Impact of Climate Change on the Annual Water Balance in a Humid Climate

Lithuania and Bosnia and Herzegovina are considered as countries with high vulnerability and low adaptive capacity to cope with climate change. The entire territory of these countries is characterized by the warming trend, with positive trends in both the maximum and the minimum temperatures throughout the year. The increase in air temperature has resulted in change of evapotranspiration and mean annual water balance values. These countries are also frequently faced with an occurrence of severe droughts and heavy floods. The main purpose of this study was to determine and compare the severity of changes in mean annual water balance for two humid climatic zones, in order to understand how different areas of similar climate characteristics react to climate change and to analyze the significance of their influence. Monthly weather data from two weather stations, Kaunas (Lithuania) and Sarajevo (Bosnia and Herzegovina), for the time period of 30 years (1988 - 2017) were used to determine and analyze the mean annual water balance. The results indicate that climate change has a different effect on the water balance of these two humid areas. Both locations showed a positive trend of reference evapotranspiration, with an increase of 1.450 mm year1 to 1.503 mm year1. However, the total runoff and soil moisture deficit are decreasing in Kaunas (-0.480 mm and -2.114 mm year1, respectively), while they are increasing in Sarajevo (0.492 mm and 0.485 mm year1, respectively)Vytauto Didžiojo universitetasŽemės ūkio akademij