Surface Circulation in Northeastern Gulf of Mexico
Surface Circulation in Northeastern Gulf of Mexico

Author: Kirby L. Drennan

Publisher:

Published: 1963

Total Pages: 158

ISBN-13:

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The general features of the surface circulation in the northeastern Gulf are presented from an analysis of surface density distribution and an extensive drift bottle study. Results of drift bottle study are based on 6,400 recoveries. Twenty cruises were conducted in the regions east and south of the Mississippi Delta, during the period September 1960-October 1962. Data obtained at this time indicate a surface flow of approximately 0.7 kt. to the east and northeast during March-June. Hydraulic heads formed by discharge from eastern Passes extend some 70-90 miles seaward. Convergence lines associated with strong density gradients are commonly found along southern boundary of these areas. Surface circulation for the area is depicted as follows: An eastward flow during spring and early summer, which diverges into northeast and southeast flow at varing distances east of the Delta depending on local winds and river discharge; a southwest flow over continental shelf during late summer and fall, which appears to continue westward and into southwestern Gulf. The existence of the southeast flowing loop current also is indicated in the offshore region southeast of the Delta at this time. Flow during winter months is to the southeast and appears to be a result of the northward migration of the loop current. (Author).

Surface Currents in the Northeastern Gulf of Mexico
Surface Currents in the Northeastern Gulf of Mexico

Author: G.G. Salsman

Publisher:

Published: 1963

Total Pages: 43

ISBN-13:

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During the 28-month interval from September 1960 through December 1962, drift bottles were re leased periodically from a stationary platform located 11 nautical miles offshore from Panama City, Florida. Of the 951 bottles released, 276, or 29% were recovered. Approximately 67% of the returns have been found along a 200-mile section of coastline extending from Cape St. George west to the Florida-Alabama line; 20% of the returns were from the Florida east coast and Keys; and 12% of the returns were found along the coasts of Alabama, Mississippi, Louisiana, and Texas. Comparison of the drift bottle data with local wind information indicates that the primary mechanism of surface water transport in the vicinity of the release point is wind-in duced currents, which either transport the bot tles to local s or to regions where perma nent or semi-permanent currents can displace them to western or southern shores. The results of this study are also compared with other drift bottle studies conducted in the Gulf of Mexico. (Author).

Circulation Over the Continental Margin of the Northeast Gulf of Mexico
Circulation Over the Continental Margin of the Northeast Gulf of Mexico

Author: Roy D. Gaul

Publisher:

Published: 1966

Total Pages: 274

ISBN-13:

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The ocean circulation over the continental margin of the northeast Gulf of Mexico has been delineated on the basis of three years of hydrographic and direct current observations. A wide range of measurement techniques was used at two fixed platforms in the nearshore region off Panama City, Florida, and from small vessels during periodic surveys conducted over a larger area. Evidence is presented for a close coupling between circulation over the continental margin and that in deeper water. The "loop" current, which transports water into the Gulf from the Yucatan Channel, is identified on the basis of water mass characteristics as far north as the edge of the northeast continental slope. Lateral mixing with waters over the continental margin is evidenced by smooth transitions of salinity-temperature relations characterizing offshore and nearshore waters. It is suggested that the loop current is the main driving influence for circulation over the continental margin, especially below the seasonal thermocline. Flow over the continental margin is modified markedly by ocean bottom topography. De Soto Canyon, the most prominent single bathymetric feature, appears to have a dominant influence on replenishment of water in the lower layer over the shelf. A zone of horizontal transition in hydrography and currents has been noted along the break between shelf and slope, especially during the spring months when stratification over the shelf is incipient. ...