A THEORETICAL STUDY ON THE GENERAL CIRCULATION 

 OF THE PACIFIC OCEAN * 



By Koji HiDAKA** 



L iNTRODUCnON 



The following discussion is one of the results of the research for 

 determining the vertical structure of the wind-driven circulation in an 

 enclosed basin comparable in size to the Pacific Ocean. 



The first attempt to verify the effect of prevailing winds in main- 

 taining the oceanic circulation was undertaken by H. U. Sverdrup 

 (1947). According to his result, the oceanic currents in the eastern 

 part of the Equatorial Pacific are largely fed by the energy of the winds 

 blowing over the surface of the ocean. R. O. Reid (1948) also confirmed 

 this conclusion. At nearly the same time Henry Stommel (1948) could 

 explain the intensification of the wind-driven currents along the west 

 coast of an ocean by assuming the existence of horizontal friction and 

 the meridional variation of Coriolis forces. These investigations alto- 

 gether have enabled us to ascribe the major part of the oceanic circu- 

 lation to the result of the superincumbent wind system prevailing over 

 the oceans. 



Munk (1950) published a very important paper on the wind-driven 

 circulation of the oceans. The next year (1951) he treated the circu- 

 lation of the North Pacific, regarding this ocean as a triangular basin. 

 He could explain the pattern of the actual ocean circulation very well, 

 so that at the present, there seems to be little room left for us to discuss 

 much more on this subject, so far as the major characteristics of the 

 general circulation in the Pacific Ocean are concerned, 



Hidaka (1951) solved the problem of the general circulation which 

 would be produced by both zonal and anticyclonic wind systems. In 

 this computation spherical coordinates were used, thus taking the effect 

 of the sphericity of the earth into account. But both assumptions on 

 the wind distribution gave no essential difference in the results except 

 for the magnitude of mass transport. Moreover, the result for zonal 

 distribution gave no sensible difference in the pattern of the circulation 

 compared with Munk's which was derived by using a rectangular coor- 



• Contribution from the Department of Oceanography of the Agricultural and Mechanical 

 College of Texas, Oceanographic Series No. 42. Based in part upon work done under the 

 sponsorship of the Office of Naval Research and the Bureau of Ships. Previously published 

 in Pacific Science, 3(2): 183-220, 1955. 



** Visiting Graduate Professor 1952-53, Department of Oceanography, Texas Agricultural 

 and Mechanical College; Professor of Physical Oceanography, Tokyo University, Tokyo, Japan. 



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