23.35° C. at the surface at station 5, to a maximum of 29.68° C. at the sur- 

 face at station 27. Isotherms followed an irregular pattern which reflected no 

 indication of the divergence between 10° and 18° S . latitude. The 2°isotherm, 

 which started at station 5 at around 2300 meters, dropped slowly to a depth of 

 almost 2600 meters at station 27. The thermocline (again employing the term 

 in its strict interpretation) varied from about 30 to 50 meters (at station 27, It 

 commenced at 75 meters) to a depth of 250 to 300 meters. Below the lower 

 limit of the thermocline proper, temperature decreased in a more or less even 

 curve to about 1500 to 2000 meters, below which there was only a slight de- 

 crease to the bottom of the cast. 



Stations 27, 28, 29, and 30 have been connected together in a section 

 which extends from west of Ceylon to off Socotra Island at the mouth of the 

 Gulf of Aden. A profile along this section is shown in Figure 14, while the 

 vertical distribution of temperature at three of the stations Is given in Figure 

 22. The bottom, which at first Is fairly even, becomes highly Irregular between 

 stations 29 and 30 and shallows greatly as Socotra Island is approached. The 

 zone of turbulence In this section decreased In extent from station 27, where 

 it extended from the surface to a depth of 75 meters, to 30 meters depth off 

 Socotra Island. Isotherms to a depth of about 200 meters were roughly parallel 

 with the surface; below that depth they tended to slope downward commencing 

 with the 16° isotherm. The 2° isotherm was found between depths of 2600 and 

 2850 meters, and It dropped fairly sharply between stations 28 and 29. The 

 thermocline was found between depths of 50 and 250 meters. Below the thermo- 

 cline, temperatures followed a gently arched curve to 1500-2000 meters depth, 

 a pattern similar to that observed at the other stations occupied. 



The maximum temperature observed at any station was noted at station 28 

 on 22 April 1961 at the surface (29.71° C ). The minimum temperature was 

 noted at a depth of 2940 meters at station 5 on 5 April 1961 (1 .66° C). 



B. Salinity 



Figures 3, 9, and 15 show profiles of sections giving salinity values with 

 depth along the 32° S. parallel, the south-north track along the 78° E. merid- 

 ian, and from station 27 to station 30 in the northern part of the Indian Ocean. 

 Vertical distribution of salinity at selected stations is shownin Figures 20, 21, 

 and 22. In general, salinity values followed closely those reported by Muromtsev 

 (1959), variations from the general pattern being caused by the time of year at 

 which observations were made. In observations made by EASTWIND, although 

 there was clear evidence of Antarctic Intermediate water at depth, there was no 

 indication of Antarctic Bottom water at any of EASTWIND 's stations because of 

 the fact that casts were made only to 3000 meters. 



32 



