Satellite-based drought assessment in major Sudan’s mechanized rain-fed agriculture

Abstract

Climate change-induced drought poses a significant threat to global food security, particularly in agriculture-dependent nations like Sudan, where over 90% of agricultural land is rain-fed. This study provides a comprehensive, long-term spatiotemporal assessment of drought conditions in Sudan’s major mechanized rain-fed agricultural areas from 2000 to 2024. Using the Google Earth Engine (GEE) platform, we analyzed time-series data from Moderate Resolution Imaging Spectroradiometer (MODIS) to compute multiple satellite-derived indices: Normalized Difference Vegetation Index (NDVI), Temperature Condition Index (TCI), Vegetation Condition Index (VCI), and Vegetation Health Index (VHI) alongside ground-based Standardized Precipitation Index (SPI) data. The analysis reveals a clear pattern of severe to extreme drought events from 2000 to 2016 with significant peaks in 2000, 2002, 2009 and 2013 followed by a sustained recovery in 2017 marked by a decline in drought intensity and an increase in vegetation, and culminated in the most favorable conditions by 2024. Spatial analysis shows that northern and central regions (e.g., Al Gadarif and White Nile) were more drought-prone, whereas southern and irrigated zones demonstrated greater resilience. Correlation analysis results indicate that VHI provides a more comprehensive representation of agricultural drought conditions compared to single-variable indices, owing to its ability to integrate vegetation and temperature stress in the former than latter. Crop analysis revealed that cotton and sesame were sensitive to heat stress, while sorghum was heat stress resilient. These findings underscore the urgent need for data-driven, region-specific strategies to strengthen agricultural resilience in Sudan and comparable semi-arid regions.