Evolution of solitary eddies over a Gaussian topographyand their interaction

A new nonlinear equation describing mesoscale eddies in the oceanic flow is established. Using the variational principle, the Liapunov stability of the solitary eddies is discussed. It can be found that both cyclonic and anticyclonic solitary eddies are stable. Numerical computations show that the anticyclonic solitary eddies propagate westward due to the β effect. However, when a Gaussian topography (seamount) is located in upstream of an anticyclonic eddy, the solitary topography can make the anticyclonic eddy move southwards, and its path depends on the location of the Gaussian topography. Furthermore, when two anticyclonic eddies interact, the upstream solitary topography can snake them produce weak merging and weak separation. It is found that the localion of the solitary topography affecu the migration and rotation of these two eddies.