DAVIS STRAIT AND LABRADOR SEA 27 



larly as to the range and degree of thermal and saline character of 

 the mass where and when observed. In this respect the employment 

 of temperature-salinity correlation graphs has been found helpful. 



Atlantic water, for example, is found at certain times off the Tail 

 of the Grand Banks with a temperature of 16° C, and a salinity of 

 36.00%o. Atlantic water off Cape Farewell at the same time, how- 

 ever, has, as might be expected, different criteria; a temperature of 

 about 6° C, and a salinity of about 35.00%o. Vestiges of Atlantic 

 water still farther north in the northern sector of the Labrador Sea 

 can be traced where the temperature is only about 4° C, and a 

 salinity of about 34.80%o. 



The w^ord "Arctic" has been used mainly to designate w^ater, the 

 temperature of which is so low as to indicate a far northern source. 

 In the present case, where the area extends beyond the Arctic Circle 

 itself, the term Arctic water is intended to signify water which has 

 originally flowed from a more northern point than where the ob- 

 servation in question was made. Reflecting, therefore, the frigidity 

 of its polar sources, Arctic water often has a minimum temperature 

 asi loAV as —1.7° C. Such water masses, when insulated by lighter 

 layers, may be transported great distances without appreciable 

 change in temperature, readings of —1.5° C. having often been ob- 

 served in latitudes as low as 43° near the Tail of the Grand Banks, 

 more than halfway from the Pole to the Equator. The salinity of 

 Arctic water lies between that of Atlantic and coastal, and for that 

 reason it is best identified by its temperature. 



Coastal water naturally is in the lowest brackets of salinity. The 

 term is associated primarily with land drainage and river discharge 

 and later as such water expands seaward over shelves or banks or is 

 transported along coastal slopes. Identification: is most easily made 

 during summer when coastal water from its lightness lies uppermost 

 and thus absorbs greater quantities of solar radiation. Winter chill- 

 ing, on the other hand, especially severe in the noi-thwestern North 

 Atlantic, may cool coastal water to temperatures approaching closely 

 that of minimum Arctic character. 



79020—37 3 



