Multi-Functional Heat Pulse Probe Measurements of Water, Heat, and Solute Transport in the Vadose Zone.
Jan Hopmans1, Yasushi Mori2, Annette P. Mortensen3, Gerard Kluitenberg4, Atac Tuli1, and Antonio Valente5. (1) University of California, 123 Veihmeyer Hall One Shields Ave, Davis, CA 95616, (2) Shiman University, 1060 Nishikawatsu-cho, Matsue, 690-8504, Japan, (3) Geological Institute, ุster Voldgade 10,, Copenhagen University, Copenhagen,, 1350, Denmark, (4) Kansas State University, 2004 Throckmorton Pl.Sci.Ctr., Manhattan, KS 66506-5501, (5) CETAV-UTAD University, Department Engineering, Vila Real, Portugal
A Multi-Functional Heat Pulse Probe (MFHPP) for vadose zone measurements was developed and tested in the laboratory. The probe combines a heat pulse technique for estimating soil heat properties, water flux, and water content with a Wenner array measurement of Electrical Conductivity (EC). The probe thus provides a simultaneous estimate of water, heat, and solute transport parameters at the same location and spatial scale. Using an integrated circuit within the probe body, pre-and postprocessing of the data occurs real time. To test the MFHPP, highly controlled steady-state flow column experiments in sand were conducted over a wide range of saturations, flow velocities, and EC concentrations. The data were analyzed using the modified HYDRUS model, which includes an option for inverse modeling of simultaneous water, vapor, heat, and solute transport. The inverse estimated parameters included volumetric heat capacity, thermal conductivity, heat dispersion, water flux, moisture content, and solute dispersion. The performance of the MFHPP was compared and evaluated with independently measured data. Thermal properties, including thermal conductivity and thermal diffusivity, compared well with previously measured data for the sand. The MFHPP probe constitutes a new promising technique for combined water, solute and heat transport measurements in the vadose zone.