Spatio-Temporal Analysis of Rainfall Patterns in Guinea and Sudano-Sahelian Agro-Ecological Zones of Nigeria.

Abstract

globally, with critical implications for regional rainfall patterns. This study evaluates long-term (1982–2021) spatio-temporal rainfall trends in Nigeria’s Guinea and Sudano-Sahelian agro-ecological zones using satellite-derived reanalysis datasets. Applying the Mann-Kendall test, Theil-Sen’s slope estimator, linear regression, and inverse distance weighting interpolation, we quantified trends, magnitudes, and spatial distributions of rainfall trend. Results reveal a non-significant decreasing trend (−1.9 mm/year; p > 0.05) in the Guinea Savannah, alongside low interannual variability (3%), signalling a gradual aridification that may threaten rain-fed agriculture and freshwater availability in this densely populated zone. In contrast, the Sudano-Sahelian region shows non-significant increases of 0.78 mm/year (Sudan Savannah) and 1.2 mm/year (Sahel Savannah), with 0.9% and 3.1% variability, respectively, suggesting a potential shift toward marginally wetter conditions. These contrasting trends underscore the potential implications for agricultural productivity, water resource availability, and ecosystem resilience in these regions. Specifically, the decreasing trend in the Guinea Savannah may exacerbate water scarcity and soil degradation, necessitating adaptive strategies such as improved irrigation systems and drought-resistant crop varieties. Conversely, the increasing trend in the Sudano-Sahelian zones could lead to heightened flood risks and land-use challenges, requiring enhanced flood management practices and sustainable land planning. Proactive measures, including sustainable land management, water conservation strategies, and policy interventions aimed at reducing greenhouse gas emissions, are essential to mitigate the adverse impacts of these climatic shifts.