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Detection of nonconductive heat transport in soils using spectral analysis
Author(s) -
Hinkel Kenneth M.,
Outcalt Samuel I.
Publication year - 1993
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 - 10.1029/92wr02596
Subject(s) - soil water , saturation (graph theory) , soil science , infiltration (hvac) , materials science , penetration depth , environmental science , advection , penetration (warfare) , spectral line , analytical chemistry (journal) , chemistry , thermodynamics , environmental chemistry , composite material , optics , mathematics , physics , combinatorics , operations research , astronomy , engineering
Variance spectra were generated for three high‐frequency near‐surface soil temperature time series representative of soil conditions typically encountered in temperate regions: saturation, strong evaporation, and soil frost penetration. For the latter two conditions, a surrogate measure of the soil water ionic concentration was also obtained and variance spectra were calculated. In a purely conductive system of multiday duration, maximum thermal variance should occur at a wavelength of 1 day and should decrease with depth. During ground saturation, when the pores are occupied by water, this pattern is observed. However, a spectral power density peak is observed in the subditirnal and subhourly range coincident with surface evaporation or freezing. In addition, the ionic concentration of soil water at depth is strongly coupled to temperature variations at the surface. These patterns are atypical of conductive systems and suggest the operation of nonconductive heat transfer processes, particularly water advection, phase transformations of water, and high‐velocity internal distillation.