Chapter VIII 



THE LABRADOR SEA 



The discussion in previous chapters has been devoted to the cir- 

 culation and physical character of the waters in the shelf and slope 

 regions and has been largely confined to the upper levels, the tropo- 

 sphere. The present chapter treats the offshore waters between 

 Greenland and Labrador and southward to the vicinity of the fiftieth 

 parallel and with special attention to the deeper levels, the strato- 

 sphere. 



SURFACE CIRCULATION 



In figure 122 is shown the dynamic topographic chart of the sur- 

 face with respect to 1,500 decibars based on the Marion observations 

 taken in 1928. The more rapid currents immediately offshore of 

 the Greenland and Labrador coasts and in the vicinity of Davis 

 Strait have been illustrated and discussed in chapters IV, V, and VI. 

 Figure 122 shows these currents and their interrelation as well a,s 

 the more slowly moving current in the central part of the area. 

 An area of weak current is shown southwestward of Cape Farewell 

 and the northward and eastward flowing borders of the Atlantic 

 Current is just discernible in about latitude 54° N., longitude 50° W. 

 Immediately south of this is what is probably the northern end of 

 the closed whorl between the Labrador Current, the Atlantic Cur- 

 rent margin, and Flemish Cap. Regarding the drift of east Green- 

 land bergs which reach Cape Farewell, reference is made to Smith 

 (1931, pp. 74-78). 



Figure 123 represents the dynamic topographic map of the sur- 

 face with respect to 1,500 decibars resulting from the survey made 

 by the General Greene in 1931. In this year the northwestern corner 

 of the Atlantic Current margin extended farther to the north and 

 west and was more pronounced than in 1928, The closed whorl 

 found in 1928 between the Atlantic Current and the Labrador Cur- 

 rent was not disclosed by the 1931 observations and probably was 

 situated southeastward of the limits of the survey. A notable fea- 

 ture in 1931 was the branching and eastward recurving of a portion 

 of the Irminger Current south of Cape Farewell as indicated by the 

 course of the 1,454.56 isobath in that locality. (See p. 51, ch. IV.) 



The dynamic topographic map of the surface with respect to 1,500 

 decibars obtained by the General Greene in 1933 is shown in figure 

 124. The high salinities observed in the central area (see ch. II) 

 account for the more rapid circulation offshore of the usual bound- 

 aries of the Labrador Current. Neither the closed whorl between 

 the Labrador Current and the Atlantic Current nor the northwestern 

 border of the Atlantic Current were present within the limits of the 

 survey unless that portion of the map eastward of longitude 50° W. 



167 



