Spatiotemporal Dynamics of Rainfall and Temperature Extreme Indices over Ethiopia, East Africa

Abstract

Climate extremes have become increasingly frequent and intense under a changing climate, posing significant challenges to water resources, agriculture, ecosystems, and socioeconomic development. Ethiopia is particularly vulnerable due to its strong dependence on rain-fed agriculture and its diverse climatic and topographic conditions. This study assessed the spatiotemporal dynamics of extreme climate indices across Ethiopia using the Expert Team on Climate Change Detection and Indices (ETCCDI) for the period 1981–2022. Daily rainfall and temperature Grid data were analyzed to quantify trends, climatology, anomaly, variability, and spatial distributions of precipitation and temperature extremes. Rainfall and temperature indices were evaluated using mannkandell and sen’slope test, trend analysis and spatial interpolation techniques, and python tool used for plotting the figures. The results revealed considerable spatial and temporal variability in both precipitation and temperature extremes across Ethiopia. Temperature-related indices showed widespread warming, characterized by increasing frequencies of warm days and warm nights and declining occurrences of cool days and cold nights. Annual extreme maximum and minimum temperatures generally increased over most regions, indicating intensifying heat extremes. Rainfall extremes exhibited substantial regional heterogeneity, with increases in heavy rainfall intensity and extreme precipitation in some parts of western and southwestern Ethiopia, while other regions experienced longer dry spells and declining rainfall totals. These contrasting patterns suggest increasing risks of both floods and droughts depending on location. Overall, the findings demonstrate that Ethiopia has experienced significant changes in climate extremes during 1981–2022, with warming trends being more spatially consistent than changes in precipitation extremes. The study provides valuable information for climate change adaptation, disaster risk reduction, agricultural planning, and sustainable water resource management, while contributing to the understanding of regional climate variability in Ethiopia.