Yasuhide Kobayashi (University of Hokkaido)
"Trajectory of Eddies in a Closed Rectangular Ocean Basin and its Determination
Mechanism by point vortex theory
Many mesoscale oceanic eddies were observed by recent satellite measurements.
In this study, we have investigated the trajectory of an isolated eddy in a rectangular ocean basin by a β-plane reduced gravity model.
The eddy translates westward until it collides with a meridional western boundary then it migrates along the western, northern and eastern boundary and separates from
the eastern boundary at a certain latitude.
The eddy trajectory and its determination mechanism are unknown.
We constructed a point vortex model including image effect and β-induced westward movement effect in order to demonstrate the eddy trajectory by Hamiltonian contour.
The model results indicate that the eddy must translate along the same Hamiltonian contour if it’s a point vortex.
However, the eddy cannot translate along the same contour because of the eddy size.
We constructed our new point vortex model including the eddy size which is connected to the diffusive effect. In this seminar, we talk about these topics and new research
results. We suggest that “transfer Hamiltonian countour mechanism” is one of the dominant factors for the eddy translation."