Spatial and temporal variability of Aridity Index in lowland areas of Slovakia

Abstract

Changes in precipitation and temperature caused by global warming are reasons for the increasing occurrence of hydrological extremes such as floods or droughts. The aridity index is a significant indicator of local climate changes and is often used for quantifying the long-term climate conditions of a given location. In addition, the values of the aridity index are indicators of the water conditions of the area and their potential tendency to change in humidity. Therefore, understanding the spatio-temporal patterns of the aridity index is a crucial goal for agricultural and water management of watersheds. This research investigates the spatial and temporal variations of the aridity indices at 27 climatological stations situated in the lowland areas of Slovakia. The stations were divided into three main lowland areas according to their spatial location. The United Nations Environmental Program (UNEP) method was used, and 40 years climatological measurements data from the Slovak Hydrometeorological Institute (SHMI) was considered for calculating the monthly and yearly mean values of the aridity index and assessing its spatial and temporal patterns. Trends in the monthly and yearly spatial mean values of the aridity index showed significant variability between selected areas. The annual mean of the aridity index of stations situated in the Juhoslovenská kotlina lowland indicates increasing trends in the aridity index in winter months and in July. In the case of other lowlands, there were no trends in the monthly and yearly values. Other significant differences were observed in the seasonal variability of the mean monthly values of the aridity index in selected areas.