LysimeterGEO for modelling soil-vegetation-atmosphere 1D system in the Critical Zone

2021 ◽  
Author(s):  
Concetta D'Amato ◽  
Niccolò Tubini ◽  
Riccardo Rigon
Keyword(s):  
Water Stress ◽  
Soil Column ◽  
Critical Zone ◽  
Stress Factor ◽  
Richards Equation ◽  
Travel Times ◽  
One Dimensional ◽  
Solute Fluxes ◽  
The One ◽  
Non Linear System

<p>Measuring and modelling of water and solute fluxes in the Critical Zone across soil-vegetation-atmosphere system is nowadays a very important challenge because of the complexity of both soil and plants. Considering the one-dimensional problem, we implement a virtual lysimeter model, LysimeterGEO, in which we coupled infiltration and evapotranspiration by using stress factor (Jarvis, 1976; Ball et al., 1987), with which we can compute effective evapotranspiration and remove it from Richards’ equation balance (Casulli and Zanolli, 2010).</p><p>As regards the IT implementation, LysimeterGEO is a system of components built upon the Object Modelling System v3 (OMS3). The infiltration component of the virtual lysimeter is WHETGEO 1D - Water, Heat and Transport in GEOframe (Tubini N. 2021), which solves the mass and energy balance for the one-dimensional case. The mass balance is represented by the Richards equation and the non-linear system is solved using the nested Newton algorithm (Casulli and Zanolli, 2010). Evapotranspiration flows are instead estimated using the GEOframe-Prospero model (Bottazzi M. 2020) which estimates the effective transpiration through the equilibrium temperature of the canopy as a function of the stomatal conductance. Finally, the transpiration is calculated starting from the method of Schymanski and Or (2017) and modified by including the dependence on the transpiring surface, the model of conductance of the stomata, as well as the conservation of mass. In LysimeterGEO the interaction between infiltration and evapotranspiration is made possible by BrokerGEO component (D’Amato C. 2021), which computes the water stress factor for vegetation by using Jarvis or Ball-Berry model. BrokerGEO computes the water stress factor considering the water content information by WHETGEO in each control volumes of the soil column discretization. Moreover, it computes a representative water stress factor for the whole column of soil for the evapotranspiration component. Finally, the density root distribution is considered to remove water into the soil used for evapotranspiration flows.</p><p>The modelling of water and solute fluxes across soil-vegetation-atmosphere is made possible by implementation of travel times of waters within vegetation, the growing of the roots and in general the growing of the plants. The idea of a joint infiltration-evapotranspiration model allows us to investigate also problems related to radical growth and the different effect of roots on vegetation. Furthermore, the implementation of travel times on a vegetation scale allows a careful analysis of the behaviour of the same as the soil moisture conditions vary.</p>

scholarly journals Stability regions for an explicit numerical solution of the one-dimensional Richards equation applied to water soil infiltration

2022 ◽  
Vol 13 (2) ◽  
pp. 01-36
Author(s):  
H. Alejandro Pedrozo ◽  
◽  
Mario R. Rosenberger ◽  
Carlos E. Schvezov ◽  
◽  
...  
Keyword(s):  
Numerical Solution ◽  
Richards Equation ◽  
Soil Infiltration ◽  
Stability Regions ◽  
One Dimensional ◽  
The One

scholarly journals Variable Saturation Infiltration Model for Highly Vegetated Regions

2016 ◽  
Author(s):  
James Polsinelli ◽  
M. Levent Kavvas
Keyword(s):  
Water Content ◽  
Pore Space ◽  
Soil Column ◽  
Richards Equation ◽  
Universal Method ◽  
Infiltration Capacity ◽  
Rectangular Profile ◽  
Numerical Effort ◽  
Non Linear ◽  
Non Linear System

Abstract. Observations have been made in studies that in watersheds with moist soils and lush vegetation, water does not pond on the soil surface, even during significant rainfall events. In these cases, all the water infiltrates into the soil. Furthermore, the water content in the pore space is below saturation. The tools for modeling such situations are limited. A universal method for estimating groundwater in the unsaturated zone is the Richards' equation, a non linear system of 1D or 3D equations based on physical flow principles. While effective, the difficulties in solving Richards' equation can pose a significant problem in a complex system, which may require extensive amounts of calibration and numerical effort in procuring a solution. A second method is based on the idea of approximating the movement of moisture through the soil as a rectangular profile, e.g. assuming that the water moves through a soil column like a piston. Rectangular profile methods have been developed in the past for cases in which ponding occurs at the surface, and the water content inside the column is at saturation. More general rectangular profile methods allow the water in the column to move at sub-saturation. Both of these existing methods involve solving a non linear algebraic equation for the hydrologic system, involving constant flux at the boundary, due to a wetting event such as rainfall. The method proposed in this article may be used for situations in which the soil does not become saturated, and the soil and rainfall properties, specifically the rates of hydraulic conductance and rate of rainfall respectively, are allowed to vary in space or time. The method proposed is based on a simple principle in infiltration hydrology, that the rate at which water will infiltrate through the soil equilibrates with the rate of rainfall, when the rate of rainfall is smaller than the infiltration capacity of the soil. In application, this method does not require the solution of a non linear algebraic (or differential) system of equations, thus affording modelers computational economy. Furthermore, this new method can be made to interact with the saturated profile methods in the event that the rainfall overwhelms the ability of soil to absorb moisture. If this happens, a portion of the field will come to saturation while other parts will be below saturation. The sub-saturation models can be made to interact with the redistribution and evapotranspiration processes by providing the initial and boundary condition for those events.

One-Dimensional Infiltration and Vertical Flow

2003 ◽  
Author(s):  
Arthur W. Warrick
Keyword(s):  
Steady State ◽  
Numerical Methods ◽  
Analytical Solutions ◽  
Finite Differences ◽  
Numerical Solutions ◽  
Water Dynamics ◽  
Richards Equation ◽  
Vertical Flow ◽  
One Dimensional ◽  
The One

This chapter addresses one-dimensional infiltration and vertical flow problems. Traditionally, infiltration has received more attention than other unsaturated flow procedures, both for empirical formulations and for applications of Richards’ equation. Rarely is infiltration the only process of interest, and from an overall point of view it is only one example of soil water dynamics. Here, we will first emphasize systems for which analytical (or quasi-analytical) solutions can be found. These include the Green and Ampt solution (1911), which adds gravity to the simplified analysis discussed in chapter 4. Then a linearized form of Richards’ equation will be examined, followed by the perturbation of the horizontal problem of Philip leading to his famous series solution. Although the closed-form and quasi-analytical solutions are convenient for calculations and discussing the physical principles, generally, the nonlinearity of Richards’ equation precludes such convenient forms. However, numerical approximations can be used. The conventional numerical methods applied in water and solute transport are based on finite differences and finite elements. Because of its greater simplicity, we will emphasize finite differences and build on the methodology from the saturated-flow example in chapter 3. Richards’ equation is a parabolic partial differential equation reducing to an elliptical form for steady-state cases. The analyses and methods parallel developments for techniques developed primarily for the linear diffusion equation. Many texts exist for numerical methods; one to which we refer is by Smith (1985). Ideally, numerical methods give solutions that are as accurate as the input warrants or as necessary for application. In some cases, results may be easier or more accurate than the evaluation of a complex analytical expression. Clearly, infiltration is of limited duration, with drainage and redistribution occurring over much longer time frames. We will visit briefly some steady-state examples, including layered profile and upward flow from a shallow water table. Other examples include modeling plant water uptake from the profile and drainage of initially wet profiles. The rapid increase in computational power and availability of computers make solutions feasible and routine for problems that were very tedious or time consuming only a few years ago. This is particularly true of the one-dimensional numerical solutions.

scholarly journals Deep ice layer formation in an alpine snowpack: monitoring and modeling

2020 ◽  
Vol 14 (10) ◽  
pp. 3449-3464
Author(s):  
Louis Quéno ◽  
Charles Fierz ◽  
Alec van Herwijnen ◽  
Dylan Longridge ◽  
Nander Wever
Keyword(s):  
Preferential Flow ◽  
Richards Equation ◽  
One Dimensional ◽  
Dimensional Modeling ◽  
Combined Use ◽  
Formation And Evolution ◽  
The One ◽  
Complex Phenomena ◽  
Snow Microstructure ◽  
Ground Penetrating

Abstract. Ice layers may form deep in the snowpack due to preferential water flow, with impacts on the snowpack mechanical, hydrological and thermodynamical properties. This detailed study at a high-altitude alpine site aims to monitor their formation and evolution thanks to the combined use of a comprehensive observation dataset at a daily frequency and state-of-the-art snow-cover modeling with improved ice formation representation. In particular, daily SnowMicroPen penetration resistance profiles enabled us to better identify ice layer temporal and spatial heterogeneity when associated with traditional snowpack profiles and measurements, while upward-looking ground penetrating radar measurements enabled us to detect the water front and better describe the snowpack wetting when associated with lysimeter runoff measurements. A new ice reservoir was implemented in the one-dimensional SNOWPACK model, which enabled us to successfully represent the formation of some ice layers when using Richards equation and preferential flow domain parameterization during winter 2017. The simulation of unobserved melt-freeze crusts was also reduced. These improved results were confirmed over 17 winters. Detailed snowpack simulations with snow microstructure representation associated with a high-resolution comprehensive observation dataset were shown to be relevant for studying and modeling such complex phenomena despite limitations inherent to one-dimensional modeling.

A Note on the Influence of Site Conditions on Ground Motion Values Observed for the Southeastern Illinois Earthquake of June 10, 1987

1993 ◽  
Vol 64 (2) ◽  
pp. 149-156
Author(s):  
M. Zhang ◽  
R. Street ◽  
J. Harris ◽  
V.P. Drnevich
Keyword(s):  
Ground Motions ◽  
Soil Column ◽  
Quantitative Description ◽  
Response Analysis ◽  
Site Conditions ◽  
Sh Wave ◽  
One Dimensional ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
The One

Abstract Site conditions (i.e., depth to bedrock and intermediate horizons within the soil column, and the shear wave velocities of-the soils and bedrock) have been investigated using and SH-wave velocity data at eight sites in Illinois and Indiana where the June 10, 1987, southeastern Illinois earthquake was recorded on blast monitors. The site effects have been calculated using the site conditions and the one dimensional response analysis program WAVES (Hart and Wilson, 1989), and it was found that the site conditions caused the peak particle accelerations to be amplified by a factor of 2.7 to 4.8. It is suggested that the records of ground motions obtained at sites not on rock be considered inadequate for usage at other sites unless accompanied by a quantitative description of the site conditions.

scholarly journals Traveling wave solutions for the Richards equation with hysteresis

2019 ◽  
Vol 84 (4) ◽  
pp. 797-812 ◽  
Author(s):  
E El Behi-Gornostaeva ◽  
K Mitra ◽  
B Schweizer
Keyword(s):  
Traveling Waves ◽  
Traveling Wave ◽  
Traveling Wave Solutions ◽  
Richards Equation ◽  
One Dimensional ◽  
Homogeneous Solutions ◽  
Wave Solutions ◽  
Relevant Effect ◽  
Saturation Overshoot ◽  
The One

Abstract We investigate the one-dimensional non-equilibrium Richards equation with play-type hysteresis. It is known that regularized versions of this equation permit traveling wave solutions that show oscillations and, in particular, the physically relevant effect of a saturation overshoot. We investigate here the non-regularized hysteresis operator and combine it with a positive $\tau $-term. Our result is that the model has monotone traveling wave solutions. These traveling waves describe the behavior of fronts in a bounded domain. In a two-dimensional interpretation, the result characterizes the speed of fingers in non-homogeneous solutions.

Exploring the Multidimensional Facets of Authoritarianism: Authoritarian Aggression and Social Dominance Orientation

2008 ◽  
Vol 67 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Stefano Passini
Keyword(s):  
Social Dominance ◽  
Factor Model ◽  
Three Dimensional ◽  
Social Dominance Orientation ◽  
Model Fit ◽  
Regression Analyses ◽  
One Dimensional ◽  
Confirmatory Factor ◽  
The One ◽  
Better Than

The relation between authoritarianism and social dominance orientation was analyzed, with authoritarianism measured using a three-dimensional scale. The implicit multidimensional structure (authoritarian submission, conventionalism, authoritarian aggression) of Altemeyer’s (1981, 1988) conceptualization of authoritarianism is inconsistent with its one-dimensional methodological operationalization. The dimensionality of authoritarianism was investigated using confirmatory factor analysis in a sample of 713 university students. As hypothesized, the three-factor model fit the data significantly better than the one-factor model. Regression analyses revealed that only authoritarian aggression was related to social dominance orientation. That is, only intolerance of deviance was related to high social dominance, whereas submissiveness was not.

Sign in / Sign up

Export Citation Format

Share Document