GIS and Remote Sensing Based Meteorological Drought Risk Assessment:

the case of East Hararge Zone, Oromia, Ethiopia

Abstract

Ethiopia, located in the Horn of Africa, is one of the sub-Saharan countries highly prone to drought hazards. Drought is a water-related natural disaster that impacts a wide range of environmental factors. It is primarily a climatic phenomenon that cannot be fully eradicated. The study sought to identifies the occurrence of meteorological drought in the study area by using geospatial tools. It examined the spatial and temporal meteorological drought patterns of the study areas using different appropriate meteorological drought indices and identified the most drought-vulnerable areas using geospatial data and modeling techniques in the drought- prone East Hararge Zone of Ethiopia. To assess the spatiotemporal variation of seasonal drought patterns and severity, four drought indices Normalized Difference Vegetation Index (NDVI), Vegetation condition index (VCI), Standard precipitation index (SPI) and Drought severity index (DSI) were applied. MODIS NDVI data and monthly rainfall data from 2012 to 2022 were used as input data, while crop yield data served as ground truth for validating the strength of the drought indices. To validate the drought indices, correlation and regression analyses were conducted between NDVI and rainfall (r = 0.76), NDVI and crop yield (r = 0.74), and VCI and SPI (r = 0.78). The results of this study showed that the region experienced extreme drought in 2016, 2017, 2018, and 2022. The findings indicate that the study area is highly prone to drought, although the severity levels varied across these years. A result map was generated based on the frequency maps of the four indices. The map revealed that 35%, 49.1%, and 13.8% of the total area of the zone were classified as severely, moderately, and mildly vulnerable to drought, respectively. This result map can be valuable for decision makers and policymakers in developing pre and post drought risk management plans.