Long term variability of the relationshops between atmospheric circulation and surface climate elemets

The stability of the relationships between atmospheric circulation and the surface climatic variables is an important precondition to construct scenarios of climate change by statistical methods. The aim of the work is therefore to examine if and how the relationships between atmospheric circulation (characterized by geopotenial heights of 500 hPa level) and surface climatic elements (mainly temperature and precipitation) are changing in European region and in the Czech Republic. The relationship between the NAO index and both temperature and precipitation were analysed for long period (1901-99) at 29 resp. 27 European stations. The NAO index strong influences climate in Europe. However, the relationships were changing in time. The course of 31-years running correlation differs between different European regions and different seasons. The circulation modes were identified in geopotential heights of 500 hPa level by rotated principal component analysis for period 1958-98. The climate in Europe is influenced by NAO, EA, EU1, EU2 and NA mode. The variability of the relationships was represented by 15-year running correlations at more than 100 European stations. The regions with similar courses of running correlations were identified by cluster analysis (PAM method). Despite the considerable variability of the..