Changes in water balance, drought and aridity over Romania since 1901

Drought assessment in Romania since 1961 is well documented. However, studies coveringing longer time intervals in the region are scarce, and employ either modeled or sparse observational data. This study presents a 123-year analysis of water balance, drought and aridity over Romania using monthly, homogenized data from 156 meteorological stations belonging to the RoCliHom dataset. Drought is analyzed by means of two well known indices, namely the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI). Changes in aridity are investigated with the De Martonne Aridity Index. The non-parametric Mann-Kendall test is used for trend detection – which allows a direct comparison with the vast majority of studies on aridity and drought over the Romanian territory. Trend magnitude is computed with Sen's slope estimator (also known as Kendall-Theil robust line).