Changes in Different Type of Clouds in South-Eastern Europe in Association with Climate Change

The aim of the presented study is to estimate regional changes in different cloud types in association with climate change in South Eastern Europe. A statistical method of downscaling is applied to calculate how cloudiness changes parallel to an increase in hemispheric temperature of 0.5 K. The regression of local variables against hemispheric mean temperature is analysed using the method of instrumental variables in the recent monotonously warming period of 1973-1996. The changes in total cloudiness and in different types of clouds (Ci, As, Ac, Cb, Cu, Sc, St and Ns) are both positive and negative, displaying a regional distribution. To find out the geographic distribution of these changes, they are enrolled in clusters and analysed in relation to geographic latitude, longitude and altitude. The results obtained show that total cloudiness, as well as Ac, Cb, Sc and St cloud types have a significant correlation to geographical longitude, while only cirrus clouds changes have a negative correlation to geographical longitude, and only cumulus cloud changes statistically depend on altitude.