Climate, Snow Cover, Microclimate, and Hydrology 37 



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FIGURE 2-3. Ten-day mean soil temperatures at the Biome research area 

 as measured during 1970-73 and simulated for the extreme years during 

 1960-73. The shaded area represents the range of the simulated soil tem- 

 peratures for the warmest year, 1968, and the coldest year, 1969. 



than average (Figure 2-2). 



A major question in any short-term observational program is how 

 representative the data are with respect to long-term conditions and 

 trends. During the 4 years of Biome measurements the positive depar- 

 tures of temperature from the long-term summer observations were espe- 

 cially pronounced during 1972: -i-2.4°C in July and -i- 1.7°C in August 

 (Figure 2-2, Table 2-1). Precipitation also varied from the long-term 

 averages during the research period: July was much drier than average in 

 1970 and 1972, and slightly wetter than average in 1971 and 1973. 



In order to compare the representativeness of soil temperatures dur- 

 ing the Biome years with those in the previous decade when temperatures 

 were not measured, a surface equilibrium temperature model was used to 

 simulate soil temperature and thaw for the period 1960-73. The model, a 

 modification of one developed by Outcalt et al. (1975) to simulate annual 

 snow and soil thermal regimes, predicted daily soil temperatures on a 

 5-cm grid for the 14-year period. The actual data obtained for the Biome 

 years are within the predicted extremes of simulated soil temperatures 

 (Figure 2-3). Therefore it is reasonable to assume that soil temperatures 

 observed during the 1970-73 Biome period are within the range of varia- 

 tion normally encountered on the tundra at Barrow. 



SNOW COVER 



Most plants and animals are small enough to live within the protec- 

 tive blanket of snow, and larger predators and herbivores depend. 



