Multi-index assessment of meteorological drought in Ethiopia's Borana and Guji zones

Abstract

ABSTRACT Extreme drought events have significantly impacted Ethiopia, especially in the Borena and Guji zones. However, studies examining their spatial and temporal features are still limited. This research evaluates meteorological drought in these areas using climate data and remote sensing indices to support the early warning and adaptation efforts. Ground-based indices, such as standardized precipitation index (SPI), were combined with remote sensing indices, including the normalized difference vegetation index (NDVI), vegetation condition index (VCI), and land surface temperature. Multitemporal satellite data from Landsat 5, 7, and 8 were analyzed, Climate-based index was generated using R programming, and satellite imageries were processed using Earth Resources Data Analysis System (ERDAS) 2015 software. The analysis revealed severe drought events, with SPI values reaching −3.32 in spring, −2.71 in autumn, and −3.8 annually during 2000, 2017, and 2020. NDVI values decreased from 0.77 in 1990 to 0.57 in 2020, demonstrating significant vegetation stress. A strong correlation (r = 0.872) between NDVI and SPI underscores the connection between precipitation vegetation conditions. By combining climate-based and remote sensing indices, this study offers valuable insights into drought dynamics and their impacts on vegetation. The result can inform targeted adaptation strategies, enhance early warning systems, and support sustainable resource management in Ethiopia's drought prone regions.