Potential climate change impacts on water balance in Slovenia

Abstract

The latest climate change projections increasingly indicate the changing of soil water balance, which is then reflected back in climate change. This paper examines soil moisture availability time dynamics in Ljubljana and Murska Sobota in the last 46 years and under climate change scenarios for these locations through the end of the century. The basis was a thirty-year period 1961-1990 serving as a comparison with the period 1991-2006 and with projections of climate changes under three scenarios, presented in the form of incremental temperature and precipitation changes as a combination of alternative projections for Slovenia. Using the SIMPEL model, we determined variability of potential evapotranspiration (the EPIC Penman-Monteith method), water deficit (difference between the volume of precipitation and potential evapotranspiration) and the number of dry days. The analysis showed growing trends for all three variables in the period 1961-2006. Another subject of observation was variability change which is evident above all in the number of dry days and increases the risk of drought. The main results are presented by means of calculations of probability for the occurrence of a certain number of dry days. The probability of over 35 dry days in the vegetation period (April-September) of the second analysed period, under the medium and increasingly so high climate change scenario is much higher than such a probability in the first analysed period and under the low scenario.