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The concise formulation of diffusive sorption of water in a dry soil
Author(s) -
Brutsaert Wilfried
Publication year - 1976
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr012i006p01118
Subject(s) - sorptivity , thermal diffusivity , exponential function , weighting , sorption , diffusion , mathematics , soil science , soil water , nonlinear system , thermodynamics , mathematical analysis , geotechnical engineering , environmental science , physics , porosity , geology , chemistry , organic chemistry , adsorption , quantum mechanics , acoustics
Several formulations for the sorption of water in a dry soil obtained on the basis of approximate solutions of the nonlinear diffusion equation are considered, and their relative merits are investigated. In addition, new solutions are developed by the application of a simple weighting of the available approximations. In a comparison with one of Philip's (1960) exact solutions it was found that the error involved in all these solutions is at most of the order of 3 or 4% however, Parlange's (1975 a ) optimization result and the weighting solutions appear to be accurate to within a few thousandths. The sorptivity and the position of the wetting front can be expressed concisely as functions of soil physical parameters by applying either the two‐parameter exponential diffusivity of Gardner and Mayhugh (1958) or the three‐parameter power function diffusivity of the author. The mathematical form suggests that on a field or basinwide scale the sorptivity of the surface soil is log normally distributed.