Spatio-temporal dynamics and agricultural implications of dry spells in the White Volta Basin, Ghana (1990–2024)

ABSTRACT Agriculture in the White Volta Basin (WVB) of Ghana is predominantly rain-fed and has a high vulnerability to variations in climate. Dry spell occurrence within the WVB poses a significant threat to agriculture. This study examines the spatial and temporal dynamics of dry spells in the WVB using daily rainfall data from 1990 to 2024. The approach included the characterization of dry spells using different thresholds (7-day, 15-day and 20-day) to understand the occurrence, duration and distribution of dry spells throughout the growing season of the WVB. The results revealed different temporal trends and patterns, with May and October having significantly higher occurrences and durations of dry spells. The spatial analysis identified the Upper East region as consistent with severe and extreme cases of dry spells. The highest length of dry spell for each grid within the WVB exceeds 20 days, with some areas recording close to 2 months. This prolonged spell of dryness suggests a significant risk to productivity in agriculture. The understanding gathered enables stakeholders to develop adaptation strategies that are targeted to hotspot areas. Stakeholders can allocate resources, adjust cropping patterns and seek early warnings to reduce the risk associated with food security.