Presenter: Alfredo Aretxabaleta (US Geological Survey)

Description:
Ocean wave properties are modified by strong oceanic currents causing variations in wave characteristics. However, wave conditions are usually estimated using wave models that do not include the effects of wave-current interactions and our understanding of historical and future wave conditions is likely affected by this omission. In this study, we analyzed archived model solutions from the coupled ocean-wave model COAWST along the United States East Coast and Gulf of Mexico. Average wave conditions showed enhanced significant wave heights along the path of the Gulf Stream, in the Gulf of Maine, and over Georges Bank. These regions feature strong western-boundary and tidal currents. Average wave heights were highest in the deeper areas of the northeastern part of the domain and decreased in shallow regions and in areas partially sheltered from open-ocean wave propagation (e.g., Gulf of Mexico). The highest wave height variability were in the northern part of the domain (associated with stronger winds) and extended west to the Gulf of Maine and Mid-Atlantic Bight (MAB) and south along the path of the Gulf Stream. Average wave periods were not as affected by strong currents and exhibited larger values in open-ocean areas connected to the central North Atlantic. Wave period variability was highest along the shelf-break in the South Atlantic Bight (SAB) and MAB and not directly affected by the currents. Average mean wave direction was strongly affected by the Gulf Stream (mean wave directions changing > 45 deg). Wave direction variability was highest in the Gulf of Mexico and in the shallow northern parts of the SAB and MAB. Extreme wave heights (95 percentile) similarly exhibited enhancement by strong currents and also the effects of intense events such as hurricanes. This study demonstrates the importance of including the wave variability induced by wave-current interaction for climatological studies of not only average wave conditions, but also extreme sea states.