NUMERICAL-STUDIES OF EDDY SHEDDING IN THE GULF-OF-MEXICO

We model the eddy shedding phenomenon in the Gulf of Mexico using the Sandia Ocean Modeling System. In the first part of the study a parameter sensitivity study is performed using a rectangular basin two-level model. In particular, the sensitivity of the model eddy shedding to inflow/outflow conditions, horizontal resolution (80, 40, and 20 km), and reduced gravity is examined. The results are interpreted in terms of the quasi-geostrophic vertical motion equation and vorticity conservation. In the second part of the paper we include realistic coastlines and bathymetry in the model. A horizontal resolution of 20 km is used together with 16 vertical levels. Various observed features of the eddy shedding are simulated by the model. A boundary current which follows topographic contours is generated around the Gulf because of the splitting of the flows associated with the loop current and the shed eddy. This current is likely to be important in the dissipative stages of the eddies in the western Gulf. In addition, our results suggest that higher-order baroclinic modes are important in the dissipation of loop current eddies.