The formulation and justification of a three-layer baroclinic ocean model developed to simulate the general circulation of the ocean are described in this paper. Test of the model in simulating the annual mean circulation patterns in the North Pacific under the prescribed atmospheric forcing

which consists of the climatological surface wind stress and sea surface heat flux

and comparison of the results with observations showed that the model basically simulated the large scale features of the annual mean circulation patterns in the North Pacific Ocean such as those of the intensified western boundary currents and the North Equatorial Currents and Undercurrents. But due to the coarse resolution of the model

some details of these currents were poorly reproduced. The seasonal variations of the North Pacific Ocean circulation driven by the seasonal mean sea surface wind stress was calculated

the different aspects of these results were analyzed and the main current (the intensified western boundary currents) transports were calculated and the transport versus time curve was given.