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Title: Mississippi River Plume Hydrographic Study 



The Mississippi River Plume is the nation's most significant example of a buoyancy driven flow regime. The 

 volumetric outflow greatly exceeds any other U.S. river, and the region affected (TX, LA, AL, MS shelf 

 regions) is one of the nation's most important fisheries. Although basic information is available on certain 

 features of the plume, such as salinity balance and remotely sensed gross dimensions, variability of the system 

 at time scales less than seasonal and at length scales less than hundreds of kilometers has not been 

 attempted. The entire area of the nation's most intense offshore oil and gas activity is heavily influenced, 

 biologically and hydrographically, by the plume, even to the extent that previous shelf monitoring studies have 

 been overwhelmed by the fluvial signal. The proposed study, to be closely coordinated with a companion 

 study of currents and hydrography of the TEXLA shelf, in general, would concentrate on measuring the 

 plume's dimensions, flow characteristics, mass transport (including entrained sediments and pollutants), and 

 mixing characteristics. Close attention would be paid to associated fronts, hypoxic areas, sedimentation rates, 

 benthic boundary layer phenomena, productivity, and standard nutrient and hydrographic analyses. 



Title: Gulf of Mexico Eddy Circulation Study 



This study is aimed at monitoring and characterizing three classes of "meso-scale" circulation patterns that 

 are important in abyssal and slope waters of the northwestern Gulf of Mexico. 



• The eddy-shedding process and the physics of Loop Current eddies as they move westward in the 

 Gulf of Mexico and interact with the TEXLA shelf and slope, as well as the resultant hydrographic 

 alterations of upper slope/outer shelf waters, and changes in circulation; 



Smaller anticyclonic and cyclonic eddies that appear to form around and to move with the Loop 

 Current eddies; 



• "Squirts and jets" - poorly understood shear zones, usually located near the upper slope, that appear 

 to reflect strong shelf/slope water exchange. 



This study will provide rapid, entirely airborne surveys of these features, using a suite of expendable probes 

 that can measure temperature, salinity, and current shear, as well as the aerial deployment of drifting buoys 

 to monitor flow. Satellite thermal imagery of the entire Gulf, at sufficient resolution to support the survey 

 and monitoring requirements of this study as well as the TEXLA Shelf Circulation and Transport Processes 

 Study (G-971) and the Mississippi River Plume Hydrographic Study (G-973), will be provided within this 

 study. The newest methodology available for eddy studies, satellite altimetry, will be used in an attempt to 

 locate eddies passing through any of the approximately six accurate geoid lines presently available for the 

 Gulf. These methods will make it possible to follow specific eddies in time and space, and to participate with 

 industry, academic, or other interests in near real-time information exchange about these important Gulf 

 features. 



Title: East Breaks Ship-of-Opportunity Study 



The proposed study consists of partial funding of a separately managed program of hydrographic surveys of 

 the "East Breaks" region along the TEXLA slope. The work, conducted by Texas A&M University, involves 

 nutrient and hydrographic stations on a fixed grid, three times per year. The work would be closely 

 coordinated with the Eddy Study and the Shelf Study. 



Title: Gulf of Mexico Data Buoy Study 



The proposed work consists of the provision of two 3-meter, standard meteorological buoys at locations to 

 be selected along the shelf edge offshore TEXLA. The locations would be closely coordinated with the 

 existing Meteorological and Oceanographic Monitoring System (MOMS) operated by industry, the National 

 Weather Service, and the National Data Buoy Center. 



