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Soil Science Society of America Journal Abstract -

Estimating Thermal Diffusivity Near the Soil Surface Using Laplace Transform: Uniform Initial Conditions1


This article in SSSAJ

  1. Vol. 47 No. 3, p. 397-401
    Received: Aug 31, 1982
    Accepted: Jan 10, 1983

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  1. G. Asrar and
  2. E. T. Kanemasu2



A simplified method based on the numerical integration of the Laplace transform of the one dimensional heat conduction equation in porous media was used to estimate the thermal diffusivity near the surface. The method is based on the analytical solution of the equation of heat conduction and accepts any functional relationship that realistically describes the surface soil temperature as a boundary condition. An optimization scheme was suggested for selecting proper values of Laplace transform parameter s based on maximum duration of the experiment. The method was used to compute thermal diffusivities of two different soil types for a wide range of soil moisture and temperature conditions. Thermal conductivities for each soil were calculated using the computed diffusivities and heat capacities. A comparison of the conductivities estimated with the Laplace transform and the measured values by a transient method showed good agreements between the two methods. A similar comparison between the Laplace transform and the DeVries' model showed significant differences between the two methods.

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