eurasian teleconnection （EU）, climate anomalies, East Asian winter monsoon
