Arctic Oscillation (AO) is the dominant mode of atmospheric circulation in the extratropical Northern Hemisphere regions. The spatial pattern of the AO Arctic center affects the extent of polar cold air outbreaks southward. However, the underlying nature and causes of its interdecadal variation remain unclear. Utilizing ERA5 reanalysis data, this study identifies two distinct spatial patterns of the wintertime AO Arctic center through the K-means clustering method, which alternate over different decade periods. The Double-trough pattern generates a tripolar temperature pattern of “cold Arctic-warm Eurasia-cold Tibetan Plateau” through a Rossby wave train during 1960–1997/2013–2024. While the Single-trough pattern leads to a dipolar temperature pattern in 1998–2012. Furthermore, interdecadal variations in North Atlantic sea surface temperature meridional gradient act as an influencing factor in shaping the spatial pattern of the AO Arctic center. This research aids the understanding and prediction of climate anomalies using AO signals within various decadal contexts.

中文翻译：

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冬季北极振荡北极中心空间格局的年代际变化


北极涛动 （AO） 是温带北半球地区大气环流的主要模式。AO 北极中心的空间模式影响极地冷空气向南爆发的程度。然而，其年代际变化的潜在性质和原因仍不清楚。利用 ERA5 再分析数据，本研究通过 K-means 聚类方法确定了冬季 AO 北极中心的两种不同的空间模式，它们在不同的十年周期内交替。1960-1997/2013-2024 年期间，双槽型通过罗斯比波列产生“冷北极-暖欧亚-寒冷青藏高原”的三极温度型。而单槽模式导致 1998-2012 年的偶极温度模式。此外，北大西洋海表温度经向梯度的年代际变化是塑造 AO 北极中心空间格局的影响因素。这项研究有助于在各种年代际背景下使用 AO 信号理解和预测气候异常。