ABSTRACT The study focuses on rainfall variability within Ghana's agroecological zones, employing varied techniques including spatial autocorrelation, GARCH family volatility models, vector autoregression, impulse response functions, and extreme rainfall analysis. The mean result of Moran's I (−0.317) indicates negative spatial autocorrelation. This means that extremes in rainfall are highly localised because only 1.04% of considered periods showed significant clustering. Volatility modelling reveals zones as separate regimes: highly persistent shocks in the Sudan and Guinea Savanna zones ( β 1 ≈0.97), asymmetric drought sensitivity in the Deciduous Forest under the E‐GARCH ( α 1 ≈ −0.206), and event‐driven volatility in the Transitional Zone. Weak correlations between the savannas and the forest zones are found within the VAR analysis, which suggests correlations lagged in time within defined zones. The forest zone leads rainfall over the Guinea and Sudan Savannas 2–3 days later. IRF results indicate systematic moisture‐carrying flows operating at 1–2‐day intervals, with sustained northward cross‐border zonal responses lasting over 20 days. Criteria for extreme rainfall show a strong north–south gradient, with the transitional zone containing the most intense events (95th percentile = 25.3 mm; 99th = 53.5 mm) and the deciduous forest enduring persistent droughts. The results of this study exemplify the fragmentation of rainfall regimes and their ecological volatility with a specific focus on the negative impacts of unadopted volatility. This study serves as a clarion call for zonal‐specific measures to safeguard agriculture, water, climate adaptability and resilience.
Agyarko et al. (2026) studied this question.