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ABSTRACT 



Estimates of poleward transport of heat based on the heat balance of 

 the ocean surface indicate that ocean currents in the North Atlantic trans- 

 port from 10-20 percent as much heat poleward as the entire atmosphere in 

 middle latitudes. Similar measurements for the Pacific based on heat balance 

 are less reliable . An analysis of hydrographic data obtained during the IGY 

 and NORPAC expeditions permits the examination of different components of 

 the heat transport. Of particular interest are the two components associ- 

 ated with the thermohaline circulation, and the wind-driven subtropical 

 gyre . The poleward heat transport by these two agencies is of the same 

 order of magnitude . In the North Atlantic the thermohaline circulation 

 and the wind-driven gyre both transport heat poleward. On the other hand, 

 present evidence on the circulation of the North Pacific suggests that 

 there these two important components tend to cancel each other. The rela- 

 tive contribution of smaller scale, transient motions is unknovm. 



A numerical model is proposed to gain further insight into the mech- 

 anism of poleward heat transport. Solutions are obtained for an enclosed 

 basin of planetary scale bounded by two parallel meridians. The equations 

 of the model closely correspond to the complete Navier- Stokes equations 

 with viscosity and conductivity terms replaced by equivalent terms repre- 

 senting the effects of small-scale diffusion of momentum and heat, respec- 

 tively. For the case of no wind, scale analysis suggests that the total 

 poleward heat transport in the basin should be proportional to 



icL2Ae*/d 



where ic is the diffusion coefficient in the vertical, Ae*/L is the north- 

 south temperature gradient imposed at the air- sea interface, and d is the 

 scale depth of the thermocline . The constant of proportionality obtained 

 by the numerical calculations is consistent with estimates of poleward 

 heat transport based on the heat balance method, and empirical determina- 

 tions of tc . 



