A Theoretical Study on the General Circulation 
of the Pacific Ocean 1 
Koji Hid aka 2 
INTRODUCTION 
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 maintaining the oceanic 
circulation was undertaken by Sverdrup (1947). According to his result, the oceanic cur- 
rents in the eastern part of the Equatorial Pacific are largely fed by the energy of the 
winds blowing over the surface of the ocean. Reid (1948) confirmed this conclusion. At 
nearly the same time, 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 force. Altogether, these investigations 
have enabled us to ascribe the major part of the oceanic circulation 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 Munk and Carrier (1951) treated the circulation of the North 
Pacific, regarding this ocean as a triangular basin. They could explain the pattern of the 
actual ocean circulation very well, so that there seems to be little left to discuss on this 
subject, as 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 co-ordinates 
were used, thus taking the effect of the sphericity of the earth into account. But both 
assumptions of 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 co-ordinate system, except in the magnitude of the mass 
transport. These facts show us that we have only to treat the circulation driven by a 
zonal wind system. 
An earlier paper (Hidaka, 1950) contained a theory of ocean circulation using the cur- 
rent velocity in place of the mass transport. The analysis was complex because the vertical 
variation of the movement of water had to be taken into account. The result was, none- 
theless, quite ridiculous; no perceptible concentration of the streamlines toward the west 
coast could be found. The explanation for this result was that the approximation to the 
1 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. Manuscript received July 2, 1953. 
2 Geophysical Institute, Tokyo University, Tokyo, Japan. Visiting Graduate Professor, 1952-53, Depart- 
ment of Oceanography, Texas Agricultural and Mechanical College. 
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