A NEW NESTED BOUNDARY-CONDITION FOR A PRIMITIVE EQUATION OCEAN MODEL

Nested boundary techniques are developed based on the results of Perki ns [1993] and Blake [1991]. We focus on the numerical and physical con sistency needs across the nested boundary. These techniques replace th e transition zone used by other researchers with a numerically and a p hysically based correction step. We demonstrate our method using a nes ted, reduced gravity version of the Naval Research Laboratory (NRL) pr imitive equation ocean model and a two-layer hydrodynamic finite-depth version of the same model. Numerical experiments are performed using integrations of both an idealized double gyre and a realistic Greenlan d Iceland Norwegian (GIN) Sea configuration. To illustrate the need fo r improved boundary treatment, we present a numerical study of boundar y errors. The study illustrates the fragile nature of nested boundary conditions. With even small errors, a dramatic impact is observed on t he formation (or lack thereof) of the Atlantic-Norwegian Current, whic h is responsible for transporting North Atlantic water to the Arctic O cean, in the GIN Sea configuration.