arctic sea ice 97 



Annual Life Cycle of the Arctic Sea Ice 



the arctic pack 



The piled-up, telescoped, or hummocked character of the ice of 

 the Arctic Pack develops mainly late in summer and early in autumn, 



Fig. 7 — An area in the Arctic Pack. Slightly oblique air view from the Norge. 

 Exact locality not known. So shattered a condition of the Pack was met with only as 

 a rare exception on the transpolar flight. (Photograph from Lincoln Ellsworth.) 



when the areas of open water amidst the ice fields and ice floes of 

 which it is composed make possible, under the influence of winds, 

 currents, and tides, a complicated motion of its parts in various 

 directions. The result of this motion is that water areas close up in 

 one place and open up in another. Owing to the inertia of the ice 

 masses in motion, and proportionally to it, this process may be 

 accompanied either by the formation of "pressure ridges" (ridges 



