The Seasonal Cycle of Significant Wave Height in the Ocean: Local Versus Remote Forcing

Significant wave height (SWH) stems from a combination of locally generated “wind-sea” and remotely “swell” waves. In the Northern Southern Hemispheres, heights typically undergo sinusoidal annual cycle, with larger SWH in winter response to seasonal changes high-latitude storm patterns that generate equatorward propagating swell. However, some locations deviate this hemispheric-scale pattern SWH. For example, California coastal region, local wind events occur boreal spring summer, leading speed (WSP) cycle distinct maximum corresponding Here ocean regions WSP reaching late spring, or early fall are designated as anomaly (SWARs). Intra-annual variability surface gravity waves is analyzed globally using two decades satellite-derived data. The phasing used metric identify SWARs. Global maps probability swell based on age confirm during summer months, forced statistically more likely SWARs than surrounding regions. magnitude deviation determined by exposure characteristics field within region. Local winds have identifiable impact Hemisphere due seasonality winds.