PREVAILING WIND -FEB. 1958 



96 94 92 90 88 86 84 82 W. 



Figure 40. — The prevailing winds over the Gulf of Mexico in February 1958. Note the 

 converging winds in the southern Gulf. 



climatologists of the Seewetteramt, Deutscher 

 Wetterdienst.) The sea-atmosphere coupling 

 of the Caribbean-Gulf-Atlantic system is not 

 yet clear. There is, however, an apparent 

 correspondence with variations in the intensity 

 of the Bermuda High Pressure System. 



WATERS ENTERING THE GULF 



The waters which bathe the shrimping 

 grounds of the Gulf cind which make up the 

 significant water mass to depths of 200 m., 

 originate in the Atlantic Ocean to the east of 

 the Virgin Islands (near 20° N. and 60° W.). 

 The water, called SUW (Subtropical Under- 

 water), connes into the Caribbean Sea over the 

 Antilles Ridge and through the Windward 

 Passage between Cuba and Hispaniola. During 

 its residence in the Caribbean Sea, SUW is 

 mixed with warmer and less -saline waters. 

 Thus it enters the Gulf of Mexico through the 

 Yucatan Channel with a salinity of 36.7 p.p.t. 

 and temperature of 22° C. (fig. 41). 



SUW comprises the upper water mass car- 

 ried in the Yucatan-Florida-Gulf Stream sys- 

 tem. The main axis of this current swings 

 abruptly to the east after passing through 

 the Yucatan Channel, so that the main volume 

 of SUW is directed into the Florida Straits, 

 not into the Gulf of Mexico. In a sense, the 

 circulation in the Gulf is a backwater of 

 the mainstream. As a consequence, the 

 introduction of SUW into the Gulf varies 

 from time to time. The range and charac- 

 teristics of the variations have yet to be 

 defined. 



An examiination of the spread of SUW through 

 the Gulf of Mexico is possible from data 

 collected from the R/V Hidalgo , Texas A&M 

 University, in February cind March 1962. 

 (This was the only cruise ever made which 

 covered the entire Gulf during one period of 

 time.) The main axis of SUW in the Gulf was 

 more or less east-west after the water pene- 

 trated north of the Yucatan Shelf (fig. 42). The 

 salinity and temperature decreased awayfrom 

 the axis (fig. 41) and from the area of concen- 

 tration in the southeastern Gulf. The depth 



36 



