INTERNATIONAL JOURNAL OF CLIMATOLOGY Int. J. Climatol. 21: 63–75 (2001) ATMOSPHERIC CIRCULATION AND SURFACE TEMPERATURE IN EUROPE FROM THE 18TH CENTURY TO 1995 V.C. SLONOSKY a, *, P.D JONES b and T.D. DAVIES c a Climate Research Branch, Meteorological Serice of Canada, 4905 Dufferin St., Ontario, Canada M3H 5T4 b Climatic Research Unit, Uniersity of East Anglia, Norwich, NR47TJ, UK c School of Enironmental Sciences, Uniersity of East Anglia, Norwich, NR47TJ, UK Receied 21 December 1999 Reised 27 May 2000 Accepted 29 June 2000 ABSTRACT The relationship between surface atmospheric circulation and temperature in Europe from the 1770s to 1995 is examined using correlation analysis. The atmospheric circulation is represented by six indices: the three leading principal components (PCs) of an empirical orthogonal function (EOF) analysis of 20 European pressure series from 1822 to 1995, which represent the central tendency of European pressure (EOF 1), a zonal circulation pattern (EOF 2) and a meridional pattern (EOF 3), a North Atlantic zonal index constructed from Gibraltar and Reykjavik pressure series for 1821 – 1995; a Western European zonal index constructed from Madrid, Barcelona, Lund and Trondheim for 1786 – 1995; and an index constructed from Paris and London, 1774 – 1995. Eight long temperature series from northwestern and central Europe were correlated with these circulation indices. European temperatures in general had the highest correlations with the zonal circulation indices in winter, with almost 70% of the variability in the temperature records explained by variations in the zonal index. The correlation coefficients between PC 3 (representing meridional circulation) and temperatures were highest in spring and autumn, particularly for Scandinavia. Running correlation series calculated over 25-year windows reveal significant non-stationarities in the relationship between surface temperature and atmospheric circulation on decadal time scales, suggesting caution must be used in extrapolating current relationships between circulation and temperature for future climate predictions based on downscaling or past palaeoclimatic reconstructions. Copyright © 2001 Royal Meteorological Society. KEY WORDS: Europe; North Atlantic Oscillation; temperature; climate variability; early instrumental records; correlation; circulation/climate relationship 1. INTRODUCTION Given the current concerns about climate change, particularly the anthropogenic influence on climate, it is of fundamental importance to investigate past climates and determine the role of natural variability in climate change. In this paper, long monthly series of European temperature and pressure dating back to the 18th century are examined, and the relationships between the atmospheric circulation and temperature over decades to centuries are investigated using historical instrumental data. There exists a great degree of natural variability in the atmospheric circulation and surface climate system, from interannual timescale changes such as those due to the Southern Oscillation and associated El Nin ˜o/La Nin ˜ a events to the changes on the millennial scale related to the Ice Ages. This natural variability is also present on the decadal-to-century timescale. The past five centuries have been dominated by colder and more variable climatic conditions during the 16th – 19th centuries (Lamb, 1995; Jones, 1998) and a recovery during the present century, probably enhanced by anthropogenic warming from the increased emission of greenhouse gases (Jones, 1998; Mann et al., 1998). Natural variability in climate on decadal-to-century timescales is caused by changes in solar output, volcanic activity, and * Correspondence to: Climate Research Branch, Meteorological Service of Canada, 4905 Dufferin St., Ontario, Canada M3H 5T4; e-mail: Vicky.Slonosky@ec.gc.ca Copyright © 2001 Royal Meteorological Society