Date of Award

1996

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Oceanography and Coastal Sciences

First Advisor

Masamichi Inoue

Abstract

The Gulf of Mexico is an ideal location for paleoceanographic study using a three-dimensional ocean circulation model because of the availability of data to verify the model for the present. A description of the Gulf of Mexico circulation during the last glacial maximum is beneficial in interpreting the distribution of glacial fauna and adds to the understanding of global climate change because the Gulf of Mexico is an important link in the circulation of the Atlantic Ocean. The Florida Current originates in the Gulf of Mexico and contributes warm, salty water to the Gulf Stream. The Gulf Stream influences the climate of the North Atlantic and is a factor in the production of North Atlantic Deep Water, thus contributing to the global thermohaline circulation. The Modular Ocean Model is used with fine horizontal grid resolution to be truly eddy-resolving and with a high number of vertical levels to resolve the bottom topography. A unique method of forcing the inflow through the Yucatan Channel is developed that results in a realistic annual cycle in the volume transport and baroclinic shear of the Loop Current. Seasonally varying wind forcing and surface relaxation toward observed temperature and salinity fields are implemented. The present-day seasonal simulations were able to realistically reproduce many of the observed features of the general circulation as well as the formation, migration, and decay of Loop Current rings. The model deep circulation is dominated by large cyclones that are associated with the upper layer Loop Current rings. The model grid was then configured to represent the lowstand in sea level at 18,000 years before present and the model was forced with glacial estimates of wind stress and surface temperature. The response of the model to different inflow conditions through the Yucatan Channel was tested. Volume transport of the Florida Current during the last glacial maximum that is lower than present is supported by glacial estimates of the volume transport of the North Atlantic gyre and by the results of a global ocean circulation model for the last glacial maximum.

ISBN

9780591133868

Pages

207

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