CHAPTER XII 



CIRCULATION OF WATER AND ICE 



OF THE ARCTIC BASIN 



Section 144. Certain Information Concerning 

 the Balance of Water and Ice 



As we have seen, the Arctic Basin consists of a central, deep water part which is bordered 

 by the Kara, Laptev, East Siberian and Chukchi Seas north of the European- Asiatic continent and by 

 the Beaufort, North American and Lincoln Seas north of the North American continent. 



In the western hemisphere, of these seas, only the North American is a sea in the full sense 

 of the word. In the eastern hemisphere, only the southwestern part of the Kara Sea may be so re- 

 garded. All the other seas are, in relation to the central Arctic Basin, only gulfs with extremely 

 wide mouths. In these sea-gulfs there are hardly any obstacles which would limit the exchange of 

 water and ice between them and the Arctic Basin proper. Only the Kara Sea presents a slight ex- 

 ception, since the 5adfcol shoals which extend in a meridional direction, and Ushakov Island, sit- 

 uated on them, divide the northern part of this sea into two parts, eastern and western. These 

 parts in turn represent sharply defined gulfs. On account of this the circulation of water and ice in 

 the Central Arctic Basin has a strong influence on the corresponding circulation in the adjacent 

 seas and is in its turn determined by the circulation in the latter. 



But while the Arctic Basin is closely connected with the seas and gulfs directly adjacent to it, 

 its connection with the adjacent basins of the World Ocean is extremely limited. It is connected 

 with the Pacific Ocean by the narrow and shallow Bering Straits. The Arctic Basin is connected 

 with Baffin Bay of the Atlantic Ocean through numerous , but very narrow and shallow straits of the 

 North American archipelago. Due to this, the water exchange and ice exchange between the Arctic 

 Basin and Baffin Bay is so insignificant that it may be ignored for all considerations. 



The water and ice exchange between the Arctic Basin and Barents and Greenland Seas is 

 more significant. 



In considering the water and ice balance of the Arctic Basic, in the first approximation we may 

 ignore precipitation and evaporation. This assumption is evidently justified if we take into consid- 

 eration the fact that for the balance we must consider only the advective precipitation, i. e. , water 

 from precipitation which has been carried in from other basins. Local precipitation which falls as a 

 result of local evaporation and subsequent condensation must clearly be excluded from the balance. 



Coastal flow or drainage is the first factor which determines the balance of the Arctic Basin. 

 The coastal drainage, plus the slight but indubitable excess of precipitation over evaporation, de- 

 fines the character of the general circulation in the Arctic Basin as a drainage circulation. Such a 

 circulation is of course most strongly felt in the Kara and Laptev Seas. 



The second factor which determines the general circulation in the Arctic Basin is convective 

 phenomena. Due to their low salinity, the surface arctic waters have a low density, despite their 



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