272 Ice in the Sea 



reach the sea in a broad front. The part played by the other Arctic islands in the 

 production of icebergs is quite insignificant ; only very few of the ice streams of the 

 other islands reach the sea as calving glaciers, and even these produce only small 

 icebergs. 



In Greenland the inland ice reaches the sea through more or less narrow fiords 

 which act as funnels collecting the converging streams of inland ice, but in the Southern 

 Hemisphere the inland ice reaches the sea in an open front. At the edge of the Ant- 

 arctic the snow-line is everywhere in or below the sea-level. Here the ice takes the form 

 of an ice barrier which in the Ross Sea, for example, is about 750 km long and has a 

 mean height of 36 m, but sometimes exceeds 50 m. Enormous icebergs break away 

 continually from the edge of the inland ice cover, and though at first often trapped in 

 the shelf ice, they are carried away with it later on or melt completely in their place. 



{b) The Productivity of Glaciers Calving into the Sea in the Arctic 



Statistics of iceberg production by glaciers calving into individual oceanic regions 

 are rather poor; reasonably reliable figures can only be given for very few ice streams. 

 Smith (1931) has attempted to give such a preliminary survey for the Arctic. In the 

 Eurasian Arctic there are only a small number of glaciers producing icebergs. In Spitz- 

 bergen, probably the Negri glacier in the Storfjord; the east coast of North-east Land 

 has some calving glaciers as has the completely glaciated Franz Josef Land. But the 

 number of icebergs produced, which are seldom large, is not known and is presumably 

 small. The productivity of Novaya Zembla and Sevemaya Zembla is equally not 

 known, but is probably also very small. The few icebergs which are formed at the 

 islands of the Siberian Shelf move mostly to the west and increase somewhat the 

 number from the East Greenland icebergs. Smith estimated the number of icebergs 

 produced annually in the north-east sector of the polar Atlantic ocean as about 600, 

 which is only about 4% of the annual supply of icebergs from Greenland. 



Smith believed that the productivity of the eastern Greenland glaciers was some- 

 what less than that of the west coast (7500 icebergs per year). There is, however, the 

 important difference that in the east most of the icebergs are retained in narrow fiords 

 and are prevented by the solid ice-barrier of the East Greenland Current from drifting 

 southwards. Their importance to the Atlantic is therefore slight; about twenty to 

 thirty a year reach Cape Farewell and then drift northwards with the West Greenland 

 Current. They reach Davis Strait in a collapsing state. The iceberg survey of the 

 "Marion" Expedition during the summer of 1928 found only seventeen icebergs off 

 the south-west coast of Greenland; a very small number compared with the enormous 

 amount that were found in Disko Bay to the north. On the western side of Baffin Bay 

 only Ellesmere Land with two large ice caps shows any extended inland ice. About 

 sixty glaciers reach the sea as calving glaciers, but according to Smith the productivity 

 is not very large (about 1500 icebergs a year). The major source of icebergs is in the 

 great glaciers of West Greenland from Cape Alexander to Disko Bay. The main part, 

 from the North-east Bay as far as Disko Bay has more than 100 calving glaciers, the 

 twelve largest and most productive ones alone producing more than 5400 icebergs 

 a year. The most important of this group, the Jacobshavener Glacier calves about 

 1350 icebergs a year into Disko Bay. Not all of these reach the open sea immediately — 

 on the contrary most are trapped in the fiords for longer periods. In the summer of 



