Predictability

Multimodal seas, comprising independent wave systems of distinct origins, produce a complex wave climate with strong spatial variations around the Pacific Islands. The El Niño-Southern Oscillation (ENSO) significantly affects ocean conditions and weathers across the Pacific. In-depth understanding of localized ENSO impacts on ocean waves around islands, like Hawaii, is lacking. Here we analyzed 41-year of high-resolution model wave data to understand how ENSO influences wave patterns across the Hawaiian Islands. The north and west-facing shores exposed to northwest swells experience the largest interannual variation, with increases in amplitude and frequency of large events during El Niño winters. While the trade wind waves show moderate correlation with ENSO, seas mainly driven by local winds, show little variation between El Niño and La Niña phases. These findings underscore the importance of high-resolution wave data in revealing various levels of ENSO influence from shore to shore. Based on the ENSO-wave connection, we develop a semi-empirical model to reconstruct seasonal wave statistics as a function of the ENSO index with promising results for regions experiencing hazardous winter swells. The semi-empirical wave model can predict severe wave conditions seasons in advance to improve coastal safety and help inform decision-making for coastal management.

Mar 26, 2025