Non-hydrostatic algorithm and dynamics in ROMS.

Y. Kanarska, A. Shchepetkin, J. McWilliams.
UCLA

A non-hydrostatic extension for ROMS model is proposed. It includes decomposition technique on hydrostatic and non-hydrostatic components for pressure and velocity fields. The resulting equations are solved with a pressure correction scheme which includes explicit treatment of free surface and mode splitting technique. Special attention is given to the effective solution of resulting elliptic problem in terrain-following coordinates.

The algorithm is tested on several examples for barotropic and baroclinic flows where non-hydrostatic effects are important. The model is applied to the South China Sea region to explore internal wave generation, modal transformation processes in vicinity of the Luzon Strait sill. The impact of changes in stratification, differential steepening due to depth and 3D effects on these processes are studied.