GENERAL CHARACTERISTICS OF THE NORTHERN SEAS 



33 



Fig. 2. The two upper layers become thicker, while the warm Atlantic layer, 

 on the contrary, gradually loses its heat, mixes with the water layers above 

 and below, and becomes thinner. 



A comparison of the changes of temperature with depth at three points in 

 the central part of the Arctic basin — north of the Greenland Sea, near the 

 North Pole and within the region of the 'Pole of Inaccessibility' (station No. 3 

 Libin-Cherevichny air expedition, 1941, 3) — is given in Fig. 2. It is perfectly 

 clear from that figure that as one moves farther up the basin and towards the 



Fig. 4. Distribution of isotherms at depth of 300 m (isothermobaths). Penetration 



of deep Atlantic waters into northern parts of Barents, Kara and Laptev Seas is 



clearly shown (Dobrovolsky, after Shirshov). 



Bering Strait the upper cold layer becomes somewhat warmer, the inter- 

 mediate Atlantic one loses some of its heat and the cold abyssal one becomes 

 somewhat warmer. This is the result of a gradual intermixing of the inter- 

 mediate warm layer with the adjacent colder lower and upper layers. Accord- 

 ing to A. Dobrovolsky's computation the course of the Atlantic waters from 

 Spitsbergen to Kara Sea takes two years ; in one year more they reach the 

 Laptev Sea and two years later they penetrate the Chukotsk Sea. It takes 

 the Atlantic waters three years to cover the distance from Lofoten to 

 Spitsbergen. 



It is evident from Table 5 that the deep waters of the Arctic basin are 

 warmer than those of the Greenland Sea. 



