UPWELLING 



199 



The water layers which are drawn upwards or which reach the surface as a result of 

 upwelling are shown in the sections illustrating salinity, pp. 138-143 and pp. 164-169. 

 South of the subtropical convergence, upwelling involved two water layers; sub- 

 Antarctic water coming to the surface, and the return current beneath showing upward 



40 5 



°C 

 25 



so- 



ls H 



10- 



Fig. 64. Measurement of upwelling. Comparison of inshore surface temperatures (curve D) with tempera- 

 tures at a depth of 150 m. outside the upwelling zone (curve A')\ with surface temperatures offshore in 



curve j. For explanation see text and 



Table XVI. 



Note. The record marked O in cur\'e D represents the temperature of upwelled water in the Peru 

 Current, but was obtained at 35 miles from shore. The high temperature inshore represents the Equatorial 

 Counter-current and is not upwelled water (cf. Figs. 41 and 70). 



movement: only at Cape Carranza (Fig. 18) was the latter drawn at all close to the 

 surface. North of the subtropical convergence, upwelling involved as many as three 

 layers. The return current featured at the surface at two localities at Antofagasta and 

 San Juan, where upwelling was unusually strong, and sub-Antarctic water appeared 



