36 



S. L. Dingman et al. 



^T — ] — I — T-n — I — I — I — r — I — 1 — p 



August Temp: 3.2 ILe'C; Ppt. 23.6 1 14.4mm 



n — I — r — I — I — I — I — r — 1 — I — 1 — I — I — I — I — I — r — i — i — i f r — i I i — i — i — r — i — i — i — i — i — i — i — i — r "(" i — i — i — i — i — i — i — i — r- 

 1924 1930 1940 1950 I960 1970 



□ <l Std Dev ^lto2StdDev. ■>2StdDev 



FIGURE 2-2. Summary of deviations of temperature and precipitation 

 from monthly means (1924-73) during summer months for the village of 

 Barrow. 



lative thawing degree-days has been taken by Myers and Pitelka (1979). 

 They demonstrated that 7 of the 26 years from 1950 to 1975 deviated 

 more than 100 cumulative degrees Celsius from the average daily mean 

 temperature. Early spring and late July and August are shown to vary 

 more from year to year than June and early July. The high variability in 

 August is related to the strong contrasts between temperatures associated 

 with winds blowing over the Beaufort and Chukchi Seas or over land. 

 Hence, climatic conditions near the coast are closely determined by at- 

 mosphere-ocean-ice interactions (Barry et al. 1976). The precipitation 

 data, which are subject to measurement problems, have much greater in- 

 terannual variability. 



The long-term patterns of some individual months indicate that the 

 mean departure for December 1932-41 was +2.0°C, whereas that for 

 December 1953-61 was -2.2°C; this difference is significant at the 2^o 

 level by Student's t. For June, the period 1925-32 had a departure of 

 + 1.3°C; this difference is significant at the 5% level. There are no com- 

 parable shifts for July or August, ahhough July 1959-70 averaged 0.8 °C 

 below, and August 1959-71 0.9°C below, the respective 1924-73 mean 

 values. When running-mean techniques are used on individual summer 

 months at 5-year intervals, there are suggestions that the mid-1950s and 

 the late 1960s were cooler than the long-term means. Rogers (1978), us- 

 ing a linear regression of thaw season degree-days against time, found a 

 summer cooling trend over the 56-year period of air temperature records 

 at Barrow. In terms of the departure of total precipitation from the 

 1924-73 monthly averages, there was a tendency for more dry months in 

 summer between 1964 and 1972, whereas the 1950s were generally wetter 



