Developing a temperature‐dependent Kersten function for soil thermal conductivity

This paper describes the development of the Kersten function (Ke), which depends on soil temperature and the degree of saturation. The new Kersten function enables the prediction of thermal conductivities of moist soils also including high temperatures. The eight soils used in this paper represent three distinct textural groups, each having a comparable shape of Kersten function. The soil thermal conductivity is obtained from a linear interpolation between the dryness and saturation states with the Ke as the slope. The new Kersten function is valid when the degree of saturation (S_r) is greater than 0.125 and soil temperature is between 30 and 90°C. At a lower degree of saturation (i.e. 0<S_r<0.125), a linear approximation is applied to Ke. The new Ke function gives particularly good agreement with experimental data for temperatures of 30 and 50°C and for low moisture contents at all temperatures. At higher temperatures (i.e. 70 and 90°C) and moisture contents above the permanent wilting point, generally good or acceptable results were obtained. Copyright © 2000 John Wiley & Sons, Ltd.