Date of Award

Spring 1992

Document Type


Degree Name

Doctor of Philosophy (PhD)


Ocean & Earth Sciences



Committee Director

A. D. Kirwan, jr.

Committee Member

Chester E. Grosch

Committee Member

Gabe Csanady

Committee Member

Dana Thompson


The interaction of a recently-formed Loop Current ring and a fossil ring is studied using observations and a two-layered eddy-resolving general circulation model of the Gulf of Mexico. This interaction is investigated by following the evolution of volume, energy, potential vorticity, angular momentum and enstrophy within a model ring as it moves westward and encounters a fossil ring along the continental slope of the Gulf of Mexico. By comparing the model results with drifter and hydrographic data several new insights into ring/ring and ring/slope interactions are seen. A Loop Current ring may merge with a fossil ring along the slope. The signature of this merger is evident in many drifter tracks suggesting that this occurs in the Gulf quite frequently. This merger explains several observations. There is an offshore transport induced by the merging of the rings that is comparable to the transport out of the Florida Straits. The volume of the Loop Current ring decreases sharply during the merger indicating an exchange of mass is occurring. A cyclone is generated when the ring interacts with a fossil ring and there is a transfer of energy from the surface layer to the lower layer.

Analysis also shows that during the merger, as expected, a decrease in energy, potential vorticity and angular momentum and an increase in enstrophy occur. Other cyclones are seen first in the lower layer, prior to the ring's arrival in the slope area, and then appear in the upper layer as the ring interacts with another ring and/or the slope.


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