Multi-decadal drought variability and regime dynamics in Darfur, Sudan (1981–2025)

Abstract

Understanding drought dynamics in arid and semi-arid regions is essential for climate adaptation and sustainable resource management. This study assessed multi-decadal drought variability in Darfur, western Sudan, from 1981 to 2025 using the Standardized Precipitation–Evapotranspiration Index at a 12-month timescale (SPEI-12). Monthly precipitation and temperature records from North, West, and South Darfur were analysed using piecewise linear regression, Bayesian Information Criterion (BIC)-based breakpoint detection, and Breaks for Additive Seasonal and Trend (BFAST) analysis. A precipitation–temperature proxy was used for climatic water balance because potential evapotranspiration data were unavailable. Results revealed statistically significant positive SPEI-12 trends across all regions, indicating a gradual reduction in cumulative drought severity. West Darfur exhibited the strongest trend (0.0463 yr⁻¹; R² = 0.356), followed by South Darfur (0.0407 yr⁻¹; R² = 0.277), whereas North Darfur showed a weaker trend (0.0198 yr⁻¹; R² = 0.065) and greater interannual variability. Although piecewise regression detected no long-term structural breaks, BFAST identified episodic climatic transitions. Severe drought events persisted, particularly during the early 1980s and in recent years. Overall, drought evolution in Darfur is consistent with the broader post-1990s Sahelian hydroclimatic recovery while exhibiting pronounced spatial heterogeneity, providing a basis for drought monitoring and climate adaptation in arid environments.