and persistent when pressure changes provide gradients which 

 accentuate and strengthen the catabatic winds. 



There is heavy snowfall on the ice cap even in summer. Rela- 

 tive humidity is constantly high. Over the entire island there is 

 an average precipitation of about 16 inches a year. A notable 

 exception to this average is the extreme southern section near 

 Ivigtut which receives over 45 inches of precipitation a year. The 

 far northern areas, on the other hand, are quite arid. On the 

 interior plateau and in the north several feet of snow is almost 

 constantly blowing around on the surface. Under the influence of 

 strong winds the snow may be lifted to over 100 feet above the ice. 



Temperatures on the icecap in winter average minus 40° F. 

 Local temperatures may go up to 0° F. or down to minus 70° F. 

 By the time this air reaches the coastal area it usually is about 

 minus 40° F. In the ice-free coastal areas temperatures differ 

 noticeably between the sea border and the interior of the fiords. 

 In spring and summer the inner sections are warm, even oppres- 

 sively hot. In winter this area is colder than the outer coasts. 

 Local temperatures differ markedly in the winter between north 

 and south. Southern Greenland is under the influence of cyclones 

 over the ice-free seas, while the northern areas receive the full 

 climatic effect of the ice- and snow-covered land and sea. 



The warmer, ice-free southern end of the island with its abun- 

 dant rainfall supports a luxuriant vegetation. Willows, junipers, 

 birch, and aspen grow in open stands in the valleys. Most of 

 these are low and stunted but willows have been found reaching 

 to 30 feet. Associated with these thickets is a thick growth of 

 shrubs and herbs. In the open places, grass grows in the meadows. 

 In general, the vegetation consists of small plants, mosses, and 

 lichens. Vegetation is sparse along the cold, foggy, and wind- 

 exposed headlands of the fiords. The vegetation toward the north, 

 along the margins of the island is predominantly shrubs and mosses 

 with an increasing number of meadows. Large areas are covered 

 with heath and swamps. The uneven surface has many lakes, 

 which swarm with mosquitoes during the summer. Even the far 

 northern areas support hundreds of flowering plants. Off the 

 western coast there is verdant growth of seaweed and algae. 



Although most of the animal life is confined to the coastal mar- 

 gins, foxes and birds have been found on the inland ice. The num- 

 bers and varieties of animals increase toward the north. This is 

 due to the abundance of pasture areas and the relative safety from 

 man. Reindeer, musk-oxen, wolves, foxes, lemmings, and ermine 



64 



