On parameterization of heat conduction in coupled soil water and heat flow modelling

Abstract

Soil water and heat transport plays an important role in various hydrologic, agricultural, and industrial applications. Accordingly, an increasing attention is paid to relevant simulation models. In the present study, soil thermal conditions at a mountain meadow during the vegetation season were simulated. A dual-continuum model of coupled water and heat transport was employed to account for preferential flow effects. Data collected at an experimental site in the Šumava Mountains, southern Bohemia, during the vegetation season 2009 were employed. Soil hydraulic properties (retention curve and hydraulic conductivity) determined by independent soil tests were used. Unavailable hydraulic parameters were adjusted to obtain satisfactory hydraulic model performance. Soil thermal properties were estimated based on values found in literature without further optimization. Three different approaches were used to approximate the soil thermal conductivity function, λ(θ): (i) relationships provided by Chung and Horton (ii) linear estimates as described by Loukili, Woodbury and Snelgrove, (iii) methodology proposed by Côté and Konrad. The simulated thermal conditions were compared to those observed. The impact of different soil thermal conductivity approximations on the heat transport simulation results was analysed. The differences between the simulation results in terms of the soil temperature were small. Regarding the surface soil heat flux, these differences became substantial. More realistic simulations were obtained using λ(θ) estimates based on the soil texture and composition. The differences between these two, related to neglecting vs. considering λ(θ) non-linearity, were found negligible.

Water infiltration in an aquifer recharge basin affected by temperature and air entrapment

“…preferential flow in heterogeneous soils) and their coupling with heat transfer. In fact, both water and solid phases may conduct heat meaning that heat transfer may be much more complex than considered in this study (Vogel et al, 2011;Votrubová et al, 2012). During summer or winter seasons, the soil may exhibit an important vertical temperature gradient due to very hot or cold temperatures, respectively (Hillel, 1998).…”

Rainfall interception and spatial variability of throughfall in spruce stand

“…Recent research utilizing data from Liz experimental catchment included studies on evapotranspiration (Pražák et al, 1996), cloud and fog water deposition (Eliáš et al, 1995), water regime affected by vegetation cover changes (Buchtele et al, 2006), hydraulic redistribution of water by roots (Nadezhdina et al, 2010), development and testing of macroscopic root water uptake model (Vogel et al, 2013), and predictions of heat fluxes in structured soil profile (Votrubová et al, 2012).…”

Thermal properties of representative soils of the Czech Republic

“…The volumetric heat capacity, C s (M/L/T 2 /K), of solid was then calculated as follows: Buchner et al 2008;Sakai et al 2011;Bauer et al 2012;Votrubová et al 2012).…”

“…Some expressions also include average thermal conductivity of mineral grains and thermal conductivities of organic matter content and water. Votrubová et al (2012) studied the impact of different estimates of λ(θ) relationship on simulated thermal regime in the soil profile. They found that differences between the simulated soil temperatures were small, but the surface soil heat fluxes were substantially different.…”