HYDROLOGY OF THE SOUTH ATLANTIC 



175 



cold surface layer, in which the temperature is for the greater part less than - i° C. 

 The discontinuity layer is shown where the -i°, o°, and i° C. isotherms crowd close 

 together, and the depth of this layer below the surface increases gradually from about 

 100-150 m. in 67° S to 150-200 m. in 64'' S. Below the discontinuity layer lies the 



LATITUDE 

 STATION 590 



66°S 

 589 



67°S 



588 



587 



586 



585 



584 



250 m 



500m 



750 



I'l 



Fig. 3. Section II, distribution of temperature (° C). 



warm deep water. At each of the four stations made in Antarctic surface water the 

 temperature does not alter until at least 100 m. below the surface, and the temperature 

 of this loo-m. stratum at each station is shown in the section. The water is not coldest 

 in the extreme south, for there, as will be shown later, it is warmed slightly by up- 

 welling deep water. Instead, the temperature decreases from — 170° C. at the edge of 



