Coastline geometry effect on Rossby wave generation

We are using a simple, 1.5 layer model of the equatorial Pacific with idealized boundaries to study the effect of coastline orientation on Rossby wave generation.

The model was run with idealized wind forcing and basin geometry. In all cases, the model basin is from 30S to 30N, from 120E to 80W. The grid spacing (C-grid) is 1 degree in longitude by 0.5 degrees in latitude. The basin is closed on all sides. Only the eastern boundary is not straight, and it has a simplified approximation to the eastern Pacific. The model is reduced-gravity, 1.5 layer (one active layer). The initial upper layer thickness (ULT) is 300m in each case, and the value for g' is 0.0229 m/s2, giving a value of 2.62 m/s for c. The applied wind stress is purely zonal, and is Gaussian, centered on the equator at 150E, and oscillates with a fixed frequency.

Four cases have been run so far, with 30-, 60-, 90- and 120-day forcing. For an animation of the ULT field (deviations from initial conditions) for the entire basin, click Full Basin For a close-up of the eastern Pacific, click Eastern Side Basin

Figure 1. Model ULT variations along 12N for the last five months of the three model cases.

Figure 1. Model ULT variations along 15N for the last five months of the three model cases.

Figure 1. Model ULT variations along 18N for the last five months of the three model cases.