40.0 I ■ ■ • I ■ ■ ■ ■ I ' ■ ■ ■ t 



S.O It ■ ' ■ I 



tO.Q 



t-'-l' 



Figure 10. Progression of soil thaw on site 1 plots. 



't' ■■■!■ ■■■!■■ " !■ ■■'! . . . 'I . ■. ■ |.. . .|. . ..I....!....!....)... .1. .. .|.. . I I . . . . I . 



*26.0 



E 

 IS 



c 



119.0 -- 



IJ.O -- 



S.O - < " ' t ■ . ■ I I . ■ . . I I I . I I ■ I ■ I I I ■ ■ . ) I I I ■ I . i . . I I I I I I I i I I I I I I I I I I ■ . I . ■ ■ I I . ■ . . ) . . ■ . ) ■ . ■ . ) . . ■ ■ ) . 



IS 10 15 20 ?S 3() S 10 15 20 25 30 



JUNE 70 I J"^1 70 



H 9 114 19 2<( ?3 



flUGU51 70 



Figure 11. Progression of soil thaw on site 2 plots. 



The effect of mass transfer, especially water transport, on heat transfer is also an important 

 factor to be considered. It is anticipated that the chanj^e of thermal properties of soil with water 

 content and convective heat transport associated with water transport are major contributions to the 

 thermal regime. Efforts have been initiated to determine the effect of mass transport on heat trans- 

 port. Besides water transport, the quantities and migration of organic and inorganic chemicals 

 through tundra soils are particularly important during periods of freezing and thawing. 



The thaw-temperature model involves a program in which an implicit finite difference scheme is 

 adopted to solve the one-dimensional heat conduction problem as soil water undergoes phase changes. 



23 



