Spatio-Temporal Trends in Precipitation Indices Over Mediterranean Using ERA5-Land Data (1950–2024)

Abstract

The Mediterranean region is a climate hotspot, where precipitation patterns play a crucial role in the hydrological cycle, influencing water resources, agriculture, and socio-economic aspects. This study aims to analyse the long-term trends in precipitation indices over the Mediterranean using the high-resolution ERA5-Land dataset from 1950 to 2024. A suite of precipitation indices was calculated, including frequency, intensity, and persistence metrics, to provide a comprehensive assessment of the region's precipitation dynamics. The Mann-Kendall test and Sen's slope estimator were employed to detect and quantify statistically significant trends. Notably, our analysis indicates that heavy precipitation days (R10 mm) decreased by approximately 2 days per decade in the western Mediterranean while increasing by about 0.5 days per decade in the northeastern Mediterranean. In addition, total annual precipitation (PRCPTOT) showed declines of up to 60 mm per decade in specific areas, and the maximum one-day precipitation (Rx1day) increased by up to 3 mm per decade in localised regions. This study contributes to the growing body of literature on the impacts of climate change on precipitation patterns, particularly in the context of the Mediterranean, a region known for its sensitivity to environmental shifts.