1S4 
PACIFIC SCIENCE, Vol. IX, April, 1955 
y =--~a ( 60° S ) 
Fig. 1. A rectangular ocean comparable in size to the Pacific Ocean. 
mass transport was inadequate for its east-west variation. Thus, the solution smoothed 
out the western currents and boundary vortices which were apparent in Munk’s paper. 
The mass transport method which has been adopted by Defant (1941), Stockmann 
(1945-46), Sverdrup (1947), Reid (1948), Munk (1950, 1951), and recently by Hansen 
(1952) is surely eminent, especially in that it enables us to reduce the analysis to two 
dimensions and makes the mathematical procedure very simple. Moreover, it is not 
necessary for us to consider the vertical variation of density and vertical coefficient of 
eddy viscosity. These authors have indeed contributed greatly to the solution of many 
important problems of oceanic circulation by this method. The author himself also em- 
ployed this method several times in discussing the problems in this direction. However, 
it is impossible for this method to show how the wind-driven circulation varies in a vertical 
