it would seem that the explanation of the delioiency in volume of 

 flow of the Labrador Current in the Grand Banks region accom- 

 panied by a subnormal mean temperature is to be sought in a pos- 

 sibly decreased contribution from the "West Greenland Current. 



In 1948 a beginning was made in the study of the area just north- 

 ward of the Grand Banks where the Labrador Current divides into 

 a western branch which flows southward along the Avalon Peninsula 

 of Xewfoundland, and an eastern branch which follows the eastern 

 edge of the Grand Banks. Three sections, disposed in the form of 

 a triangle which included the branch point, were occupied. In 1949 

 this triangle was occupied twice; once during the period 3-6 June, 

 and again about two weeks later on 17-20 June. 



Figures 18 and 19 show the dynamic topography at the sea surface 

 and at the 100-decibar surface respectively, derived from the first 

 occupation of the triangle; and figures 20 and 21 show the topography 

 at similar surfaces from the second occupation of the triangle. From 

 figure 18 it is concluded that bergs crossing the 49th parallel east- 

 ward of about 51°45' "W. Avould probably follow the eastern branch 

 of the current; that bergs crossing the 49th parallel westward of 

 about 52°00' AV. would probably follow the western branch along 

 the Avalon Peninsula ; and that bergs crossing this parallel at inter- 

 mediate longitudes would probably strand on the northern slope of 

 the Grand Banks. Figure 20 indicates that these critical longitudes 

 were much the same (51°50' W., and 52°00' "\V., respectively) during 

 the second occupation of the triangle. 



One of the questions of primary importance to the practical appli- 

 cation of studies of the oceanography of this region is whether the 

 current pattern at the sea surface is sufficiently representative of the 

 circulation in the upper 150 or 200 meters to permit the movement 

 of deep-draft bergs to be deduced from the dynamic topography of 

 the sea surface. Comparison of figures 19 and 21 with figures 18 and 

 20 respectively shows a very encouraging similarity of current pattern 

 at the sea surface and at the 100-decibar surface for each of the two 

 occupations of the triangle. 



In considering figures 18 through 21, it should be borne in mind 

 that the occupations of the triangle differ from the usual survey in 

 that the measurements have been confined to the periphery of the area 

 involved and that consequently the deduced current pattern within 

 the triangle is subject to errors which increase with the distance from 

 the sides of the triangle. Thus, while the points of entry or emergence 

 of the dynamic isobaths are well defined, their courses within the 

 triangle can be shown with much less certainty. 



The drift of an iceberg which entered the area at about the time 

 of the first occupation of the triangle added information on the ques- 

 tion of whether or not the dynamic topography of the sea surface 



65 



