Ocean surface gravity waves can modulate the upper ocean circulation and vertical mixing through air‐sea interactions, wave breaking, Coriolis‐Stokes forcing, Langmuir turbulence and the grid resolved vortex force. However, the roles of these wave induced processes remain uncertain under hurricane conditions. This study examines the impact of these surface wave associated dynamics on the turbulent kinetic energy (TKE), thermal structure and currents in the upper ocean under idealized hurricane forcing using a coupled wave‐circulation model. Eight experiments were conducted with hurricanes moving at three translational speeds. The simulations include two fully coupled experiments and five additional coupled experiments in which wave effects are selectively disabled. All coupled experiments are compared with a baseline circulation simulation. Consistent with previous studies, our results indicate that Langmuir turbulence has the biggest impact on upper ocean currents, temperature and TKE during hurricanes. However, all considered wave effects contribute to vertical mixing and the two‐way fully coupled experiment differs the most from the baseline experiment. The combined wave effects reduce the surface currents by over 0.8 m/s in the front two quadrants of the slow hurricane and enhance the cold wake and near‐surface cooling by as much as 0.6°C, predominantly to the right of the storm track. The wave contributions to the cooling are inversely related to the hurricane translational speed, although their contributions to currents and TKE are correlated with hurricane translational speed. SST differences can alter the latent heat flux driving hurricanes, suggesting that wave dynamics should be included in hurricane forecast models.

We present a modified version of a coupled circulation–wave modelling system for the northwest Atlantic (CWMS-NWA) by including additional physics associated with wave–current interactions. The latest modifications include a parameterization of Langmuir turbulence and surface flux of turbulent kinetic energy from wave breaking in vertical mixing. The performance of the modified version of CWMS-NWA during Hurricane Arthur in 2014 is assessed using in situ measurements and satellite data. Several error statistics are used to evaluate the model performance, including correlation (R), root mean square error (RMSE), normalized model variance of model errors (${\gamma }^2$) and relative bias (RB). It is found that the simulated surface waves (R ≈ 94.0%, RMSE ≈ 27.5 cm, ${\gamma }^2\approx$ 0.16) and surface elevations (R ≈ 97.3%, RMSE ≈ 24.0 cm, ${\gamma }^2\approx$ 0.07) are in a good agreement with observations. The large-scale circulation, hydrography and associated storm-induced changes in the upper ocean during Arthur are reproduced satisfactorily by the modified version of CWMS-NWA. Relative to satellite observations of the daily averaged sea surface temperature (SST), the model reproduces large-scale features as demonstrated by the error metrics: R ≈ 97.8%, RMSE ≈ 1.6 °C and RB ≈ 8.6 $\times {10}^{-3}$°C.

Upper oceans are highly energetic during a severe weather event, with large surface waves and intense ocean currents over areas affected by the storm. An advanced and coupled wave–current modelling system for the northwestern Atlantic (WCMS-NWA) was developed by the Regional Modelling Group at Dalhousie University for simulating surface waves and three-dimensional ocean currents over the eastern Canadian shelf and adjacent waters. Applications of this modelling system during different weather events have been discussed separately in the past. In this overview, the model performances of WCMS-NWA and major hydrodynamics over the study region during 11 severe storms are summarized. Comparisons of model results with in situ oceanographic observations and satellite data demonstrate the suitability and accuracy of WCMS-NWA in simulating ocean circulation and surface waves during normal weather conditions and intense ocean currents and extreme surface waves during severe storm events. It is shown that satisfactory model performance of WCMS-NWA requires reliable temporal–spatial representations of atmospheric forcing and inclusions of interactions between waves and currents (WCIs). Important contributions from WCIs during these severe weather conditions are discussed based on the model results.