260 Ice in the Sea 



evaporation, melting and the southward drift of ice away from the edges. It can 

 reasonably be assumed that the equilibrium is of a quasi-stationary nature. 



Our knowledge of the movements of the polar ice is largely obtained from the drift 

 of vessels beset in, i.e. frozen into, the ice. These show that, at least in the western 

 half of the polar ice cap, there is an east-west drift ; on the North American side there 

 appears to be a drift in the opposite direction so that in the North Polar Basin there 

 is a general anticyclonic ice drift. North of Greenland and Grant's Land, however, 

 the drift is directed towards the area between Greenland and Spitzbergen. The speed 

 of the ice drift to the north of Franz Josef Land and towards Spitzbergen is about 1 

 nautical mile a day; the "Sedow" found values twice as great; the "Maud" found 

 values between 0-6 and 3-2 nautical miles a day; the "drifting polar station" found at 

 first, near the pole about 4 nautical miles a day and then, after a decrease to 2-4 

 nautical miles a day, a further increase to 5-6 off the Greenland coast. Similar values 

 have also been found by means of drifting buoys which have been laid out recently 

 inside the North Polar basin by the Russians. 



The pack ice zone is continuous with the polar ice zone and covers about 25% of 

 the North Polar Basin ; in summer it usually forms the southern limit of the drift ice 

 fields, here broken up by kilometre-long channels. The part over deep water pro- 

 ceeds with the motion of the ice drift though probably at a lower speed, but in shallow 

 waters (over the shelf) its movement is towards the east. As a consequence of this 

 opposite movement, the ice fields in the intermediate areas are very much broken up 

 and large, and sometimes navigable, fracture zones appear (termed "polynya" by 

 Russian research workers). The main fracture zones run north of Spitzbergen, Franz- 

 Josef Land, Sevemaya Semlja the New Siberian Islands and Wrangel Island. They are 

 particularly well marked to the north of these islands and may occur even in winter 

 during persistent south-easterly and southerly winds. The pack ice penetrates extremely 

 far southwards into the North Atlantic in two places; (1) along the east coast of 

 Greenland until Cape Farewell and around it ; (2) along the eastern coast of North 

 America from Baffin Bay southwards in the Labrador current as far as the Grand 

 Banks of Newfoundland. These ice currents carry not only pack ice from the North 

 Polar Basin but also winter ice and solid ice from the Greenland Sea and from the 

 northern part of the Baffin Sea. In both outflows there is an outer zone of drifting ice 

 floes, a middle zone of more compact ice with occasional channels running through it 

 and finally an inner core of solid ice joining the solid ice along the coast. Smith gives 

 the following data (Table 99) for these two ice currents. 



The pack ice zone is bordered by a zone of solid ice which transforms into the land 

 in coastal areas. During the winter in both Northern Siberia and in the North Ameri- 

 can Archipelago it covers all channels, bays and fiords, etc., and these only become 

 free of ice again in summer. In coastal areas the solid ice at the beginning of the sum- 

 mer contains earthy material (stones and shells) picked up by freezing of ice of the 

 sea bottom melting out in sunraier; the surface of the ice is then often brownish 

 (Transche, 1928). 



In the Antarctic (Drygalski, 1921) floe ice occurs only outside a certain broad belt 

 containing icebergs and the remains of icebergs. This belt extends for the most part 

 to about 60° S. but reaches farther north near the Falkland Islands and South Georgia 

 and past 50° S. only near Bouvet Island. The ice floes are frequently found in large 



