| Summary: | The relationships between climatic elements like the temperature and the precipitation over the Europe region and atmospheric circulation represented by modes of low-frequency circulation variability in sea level pressure (SLP) and 500-hPa heights (Z500) are described using the Person correlation coefficient. More detailed analysis is achieved for central Europe.Four circulation patterns in Z500 and SLP over the Euro-Atlantic sector that influence climate in Europe all over the year were obtained by using Principal component analysis: the North Atlantic Oscillation (NAO) pattern, the East Atlantic pattern, and two Eurasian patterns. Statistically significant correlations of modes in both levels with maximum, minimum and mean temperature and with precipitation amounts and occurrence at European stations were identified in all seasons. In addition, several modes have strong influence on duration of sunshine, relative humidity, cloud cover, wind speed and direction at stations in Czech Republic. The other part of this work studies the sensitivity of the effects of NAO on surface climate to the way how the NAO is defined. Six different NAO index definitions including scores of modes from PCA were compared. The correlations with precipitation and surface temperature were used to illustrate the influence of individual NAO indices. Although all NAO indices mutually strongly correlate and seem to represent atmospheric circulation similar way, this is true only in winter.
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