Heat and mass exchange within the soil - plant canopy-atmosphere system : a theroretical approach and its validation

R.M.M. El-Kilani

Research output: Thesisinternal PhD, WU

Abstract

<p>Heat, mass and momentum transfer between the canopy air layer and the layer of air above has a very intermittent nature. This intermittent nature is due to the passage at the canopy top of coherent structures which have a length scale at least as large as the canopy height. The periodic passage of these coherent structure at the canopy top leads to the ejection of the air inside the canopy and the replacement of this air by fresh air from above. It is through this process of ejection and sweep that the coherent structures become responsible for most of the large time average flux.<p>This study considers the effect of these coherent structures on the modelling and the dynamics of interaction between the plant canopy and the soil with the layer of air above and the effect of these coherent structures on the soil temperature profile. so, three parts are considered: Modelling , mathematical analysis and validation.<p>In the Modelling part: a discussion of the limitations of the available approaches and a suggestion of an intermittency approach are given.<p>First, there is a qualitative analysis of the effect of these coherent structures and their role in the momentum, heat and mass transfer on the validity of the Eulerian approaches used to describe canopy flow. We outline the limitations of these approaches and later suggest an intermittency approach to describe heat and mass transfer between the canopy layer and the layer of air above. We describe the used averaging procedure, the resulting correlations, the closure parameterization used and their justification.<p>Then we give a discussion of the effect of these coherent structure on the Lagrangian model approach qualitatively and then quantitatively and a method to correct for this is suggested.<p>From this, a mathematical analysis of the effect of coherent structure on the soil temperature profile is done by first analysing the effect of coherent structures on the mean temperature and vapour pressure deficit of the air. It is shown from the equations governing the system's behaviour that there is a non linearity in the canopy system. The effect of this non linearity depends on the ratio between the period between consequent gust intrusions into plant canopy with respect the air time constants. The effect of this non linearity on the soil temperature profile is shown through its effect on the coefficients of an Eigenfunction expansion of the soil temperature profile. Different scenarios for the effect of different parameters such as the stomatal resistance, the turbulent transport coefficient and the period between gust intrusion are studied and explained.<p>In the validation part, a comparison of a simulation for 7 days against a data set shows that the model gives very good agreement between the radiative environment and the temperature and vapour pressure of the air. Anyhow there is a interplay between three degrees of freedom. These are represented by the turbulent transport coefficient , the stomatal resistance and the gust intrusion into plant canopy.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
Supervisors/Advisors
  • Wartena, L., Promotor, External person
  • Goudriaan, L., Promotor, External person
  • Jacobs, A.F.G., Promotor, External person
Award date18 Feb 1997
Place of PublicationS.l.
Publisher
Print ISBNs9789054856443
Publication statusPublished - 1997

Fingerprint

canopy
atmosphere
air
soil
temperature profile
soil temperature
gust
nonlinearity
heat transfer
mass transfer
mathematical analysis
momentum transfer
vapor pressure
effect
modeling
qualitative analysis
parameterization
replacement
temperature
simulation

Keywords

  • microclimate
  • plants
  • boundaries
  • air temperature
  • thermodynamics
  • heat
  • heat transfer
  • thermal conductivity
  • transmission

Cite this

@phdthesis{bac442c5b5e14be78d5896d1b5f8ba05,
title = "Heat and mass exchange within the soil - plant canopy-atmosphere system : a theroretical approach and its validation",
abstract = "Heat, mass and momentum transfer between the canopy air layer and the layer of air above has a very intermittent nature. This intermittent nature is due to the passage at the canopy top of coherent structures which have a length scale at least as large as the canopy height. The periodic passage of these coherent structure at the canopy top leads to the ejection of the air inside the canopy and the replacement of this air by fresh air from above. It is through this process of ejection and sweep that the coherent structures become responsible for most of the large time average flux.This study considers the effect of these coherent structures on the modelling and the dynamics of interaction between the plant canopy and the soil with the layer of air above and the effect of these coherent structures on the soil temperature profile. so, three parts are considered: Modelling , mathematical analysis and validation.In the Modelling part: a discussion of the limitations of the available approaches and a suggestion of an intermittency approach are given.First, there is a qualitative analysis of the effect of these coherent structures and their role in the momentum, heat and mass transfer on the validity of the Eulerian approaches used to describe canopy flow. We outline the limitations of these approaches and later suggest an intermittency approach to describe heat and mass transfer between the canopy layer and the layer of air above. We describe the used averaging procedure, the resulting correlations, the closure parameterization used and their justification.Then we give a discussion of the effect of these coherent structure on the Lagrangian model approach qualitatively and then quantitatively and a method to correct for this is suggested.From this, a mathematical analysis of the effect of coherent structure on the soil temperature profile is done by first analysing the effect of coherent structures on the mean temperature and vapour pressure deficit of the air. It is shown from the equations governing the system's behaviour that there is a non linearity in the canopy system. The effect of this non linearity depends on the ratio between the period between consequent gust intrusions into plant canopy with respect the air time constants. The effect of this non linearity on the soil temperature profile is shown through its effect on the coefficients of an Eigenfunction expansion of the soil temperature profile. Different scenarios for the effect of different parameters such as the stomatal resistance, the turbulent transport coefficient and the period between gust intrusion are studied and explained.In the validation part, a comparison of a simulation for 7 days against a data set shows that the model gives very good agreement between the radiative environment and the temperature and vapour pressure of the air. Anyhow there is a interplay between three degrees of freedom. These are represented by the turbulent transport coefficient , the stomatal resistance and the gust intrusion into plant canopy.",
keywords = "microklimaat, planten, grenzen, luchttemperatuur, thermodynamica, warmte, warmteoverdracht, thermische geleiding, transmissie, microclimate, plants, boundaries, air temperature, thermodynamics, heat, heat transfer, thermal conductivity, transmission",
author = "R.M.M. El-Kilani",
note = "WU thesis 2224 Proefschrift Wageningen",
year = "1997",
language = "English",
isbn = "9789054856443",
publisher = "El-Kilani",

}

Heat and mass exchange within the soil - plant canopy-atmosphere system : a theroretical approach and its validation. / El-Kilani, R.M.M.

S.l. : El-Kilani, 1997. 390 p.

Research output: Thesisinternal PhD, WU

TY - THES

T1 - Heat and mass exchange within the soil - plant canopy-atmosphere system : a theroretical approach and its validation

AU - El-Kilani, R.M.M.

N1 - WU thesis 2224 Proefschrift Wageningen

PY - 1997

Y1 - 1997

N2 - Heat, mass and momentum transfer between the canopy air layer and the layer of air above has a very intermittent nature. This intermittent nature is due to the passage at the canopy top of coherent structures which have a length scale at least as large as the canopy height. The periodic passage of these coherent structure at the canopy top leads to the ejection of the air inside the canopy and the replacement of this air by fresh air from above. It is through this process of ejection and sweep that the coherent structures become responsible for most of the large time average flux.This study considers the effect of these coherent structures on the modelling and the dynamics of interaction between the plant canopy and the soil with the layer of air above and the effect of these coherent structures on the soil temperature profile. so, three parts are considered: Modelling , mathematical analysis and validation.In the Modelling part: a discussion of the limitations of the available approaches and a suggestion of an intermittency approach are given.First, there is a qualitative analysis of the effect of these coherent structures and their role in the momentum, heat and mass transfer on the validity of the Eulerian approaches used to describe canopy flow. We outline the limitations of these approaches and later suggest an intermittency approach to describe heat and mass transfer between the canopy layer and the layer of air above. We describe the used averaging procedure, the resulting correlations, the closure parameterization used and their justification.Then we give a discussion of the effect of these coherent structure on the Lagrangian model approach qualitatively and then quantitatively and a method to correct for this is suggested.From this, a mathematical analysis of the effect of coherent structure on the soil temperature profile is done by first analysing the effect of coherent structures on the mean temperature and vapour pressure deficit of the air. It is shown from the equations governing the system's behaviour that there is a non linearity in the canopy system. The effect of this non linearity depends on the ratio between the period between consequent gust intrusions into plant canopy with respect the air time constants. The effect of this non linearity on the soil temperature profile is shown through its effect on the coefficients of an Eigenfunction expansion of the soil temperature profile. Different scenarios for the effect of different parameters such as the stomatal resistance, the turbulent transport coefficient and the period between gust intrusion are studied and explained.In the validation part, a comparison of a simulation for 7 days against a data set shows that the model gives very good agreement between the radiative environment and the temperature and vapour pressure of the air. Anyhow there is a interplay between three degrees of freedom. These are represented by the turbulent transport coefficient , the stomatal resistance and the gust intrusion into plant canopy.

AB - Heat, mass and momentum transfer between the canopy air layer and the layer of air above has a very intermittent nature. This intermittent nature is due to the passage at the canopy top of coherent structures which have a length scale at least as large as the canopy height. The periodic passage of these coherent structure at the canopy top leads to the ejection of the air inside the canopy and the replacement of this air by fresh air from above. It is through this process of ejection and sweep that the coherent structures become responsible for most of the large time average flux.This study considers the effect of these coherent structures on the modelling and the dynamics of interaction between the plant canopy and the soil with the layer of air above and the effect of these coherent structures on the soil temperature profile. so, three parts are considered: Modelling , mathematical analysis and validation.In the Modelling part: a discussion of the limitations of the available approaches and a suggestion of an intermittency approach are given.First, there is a qualitative analysis of the effect of these coherent structures and their role in the momentum, heat and mass transfer on the validity of the Eulerian approaches used to describe canopy flow. We outline the limitations of these approaches and later suggest an intermittency approach to describe heat and mass transfer between the canopy layer and the layer of air above. We describe the used averaging procedure, the resulting correlations, the closure parameterization used and their justification.Then we give a discussion of the effect of these coherent structure on the Lagrangian model approach qualitatively and then quantitatively and a method to correct for this is suggested.From this, a mathematical analysis of the effect of coherent structure on the soil temperature profile is done by first analysing the effect of coherent structures on the mean temperature and vapour pressure deficit of the air. It is shown from the equations governing the system's behaviour that there is a non linearity in the canopy system. The effect of this non linearity depends on the ratio between the period between consequent gust intrusions into plant canopy with respect the air time constants. The effect of this non linearity on the soil temperature profile is shown through its effect on the coefficients of an Eigenfunction expansion of the soil temperature profile. Different scenarios for the effect of different parameters such as the stomatal resistance, the turbulent transport coefficient and the period between gust intrusion are studied and explained.In the validation part, a comparison of a simulation for 7 days against a data set shows that the model gives very good agreement between the radiative environment and the temperature and vapour pressure of the air. Anyhow there is a interplay between three degrees of freedom. These are represented by the turbulent transport coefficient , the stomatal resistance and the gust intrusion into plant canopy.

KW - microklimaat

KW - planten

KW - grenzen

KW - luchttemperatuur

KW - thermodynamica

KW - warmte

KW - warmteoverdracht

KW - thermische geleiding

KW - transmissie

KW - microclimate

KW - plants

KW - boundaries

KW - air temperature

KW - thermodynamics

KW - heat

KW - heat transfer

KW - thermal conductivity

KW - transmission

M3 - internal PhD, WU

SN - 9789054856443

PB - El-Kilani

CY - S.l.

ER -