Interaction of an Eddy with a Continental Slope
WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
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This study concerns the barotropic interactions between a mesoscale eddy and a straight monotonic bottom topography. Through simple to relatively complicated modeling effort, some of the fundamental properties of the interaction are investigated. The fundamental aspects of the interaction are examined using a simple contour dynamics model. With the simplest model configuration of an ideal vortex and a step topography, the basic dynamical features of the observed oceanic eddy-topography interaction are qualitatively reproduced. The results consist of eddy-induced cross-topography exchange, formation of topographic eddies, eddy propagation and generation of topographic waves. A more complicated primitive equation model is used to investigate a mesoscale eddy interacting with an exponential continental shelfslope topography on both f and beta-planes. The roles of the eddy size and strength and the geometry of topography are studied. It is seen that the multiple anticyclonic eddy-slope interactions strongly affect the total cross-slope volume transport and the evolution of both the original anticyclone and the topographic eddy. Since a cyclone is trapped at the slope and eventually moves on to the slope, it is most effective in causing perturbation on the shelf and slope. The responses on the shelf and slope are mainly wavelike with dispersion relation obeying that of the free shelf-trapped wave modes. It is found that the straight eddy incident is more effective in achieving large onslope eddy penetration distance than the oblique eddy incident.
- Physical and Dynamic Oceanography