Measurement of Apparent Thermal Diffusivity of Frozen Soil during 
the Melting Process 

Masaru MIZOGUCHI

Faculty of Bioresources, Mie University 

Abstract 

Apparent thermal diffusivity measurements of two frozen soils. 
Toyoura sand and Kanagawa sandy loam, have been made during 
the melting process at temperatures between -30 and O'C using 
the least squares method based on a finite difference scheme. Both 
measured values showed a similar trend of increasing the apparent 
thermal diffusivity as the water and ice content increased. This 
increase is associated with the increase in the thermal conductivity 
based on the mechanical arrangement of soil components. The 
apparent thermal dlffusivities decreased as the temperature was 
increased and became zero near O"C. The apparent thermal 
diffusivity of sandy loam began to decrease at lower temperatures 
than that of sand. This result can be explained in terms of the 
temperature dependence of the unfrozen water content. It is 
concluded from these results that the apparent thermal diffusivity 
of frozen soil can be expressed by the ratio of an apparent thermal 
conductivity to an apparent heat capacity related to the 
temperature dependence of the unfrozen water content.