Circulation indices and thermal regime of Eastern Europe in winter

Analyzed is the impact that basic spatiotemporal modes in the ocean-atmosphere system of the Northern Hemisphere characterizing interannual variability, produce on the anomalies of surface air temperature in Eastern Europe and the Black Sea countries in winter. It is demonstrated from the data of NCEP reanalysis and standard meteorological observations for 1950-2012 using the composite method that the maximum influence on the anomalies of monthly mean air temperature is exerted by the North Atlantic Oscillation in the northwestern part of the region and by the Scandinavian pattern in its eastern part. Typical anomalies of monthly mean air temperature caused by these modes reach 4-5A degrees C. The effects of East Atlantic and East Atlantic-West Russia patterns prevail in the Black Sea region. Regional monthly mean air temperature anomalies caused by them reach 2-2.5A degrees C. The positive phases of the North Atlantic Oscillation and East Atlantic pattern that describe the intensity of zonal atmospheric circulation, are accompanied by the positive anomalies of surface air temperature in the most part of Eastern Europe. The positive phases of the Scandinavian and East Atlantic-West Russia patterns associated with the anticyclonic blocking are accompanied by negative anomalies. Extreme negative anomalies of temperature in January and February are registered most frequently if the negative phase of the East Atlantic pattern coincides with the positive phase of the Scandinavian pattern, and extremely high positive anomalies, at the combination of the positive phase of the East Atlantic pattern and the negative phase of the Scandinavian pattern.