HR: 0800h
AN: C21A-1055    [Abstracts]
TI: Field Validation of a New Method for Inverting GPR Measurements for the Liquid Water Content in Snow
AU: * Harper, J T
EM: joel@mso.umt.edu
AF: Department of Geosciences University of Montana, 32 Campus Drive, #1296, Missoula, MT 59812 United States
AU: Bradford, J H
EM: jbradfor@boisestate.edu
AF: Department of Geosciences Boise State University, Mailstop-1535 1910 University Drive , Boise, ID 83725-1535
AB: The primary source of water for much of the semi-arid western U.S. is snow stored in mountain basins. Large-scale monitoring of snow water equivalent (SWE) is therefore critical in water resource management. There are currently no methods for accurate and continuous measurement SWE along ground transects. Ground-penetrating radar (GPR) is a tool that provides laterally continuous measurements over relatively short time intervals. Previous studies have shown that measurements of GPR velocity can provide accurate estimates of SWE in dry snow. The introduction of liquid water within the snowpack, however, results in a 3-phase system that cannot be accurately characterized with GPR velocity alone. Measuring the frequency dependence of GPR signal attenuation provides a direct estimate of the complex dielectric permittivity. We show that this additional parameter allows measurement of liquid water content, snow density, and SWE. We present this new method along with a suite of field experiments used for validation. The experiments were performed on vastly different snowpacks located in Colorado, Idaho and Alaska. Detailed characterizations of the snowpack were done using gravimetric methods and a permittivity probe which measures density and wetness. Comparisons between the field characterizations and GPR inversions show that the new method is capable of determining SWE in both dry and wet snowpacks.
DE: 0740 Snowmelt
DE: 0794 Instruments and techniques
DE: 1863 Snow and ice (0736, 0738, 0776, 1827)
SC: Cryosphere [C]
MN: Fall Meeting 2005