Comprehensive analysis of extreme wave events along the West African Coast: a study using WAVERYS data and peak over threshold (pot) method

Extreme waves pose severe threats to coastal infrastructure and communities, yet their long-term patterns and risks remain understudied in vulnerable regions. Here, we present a comprehensive 30-year analysis (1992–2022) of extreme wave events along the West African coast, leveraging high-resolution WAVERYS significant wave height (Hs) data. Focusing on four critical coastal zones; Ivory Coast, Ghana, Togo/Benin, and Nigeria, we employed the Peaks Over Threshold method and Generalized Pareto Distribution to model exceedances above the 99th percentile Hs threshold. Our analysis revealed 113 extreme events in Ivory Coast, 102 in Ghana, 105 in Togo/Benin, and 114 in Nigeria, with Hs (duration) reaching 3.18 m (87 hours), 3.04 m (48 hours), 3.22 m (57 hours), and 3.04 m (126 hours) extremes, respectively. Notably, we identified a strong correlation between extreme Hs magnitudes and prolonged durations, suggesting compounding hazards for coastal systems. Our derived 100-year return level maps provide unprecedented spatial risk quantification, highlighting regions most susceptible to severe wave impacts. These findings advance the predictive understanding of extreme wave climatology in West Africa and offer actionable insights for resilient coastal engineering, disaster preparedness, and climate adaptation policies.