ANTARCTIC INTERMEDIATE CURRENT 6g 



A section showing the temperature distribution across the Indian Ocean, based on the observations 

 made by the ' Gazelle ' between 28 and 38 S, has been published by Moller (1929, fig. 13). Through- 

 out the section from 50 to no E there is a very cold layer corresponding to the intermediate layer, 

 with temperatures for the most part less than 3 C. between the surface and warm deep layers. In 

 102 E the layer has a temperature of less than 2° C, and actually the Gazelle data show that the 

 2 C. isotherm at a depth of about 1250 m. reaches as far north as 34 S. The occurrence of such a 

 low temperature so far north seems, however, to be quite impossible ; even in the western part of the 

 Atlantic Ocean, where our data give every indication of the existence of a stronger current, it is not 

 found north of 46 S. A comparison of M oiler's section with section 9 leaves little doubt that the 

 Gazelle data are unreliable. They show that there is a temperature inversion of as much as 3° C. 

 between the intermediate water and the warm deep water, and, as will be proved later, this is most im- 

 probable, section 9 showing that there is probably no temperature inversion in the eastern part of the 

 ocean. 



The observations in sections 10, n, and 12 (Plates XIX-XXVII) south of Australia 

 and Tasmania show that the intermediate layer has a very small volume and high 

 salinity. The smallness of the current is probably due in a large degree to the restrictions 

 placed upon it by the presence of such a large land mass to the north, and partly, 

 perhaps, to the fact that a large volume of highly saline water is forced towards the 

 south in the subsurface layer, in order to flow southward of Australia. The northward 

 movement of Antarctic water in the Antarctic Zone itself may also be smaller owing to 

 the relatively low latitude of the shores of the Antarctic continent and the consequent 

 narrowness of the zone. At none of the stations north of the Antarctic convergence was 

 there any indication of a temperature inversion. 



South of the eastern half of the Tasman Sea (section 13, Plates XXVIII XXX) the 

 layer has a slightly greater volume and lesser salinity than south of Australia. The dif- 

 ference is probably due to the northward movement being less restricted, as the highly 

 saline water which flows eastwards south of Australia and southwards in the East 

 Australian current escapes towards the north along the west coast of New Zealand. It 

 may also be due partly to an increased northward movement of Antarctic water, since 

 some of the Ross Sea current finds its way northwards in this region (see pp. 17, 31). 



The salinity distribution in section 14 (Plates XXXI-XXXIII) south-east of New 

 Zealand suggests a further increase in the strength of the intermediate current. Wiist 

 (1929, p. 39) shows that the northward movement in this region, combined with the 

 intermediate current in the eastern part of the Tasman Sea, give rise to a poorly saline 

 layer which can be traced as far as 0-16 N, where it mixes with a similar current of 

 Arctic origin. 



In the deep basin east of the Antipodes and Chatham Islands, where there are greater 

 movements towards the south in the surface and subsurface strata (see pp. 55, 65), the in- 

 termediate current has a greater salinity ; but farther east still, in the central part of the 

 ocean, the great volume and low salinity of the layer in sections 15 and 16 (Plates 

 XXXIV-XXXIX) suggest that the current is stronger than it is east of New Zea- 

 land. The two sections constructed by Wiist (1929, pis. ii and iv) also suggest that the 

 current is stronger in the central part of the ocean, and Wiist was able to show that 

 the increase of salinity towards the north in the current is remarkably small ; between 



