Co-Authors:
Kluitenberg, G.J., Dep. of Agronomy Kansas, State Univ., Manhattan, KS 66506, United States
Kamai, T., Dep. of Land, Air and Water Resources, Univ. of California, Davis, CA 95616, United States
Vrugt, J.A., Los Alamos National Lab., P.O. Box 1663, Los Alamos, NM 87545, United States, Dep. of Civil and Environmental Engineering, Univ. of California, Irvine, CA 92697, United States
Hopmans, J.W., Dep. of Agronomy Kansas, State Univ., Manhattan, KS 66506, United States
Abstract:
The dual-probe heat-pulse (DPHP) method is useful for measuring soil thermal properties; however, the probes of a DPHP sensor can deflect when inserted into the soil. Theoretical analysis has shown that measurements of thermal conductivity (λ) should be unaffected by deflection-induced changes in probe spacing. To verify this result, the conductivities of water, dry sand, and saturated sand were measured using DPHP sensors with probes subject to inward deflection, no deflection, and outward deflection. No error in λ was detected when probes were deflected inward by an amount that caused a 14% reduction in probe spacing. Outward deflection (15% increase in spacing) caused error in λ estimates, but the errors were small (≤0.04 Wm-1K-1) and likely to be of little consequence in most applications. We conclude that estimates of λ obtained with the DPHP method are largely unaffected by changes in probe spacing caused by deflection. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA All rights reserved.