Barotropic tidal dynamics in a frictional subsidiary channel

- The barotropic M2 tidal dynamics are studied in Kyuquot Sound, Canada.
- Analytical model from FVCOM results to describe subsidiary channel dynamics.
- Dynamics in subsidiary channels are sensitive to viscous parameterizations.
- Increasing the lateral viscosity decreases the dissipation.
- Numerical model validation using only pressure gauges may not be sufficient.

Barotropic M2 tidal dynamics are studied in a subsidiary tidal channel in Kyuquot Sound, Canada, a site proposed for multi-trophic aquaculture. A regional model with no stratification or forcing other than the tide found that the sea level in the subsidiary channel responded in phase with the rest of Kyuquot Sound, but that the velocity response was almost 180° out of phase. Further, this velocity difference was strongly dependent on the choice of viscous parameterization in the model. A simple linear analytical model was developed to explain the simulated changes in terms of the phase lag induced by viscosity, and allowed a larger parameter regime to be explored. These results suggest that verifying models of smaller channels using sea level measurements alone is inadequate, and velocity measurements are necessary.