GULF OF MEXICO 



131 



Slocum (1934-36) lias made a comparative 

 study of sea surface temperatures for various 

 regions of tlie Gulf in different years. This study 



is based on temperature observations taken from 

 1912 to 1933. The year-to-year changes are 

 summarized in table 2 for the regions shown by 



Table 2. — Some variatiotis of mean annual sea surface temperatures for 1912-33 ' in various regions of the Gulf {° F.) 



[After SlocumJ 



Variation 



High 



Dif 



Mean 



Dif 



Low 



High-Low Dif.. 



(1) 

 25-26° N. 

 84-86° W. 



79.5 

 78.4 

 76.8 



1.1 

 1.6 

 2.7 



(2) 

 27-29° N. 

 90-93° W. 



77.0 

 75.5 

 73.9 



1.5 

 1.6 

 3.1 



(3) 

 26-28° N. 

 86-89° W. 



78.7 

 77.8 

 76.6 



0.9 

 1.2 

 2.1 



(4) 

 21-25° N. 

 90-94° W. 



79.7 

 78.5 

 77.6 



1.2 

 0.9 

 2.1 



(5) 

 23-24° N. 

 82-84° W. 



1.0 

 2.1 

 3.1 



(6) 

 21-22° N., 8.')-87° \V. 

 22-23° N.. 84-87° W. 



81.1 

 80.3 

 79.3 



0.8 

 1.0 

 1.8 



I The number of observations varies from year to year. Few observations were made in 1917-19. In other years, the number ranged from 100 to over a 

 thousand in each region. Locations are shown in figure 41. 



encircled numbers in figure 41. The mean tem- 

 perature for each year has been computed. It is 

 of interest to note that in one case the minimum 

 mean yearly temperature for a given region for 

 this period of years differed from the overall mean 

 temperature for the region by 2.1° F. Moreover, 

 the maximum and minimum mean yearly tem- 

 peratures differ by 3.1° F. m two localities. For 

 one of these extreme examples, in the region 

 27-29° N., 90-93° W., the lowest mean yearly 

 temperature recorded was for the year 1915 which 

 showed a mean temperature of 73.9° F. In 1922 

 and 1927, the highest mean temperatures were 

 recorded here, being 77.0° F. For the other 

 example, the low was 77.8° F., the high 80.9° F. 

 Siocum's stud}' also iacluded consideration of the 

 means for the different months of the year. 



SEA TEMPERATURE VARIATIONS WITH 

 DEPTH 



The sea temperatures obtained by the Mabel 

 Taylor below the surface have been -published by 

 Parr (1935). Although the depths of these obser- 

 vations are not known accurately, they do give 

 considerable information about vertical tempera- 

 ture distribution. An average temperature-salinity 

 correlation in the Gulf of Mexico proper as woi'ked 

 out by Parr for the months February-April is 

 given as table 3. 



In the early 1940's the United States Navy 

 developed the bathythermograph for making 

 observations of sea temperature continuously from 

 the surface to depths as great as 900 feet. To 

 date, some 10,000 observations or bathy thermo- 

 grams have been made in the Gulf. Copies of 



259534 O— 54 10 



these are now filed at the Woods Hole Oceano- 

 graphic Institution where they are processed and 

 in the Department of Oceanographv at Texas 

 Agricultural and Mechanical College. Their dis- 

 tribution b}' 1° quadrangles is shown in figure 42. 



Table 3. — An average temperature-salinity correlation for 

 the Gulf of Mexico proper 



lAfter Parr] 



Two bathy thermograms, one for summer and 

 the other for winter, were chosen from each of 

 four parts of the Gulf within the 1 ,000-fathom line. 

 These locations are indicated by encircled crosses 

 in figure 41. The bathythermograms were chosen 

 as being typical after considering range of tempera- 

 ture variation, general shape of temperature-depth 

 curve, depth of thermoclinc, and other features. 

 Unfortunately, due to the paucity of observations 

 it was not possible at any one of the four positions 

 to obtain "typical" summer and winter bathy- 

 thermograms from the same year. However, by 

 plotting a typical summer and a typical winter 

 bathy thermogram for each position on the same 

 coordinates it was possible to show in a general 



