Zonal indices for Europe 1780-1995 and running correlations with temperature

Zonal circulation indices with monthly and seasonal resolutions are calcula ted based on gridded monthly mean sea-level pressure (SLP) reconstructed ba ck to 1780 by Jones et al. (1999): an overall zonal index for the whole Eur opean area between 30 degreesW and 40 degreesE, a normalized index for the North Atlantic Oscillation (NAO), and a similar index for Central Europe. F or most of the early time up to the mid-nineteenth century we get preferred negative anomalies in the NAO index for winter and preferred positive ones for summer. The turning points in cumulative anomalies during the 1850s fo r winter and during the 1870s for summer - indicate a transition period in circulation modes from the "Little Ice Age" to the recent climate in Europe . Running correlations (time windows of 21 years with time steps of one yea r) between zonal indices and regional temperature time series from Central England, Stockholm and two Central European regions are all indicating majo r instationarities in these relationships with a particular decline in wint er correlations around the turn from the nineteenth to the twentieth centur ies. Aspects of different circulation patterns linked with these variabilit ies are discussed.