Impacts of Frontal Stability and Topography On Cross-Shelf Exchange in the Northern Gulf of Mexico

Document Type

Article

Publication Date

10-1-2006

Department

Marine Science

Abstract

The shelfbreak wintertime thermal front in the Northeastern Gulf of Mexico often exhibits meandering, eddy formation and warm-water intrusion. A high level of frontal variability plays an essential role in exchange processes across the shelf. This study examines the impacts of local frontal instability and bottom topography on turbulent heat exchange across the front using the results of two numerical models. Analysis of a series of numerical experiments reveals that the flow is baroclinically unstable. Predicted frontal instability contributes significantly to cross-frontal exchange and accounts for about 35% of the total eddy heat flux. Onshore eddy heat flux has the highest intensity at the frontal position. In addition, eddy activity and heat flux are sensitive to variation of bottom topography. For topographic features and frontal characteristics that are typical of the area, bottom steepness enhances the flux and is nearly proportional to the cross-frontal heat exchange. The study attempts to explain physical mechanisms that drive frontal circulation in the area and to quantify heat transport across the shelf. Estimated heat fluxes can provide important information for climate and ecosystem modeling of the Mississippi Bight.

Publication Title

Journal of Oceanography

Volume

62

Issue

5

First Page

667

Last Page

680

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