Impacts of topography on wave-current interactions during Hurricane Arthur

During hurricanes and other extreme weather events, wave-current interactions are important over shelf and coastal waters. A state-of-the-art circulation-wave modelling system with parameterizations of Langmuir turbulence (LT) and wave breaking (WB) is used in this study to examine wave-current interactions during Hurricane Arthur (2014). Unlike previous studies, the effects of local topography on wave-current interactions are investigated during Hurricane Arthur. In particular, we focused on the dynamics within the Gulf of Maine and Gulf of St. Lawrence. The significant wave heights, vertical mixing and near-inertial currents all have highly asymmetric spatial distributions due to the proximity of the storm track to the coastline, which limits the fetch. Both LT and WB alter the storm-induced changes to the temperature and circulation in our results. Due to LT, the cold wake over the Mid-Atlantic Bight is enhanced by 0.5 °C. There is also clear LT-enhanced cooling over the area between the Gulf of Maine and the Scotian Shelf. However, the LT-enhanced cooling in the Gulf of St. Lawrence is mostly a cumulative effect from earlier storms. In the Mid-Atlantic Bight, WB increases horizontal advection. WB affects the momentum and cooling in the Gulf of Maine and Scotian Shelf asymmetrically, with larger impacts to the right of the storm track. WB also enhances the surface cooling in the southern part of the Gulf of St. Lawrence. Both LT and WB have a much bigger impact on the upper-ocean dynamics than the wave-induced bottom boundary layer and conservative Stokes drift effects.