Generation and Propagation of Internal Waves in a Network of Fjords

A three-dimensional, unstructured grid numerical coastal ocean model (FVCOM) is used to simulate the tidal circulation in a complex network of interconnected fjords located along the northern coast of British Columbia, Canada. In particular, we examine the flow over two sills, the first located at the intersection of Verney Passage and Ursula Channel and a second located at the intersection of Devastation Channel and Gardiner Canal. The model accuracy is assessed using ADCP and MVP observations collected during cruises in 2014 and 2015. Results show that the model is able to simulate the internal waves generated as a baroclinic response to tidal outflow over the sill located at the intersection of Verney Passage and Ursula Channel. Analysis of the densimetric Froude number yields a peak value of F₁≈1.5 at the crest of the sill which is consistent with the presence of a hydraulic jump. Internal waves are also generated at the sill located at the intersection of Devastation Channel and Gardiner Canal. The generation and propagation of internal waves at the sills are further examined for different conditions representative of the spring, summer, and fall conditions.