256 



WOOSTEK AND KEID 



[CHAP. 11 



These differences reliect the surface salinities of the source regions in the 

 various oceans. It should also be noted that coastal upwelling seasonally tends 

 to increase or decrease surface salinity depending on whether salinity increases 

 or decreases with depth. For example, in the California Current, upwelling 

 causes an increase in surface salinity whereas in the Peru and Benguela Currents 

 its effect is to decrease surface salinity. 



C. Flow 



Surface ocean flow is predominantly in the sense of the prevailing winds, 

 which are anticyclonic about the mid-ocean highs and cyclonic about the sub- 

 polar lows. This similarity between atmosphere and ocean circulation is, of 

 course, more than coincidence, and many of the basic features of the eastern 

 currents are contained in the general theory of the wind -driven circulation 



1 60° 140° 120" 100* SO' 



160° 140° 120° 100° 80° 



20° 0° 20° 40° 60° 



(a) 



(b) 



Fig. 2. Average surface drift for Northern -Hemisphere summer. (Adapted from Dentschen 

 Seevxirte, 1942, and U.S.S.R. Ministerstvo Oborony, 1953.) 



