HR: 0800h
AN: H51C-0647    [Abstracts]
TI: 2-D water flux using a penta-probe heat-pulse sensor: laboratory experiment and numerical evaluation
AU: * yang, c
EM: cb.yang@usu.edu
AF: Dept. Plants, Soils, and Biometeorology, Utah State University, 4820 Old Main Hill, Logan, UT 84322-4820, United States
AU: Jones, S
EM: scott.jones@usu.edu
AF: Dept. Plants, Soils, and Biometeorology, Utah State University, 4820 Old Main Hill, Logan, UT 84322-4820, United States
AB: The fate of precipitation and snowmelt are not only important sources for water supply, but also crucial inputs to hydrological modeling and therefore measurements of subsurface flux in soils are of great interest. Recent work using heat-pulse measurements to assess water flux in soil have shown promise for determination of infiltration rates. Within the research realm, heat-pulse based sensors typically have one heater probe and one pair of upstream and downstream temperature sensing needles for flux determination. One-dimensional sensors may not be suitable for inferring hillslope percolation rates due to the liklihood of multidimensional water flux. Advanced heat-pulse based sensors with one heater probe and two pairs of orthogonally arranged temperature sensors have been proposed to measure horizontal and vertical fluxes simultaneously. In order to evaluate the penta-probe heat-pulse (PPHP) method a laboratory experiment was performed in conjunction with numerical modeling. A cylindrical flow cell comprised of an outer lexan wall and inner porous stainless steel wall was divided into four sections (i.e., two inlets and two outlets) leaving the center of the cylinder packed with porous media (glass beads). By adjusting pressure head at each inlet and outlet, a 2-D flow field was formed at the center where the sensor was located. We used the analytical model by Wang et al. (2002) to estimate 2-D water fluxes (e.g., vertical and horizontal) from the temperature increases measured by each pair of temperature sensing needles. The calculated 2-D flux was compared to the results of a CORE2D V4 (Yang et al., 2006) numerical model which simulated flow and heat transport in the flow cell. Water velocities derived from numerical simulations and temperature responses show good agreements.
DE: 1865 Soils (0486)
DE: 1866 Soil moisture
DE: 1875 Vadose zone
DE: 1899 General or miscellaneous
SC: Hydrology [H]
MN: 2007 Fall Meeting