the surface water offshore and produce continuous vertical circulation. 

 Upwelling occurs between about 30" and J'S as shown in Figure 10 and 

 is limited mainly to the upper 200 to 300 meters. South of 15°S, 

 upwelling is less intense. 



Results of direct current measurements Indicate a southward 

 subsurface flow along the edge of the Continental Shelf at depths 

 below 300 meters between northern Peru and at least as far south 

 as ifl°S. Off Peru and northern Chile, speeds to O.k knot were 

 recorded; like the surface current, the speed of this underctirrent 

 is weaker in the southern part of the Peru Ciirrent, especially 

 south of 15°S. Figure 9 shows results of direct subsurface current 

 measurements at four locations within the Peru Current. 



VoIuhe transport of this undercurrent has been conputed at 

 about 21 X 10° m3/sec at 5°S, decreasing to about 3 x 10° m3/sec 

 at 15°S. The decrease in volume of southward flow occurs mainly 

 in the region of strongest upwelling and may be due to continual 

 loss through vertical and horizontal transport. 



31 



