Simulations of coupled non-isothermal soil moisture transport and evaporation fluxes in a forest area

Abstract

This study focuses on the quantification of non-isothermal soil moisture transport and evaporation fluxes in vegetated area. A one-dimensional numerical model is developed by integrating a multi-phase flow model with a twolayer energy-balance model. The non-isothermal multi-phase flow model solves four governing equations for coupled air, vapour, moisture, and heat transport in soil porous medium. The two-layer energy balance model estimates evaporation fluxes from transpiration, interception, and soil surface. The model was implemented to an oak forest area in Missouri, USA. For model calibration and validation, measurements of energy fluxes, soil moisture, and soil temperature were used. The proposed model is compared with a simple model that couples the Penman-Monteith equation with the Richards' equation. The results indicate that the simple model underestimate the total evaporation rate. On the contrary, the proposed model includes a more detailed description of energy transfer, which could improve the accuracy in estimating evaporation rates. The proposed model could be a promising tool to quantify the energy and moisture fluxes in a soil-vegetation-atmosphere continuum in vegetated area.

Ecohydrological Behaviour of Mountain Beech Forest: Quantification of Stomatal Conductance Using Sap Flow Measurements

“…These standard parametrizations have been used to estimate the moisture flux from land surface at a catchment scale or even at a global scale [51][52][53]. However, stomatal behaviour commonly shows distinct properties even within a certain tree species [54,55]. For a certain study site, general parametrization of one type of vegetation species may not be fully represented [42].…”

Water percolation in a thick unsaturated loess layer considering the ground‐atmosphere interaction

“…However, these studies do not take account of the ground‐atmosphere interaction, which has a significant influence on the amount of water that recharges the GWT. On the other hand, available studies on ground‐atmosphere interaction provide limited information on its influence on water movement at greater depths (An et al, ; Shao, Su, & Langhammer, ; Wilson et al, ). A few studies have focused on the influence of atmospheric factors on the water percolation within a thick unsaturated soil zone (for example, Scanlon & Milly, ).…”

The impact of non-isothermal soil moisture transport on evaporation fluxes in a maize cropland

“…We developed a numerical model by coupling a soil multiphase flow model with a two-layer energy balance model to simulate energy and moisture transport in a SVAT continuum, and the basic model validation in a forest area under humid environment can be found in Shao et al, (2017b). This study focuses on explicit simulation of detailed interactions between non-isothermal soil moisture transport and evaporation fluxes, and furthermore we included the radative transfer model (for detail see Supplementary material).…”

“…Both moisture and temperature at the soil surface mutually dictate the variations of albedo, emissivity, and vapour pressure, which can further influence energy budget and evaporation fluxes (Eltahir, 1998;Seneviratne et al, 2010). Direct observations of soil moisture transport and evaporation fluxes are impractical (Wei et al, 2017), therefore, numerical modelling is commonly used to study the physical processes of evaporation (Bittelli et al, 2008;Shao et al, 2017b). The model for energy and moisture transport in a soil-vegetation-atmosphere transfer continuum, being named as an SVAT model, is developed by incorporating theories from soil physics, vegetation physiology, and atmospheric science (Gran et al, 2011;Overgaard et al, 2006).…”