Spatial distribution and long-term changes in water balance components in Croatia

Abstract

Drought causes great damage to the economy and agriculture in Croatia. Therefore, it is important to gain a better insight into the spatial distribution of water balance components (precipitation (P), potential evapotranspiration (PET), actual evapotranspiration (ET), soil moisture content (S), runoff (RO), recharge (R), and soil moisture loss (L)) and their long-term changes in Croatia. Since measurements of the mentioned components in Croatia are very rare, the Palmer model has been applied to estimate them. The meteorological data from 82 stations have been used in the period 1981–2010. To determine the climate variations long-term trends in water balance components have been analyzed in the period 1901–2017. The PET and ET linear trends in the last decades show a faster growth than in the long-term trends, and the increase in PET (50–80 mm/decade) is significant in most of Croatia, except in the eastern part (27 mm/decade). The results of the mean annual PET and ET spatial distribution revealed that the maximum PET is estimated in the mid-Adriatic area of about 1500 mm, but the lack of precipitation caused the ET (about 700 mm) to be insignificantly different from the values in other parts of Croatia. The analyzed meteorological data from the period 1981–2010 indicated a higher air temperature and lower precipitation amount than in the reference climatic period of 1961–1990. This reduces the ET in areas with insufficient precipitation, i.e., on the Adriatic coast and in the eastern part of Croatia, where an increasing soil moisture deficit during the vegetation period can have a potentially negative effect on agricultural production.