An ocean circulation model with surface wave parameterization

Breaking waves are considered an important source of turbulent energy, supplementing to shear production. Breaking waves also play an important role in development of thermo-dynamical and turbulent structures in the ocean. No circulation models presently used take the wind-wave-current-turbulence relationship into account. To improve understanding and prediction, an ocean circulation model with a surface wave parameterization is developed taking wind-wave-turbulence-current interaction into account. This model is called the NAM ocean model. Important features of NAM include a true coupling to wave prediction models and a numerical grid generation (multi-block) technique.The pivotal-condensation method is stable, simple and has rapid convergence. The method is especially effective for ocean modeling when primitive equations for momentum, temperature, salinity, turbulence kinetic energy, and turbulent dissipation are solved with the same procedure using advection and vertical diffusion equations. The latter requires only surface and bottom boundary conditions. The parameterization in the model uses a wave breaking condition of the linear wave theory and is able to relate model variables to wave parameters such as wave height, age, phase speed, period, and length. The model can be used for studying current-wave-turbulence interaction in realistic environments of varying topography, and complex temperature and salinity structures. The model is used in two numerical experiments to demonstrate ocean surface wave effects on current fields and to show the model capability for upwelling prediction. The model code is presently being parallelized using numerical multiblock grid and dual-level parallelism techniques.