Ice in the Sea 273 



1928 the "Marion" Expedition found that all the icebergs produced during the pre- 

 vious 3-4 years (about 4000 to 6000) were accumulated in the Eisfjord. They were all 

 released from their ice chains during favourable weather at once. Then they arrived 

 all together in Baffin Bay and drifted slowly to the south. 



Table 105. Production of icebergs in different regions on the Arctic 



Table 105 is a summary given by Smith of iceberg production in the Arctic. This 

 estimate gives a total annual contribution from Baffin Bay of 7500 icebergs, of which 

 70% come from North-east and Disko Bays. The table gives only a rough idea of the 

 ice amount available in Baffin Bay. Direct estimates of the ice outflow from the Green- 

 land Inland ice by measurement of the speeds of the different glaciers along the western 

 side of the island still differ widely. De Quervain and Mercanton (1925) estimated 

 this ice flow as being between 10 km^ and 100 km'' a year. Assuming an average size of a 

 large iceberg to be about 1-5 miUion m^ and assuming, further, that on calving about 

 one-third of the ice forms icebergs and two-thirds gives debris and smaller pieces, 

 then the total mass of ice released on calving is about 4-5 million m^. About 7500 

 such calvings per year gives approximately 35 km^ of ice. This value lies within the 

 above Umits. Helland (1876) found values of 5-8 km^ and 2-3 km^ for the annual ice 

 supply from the Jakobshaven and the Torsukatak Glaciers. Drygalski (1897) found 

 13-5 km^ for the large Karajak Glacier. According to these figures about 2-6 milhon 

 m^ of ice are broken off in an average calving of a medium sized glacier ; from this about 

 one-third is used for production of icebergs. 



(c) Calving, Size, Shape and Destruction of an Iceberg 



Careful observation of iceberg calving at the eastern Greenland glaciers led Dry- 

 galski to distinguish according to the size of the icebergs formed between three types 

 of calving. The third one proceeds almost continually over several days ; small blocks 

 of ice break away from the face of the glacier and fall into the sea, often in such large 

 amounts that the surface is covered with these broken pieces far out into the fiord. 

 In the second type, large masses are suddenly released in the water from the lower 



