Characterizing air-water interfacial area in variably saturated porous media
Abstract
The air-water interface plays an important role in many mass and energy transfer processes in unsaturated soils. In this research, the gas-phase partitioning tracer method was used to measure air-water interfacial area as a function of water content for several porous media. The porous media comprised a series of sands with narrow particle-size ranges, a sand with a wider particle-size distribution, a sandy soil, and a loamy soil. The measurement range was extended to very low water contents in an attempt to determine maximum air-water interfacial areas. The measured values were compared to the normalized surface areas of the porous media. Experiment results showed that the magnitude of the air-water interfacial areas approached that of the normalized surface areas. Generally, air-water interfacial areas were higher for media with higher specific surface areas. The change in air-water interfacial area with changing water content was less near saturated water contents and greater at smaller values. In addition, the change was greater for poorly-sorted media. Measured air-water interfacial areas were compared to values estimated using various models.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2004
- Bibcode:
- 2004AGUFM.H33A0452P
- Keywords:
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- 1875 Unsaturated zone