Impact of the Gulf Stream on ocean waves

Surface wave propagation and the modulations of wave parametric and spectral properties over the Gulf Stream (GS) are studied using a high spatial resolution (1 km) wave model that considers an idealized GS. While simulation results are generally consistent with a previous modelling study, we found that for following-current (FC) cases, reflection from the GS substantially increases wave height on the offshore side of the GS center by up to 25%, and decreases wave height on the landward side of the GS by as much as 80%. In the counter-current (CC) cases, the wave height profile is more symmetrical relative to the GS centerline, and the maximum 33% increase of wave height is predominantly driven by straining. The GS also causes an increase (decrease) in wavelength and directional spreading in the FC (CC) case. Additional model sensitivity experiments that further consider realistic shelf-ocean topography show that current modulation and bottom dissipation work in concert as low- and high-pass filters on the wave frequency spectra. Wave parameters and spectral modulations imposed by the GS have significant impacts on ocean-atmosphere momentum flux and wave energy resource.