Current water was the T-S relationship of 6° C corresponding to 

 34.95 °/ . The area considered was that between the boundary so 

 defined and the fixed limits formed by the 45th parallel, the 49th 

 meridian, and a rhumb line extended from 43° N., 49° W., through 

 42° N., 47° W. This area was adjusted by the subtraction of 10,000 

 square kilometers for each million cubic meters per second volume of 

 flow of the Labrador Current entering the area at the northwestern 

 corner (section U). A remarkably good correspondence was found 

 to exist between the difference in sea level Charleston-Bermuda and 

 the adjusted area I31/2 months later for each of the 28 surveys made 

 during the ice seasons of 1934-41. 



Since the postwar resumption of ice-patrol oceanography, one 

 survey was carried out in 1948 and two in 1949. As the station net- 

 works of these surveys do not extend seaward far enough to include 

 all parts of the Atlantic Current water boundary in the sector under 

 discussion, the boundary cannot be delineated with accuracy. In each 

 case an estimate has been made of the course of the boundary and 

 the resulting area has been adjusted for the volume of flow past sec- 

 tion U. Whether from errors in estimating the course of the Atlantic 

 Current water boundary, or from more basic causes, these three 

 surveys do not show the same good correspondence found for the 

 earlier 8-year series of measurements. Expressed in units of 10,000 

 square kilometers, the adjusted areas differed from the values ex- 

 pected from tlie changes in sea level, Charleston-Bermuda, by the 

 following amounts: June 1948, 5.1 too large; April 1949, 1.4 too 

 small; May 1949, 5.0 too large. Thus, some of the evidence does 

 not clearly support the assumption that the position of the boundary 

 is controlled by the volumes of flow of the Labrador Current and the 

 Atlantic Current. 



In 1948 the T-S characteristics of the different water masses in the 

 Grand Banks region could not be established except in general terms, 

 partly because of the small number of stations available for examina- 

 tion and partly because the mixed water did not have the uniformity 

 which usually has characterized it as a virtual water mass. The sur- 

 veys of April and May, 1949, provided enough observations to deter- 

 mine the approximate course of the T-S curves representing the 

 Labrador Current water, the Atlantic Current water, and the mixed 

 water and these are shown in figure 17 as solid lines. The broken lines 

 represent the T-S relationship found during the 8-year period 1934-41. 

 Except for the ui)per layers, but two stations from the April survey 

 (3767 and 3779) could not be properly classified, while three stations 

 (3852, 3858 and 3869) from the May survey were atypical. In dis- 

 carding observations fi-om the upper layers at any station, we are 

 in reality recognizing tlint at those stations the mixing of water from 

 the parent water masses has not been carried far enough to attain 



62 



