DAVIS STRAIT AND LABRADOR SEA 99 



margin of the outer countercurreiit. Tlic combined set of this mixed 

 water in 1928, easterly near the fifty-fifth pai'allel of latitude, cor- 

 responds well with the surface circulation farther offshore as re- 

 ported by Soule (1936). 



The temperature and salinity maps of the 200- and 400-meter levels 

 (figs. 56 to 59) indicate the presence of water from the West Green- 

 land Current near the American slope. This feature is especially 

 pronounced in the 400-meter temperature map (fig. 58) in the offing 

 of Hudson Strait. The drift of this water southward along the Amer- 

 ican slope (figs. 58 and 60) is also indicated in the band of higher 

 temperatures at 400 and 600 meters along the American slope than 

 adjacently offshore in the Labrador Sea. 



A strong temperature and salinity gradient is to be noted along 

 the Baffin Land slope at depths of 400 to 600 meters (figs, 58 to 61) 

 where the underside of the Baffin Land current and the West Green- 

 land Current abut. 



The temperature and salinity maps for the 200-, 400-, and 600- 

 meter levels all record pools of water colder and saltier than their 

 surroundings in the depressions of the Labrador shelf. This indi- 

 cates that offshore water floods in over the shelf, where it becomes 

 pocketed and is chilled later during wanter. The fact that intrusions 

 of the slope water are occasional is indicated in the survival of the 

 above-mentioned relics as late as midsummer. The two most obvious 

 means of transportation of the deeper slope water in over the con- 

 tinental shelf are (a) a lateral bending of the current temporarily in 

 over the shelf, or (h) a screwing of the current. 



VERTICAL DISTRIBUTION OF THE TEMPERATURE AND SALINITY 



The vertical distribution of temperature and salinity in the 10 

 sections, H to Q, already discussed, is illustrated on figures 62 to 64. 



Probably the most impressive feature common to all the profiles 

 is the shelf of frigid water which extended from near the coast 

 out to the continental edge. Except for a thin, isolated surface film 

 and an undercutting by the warmer isotherms on the continental 

 edge, the shelf column is dominated by frigid water. The shallow- 

 ness of the shelf waters in the American sector, and also their loca- 

 tion north of the fiftieth parallel of latitude, might easily ascribe 

 the low temperatures to local winter chilling. Reference, however, 

 to the series of coiTesponding profiles of velocity (figs. 48, 50, and 

 51), as well as to the surface current map (fig. 47), conclusively estab- 

 lishes most of the minimum temperatured water as a transport first 

 of the Baffin Land Current and then of the Labrador Current from 

 points farther north. 



An equally striking feature common to the profiles is the distri- 

 bution of the salinity across the shelf, the isohalines sloping upward 

 from inshore near the bottom to near the surface over the continental 

 edge. This position of the isohalines portrays primarily a reservoir 

 of river discharge and other land drainage which expands offshore 

 across the shelf in the light surface layers. Melting sea ice, usually 

 more abundant along the coast in these latitudes than farther out 

 to sea, also probably augments the supply. On the other hand the 



