A 3—Dimensional baroclinic circulation model of the tropical and northern Pacific

A primitive equation 3-dimensional baroclinic ocean model without the rigid-lid approximation is described. The horizontal resolution is 2.5°×2° and the vertical variations of the velocity components are resolved by 6 layers. In order to increase the allowable integration time step which is constrained by stability requirements, the vertically integrated continuity equation is linearized and both the pressure gradient terms and the Coriolis terms in the momentum equations are finite-differenced semi-implicitly. The model is applied to simulate the circulation as well as the free surface elevation and temperature patterns in the tropical and northern Pacific Ocean in both summer and winter using the wind and temperature data at the 1000 mb pressure level as input to the model. The computed results are in general consistent with observed patterns. In particular, it is shown that the positions of the meandering axis of the Kuroshio in summer and winter are markedly different. This work was supported by the Hong Kong Polytechnic University Research Grant No. 340/854.