Linear Theories — Viscous 101 



westerly winds over the eastern Atlantic would make itself felt in 

 a much higher meridional wind factor [table 5], and it can be de- 

 monstrated that the discrepancy between computed and observed 

 transports could be largely accounted for. We are therefore led to 

 propose a higher value of C^ at low wind speeds. The transports of 

 the Gulf Stream and Kuroshio current are, after all, probably as 

 good an indicator of the overall stress exerted by the winds on the 

 ocean as any of the measurements on which the value of C^ is now 

 based. 



There have been several attempts to obtain better agreement between 

 computed and observed transports. I have expressed my own views in 

 Chapter XI . Hidaka ( 1 949 a) has performed the analysis of the linear theory 

 of wind-driven ocean currents in many different forms. In one study, using 

 spherical coordinates, he has obtained a value of transport of the Kuroshio 

 more nearly equal to that observed than has Munk. It is difficult to see 

 how a change of coordinates can make so great a difference in the transport. 

 Recently, Sarkisyan (1954) has carried out a numerical study dynamically 

 similar to Munk's, but in an ocean shaped very much hke the real North 

 Atlantic. He obtained transports for the Gulf Stream of between 70 and 

 90 X 10^2 g/sec, but as I do not know the details of the wind-stress 

 distribution which he used, the significance of his close agreement is not 

 clear to me. 



Owing to the existence of a biharmonic operator in the viscous term of 

 the governing equation, there is an exponentially decaying line of vortices 

 to the east of the counter current, centered along the axis 0,, (fig. 63). There 

 is no good evidence that such a line of vortices actually exists. By some 

 stretch of the imagination one might find confirmation in the charts of 

 Felber (1934) and Defant (1941), but to my mind this is rather special 

 pleading. 



Beyond the vortices, over most of the central regions of the ocean the 

 solution reduces to 



(39) X,= l-^; ^=-^i. (40) 



This corresponds, for zonal winds, to the solution of the equation given by 

 Sverdrup(1947, p. 322): 



^=y5-i curler, (41) 



which does not contain lateral-stress terms. This important relation is dis- 

 cussed further m Chapter XI. 



Munk and Carrier (1950) have also investigated the effects of variously 

 shaped ocean basins — in particular, a triangular one, which fits the North 



