Numerical Simulation Studies for the Oceanic Anomalies in the North Pacific Basin. I. The Ocean Model and the Long-Term Mean State.

摘要

A time dependent, three-dimensional numerical dynamic model of the North Pacific Ocean, possessing an actual coastal configuration and ten layers, has been developed in order to show the physical nature of the large-scale normal and abnormal characteristics of the ocean in response to the various normal and anomalous seasonal meteorological conditions. Based on the simulated energetics, emphasis is given to identify the major physical processes and essential dynamic mechanisms responsible for the generation, evolution, and dissipation of large-scale anomalies in the North Pacific Ocean. The model is based on time integrations of the finite difference forms of the primitive equations. The oceanic circulation is driven by atmospheric forcing, namely, the surface wind stresses and the differential heating over the ocean. The flux form of numerical scheme for energy conservation and the rigid-lid approximation for filtering out the external inertia-gravity wave are used in the formulation. The model has run for more than 80 years, simulated with the annual mean atmospheric data as the forcing boundary conditions. The long-term mean state in the model reveals the large-scale features of the circulation patterns and density distributions in the North Pacific Ocean.