Thermohaline Features 



159 



associated with a hypothetical thermohaHne process, in addition to an 

 Ekman wind-drift divergence at the top of the ocean. These additional 

 divergences are compensated for in each layer by the divergence of the 

 meridional geostrophic flow. 



THE TRANSPORT OF THE WESTERN CURRENTS 



The role of the western currents in the ocean is to maintain continuity of 

 mass in the ocean basins bounded by coasts. Generally, the solutions of the 

 interior vorticity equations lead to an accumulation of water at certain 

 latitudes and in certain layers, and conservation of mass can only be restored 

 by rapid western currents in which inertial or viscous forces become of 

 dominating importance. In order to compute the transports in the upper, 

 G^, and lower, G^, layers of the western currents, we need merely make use 

 of the interior solution for the north transport component and the equation 

 of mass continuity (11) in its integrated forms: 



|-jif«+|-jf„=(p«,),. 

 |jtf«+Jif„=-(^«,),. 



(16) 

 (17) 



Terms from the differentiation of the Umits of integration do not appear, 

 since z = 2^ is a level of no motion. Let us now consider an ocean bounded at 

 i/ = by the a;-axis and by meridional walls at a; = 0, r. The boundary con- 

 dition at x = r is taken as My.y = My.2 = 0, following Sverdrup (1947). The 

 quantities My■^^ and My^, are known from equations (15), and hence we may 

 find Jf^i, M^^: 



d 



M^^{x 



J X 



^> y) = 



J X 



dy 



Myj^+pWi 



--^y^y^-P'^i 



dx, 



dx. 



(18) 



(19) 



In general we will be led to the result M^i 4= and M^^ 4= at x = 0. These 

 fluxes must be regarded as absorbed by the boundary layer or western 

 current solution, hence the western current transports are given by 



rr ry 



(^i(y) = hiy)+\ pwdydx, 



J J 



G^{y)=h{y) 



[) 



pwdydx. 



(20) 

 (21) 



