Quasi-periodic climate teleconnections between northern and southern Europe during the 17th–20th centuries

The North Atlantic Oscillation (NAO) is the leading mode of atmospheric variability in the North Atlantic region, influencing storm tracks and creating a dipole pattern of precipitation from north to south across Western Europe. This distinct spatial distribution of precipitation provides a framework that can be potentially used to identify and reconstruct patterns of past NAO-forced climate variability. In this study we use tree-ring width series from Western Europe, in conjunction with principal components analysis and advanced spectral methods, to prospect for quasi-periodic climate signals that are forced by the NAO. We identify a robust 25-yr anti-phased synchronization in climate variability between Scandinavia and the Mediterranean during the 17th–20th centuries. The amplitude of the 25-yr beat displays a long-term modulation in northern and southern Europe, with minimum amplitude during the late Maunder Minimum. This amplitude minimum coincides with a maximum in Δ¹⁴C, suggesting a potential solar or oceanic influence on the intensity of the 25-yr band of quasi-periodic variability.