Journal Information

Online ISSN: 1520-0485
Print ISSN: 0022-3670
Publishing Frequency: Monthly

Volume 42, Issue 1 (January 2012)

Modeling Semidiurnal Internal Tide Variability in the Southern California Bight

M. C. Buijsman,*Y. Uchiyama, J. C. McWilliams, and C. R. Hill-Lindsay

Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, California


The Regional Oceanic Modeling System (ROMS) is applied in a nested configuration with realistic forcing to the Southern California Bight (SCB) to analyze the variability in semidiurnal internal wave generation and propagation. The SCB has a complex topography with supercritical slopes that generate linear internal waves at the forcing frequency. The model predicts the observed barotropic and baroclinic tides reasonably well, although the observed baroclinic tides feature slightly larger amplitudes. The strongest semidiurnal barotropic to baroclinic energy conversion occurs on a steep sill slope of the 1900-m-deep Santa Cruz Basin. This causes a forced, near-resonant, semidiurnal Poincaré wave that rotates clockwise in the basin and is of the first mode along the radial, azimuthal, and vertical directions. The associated tidal-mean, depth-integrated energy fluxes and isotherm oscillation amplitudes in the basin reach maximum values of about 5 kW m−1 and 100 m and are strongly modulated by the spring–neap cycle. Most energy is locally dissipated, and only 10% escapes the basin. The baroclinic energy in the remaining basins is orders of magnitudes smaller. High-resolution coastal models are important in locating overlooked mixing hotspots such as the Santa Cruz Basin. These mixing hotspots may be important for ocean mixing and the overturning circulation.

Keywords: Tides, Ocean circulation, Currents

Received: October 7, 2010; Accepted: July 23, 2011

* Current affiliation: Atmospheric and Oceanic Sciences Program, Princeton University, Princeton, New Jersey.

Corresponding author address: M. C. Buijsman, Geophysical Fluid Dynamics Laboratory, 201 Forrestal Road, Princeton, NJ 08540-6649. E-mail: