Interdecadal Variations in the Spatial Pattern of the Arctic Oscillation Arctic Center in Wintertime

Abstract

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.