for by the presence of a vigorous recirculation of mixed water in a 

 counterclockwise eddy between the Labrador Current and the margins 

 of the North Atlantic Current. The larger deficiency at section U 

 during the second survey was the result of the Atlantic Current salient 

 turning back a considerable portion of the Labrador Current north of 

 section U and reducing the amount of recirculating mixed water at 

 both sections U and W. During the third survey the situation at 

 section W was very little changed but section U contained more of the 

 recirculating mixed water and was further augmented by the estab- 

 lishment of the Grand Banks eddy. 



As in previous years the course of the outer boundary' of North 

 Atlantic Current water, based on a criterion of 34.95 %o salinity 

 corresponding to a temperature of 6° C, was estimated for each of the 

 three surveys. The area between the boundary and reference rhumb 

 lines ^ was measured for each survey. 



Adjustment of these areas was made by the subtraction of 10,000 

 square kilometers for each million cubic meters per second volume of 

 flow past section U. 



For the 8-year period 1934-41 a relationship, reported in Bulletin 

 No. 31 of this series, was found to exist between the differential 

 changes in sea level, Charleston-Bermuda, and the adjusted area in the 

 Grand Banks region 13^2 months later. F'rom this relationship the 

 adjusted areas predicted by tide gage readings in 1949 were computed 

 and compared with the actual areas as follows (unit of area 10,000 

 square kilometers): 



The disagreement between the adjusted area and the predicted 

 adjusted area for the first survey is not as bad as it would appear from 

 the tabulated figures when it is remembered that the adjustment for 

 the volume of flow at section U is intended to take into consideration 

 the water of the Labrador Current and Grand Banks eddy entering 

 the area from the north and that while the Grand Banks eddy was 

 very small at the time of this survey a considerable volume of recircu- 

 lating mixed water was included in the volume of flow past section U. 

 If the volume of true Labrador Current water passing section U is 

 taken as that at section T a Grand Banks eddy contribution to section 

 U of 0.8 would be re(iuired to make the adjusted area equal to the 

 pretlicted adjusted area. 



2 The 4.'')th parallel from I he hoiiiuliiry I" 19° W.. ihe 49th meridian thence to 43° N., and a rhumb line from. 

 43° N., 49° W., throimh 42° N., 47° W., eMcnded In Ihe Ixiundary. 



72 



