The Continuum of Northern Hemisphere Teleconnection Patterns and a Description of the NAO Shift with the Use of Self-Organizing Maps
The Continuum of Northern Hemisphere Teleconnection Patterns and a Description of the NAO Shift with the Use of Self-Organizing Maps
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DOI：
10.1175/2008jcli2380.1
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发表时间：
2008-12
影响因子：
4.9
通讯作者：
N. Johnson;S. Feldstein;B. Tremblay
中科院分区：
文献类型：
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作者：
N. Johnson;S. Feldstein;B. Tremblay
摘要本研究利用自组织映射（SOMs）方法和NCEP-NCAR再分析资料，对北方半球遥相关型的连续性观点进行了改进，并阐明了20世纪70年代后期开始的北大西洋涛动（NAO）的长期东移。每日，冬季，北方半球海平面气压的20模式SOM分析揭示了一个连续的模式，密切对应于众所周知的遥相关模式。这种分析还表明，半球海平面气压场的年代际变化可以理解的变化，在频率分布的连续海平面气压模式描述的SOM。基于SOM的连续体观点，NAO的上述长期变化可以理解为从西向位移的负NAO型向东向位移的正NAO型的主导变化，尽管向西向和东向位移的NAO-型。
Abstract In this study, the method of self-organizing maps (SOMs) is used with NCEP–NCAR reanalysis data to advance the continuum perspective of Northern Hemisphere teleconnection patterns and to shed light on the secular eastward shift of the North Atlantic Oscillation (NAO) that began in the late 1970s. A 20-pattern SOM analysis of daily, wintertime, Northern Hemisphere sea level pressure reveals a continuum of patterns that correspond closely with well-known teleconnection patterns. This analysis also reveals that interdecadal variability of the hemispheric sea level pressure field may be understood in terms of changes in the frequency distribution within the continuum of sea level pressure patterns described by the SOM. Based on the continuum perspective illustrated with the SOM, the above secular shift of the NAO may be understood as a change in dominance from westward-displaced, negative NAO-like patterns to eastward-displaced, positive NAO-like patterns, though westward- and eastward-displaced NAO-...