Measuring Hydraulic Conductivity of Variably-Saturated Soils at the Hectometer Scale Using Cosmic-Ray Neutrons

Persistent Link:
http://hdl.handle.net/10150/323446
Title:
Measuring Hydraulic Conductivity of Variably-Saturated Soils at the Hectometer Scale Using Cosmic-Ray Neutrons
Author:
Karczynski, Adam Michael
Issue Date:
2014
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Embargo:
Release 9-Dec-2014
Abstract:
Hydraulic conductivity of variably-saturated soils is critical to understanding processes at the land surface. Yet measuring it over an area comparable to the resolution of land-surface models is fraught because of its strong spatial and temporal variations, which render point measurements nearly useless. We derived unsaturated hydraulic conductivity at the horizontal scale of hectometers and the vertical scale of decimeters by analyzing trends in soil moisture measured using the cosmic-ray neutron method. The resulting effective hydraulic conductivity remains close to its value at saturation over approximately half of the saturation range and then plummets. It agrees with the aggregate of 36 point measurements near saturation, but becomes progressively higher at lower water contents; the difference is potentially reconcilable by upscaling of point measurements. This study shows the feasibility of the cosmic-ray method, highlights the importance of measurement scale, and provides a route toward better understanding of land-surface processes.
Type:
text; Electronic Thesis
Keywords:
cosmic-ray neutrons; infiltration; land-atmosphere interactions; scaling; unsaturated hydraulic conductivity; Hydrology; area-average
Degree Name:
M.S.
Degree Level:
masters
Degree Program:
Graduate College; Hydrology
Degree Grantor:
University of Arizona
Advisor:
Zreda, Mark

Full metadata record

DC FieldValue Language
dc.language.isoen_USen
dc.titleMeasuring Hydraulic Conductivity of Variably-Saturated Soils at the Hectometer Scale Using Cosmic-Ray Neutronsen_US
dc.creatorKarczynski, Adam Michaelen_US
dc.contributor.authorKarczynski, Adam Michaelen_US
dc.date.issued2014-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.releaseRelease 9-Dec-2014en_US
dc.description.abstractHydraulic conductivity of variably-saturated soils is critical to understanding processes at the land surface. Yet measuring it over an area comparable to the resolution of land-surface models is fraught because of its strong spatial and temporal variations, which render point measurements nearly useless. We derived unsaturated hydraulic conductivity at the horizontal scale of hectometers and the vertical scale of decimeters by analyzing trends in soil moisture measured using the cosmic-ray neutron method. The resulting effective hydraulic conductivity remains close to its value at saturation over approximately half of the saturation range and then plummets. It agrees with the aggregate of 36 point measurements near saturation, but becomes progressively higher at lower water contents; the difference is potentially reconcilable by upscaling of point measurements. This study shows the feasibility of the cosmic-ray method, highlights the importance of measurement scale, and provides a route toward better understanding of land-surface processes.en_US
dc.typetexten
dc.typeElectronic Thesisen
dc.subjectcosmic-ray neutronsen_US
dc.subjectinfiltrationen_US
dc.subjectland-atmosphere interactionsen_US
dc.subjectscalingen_US
dc.subjectunsaturated hydraulic conductivityen_US
dc.subjectHydrologyen_US
dc.subjectarea-averageen_US
thesis.degree.nameM.S.en_US
thesis.degree.levelmastersen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineHydrologyen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorZreda, Marken_US
dc.contributor.committeememberYeah, Tian-Chyi J.en_US
dc.contributor.committeememberSchaap, Marcel G.en_US
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