salinity decreased. This layer is known as the Subtropical Surface Water 

 Layer. From 150 meters down to 600 meters Indian Central Water was present. 

 Below 600 meters the effect of the Antarctic Intermediate water was beginning 

 to be felt, while between 600 and 1000 meters the station was in the Antarctic 

 Intermediate water proper with low salinity. Below 1000 meters salinity in- 

 creased toward the bottom of the cast while temperature dropped. The Antarctic 

 Intermediate water is thus represented here by a tongue of low salinity water at 

 mid-depth . It is formed at the Antarctic Convergence; there water of compara- 

 tively low salinity and temperature sinks, and the greater portion of it flows 

 toward the north forming tongues of Antarctic Intermediate water at mid-depth 

 which can be traced for long distances in all the oceans. Presence of Antarctic 

 Intermediate water is also graphically portrayed in Figure 3, between depths of 

 about 500 to 1300 meters. 



The T-S curve at station 3 shows no influence of the warm coastal current 

 along the western coast of Australia, since this station was 8 degrees farther 

 west. Otherwise, water masses appear about as they did at station 1 . The 

 Antarctic Intermediate water extends from about 800 to 1200 meters. At station 

 5, Antarctic Intermediate water is found between 1000 and 1200 meters al- 

 though a glance at Figure 23C will show that while the core of this mass is at 

 1200 meters the body extends down to around 1500 meters. Following the 

 tongue of Antarctic Intermediate water further north on the south-north profile 

 (Fig. 3), it will be seen that the core successively rises from 1200 meters at 

 station 5, to 1000 meters at station 8, 800 meters at stations 11, 14, and 16. 



The formation at the top of the T-S curve at station 8 (Fig. 23D) appears 

 to be an anomaly. Possibly heavy local rainfall caused the fresher water layer 

 to occur in the top 20 meters. EASTWIND had experienced rain neither at this 

 station nor before arriving there. However, sudden, heavy rain squalls are 

 frequent in these parts and are usually of very local extent. Between 20 meters 

 and 150 meters there is Subtropical Surface water. Indian Central water is found 

 between 150 and something under 1000 meters. Antarctic Intermediate water 

 appears on the T-S curve between 1000 and 1200 meters. 



In Figure 24A, at station 11, surface salinity ha.d decreased sharply because 

 of less evaporation that resulted from the increased humidity and because of 

 the low salinity water that was brought in by the South Equatorial Current from 

 the Malay Archipelago . An extremely sharp salinity gradient is noted between 

 75 and 100 meters. Below 100 meters is a fairly thin layer of Subtropical Sur- 

 face water. The Indian Central water begins at about 250 meters and continues 

 to 800 meters. Antarctic Intermediate water on the curve in Figure 24A for station 

 11 is between 800 and 1000 meters. Station 14 shows a T-S curve which is 

 similar to that at station 11; the low salinity water in the upper 100 meters is 

 from the South Equatorial Current. Below this down to 250 meters is subtropical 



35 



