Impacts of frontal stability and topography on cross-shelf exchange in the Northern Gulf of Mexico |
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| Authors: | Nadya T Vinogradova Dmitri A Nechaev |
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| Institution: | (1) Atmospheric and Environmental Research (AER), Inc., Lexington, MA 02421, USA;(2) Stennis Space Center, The University of Southern Mississippi, MS 39529, USA |
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| 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. |
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| Keywords: | Shelfbreak front turbulent heat exchange baroclinic instability Gulf of Mexico |
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