area is closed In with ice under pressure, it is likely that other areas 

 oppositely situated in the basin will experience light ice years with 

 little pressure. On the other hand, if the total amount of unmelted ice 

 varies greatly from year to year (more than 5% or so), it may be possible 

 that all areas will have light or heavy ice years simultaneously. On the 

 basis of present observations, especially during the svmimer of 1953, the 

 former statement seems more likely: that there is essentially the same 

 amount of ice in the Arctic each year. 



C. ECONOMY OF POLAR ICE 



If the polar ice is generally several years old and is moving around 

 the basin in an anticyclonic whirl, the only chance of its disappearance 

 is through melting or by being carried out of the polar basin into lower 

 latitudes. The polar ice that is carried away from the basin consists 

 almost entirely of the outflow of the East Greenland current through the 

 Denmark Strait. Sverdrup, Johnson, and Fleming, in The Oceans (p. 65 5 » 

 1942) estimate the volume of the current at 3 •55 million cubic meters per 

 second, or about 112,000 cubic km, per year. The estimate given by Zubov 

 (1948) is 80,000 cubic km. per year. The former estimate of 112,000 cubic 

 km. per year corresponds to a current 200 km. wide and 200 meters deep 

 moving at an average spaed of 7»65 Ian. per day. The ice floats on the 

 surface of this current v/hich m.oves at about 20 to 25 km, per day, so that 

 it is possible to estin:ate the outflovj^ of ice from the volume of the cur- 

 rent. The oldest estimate, probably that of Nansen, is usually quoted as 

 26 billion cubic yards aiinually (e.g., Brovm, 1927 and Rodahl, 1953). If 

 this figure is British and means 26 million cubic yards, it amounts to 

 about 25,000 cubic km. annually and is far too large; while if it means 

 26 thousand million cubic yards it is roughly 25 cubic km, and far too 

 small. Zubov refers to Vise's estimate of 8,000 cubic km, of ice annually 

 and gives his ov;n more conservative estiiriate of 3,000 cubic km. based on 

 his calculation of a current 200 km. wide moving at from 8 to 12 Ian. per 

 day and covered ivith ice averaging 3 m. thick. Recently V'eaver (n.d. ) 

 has estimated the total ice outflow at 3,000 to 4,300 cubic rnlles per year; 

 this is from 12,500 to 18,000 cubic km, annually and is thus several 

 times as large as Zubov' s figures. Using Zubov' s reasonable figure of 

 a current 200 1cm. vdda vdth a speed of 20 >ati. per day, and assuming an 

 average thickness of the ice of 3 m,, ice completely covering the current 

 would total 4,380 cubic km, per year, Howevei-, there are tvfo reasons 

 V(hy the total amount of ice is less than this figure. One is that the 

 area of the East Gi^eonland Current is not alv;ays covered vdth ice. During 

 the months of August and September, the current often contains only 

 scattered drift ice, and ships sometimes can go from Iceland to Greenland 

 with little interference from ice. It may be assunod that over the year 

 the average coverage is no greater than 80 pei-cent. Secondly, not all 

 of the ice carried by this current is polar ice. PreEcnt obsorvations 

 of the ice indicate that about 70 percent of the ice in the East Green- 

 land Current is polar ice, the other 30 percent comprising vdntcr ico 

 from the Greenland coast, Barents Sea, and other localities. Thus, 

 the total a-r.ount of ice of polar origiji carried scuthv.'ard through the 



