Thermal comfort trends and variability in the Croatian and Slovenian mountains
Zaninović, K.; Matzarakis, A.; Cegnar, T.
This paper deals with the climatic and bioclimatic conditions, trends and variability in the mountainous areas of Croatia and Slovenia. Two mountain meteorological observatories were chosen: Zavizan in the Croatian Dinaric Alps and Kredarica in the Slovenian Julian Alps. Both have the same monitoring protocol and similar instruments. The station's natural environment remained unchanged since 1955. Therefore, the data of both observatories are extremely valuable for studying changes in sensitive mountain ecosystems in Croatia and Slovenia. Data from the period 1955-2004 were used to assess mountain climatic and bioclimatic variability and trends in both countries. The analysis of the bioclimatic conditions has been carried out using the physiologically equivalent temperature (PET), which is based on the human energy balance models. The prevailing thermal sensation at both stations is very cold, varying from very cold winters to cold and cool summers. Results of the trend analysis indicate a significant increase in the thermal bioclimate index PET in both regions, mainly caused by rising air temperature, especially in spring and summer. The progressive trend test analysis indicated the beginning of positive PET trend in the 1980s - in 1981 on Zavizan and in 1988 on Kredarica. In spite of the considerable increase in thermal comfort in the last 50 years, the bioclimate conditions stayed within the range of the same class of thermal perception.