Development and Application of the Heat Pulse Method for Soil Physical Measurements

Abstract

Accurate and continuous measurements of soil thermal and hydraulic propertiesare required for environmental, Earth and planetary science, and engineering applications, but they are not practicallyobtained by steady-state methods. The heat pulse (HP) method is a transient method for determinationof soil thermal properties and a wide range of other physical properties in laboratory and field conditions. The HP method is based on the line-heat source solution of the radial heat flow equation. This literature review begins with a discussion of the evolution of the HP method and related applications, followed by the principal theories, data interpretation methods and their differences. Important factors for HP probe construction are presented. The properties determined in unfrozen and frozen soilsare discussed, followed by a discussion of limitations and perspectives for the application of this method. The paper closes with a brief overview of future needs and opportunities for further development and application of the HP method.Keywords thermal properties, thermal conductivity, thermal resistivity, heat capacity, thermal diffusivity, thermal inertia, dual probe heat pulse, thermal probe, hot-wire method, fiber optics, distributed temperature sensing (DTS), thermo-time/frequency domain reflectometry (thermo-TDR, thermo-FDR), soilwater content, ice content, frozen soils, instrumentation DisciplinesAgricultural Science | Agriculture | Hydrology | Soil Science Comments This is a manuscript of an article published as He, Hailong, Miles F. Dyck, Robert Horton, Tusheng Ren, Keith L. Bristow, Jialong Lv, and Bingcheng Si. "Development and application of the heat pulse method for soil physical measurements." Reviews of Geophysics (2018) This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1029/2017RG000584 © 2018 American Geophysical Union. All rights reserved.Development and application of the heat pulse method for soil physical properties in laboratory and field conditions. The HP method is based on the line-heat source solution of the radial heat flow equation. This literature review begins with a discussion of the evolution of the HP method and related applications, followed by the principal theories, data interpretation methods and their differences. Important factors for HP probe construction are presented. The properties determined in unfrozen and frozen soilsare discussed, followed by a discussion of limitations and perspectives for the application of this method. The paper closes with a brief overview of future needs and opportunities for further development and application of the HP method.

A Review and Evaluation of Predictive Models for Thermal Conductivity of Sands at Full Water Content Range

“…The LY2018 model was developed based on the basic series-parallel model using a small dataset (28 measurements) of Aeolian sands from the Tibetan Plateau [21]. The RH2018 model (Figure 1(6)) is in fact the modified form of HS2012 (Figure 1(4)) model by multiplying an F factor based on Equation (12). However, it should be noted that Equation (12a) gave an unreasonably high value at S r < 0.1 and only Equation (12b) was used for all degrees of saturation in this study.…”

“…The AA2016 model (Figure 3(4)) generally overestimated the measured λ eff as a whole, which may be attributed to the fact that AA2016 was developed based on steady-state measurements (i.e., guarded hot plates). Steady-state measurements are prone to water redistribution in unsaturated soils, which changes the thermal conductivity being measured [12,62]. This may explain why Alrtimi et al [17] found that the models of de Vries [63], Johansen [39], Côté and Konrad [41], Lu et al [48], Chen [15] and Haigh [16] could not be used to properly predict thermal conductivity of Tripoli sand measured with the steady-state measurements.…”

“…The values of λ eff can be either measured or indirectly predicted with mathematic models. The available λ eff data of sands are not sufficient to meet the demands, although great progress has been achieved in the measurement technologies of λ eff [12][13][14]. In addition, reliable λ eff data can only be measured by the transient method (e.g., heat pulse method) at full water content range, because the transient method is less likely to be affected by the water redistribution or phase change compared to the steady-state method (e.g., guarded hot plate).…”

Improving Soil Heat Flux Accuracy with the Philip Correction Technique

“…Peng et al (2015) reported that its voltage signals during and shortly after selfcalibration should be discarded from data analysis as the self-heating could bias the voltage signals. The threeneedle heat-pulse sensor (Ren et al 1999) has the ability to measured l s in situ and is a good candidate to obtain independent soil heat flux using the gradient method (Cobos and Baker 2003;Ochsner et al 2006;Heitman et al 2008a,b;Xiao et al 2011;Peng et al 2015;Lu et al 2016;He et al 2018).…”

Hydraulic Redistribution in Slender Wheatgrass (Elymus trachycaulus Link Malte) and Yellow Sweet Clover (Melilotus officinalis L.): Potential Benefits for Land Reclamation

“…In each of them, five plants per species were grown in the split-root setup for four months until the roots reached the growth mix in the lower tube segment. The soil volumetric water content was monitored with the time domain reflectometry (TDR) technique [23]. A three-rod (1.5 mm in diameter, 15 cm long) TDR stainless steel probe was vertically inserted into the upper tube.…”