| Traditionally, it has been viewed that tides dissipate 2.6 TW over the continental shelves via the shallow bottom boundary layer, and have little impact on deep ocean mixing (Munk & Wunsch, 1998). Through their tidal maps, Egbert & Ray (2001) have confirmed that while most energy is lost in the shallow sea, nearly 1 TW is lost in the deep ocean (Garrett, 2003). Internal tides may provide the mechanism to bring power to mix the deep ocean (Garrett, 2003). However, the exact amounts dissipated in the shallow coastal regional and deep ocean remain in question.; Understanding the evolution of the internal tide field within the complex coastal ocean is essential to describing the interplay between bathymetry, internal tides, and areas of elevated dissipation. In an effort to gain insight into internal tide energetics within Monterey Bay, we used high-resolution numerical simulation results from the nonhydrostatic, nonlinear, unstructured grid code SUNTANS (Fringer et al., 2006). Energy flux results show the bulk of internal tide energy propagating into the Monterey Submarine Canyon from a location north of Sur Ridge, while energy flux divergences show regions of internal tide generation and dissipation. Integrating over the domain results in net a power of about +52 MW available for pelagic mixing. With a picture of average internal tide energetics completed, three-dimensional time-dependent results show the rich structure of the internal tide. A region of elevated internal tide kinetic energy north of Sur Platform is observed, which is a result of internal tidal surfaces, that are generated from Sur Platform and the shelf break, interacting with one another. Linear internal tidal surfaces result from a low tidal Froude number flow interacting with bathymetry that is critical with respect to the semidiurnal tides. An appendix is included that investigates the effect of eddy viscosity choices on energetics and to assesses the role of nonhydrostatic pressure. Results show that lower viscosities result in somewhat greater baroclinic energy fluxes, but the domain power remains essentially the same as when larger eddy viscosities are used. The nonhydrostatic pressure plays a minimal role; effects are restricted to Monterey Submarine Canyon. |
