Meanders 



131 



TABLE 6 



Percentage of Total Transport Beneath Selected Depths at 



Different June Hydrographic Sections Along the Gulf Stream 



(2000 Meter Reference Level) 



Sotirce: Stommel (1953, table 2). 



thick, moving at 200 cm. /sec. with a density difference of A/9//9 = 2 x 10~^, is 

 critical. The wavelength of the 'just unstable' perturbation corresponding 

 to this choice of parameters is 180 km. All other wavelengths are stable 

 and do not grow. It is interesting that this wavelength corresponds very 

 closely to that of the large stationary meander observed to grow and detach 

 into an eddy (see Chapter V), but other admissible choices of parameters 

 would have led to poorer agreement. 



It is important to emphasize that the meander theory presented here is 

 not complete or proven, but merely suggestive of a type of wave motion 

 which may possibly dominate the dynamics of meanders. If the energy of 

 meanders is absorbed from the potential energy of the cross-stream mass 

 distribution rather than from the kinetic energy of the flow, the meanders 

 are a part of the thermohaHne circulation of the ocean. 



The adjustments which the water masses on either flank of the Gulf 

 Stream must make during the passage of a series of meanders should also be 

 an interesting subject of study. Recording pressure gauges set on the 

 bottom of the ocean, or on sea mounts, might give indications of these 

 motions. Unfortunately, the bathythermographic data on hand are not 

 sufficient for any statistical study of fluctuations of properties in the slope 

 waters and coastal waters. 



There is no certainty, of course, that the growth of the meanders observed 

 in the Gulf Stream is necessarily due to an instability of the flow such as 



9-2 



