Abstract
In most hydrodynamic model studies, currents and waves are simulated separately. This is especially true for the simulation of passive drifters, whose trajectories are often computed based solely on currents. Although this simplification holds for most situations, as the force exerted by waves on currents can be neglected in fair weather conditions, it may lead to significant errors in storm conditions, during which local currents are strongly influenced by wind-generated waves. In this study,current-wave interactions in heavy-wind conditions are studied by coupling the unstructured-mesh hydrodynamic model SLIM with the wave model SWAN in the Florida Reef Tract during Hurricane Irma (Sep. 2017). This coupled model successfully reproduced both the observed wave behavior and storm surge during the hurricane. The modeled currents were then used to simulate the trajectories of passive drifters during the passage of the hurricane. Our results show that taking wave force into account induces variations of up 1 m/s in modelled currents on the continental shelf break as well as in the vicinity of reefs and islands. Wave-current interactions can therefore strongly modify the transport of drifting material, such as sediments and coral larvae, during heavy-wind events. That should in particular affect connectivity modeling studies since coral mass spawning events tend to occur during the hurricane season in the Caribbean.