Aridity conditions within the region of Oltenia (Romania) from 1961 to 2015

Abstract

Aridity and drought assessment at a global level or within particular regions has lately gained an importance on the background of global warming, variability of rainfall amounts and, of course, their impact on social welfare. Aiming at understanding this impact, there were analysed spatial distribution (based on the data from 15 meteorological stations, generally covering the period 1961–2015) and temporal variability of three aridity indices. Thus, there were calculated De Martonne aridity index (IDM) at annual, seasonal and monthly level, Pinna combinative index (Ip) and Selyaninov’s hydrothermal coefficient (HTC). Ip indicates humid conditions all over the analysed area, with slight differences within the extra-Carpathian region, confirming thus that it does not give relevant results for the temperate region. IaDM illustrates a greater territorial differentiation, namely semi-humid conditions in the plain area and in the eastern part of the entire region, humid and very humid conditions in the Subcarpathians and the mountains. At monthly level, there are up to 5 months (in the plain area) with semiarid conditions, generally covering the summer period, as well as September and October. The same monthly pattern is highlighted by HTC, especially in the summer months, which are moderately or slightly arid, mainly in the plain area. However, if analysing the long-term trends (for IaDM), it results that there is not a statistically significant tendency of aridization in the analysed region.