HR: 1340h
AN: H53F-1478    [Abstracts]
TI: Evaluation of Alternative Heat Pulse Probe (HPP) Designs
AU: * Tuli, A
EM: atuli@ucdavis.edu
AF: Department of Land Air and Water Resources, 106 Veihmeyer Hall, University of California, Davis, CA 95616, United States
AU: Kamai, T
EM: tkamai@ucdavis.edu
AF: Department of Land Air and Water Resources, 106 Veihmeyer Hall, University of California, Davis, CA 95616, United States
AU: Kluitenberg, G J
EM: gjk@ksu.edu
AF: Department of Agronomy, 2004 Throckmorton, Plant Sciences Center, Kansas State University, Manhattan, KS 66506, United States
AU: Hopmans, J W
EM: jwhopmans@ucdavis.edu
AF: Department of Land Air and Water Resources, 106 Veihmeyer Hall, University of California, Davis, CA 95616, United States
AB: Water flux and content measurements in variably saturated porous media can be achieved utilizing the heat pulse probe (HPP). However, with current HPP design, the lowest possible measured water flux is approximately 5 cm/day, whereas vadose zone fluxes are generally below 1 cm/day. Furthermore, the current HPP design has relatively low durability in field applications. Numerical analysis results suggest that larger heater needle diameters might be required to make lower unsaturated water flux measurements possible. In this study, we evaluate different HPP designs, using observed data and analytical and numerical model simulation results. To enhance HPP durability, we present experimental and numerical data, demonstrating the capability of shorter HPP needles. For the lowering of the measured water flux threshold, a large-diameter needle HPP wad developed, of which model solutions and experimental data are presented. Moreover, a sensitivity analysis was conducted, evaluating the effects of heater needle diameters, temperature sensing locations, heat intensities and heat patterns on the water flux estimations.
DE: 1847 Modeling
DE: 1866 Soil moisture
DE: 1875 Vadose zone
DE: 1894 Instruments and techniques: modeling
DE: 1895 Instruments and techniques: monitoring
SC: Hydrology [H]
MN: 2007 Fall Meeting