Surface Waters of the North Atlantic Ocean. 



485 



mouth of Davis Strait, eastward in mid- Atlantic, and north-eastward 

 in the eastern region. In spring and autumn the movement is more 

 easterly over the whole distance, and a larger quantity of water from 

 the Labrador stream is therefore carried eastward. 



3. The water banked up in the manner described in (1) escapes 

 partly downwards, partly southwards, and partly northwards. It 

 occupies the whole of the eastern basin of the North Atlantic, and to 

 the north it extends westward to Da\as Strait, being confined below 

 300 fathoms depth by the ridges connecting Europe, the Faeroes, 

 Iceland, and Greenland. Above that level it escapes northward by a 

 strong current through the Faeroe-Shetland Channel and between 

 Faeroe and Iceland, and by the two branches of the Irminger stream, 

 one west of Iceland the other west of Greenland. 



(As it seems desirable that this northerly current should have a 

 distinctive name, it might be well to call it the European stream, and 

 its branches the Norwegian, Irminger, and Greenland streams respec- 

 tively.) 



The strength and volume of the European stream is liable to con- 

 siderable variation, according to the form and position of the Atlantic 

 anti-cyclone, which causes the amount of banked up water, and the 

 proportions escaping northward and southward, to vary. It is also 

 modified by the strength and direction of the surface drifts in its 

 course. It is, however, always strongest in summer. 



4. The Norwegian stream is by far the largest branch of the 

 European, and it traverses the Norwegian Sea and enters the Arctic 

 Ocean. The warm water thus sent northward melts enormous quan- 

 tities of ice, and the fresh water derived from the ice moves southward 

 in autumn, chiefly in a wide surface current, between Iceland and Jan 

 May en, which may entirely cover other parts of the Norwegian 

 stream. Part of the surface water also comes southward through the 

 Denmark Strait, but the amount is much smaller, probably chiefly 

 because the melting of the ice is slower, and the channel is longer 

 blocked. 



The Greenland branch of the European current also causes melting 

 of ice in Davis Strait, but the warm winds from the American con- 

 tinent and the water received from the land are probably more effective 

 in increasing the volume of the Labrador current. 



5. The water from the melted ice is spread over the surface of the 

 North Atlantic during late autumn and winter by the increasing 

 drift circulation, and it is gradually absorbed by mixing with the 

 underlying water. 



6. The circulation described is liable to extensive irregular varia- 

 tions, corresponding to variations in the atmospheric circulation. 



