An Exploration of the Vertical Distribution of Mixing in a Submarine Canyon

Ocean mixing is a vital process that supports the global overturning circulation and biogeochemical processes. Despite this importance, significant questions remain about the underlying processes and the vertical distribution of mixing. Here, we consider the dissipation due to internal tides (internal waves at the tidal frequency) interacting with a submarine canyon, which has previously been shown to be a hotspot for mixing. Using both observations and a high-resolution simulation of the Eel Canyon-Mendocino Ridge system, we examine the magnitude of and processes that support internal wave-driven mixing over the region. We have found that the simulations match well with observations, suggesting that the internal tides present in the model are the primary driver of observed dissipation. Given the agreement between the observations and model, we have additionally used the model to understand the dynamics of the internal tides, and subsequent dissipation, at the edges of the canyon, as well as the vertical extent of mixing throughout the canyon. Our developing understanding of the processes by which the internal tides deposit their energy to mixing, as well as the vertical structure of this mixing, will inform future parameterizations of mixing in next-generation ocean models.