Greene ran the section at about the time the Altair and Armauer 

 Hansen were conducting their work in the vicinity of the Azores 

 in connection with the International Survey of the Gulf Stream 

 Area. In 1950 the Evergreen occupied the section at about the 

 time of the multiship Operation Cabot to the westward of the 

 Grand Banks. In 1958 the Evergreen occupied the section as a 

 part of the activity of the International Geophysical Year. Fig- 

 ures 27, 28, and 29 show, respectively, the temperature, salinity 

 and velocity distribution found in 1958. In figure 29 the velocities 

 are referred to the 2,000-decibar surface. 



The dynamic topography of the sea surface relative to the 

 1,000-decibar surface is shown in figure 21. As mentioned earlier, 

 the 1,000-decibar surface gives a fair representation of the current 

 pattern in the vicinity of this section but the velocities are greater 

 than indicated by this relative topography. Current directions 

 shown in figure 21 are in good agreement with those derived 

 from GEK current fixes obtained about every 10 miles along this 

 section. In figure 27 the greater part of the section is dependant 

 upon the observations from reversing thermometers at the sta- 

 tions. In the upper 200 meters, however, these observations were 

 supplemented by bathythermograph casts made about every 5 

 miles between stations from station 6741 to station 6752. The 

 most pronounced cold wall was found near station 6749 with the 

 greater part of the Atlantic Current and its branches being found 

 south of this station. However, at station 6750 the water below 

 about 400 meters was Atlantic Current water. Southward of 

 station 6749 the inclination of the isotherms is a good indication 

 of the direction of flow across the section and the components E, 

 D, A, and B of figure 26 are apparent. Except for the water 

 above the Grand Banks, the thermal structure of the Labrador 

 Current F and the eastward moving mixed water is more complex 

 and the circulation picture is better shown by the velocity section 

 (fig. 29). 



The salinity distribution (fig. 28) shows a pattern similar to 

 that presented by the temperature distribution. The deeper ob- 

 servations of salinity have been plotted against potential tem- 

 perature in figure 30. Here the individual observations are given 

 and are identified with the last two digits of the station numbers 

 of their origin, station 6741 being the southernmost and 6750 

 being the northernmost of this series. From this small number of 

 observations there is no clear cut grading of salinity for a corre- 

 sponding potential temperature along the section. There is ap- 

 parent, however, the difference of about 0.04°/ oo in salinity 

 between the observations of the Evergreen and those of the 



45 



