89 



Atlantic Current above 2,000 decibars between these two stations are 

 too low by 6.6 centimeters per second, whence the volume of flow of 

 the Atlantic Current past this section becomes 39.3 + 25.5 + 9.7, or 

 74.5 million cubic meters per second northerly. 



An examination of figure 41 indicates that the deep water velocity 

 past the section running southeasterly from the Tail of the Grand 

 Banks is much less than it is east of Flemish Cap. Again taking the 

 2,000-decibar surface as motionless, the average velocity at the 3,500- 

 decibar surface between stations 2478 and 2480 is 2.6 centimeters per 

 second southerly whereas if the 3,500-decibar surface is motionless 

 this represents the average northerly velocity between these two 

 stations at the 2,000-decibar surface. If half this figure or 1.3 centi- 

 meters per second be taken as the average velocity of the water be- 

 tween the 2,000 and 3,500-decibar surfaces under the Atlantic Current 

 at this section, the resulting volume of flow between these two sur- 

 faces and between stations 2475 and 2481 is about 5.9 million cubic 

 meters per second, directed northerly if 3,500 decibars is the motion- 

 less surface and directed southerly if 2,000 decibars is the motionless 

 surface. Furthermore, if the 3,500-decibar surface is motionless any 

 determination of the volume of flow above 2,000 decibars relative to 

 that surface will be based on velocities wliich are uniformly too low 

 by 2.6 centimeters per second, which over the distance between sta- 

 tions 2475 and 2481 and from to 2,000 decibars will result in a dis- 

 crepancy of 15.8 milhon cubic meters per second. Thus if the 3,500- 

 decibar surface is motionless, and if we assume that the Atlantic Cur- 

 rent passing the Flemish Cap section is the same as the Atlantic 

 Current passing the southern section, a determination of the volume 

 of flow past the latter section from to 2,000 decibars, relative to 

 2,000 decibars should be 74.5, 5.9, 15.8, or 52.8 mOlion cubic meters 

 per second; but if the 2,000-decibar surface is motionless, the result 

 should be 39.3 million cubic meters per second. 



Numerical computation, again checked by planimeter measure- 

 ments of a velocity profile of the Atlantic Current past this southern 

 section, actuafly showed a volume of flow of 42.8 miflion cubic meters 

 per second, which is much nearer the figure of 39.3 than the alternate 

 figure of 52.8. Thus it is considered that from another standpomt 

 the 2,000-decibar surface is indicated to be more nearly motionless 

 than the 3,500-decibar surface. 



Attention must again be directed to some of the assumptions in- 

 volved in the foregoing; namely, that the deep water velocities are 

 sufficiently reliable to make the check significant, that the vertical 

 distribution of the deep-water velocity is near enough to being linear 

 for purposes of the check, and that the volume of flow of the Atlantic 

 Current past the two sections is the same. Further consideration of 

 the volumes of flow past the various sections shows the following, in 



