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These parcels are consequently warmer than the surrounding 

 water and in a position to transport heat across the mean flow 

 in the direction of the ocean. This would be equivalent to the 

 existence of a negative correlation between the vertical motion 

 and the instantaneous cross stream velocity. Such a possible 

 mechanism throws^ however, no light on the question of the 

 cause of the countergradient heat flux. Since the meanders 

 draw their energy neither from the kinetic energy of the main 

 stream (Webster 1961b), nor according to this study from the 

 available potential energy of the mean current, these eddies 

 must have an outside source of energy. The following possi- 

 bilities seem to be left: (l) the meanders at or near the surface 

 are forced by the ocean circulation at greater depths (2) the 

 meanders are forced by the tropospheric circulations (3) the 

 meanders receive energy by advection or pressure work at the 

 vertical boundaries. It might be thought that the expression 

 for C » is inadequate in that it involves only the temperature 

 effects and not those due to the salinity. A more accurate sub- 

 stitute incorporating salinity would formally 



