Soil Moisture Transport Due to Thermal Gradients: Practical Aspects

Cary, J.W. (1966) Soil Moisture Transport Due to Thermal Gradients: Practical Aspects. Soil Science Society of America Proceedings. 30(4):428-433.

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Abstract

The present status of knowledge concerning thermally induced
transport of moisture in soil is reviewed. This includes the
various theories on mechanisms of transport and experimental
data showing the magnitude of moisture flow in various porous
materials. Wherever possible these data were chosen to show
the relative importance of thermal versus head-type flow and
some general trends are noted.

Simple equations are developed to describe the thermally
induced moisture flow near the soil surface which arises from
transient thermal gradients produced by the diurnal temperature
cycle. Calculations of the moisture flux over 2 ten-hour time
intervals for a typical field situation indicate that thermal water
transport should be considered whenever moisture, salt, or heat
fluxes are being studied in the soil's surface layers.

The upward flow of soil water against a moisture content
gradient in the winter is also considered. A sample calculation
of the amount of thermally driven moisture was made using data
available in the literature. The result suggested that the thermal
moisture flow was too small to account for the net movement
of soil moisture into the frost zone.

Item Type:	Article
NWISRL Publication Number:	0014
Subjects:	Soil > Soil water (soil moisture) Mass Import - autoclassified (may be erroneous)
Depositing User:	Dan Stieneke
Date Deposited:	20 Nov 2010 21:49
Last Modified:	15 Mar 2017 22:53
Item ID:	83
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/83