摘要
首先对各种北大西洋涛动 (NAO)指数的定义进行了比较。发现冬季和夏季NAO的涛动中心有显著的差异 ,所以分别进行定义 ,定义时的中心由EOF分析及相关分析确定 ,新的定义能解释更多的海平面气压方差。在此基础上建立了 1873年以来的冬、夏NAO指数序列。近百年来的NAO指数最突出的年代际变化是 ,夏季在 1910～ 192 0年期间的突变性质的增强 ,以及冬季近 2 0多年来的持续加强。最后还对NAO年代际变化产生的可能原因进行了分析。
The different definitions of North Atlantic Oscillation indices are compared Because the locations and intensities of the centers of atmospheric action change significantly with seasons So it must be differently defined in summer and winter The summer index of North Atlantic Oscillation is defined as p (45 oN,40～60 oW)-p (65 oN,10～30 oW), and winter index as p (35 oN,10 oW～10 oE)-p (65 oN,10～30 oW), where P is the sea level pressure, * means standardization Following this definition, the summer and winter NAO indices from 1873 through 1997 are established During the past century, NAO showed significant interdecadal variability In summer NAO has an abrupt change during the mid 1910s, and in winter the continuous increasing during the last 2 decades is most striking Three possible mechanisms associated with the interdecadal variability are also discussed First one is the thermal and dynamic interaction between the North Atlantic Ocean and the overlaying atmosphere, the second one is the global warming, and the third one is the variation of planetary-scale atmospheric circulation affecting (or controlling to some degree) the NAO
出处
《大气科学》
CSCD
北大核心
2000年第2期187-192,共6页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金资助项目!4 963 51 90
国家重点基础研究发展规划项目!G1 9980 4 0 90 0第一部分
关键词
北大西洋涛动
指数
年代陆变率
海洋
大气
North Atlantic Oscillation (NAO) index
interdecadal
variability
