346 FOFONOFF [sect. 3 



There remains an arbitrary constant C to be determined by the boundary 

 conditions at the eastern boundary. We can obtain a boundary-layer equation 

 similar to (73) for the region adjacent to the eastern boundary {x — L). How- 

 ever, only the term with exponential coefficient ai and the constant Co of (74) 

 do not diverge with distance from the boundary. Thus, we have one less 

 constant to determine than we had at the western boundary and, consequently, 

 can evaluate the arbitrary constant in (77). If we neglect the curl of wind stress 

 in the boundary layer, we obtain the simple result i/( = )/rj = and Ai = 0. The 

 constant must, therefore, have the value 



' ^Tsy _ drsx 



8x By 

 so that 



C = iQ2If-«_fl2id:,, 



In neglecting terms of the order of W/L, we have eliminated the boundary 

 layer altogether at the eastern boundary. The boundary-layer equation does 

 not yield a strong flow along the east coast in contrast to its behaviour at the 

 western boundary. If terms of the order of W/L are retained, i.e. curl of wind 

 stress in the boundary region, we find that the tangential component of trans- 

 port is diminished by friction for distances of less than W = {AhI^Y''^ from the 

 eastern boundary. The effect is to diminish slightly the magnitude of the 

 interior transport function. By neglecting the eastern boundary layer, we can 

 extend the approximate solution given by (76) and (78) to the entire ocean. 



The function T(|), defined in (75), is plotted in Fig. 2. It exceeds its asymp- 

 totic value by about 17% at | = 3.73 and decreases for higher values of |. For 

 ^^=108 cm2 sec~i and jS = 2xlO~i3 cm~i sec~i, the characteristic width W 

 is 80 km. Hence, for these values of the parameters, the transport function 

 reaches its maximum magnitude about 300 km from the western boundary. 

 Eastward of the maximum, there is a region of counterflow amounting to 

 roughly a sixth of the maximum transport. The counterflow occurs both in 

 interior flow approaching the western boundary and in flow leaving the 

 boundary. 



A comparison of the theoretical results obtained from the analysis of stress- 

 driven baroclinic circulation with geostrophic transport computed from 

 oceanographic data for the Pacific and Atlantic Oceans was made by Munk 

 (1950). He found the counterflow eastward of the Gulf Stream and Kuroshio 

 to be in reasonable agreement with theory. However, counterflow is observed 

 also between the strong meridional flow and the coast. This feature cannot be 

 explained in terms of the viscous boundary layer. 



The maximum transports computed from (78) are about half of the geo- 

 strophic transports. As the maximum transport is relatively insensitive to the 

 magnitude of eddy viscosity, the discrepancy had been attributed to incorrect 

 estimates of the mean-wind stress particularly at low wind speeds. Stommel 



