274 



WOOSTER AND RE1D 



[CHAP. 1 1 



shore to be further evidence of sub -surface flow from the north. Similarly, 

 evidence of sub -surface poleward flow off" the Canary coast was inferred by 

 Montgomery (1938) from the distribution of properties and can be traced as far 

 as 20°N on the 200-db chart (Fig. 15). 



The relation between coastal upwelling and counterflow at depth has been 

 discussed by Yoshida and collaborators (Yoshida, 1955; Yoshida and Mao, 

 1957; Yoshida and Tsuchiya, 1957; Yoshida, 1958), but the exact nature of 

 the boundary processes is not yet well understood. 



(a) 



160' 140° 120 



100° 80° 



(b) 



160° 140° 120° 100 



Fig. 15. Geostrophic circulation at 200 m (dynamic height anomalies, 200 over 1000 db.) 

 (Prepared by Reid from a variety of Pacific data ; Atlantic derived from Defant, 

 1941.) 



B. Subpolar Eastern Currents 



Where the continents extend to sufficiently high latitudes, they form a 

 barrier to the west-wind drift and cause some portion of the waters to turn 

 poleward. These poleward currents form the eastern limbs of the subpolar gyres 

 and are observed in the North and South Pacific and in the North Atlantic. 

 They are similar to the subtropical eastern currents in that they are broad and 



