Climate, Snow Cover, Microclimate, and Hydrology 



33 



204- 



u 



S -!0 - 



E 



-20 - 



-30- 



-40- 



-50 



\ January 



_i L. 



_i L. 



4 8 12 



Wind Speed, m s"* 



FIGURE 2-1. Cumulative fre- 

 quencies of hourly air tempera- 

 tures and wind speeds at the vil- 

 lage of Barrow, 1945-54. The fre- 

 quencies are expressed as the 

 cumulative percentage frequen- 

 cies of the total distribution. 

 (After Rayner 1960a, b.) 



effect of clouds on infrared radiation, rather than by changes of air 

 mass. Deep Pacific cyclones affect southern Alaska and the Bering Sea 

 but seldom penetrate to the Arctic Slope. When they do, the frontal sys- 

 tems tend to move above the 1000- to 1500-m-deep inversion layer and 

 may not affect the weather at the surface. 



The persistence of anticyclonic conditions during late winter leads to 

 clear skies and the receipt of a high percentage of the possible solar radia- 

 tion. The mid- to late winter period has an average of 10 or more days 

 per month with clear skies, associated with the 45 to 5097o frequency of 

 anticyclonic patterns. 



Temperatures begin to rise in late winter but lag 4 to 6 weeks behind 

 the increase in solar radiation. The mean daily temperature is above 

 freezing from June through August, but fails to reach 5°C even in July as 

 a result of coastal cloudiness and the effect of the Arctic Ocean. The Arc- 

 tic Ocean maintains a cover of close pack ice in summer except for open 

 water areas which extend some 30 to 100 km from the coast by August or 

 September. Even in August the open water is only about 3 °C (Searby and 



