Cross-Shelf Exchange Processes and the Deepwater Circulation of the Gulf of
Mexico: Dynamical Effects of Submarine Canyons and Interactions of
Loop Current Eddies with Topography, Final Report

OCS Study MMS 2004-017

The Minerals Management Service (MMS), Gulf of Mexico OCS Region, announces the availability of a new study report, Cross-Shelf Exchange Processes and the Deepwater Circulation of the Gulf of Mexico: Dynamical Effects of Submarine Canyons and Interactions of Loop Current Eddies with Topography, Final Report.

This report contains results of a 4-year, process-oriented numerical modeling study focused on investigating the interaction of deep ocean circulation features in the Gulf of Mexico, e.g., Loop Current eddies, with continental shelf and slope. Loop Current eddy interactions with topography were studied in four regions: the central Gulf of Mexico, the northern Gulf of Mexico, the northeast corner of the Gulf of Mexico, and the western Gulf of Mexico. Several new dynamical mechanisms controlling the interactions of Loop Current eddies with topography were identified, and other more familiar mechanisms were clarified. Simulations and investigations of physical processes within, and in the vicinity of, DeSoto Canyon were based on three conceptual models of DeSoto Canyon circulation derived from observational data collected during the DeSoto Canyon Eddy Intrusion Study (1997-1999).

It was demonstrated that deep eddies can form during Loop Current eddy interaction with the western shelf particularly in the region around 25°W. The deep eddies are characterized by relatively strong currents (up to 20 cm/s) and large size (200-300 km in diameter), and have significant impact on the deep local environment. Deep eddies were also shown to affect significantly the evolution of Loop Current eddies interacting with the western shelf. It was also demonstrated that Loop Current eddies interacting with a thermocline-penetrating shelf can form small to intermediate-scale cyclones as a result of water advection from the shelf. The cyclones generated by this process can reach considerable strength depending upon the exact shape of the bathymetry and the motion of the Loop Current eddy. The intermediate layer, i.e., the density layer defined with moderate to weak stratification extending from approximately 400 to 1,200 meters, was found to play a central role in the interaction of Loop Current eddies with topography.

This report is available only in compact disc format. The discs are available from the Minerals Management Service, Gulf of Mexico OCS Region, at a charge of $15.00 by referencing OCS Study MMS 2004-017. The report may be ordered through the Minerals Management Service’s on-line ordering system at http://www.gomr.mms.gov/WebStore/front.asp. You will be able to obtain this report also from the National Technical Information Service in the near future. Here are the addresses. You may also inspect copies at selected Federal Depository Libraries.