Computational Modeling of the Circulation of the Southern California Bight

The coastal zone is defined here as spanning from the offshore continental slope to the shoreline as determined by averaging over the incoming waves. Its physical circulation phenomena include seasonal and interannual cycles, wind-driven currents, tides, mesoscale eddies (more offshore), submesoscale density fronts and filaments, topographic wakes, internal and inertial waves, surface waves and wave-driven littoral currents, and turbulent boundary layers near the surface and bottom. It is distinctive in many ways from the deeper sea, most conspicuously in its smaller, faster scales of evolution and the greater influence of the proximate bottom in shallow water. As such, it requires special modeling techniques.

The project task is to develop improvements to oceanic model simulations and demonstrate their consequences for realistic, fine-scale simulations at a variety of locations and time periods of interest throughout the Southern California Bight. Emphasis will be given to the nearshore zone and the continental shelf and slope, as well as around the islands. The model code framework is the Regional Oceanic Modeling System (ROMS) for the physical circulation, including its coupling to regional atmospheric and surface wave codes. The purposes of this project are to provide a better framework for interpreting the measurements in the region and to construct prototype capabilities for future operational models. The approach is to adjust the model formulation where measurements indicate deficiencies and to expand its scope by adding processes for greater completeness and realism; examples of the latter include current interactions with surface gravity waves and material transports between the nearshore region and the open ocean.

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Principal Investigator

• James C. McWilliams, UCLA (jcm@atmos.ucla.edu) 

Publications: