Biophysical Processes and Primary Production 



89 



E 

 u 



o. 

 Q 



o 



38 



-100 



■50 



0% 



600% 



FIGURE 3-14. Simulated sensitivities of the depth of thaw on 8 August 

 to changes in various canopy parameters. The parameters were changed 

 from the standard case values by the percentage indicated on the 

 abscissa, except for the boundary layer resistances of the soil surface and 

 the resistance of the soil to evaporation. The canopy parameters are a) 

 leaf inclination, b) foliage area index, c) extinction coefficient for turbu- 

 lent exchange, d) soil surface reflectance, e) relative humidity of the ef- 

 fective evaporating surface of the soil, f) boundary layer resistances of 

 the soil surface, g) conductivity of the organic layer, and h) depth of the 

 organic layer. In (c) the sensitivity of the thaw depth to the extinction 

 coefficient for turbulent exchange was calculated with midseason foliage 

 area indices of 1.56 (o) and 4.68 (•). Otherwise, where two lines are 

 given, ▲ indicates sensitivities run with the foliage area index of a 

 canopy from which the foliage was removed. Dashed lines indicate end 

 points off scale. (After Ng and Miller 1977. J 



