2. Statement of the Problem 



2.1 Outline of Procedure 



The basic premise is that the mass transport calculations tabulated by Fofonoff (1960) 

 describe the total transport, and that they can be used as reference values for transport 

 calculations by the dynamic heights method. The procedure for determining these 

 reference values is as follows: 



a. The geostrophic mode of the total transport is extracted from Fofonoffs tabula- 

 tion for the section separating two oceanographic stations. 



b. Transport through the same section is computed from the dynamic heights at 

 the two stations. These dynamic height calculations are based on a level at 

 4,000 or 5,000 meters, whichever more nearly equals the mean depth of the 

 section. 



c. The transport determined in b (as described by the dynamic heights) is the 

 total baroclinic transport (provided the flow due to internal structure vanishes 

 at the bottom) and the difference between the transports determined by methods 

 a and b must be the barotropic transport. This barotropic transport divided 

 by the water density and the area of the section gives the barotropic velocity. 



d. Combining the barotropic velocity with baroclinic velocities determined from 

 the dynamic height calculations results in a description of the total geostrophic 

 flow through the section. If the assumption in c (that baroclinic flow is zero at 

 the bottom) is not valid, then the division of the flow into barotropic and baro- 

 clinic modes is indeterminate; but the description of the total geostrophic flow 

 and its variation with depth is still valid. 



To establish a basis in theory for the method, to determine the limitations of (and the 

 assumptions made in) Fofonoffs (1960) transport calculations, and to justify using his re- 

 sults in the present manner, it is necessary to develop applicable expressions for transport. 

 This has been done in appendix I. Based on Fofonoffs (1962) treatment of Munk's (1950) 

 wind-driven flow formulation, the expressions developed for barotropic velocities «& and 

 Vb are: 





Ub 



p,„hRA<]) 

 (^-<K,)-£ V E R cos ^k-( XK "~ Xx " 



Xll \ J . 



Vh ~ T^ 771 (35a, b) 



pmhR cos </>AA. 



In (35a), i/> is a transport function for total transport, and so the first term in the numerator 

 on the right expresses the total transport through a meridional section. Zonal Ekman 

 transport per unit length along the meridian is denoted Ue, R is the radius of the earth, 

 and Ac/> is a change in latitude, so the second term is Ekman transport through the same 

 section. The final term is baroclinic transport, expressed as the difference in potential 

 energy anomalies, X-, across the section, divided by the Coriolis parameter./. The de- 

 nominator on the right side is the mean density, p,„, times the area of the section, hRAcp. 



