Southern-latitude wind forcing as a predictor of swell energy and coastal wave power in Peru

Abstract

The Peruvian coast is strongly influenced by remotely generated swells from the Southern Ocean. Understanding the relationship between wind stress forcing at southern latitudes and wave power variability in Peru is critical for coastal management, hazard prevention, and renewable energy planning. This study examines wind stress anomalies at 30°S, 40°S, 50°S, and 60°S and their influence on wave power off Paita, Callao, and Ilo using ERA5 reanalysis data (1979–2023). Wave power was computed from significant wave height and energy period, applying cross-correlation, wavelet coherence, and spectral decomposition. Wind stress anomalies at 50°S and 60°S explain 45–55% of the variance in wave power, with lags of 5–7 days depending on location. Interannual variability is linked to ENSO, while decadal oscillations are modulated by the Southern Annular Mode (SAM). These findings highlight the key role of Southern Ocean wind stress in controlling swell energy reaching Peru, providing predictive capacity for extreme events and strategies for coastal management and renewable wave energy.