The temperature and moisture distribution in an unsaturated soil column subjected to surface evaporation

Abstract

A number of theoretical concepts have been proposed to account for the transfer of liquid through unsaturated porous medium under isothermal conditions, but it is only recently that theoretical consideration has been given to the simultaneous transfer of both mass and energy0 This study was designed to provide an understanding of het and mass transfer in a soil-water regime and to provide scientific data applicable to analysis by recent mathematical theories 0 Several flow parameters, including both mass and energy gradients, conductivities, and fluxes were measured under controlled laboratory conditions0 Conductivity measurements followed current procedures described in the literature 0 The transfer of heat and energy operate simultaneously during most dynamic soil moisture flow processes, particularly the drying of a soil column A unique evaporation regime was designed in which a vertical soil column was subjected to surface evaporation while liquid input was induced at the bottom of the column0 It was assumed that a steady-state condition would result when the input and evaporation rate coincided0 Despite the accepted belief, a steady-state condition did not develop as the data indicate.