Reconstruction of monthly NAO and EU indices back to AD 1675

摘要: Instrumental station pressure, temperature and precipitation measurements proxy data were used to statistically reconstruct monthly time series of the North Atlantic Oscillation (NAO) Eurasian (EU) circulation indices back 1675. Systematic testing reconstruction procedure indicated generally reliable reconstructions throughout entire period, except for summertime before about 1750. Predictive skill varied different sub-periods depending on availability. It was highest autumn winter better EU than NAO index. Wavelet analysis suggested significant low-frequency variability, especially spring, summer annual averaged indices. The co-variability between found exhibit large decadal century timescale variations, indicating that climate variability over continent is temporarily decoupled from NAO.