NOTES ON THE WIND-DRIVEN OCEAN CIRCULATION 



I. Introduction 



Ocean currents with the greatest velocity are observed in 

 the upper layer of the sea with depths varying between two hundred 

 and two thousand meters. This circulation is generated and main- 

 tained mainly by the driving force of the wind. The question is, 

 to what extent can the observed conditions be explained on the basis 

 of the hydrodynamical theories as they have been developed up to 

 the present time? 



The problem may be divided into two parts. Part one is con- 

 cerned with the "gross" or general features of the oceanic circu- 

 lation, and part two with the details which recently have been re- 

 vealed in some individual branches of the general circulation by means 

 of refined techniques for oceanographical observations. 



There is no doubt that not only the details but also the gross 

 features of the oceanic circulation are the result of a complicated 

 mechanism in which different forces or factors are involved. It is 

 possible that the mechanism which governs some outstanding "gross" 

 features, such as the "intensification" of the Gulf Stream along 

 the east coast of North America and the "intensification" of the 

 Kuro Shio along the coast of eastern Asia, is essentially the same 

 as the mechanism which may account for some "details" as observed 

 in the western North Atlantic and in other individual branches of 

 the general current systems of the oceans. Such details are, for 

 example, the series of overlapping currents "arranged somewhat 

 like the shingles on a roof" (Iselin, 1952), and certain "counter 

 currents." It seems to be the tendency of ocean currents in strati- 



