Effect of cloud cover and atmospheric circulation patterns on the observed surface solar radiation in Europe

Abstract

This study aims at quantifying the most important factors affecting variations in downward surface shortwave radiation (DSW) in Europe including cloud cover and atmospheric circulation patterns. The role of observed cloud cover on DSW was analyzed through generalized linear models using DSW measurements obtained from the Global Energy Balance Archive during 1971-1996. Stations of DSW in Europe were selected to assess how they were affected by clouds. Overall cloud cover had a statistically significant negative relationship and a non-significant positive relationship on DSW for relatively nearby and distant cloud cover stations, respectively. The exception was west-central Europe where a significant negative effect over the whole continent was found suggesting an association with larger cloud structures. This showed that point DSW measurements can be spatially representative for larger scale variability. In line with other studies we found a strong seasonal effect of cloud cover on DSW mainly in northern Europe in spring and summer and in southern Europe in winter and autumn. The North Atlantic Oscillation was most important in winter with a significant negative effect in northern to central Europe and a positive non-significant effect in the south. The Mediterranean Oscillation exhibited mainly a positive effect in winter with significance in southern Europe and non-significance in central Europe. The North Sea Caspian Pattern primarily showed a positive effect with significance in east-central and northern Europe in spring and summer. The interrelationship found between these climatic variables could improve the understanding of a linkage to temperature and precipitation patterns in Europe. © 2012. American Geophysical Union.