Near Inertial Waves Generated by Hurricane Arthur on the Mid-Atlantic-Bight Shelf

Near inertial waves (NIWs) associated with extreme wind events are important as they can generate significant vertical mixing. In contrast to the well-studied open ocean NIWs, the NIWs in the shallow coastal region, such as Mid-Atlantic-Bight (MAB) shelf area, are distinct as bottom stress and bathymetry slope may play important roles. In this study, we applied a coupled WRF-FVCOM model to study the NIWs associated with Hurricane Arthur (2014) on the MAB shelf. The model successfully reproduce the surface NIWs presented in the HF Radar data. In either the model or the observation, both the NIW strength and the NIW affected area decrease with time, vanishing after 3-5 days. As indicated by the kinetic energy budget equation, downward vertical propagation term is the primary sink for surface NIW energy. With the 3-d Version of FVCOM, we are able to study NIWs energy budget, including vertical propagation in detail, in this region. The model results indicate that most of the downward propagated NIW energy is transferred to the potential energy. In addition, mean flow vorticity is calculated and the scattering of NIW energy by vorticity ridge is observed in the model results.