160 DISCOVERY REPORTS 



it strongly supports the hypothesis of an offshore influence at this point. Moreover the data to the 

 north of this line also point to the presence of oceanic water converging southwards to this position. 

 Off Walvis Bay, and to the north of this warm wedge, the water was cooler again, but both the 

 salinities and temperatures are higher than usual for the coastal water, the inshore values of 35-15 % 

 and 1 7 C. being more suggestive of some admixture between the two types of surface-water. At the 

 western end of this line of stations, in 23 S., there was again a sudden increase of temperature and 

 salinity into the northern boundary of the warm wedge, with temperatures of over 19 C. and salinities 

 over 35-2o% . 



20- 

 S 



25- 



30- 



.CAPE FRIO 



[MOWE POINT 



I0°E 



ORANGE 

 R. 



Fig. 11. Distribution of temperature at a depth of 200 m., survey I, March 1950. 



To the north of 23 S. the oceanic waters extend in a thin surface-layer apparently pressing towards 

 the coast between 22 and 20 S. 



Along the coast the cooler water becomes more and more confined, and eventually to the north of 

 1 9 S it appears to converge strongly with the very warm offshore waters (> 22 C.) in a series of 

 eddies about 25 miles from the coast. Finally all trace of it disappears in 16 S., where at 15 miles 

 offshore a temperature of 26 C. was recorded. This whole region between 16 and 19 S. is typical 

 of a convergence region, with very sharp and considerable variations of temperature. Probably the 

 observations demonstrate a compression of the normal convergence between subtropical and tropical 

 surface water, resulting from the presence along the coast of water so abnormally cool for such 

 latitudes. This marked the northern limit of the upwelling region in March 1950. 



