Spatial and temporal drought patterns in Ethiopia: integrating ground and remote sensing data for comprehensive assessment

Ethiopia’s river basins are increasingly exposed to drought due to climate variability and atmospheric teleconnections. This study presents a comprehensive drought assessment (1986–2023) across eight major basins using a multi-source validation framework that integrates ground-based observations from the Ethiopian Meteorological Institute and Ministry of Water and Energy, satellite data from TerraClimate, and reanalysis products from the European Centre for Medium-Range Weather Forecasts. Standardized indices – including the Standardized Precipitation Index, Standardized Evapotranspiration Index, and Standardized Streamflow Index – combined with statistical methods such as the Mann–Kendall test, Sen’s Slope estimator, and Inverse Distance Weighting interpolation, reveal rising drought severity, especially in the Abay, Awash, and Wabi Shebelle basins. Strong correlations (r > 0.85) between the Enhanced Moisture Index and European Centre for Medium-Range Weather Forecasts data support the robustness of observed drought trends, while TerraClimate tends to underestimate severity. Teleconnection analysis highlights the influence of the El Niño-Southern Oscillation and Indian Ocean Dipole, explaining over 40 improved precipitation accuracy, reducing root-mean-square error below 15 underscores the value of hybrid modeling and expanded ground networks for drought monitoring and recommends Intergovernmental Panel on Climate Change-aligned strategies to reduce vulnerability.