Numerical Simulations and Observations of the Internal Tide in a Submarine Canyon

Observations and model simulations of internal waves in and around the Monterey Canyon are described here with particular focus on the internal tide generated through interaction of the basin-scale barotropic tide and local topography. Observations reveal strong internal tides along the axis of the Canyon near the Canyon head. Currents are intensified near the bottom and observed to have both onshore-propagating and standing configurations at different times and stratification conditions. Bottom-mounted ADCP observations from within the Canyon axis in depths around 300 m confirm bottom intensified fluctuations throughout the internal wave band. Furthermore, strongly nonlinear fronts or bores are associated with the tidal-band fluctuations. Numerical simulations forced by semidiurnal sea level fluctuations offshore using both idealized and realistic representations of the local topography are used to investigate internal tide generation and propagation in the coastal zone. Canyons with near-critical bottom slopes play a role in bottom intensification, while the actual complex topography leads to significant horizontal variations in the internal wave characteristics on scales of less than 10 km.