WATER MASSES AND CURRENTS OF THE OCEANS 187 



north and to the south, taking the continuity of the system into account. 

 In table 21 are shown results of such computations as referred to a sec- 

 tion in 30°S. The table also contains values for the transport across the 

 Equator, but these have been obtained in a different manner. The value 

 of a northward transport of about 6 million m^/sec of upper water is 

 mainly based on a comparison between the waters of the Caribbean Sea 

 and the Sargasso Sea, and the values of the northward transports of 

 intermediate and bottom water are estimated. 



The approximate correctness of the figures can be checked by consider- 

 ing that the net transport of salt must be zero. A calculation of the net 

 transport of salt requires knowledge of the velocity distribution within 

 the different parts of the current system, but a rough computation based 

 on average salinity values confirms the above conclusions. We shall 

 have to return to some of these matters when discussing the deep-water 

 circulation, but here it will be emphasized that a large quantity of 

 South Atlantic Central and Intermediate Water crosses the Equator and 

 enters the North Atlantic Ocean, where it exercises an influence on the 

 character of the waters along the coast of South America, in the Caribbean 

 Sea, and in the Gulf of Mexico. 



Currents of the Indian Ocean 



In the southern part of the Indian Ocean a great anticyclonic system 

 of currents comparable to the corresponding systems of the North and 

 South Atlantic Ocean appears to prevail, except that it is subjected to 

 greater annual variations. Between South Africa and Australia the 

 current is directed in general from west to east. In the southern summer 

 the current bends north before reaching the Australian Continent and is 

 joined by a current that flows from the Pacific to the Indian Ocean to the 

 south of Australia. In winter the current appears to reach to Australia 

 and in part to continue toward the Pacific along the Australian south 

 coast. To the north of 20°S the South Equatorial Current flows from 

 east to west, reaching its greatest velocity during the southern winter, 

 when the southwest monsoon over the northern part of the ocean repre- 

 sents a direct continuation of the southeast trade winds on the southern 

 side of the Equator. In this season the current is reinforced by water 

 from the Pacific Ocean that enters the Indian Ocean to the north of 

 Australia, but in the southern summer the flow to the north of Australia 

 is reversed. 



In both seasons of the year, part of the South Equatorial Current 

 turns south along the east coast of Africa and feeds the strong Agulhas 

 Stream. To the south of lat. 30°S the Agulhas Stream is a well-defined 

 and narrow current that extends less than 100 km from the coast. Corre- 

 sponding to a flow toward the south in the Southern Hemisphere, the 

 coldest water is found inshore, and the sea surface rises when departing 



