Difference in the potential vorticity distribution between the two case is striking. The non-large meander case shows that the potential vorticity is almost linearly proportional to the potential vorticity. Since the model bottom topography is flat in the Shikoku basin, where H = 4000m, except for the continental slope area, the potential vorticity is dominated by the Coriolis parameter. On the other hand, the large meander case shows that the homogeneous potential vorticity exists in the large range of the transport function.
Figure 6 shows the variation of the eastward transport anomaly for both the non-large meander and the large meander cases along the ASUKA line off Shikoku (see Fig. 1 for its location) as an index of the eddy field. There are distinct 50-100 day fluctuations. Further, amplitude of the fluctuations in the large meander case (45 Sv) is much larger than that of the non-large meander case (25 Sv). Therefore, the barotropic eddy forcing is much larger in the 45 Sv case than that of the 25 Sv case.
