Modeling the exchange of water and energy over natural land surfaces = Het modelleren van de uitwisseling van water en energie over natuurlijke landschappen

Research output: Thesisinternal PhD, WU

Abstract

<p>This thesis deals with the modeling of the surface energy balance and the atmospheric boundary layer over natural land surfaces, on scales of the grid cell of large-scale atmospheric models. In the first part, a model to calculate the canopy conductance as a function of environmental variables evaluated at leaf level is developed and validated. The parameter values of this approach are retained from plant-physiological theory. For a C <sub>4</sub> prairie grass in Kansas and a C <sub>3</sub> soybean crop in southern France, the plant-physiological approach gives better estimates of the canopy conductance, compared to a traditional Jarvis-Stewart approach which relates the canopy conductance to environmental variables at a reference level, using empirical-statistical functions. For a C <sub>3</sub> grassland in the Netherlands, both the plant-physiological approach and the Jarvis-Stewart approach give comparable estimates of the latent heat flux density. In the second part, two approaches to calculate the impact of soil moisture stress on the surface flux densities over natural, heterogeneous areas are compared: a bulk approach where the soil moisture content is assumed to be uniform in a grid cell, and a distributed approach which takes account of the spatial variation of the soil moisture content. In wet conditions, the bulk approach gives larger predictions of the latent heat flux density than the distributed approach. In dry conditions the bulk approach gives lower predictions than the distributed approach. Especially for dry climates the bulk approach predicts during the dry season a severe suppression of the latent heat flux density. In the third part, using three cases that occur frequently in nature it is shown that only a tiling approach can provide estimates of the averaged surface flux densities that are consistent with the averaged temperature difference over the surface layer, the layer of air adjacent to the surface, in all situations.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
Supervisors/Advisors
  • Holtslag, Bert, Promotor
  • de Bruin, H.A.R., Promotor
  • van den Hurk, B.J.J.M., Promotor, External person
Award date15 May 2002
Place of PublicationS.l.
Publisher
Print ISBNs9789058086174
Publication statusPublished - 2002

Fingerprint

land surface
modeling
energy
water
latent heat flux
soil moisture
canopy
surface flux
moisture content
surface energy
prediction
prairie
energy balance
soybean
dry season
surface layer
spatial variation
boundary layer
grassland
grass

Keywords

  • mathematical models
  • evapotranspiration
  • precipitation
  • soil energy relations
  • boundary layer

Cite this

@phdthesis{96bb4e0cec7d4a2aafc6c52fedb9b433,
title = "Modeling the exchange of water and energy over natural land surfaces = Het modelleren van de uitwisseling van water en energie over natuurlijke landschappen",
abstract = "This thesis deals with the modeling of the surface energy balance and the atmospheric boundary layer over natural land surfaces, on scales of the grid cell of large-scale atmospheric models. In the first part, a model to calculate the canopy conductance as a function of environmental variables evaluated at leaf level is developed and validated. The parameter values of this approach are retained from plant-physiological theory. For a C 4 prairie grass in Kansas and a C 3 soybean crop in southern France, the plant-physiological approach gives better estimates of the canopy conductance, compared to a traditional Jarvis-Stewart approach which relates the canopy conductance to environmental variables at a reference level, using empirical-statistical functions. For a C 3 grassland in the Netherlands, both the plant-physiological approach and the Jarvis-Stewart approach give comparable estimates of the latent heat flux density. In the second part, two approaches to calculate the impact of soil moisture stress on the surface flux densities over natural, heterogeneous areas are compared: a bulk approach where the soil moisture content is assumed to be uniform in a grid cell, and a distributed approach which takes account of the spatial variation of the soil moisture content. In wet conditions, the bulk approach gives larger predictions of the latent heat flux density than the distributed approach. In dry conditions the bulk approach gives lower predictions than the distributed approach. Especially for dry climates the bulk approach predicts during the dry season a severe suppression of the latent heat flux density. In the third part, using three cases that occur frequently in nature it is shown that only a tiling approach can provide estimates of the averaged surface flux densities that are consistent with the averaged temperature difference over the surface layer, the layer of air adjacent to the surface, in all situations.",
keywords = "wiskundige modellen, evapotranspiratie, neerslag, bodem-energie-relaties, grenslaag, mathematical models, evapotranspiration, precipitation, soil energy relations, boundary layer",
author = "R.J. Ronda",
note = "WU thesis 3198 Met lit. opg. - Met samenvatting in het Nederlands Proefschrift Wageningen",
year = "2002",
language = "English",
isbn = "9789058086174",
publisher = "S.n.",
school = "Wageningen University",

}

TY - THES

T1 - Modeling the exchange of water and energy over natural land surfaces = Het modelleren van de uitwisseling van water en energie over natuurlijke landschappen

AU - Ronda, R.J.

N1 - WU thesis 3198 Met lit. opg. - Met samenvatting in het Nederlands Proefschrift Wageningen

PY - 2002

Y1 - 2002

N2 - This thesis deals with the modeling of the surface energy balance and the atmospheric boundary layer over natural land surfaces, on scales of the grid cell of large-scale atmospheric models. In the first part, a model to calculate the canopy conductance as a function of environmental variables evaluated at leaf level is developed and validated. The parameter values of this approach are retained from plant-physiological theory. For a C 4 prairie grass in Kansas and a C 3 soybean crop in southern France, the plant-physiological approach gives better estimates of the canopy conductance, compared to a traditional Jarvis-Stewart approach which relates the canopy conductance to environmental variables at a reference level, using empirical-statistical functions. For a C 3 grassland in the Netherlands, both the plant-physiological approach and the Jarvis-Stewart approach give comparable estimates of the latent heat flux density. In the second part, two approaches to calculate the impact of soil moisture stress on the surface flux densities over natural, heterogeneous areas are compared: a bulk approach where the soil moisture content is assumed to be uniform in a grid cell, and a distributed approach which takes account of the spatial variation of the soil moisture content. In wet conditions, the bulk approach gives larger predictions of the latent heat flux density than the distributed approach. In dry conditions the bulk approach gives lower predictions than the distributed approach. Especially for dry climates the bulk approach predicts during the dry season a severe suppression of the latent heat flux density. In the third part, using three cases that occur frequently in nature it is shown that only a tiling approach can provide estimates of the averaged surface flux densities that are consistent with the averaged temperature difference over the surface layer, the layer of air adjacent to the surface, in all situations.

AB - This thesis deals with the modeling of the surface energy balance and the atmospheric boundary layer over natural land surfaces, on scales of the grid cell of large-scale atmospheric models. In the first part, a model to calculate the canopy conductance as a function of environmental variables evaluated at leaf level is developed and validated. The parameter values of this approach are retained from plant-physiological theory. For a C 4 prairie grass in Kansas and a C 3 soybean crop in southern France, the plant-physiological approach gives better estimates of the canopy conductance, compared to a traditional Jarvis-Stewart approach which relates the canopy conductance to environmental variables at a reference level, using empirical-statistical functions. For a C 3 grassland in the Netherlands, both the plant-physiological approach and the Jarvis-Stewart approach give comparable estimates of the latent heat flux density. In the second part, two approaches to calculate the impact of soil moisture stress on the surface flux densities over natural, heterogeneous areas are compared: a bulk approach where the soil moisture content is assumed to be uniform in a grid cell, and a distributed approach which takes account of the spatial variation of the soil moisture content. In wet conditions, the bulk approach gives larger predictions of the latent heat flux density than the distributed approach. In dry conditions the bulk approach gives lower predictions than the distributed approach. Especially for dry climates the bulk approach predicts during the dry season a severe suppression of the latent heat flux density. In the third part, using three cases that occur frequently in nature it is shown that only a tiling approach can provide estimates of the averaged surface flux densities that are consistent with the averaged temperature difference over the surface layer, the layer of air adjacent to the surface, in all situations.

KW - wiskundige modellen

KW - evapotranspiratie

KW - neerslag

KW - bodem-energie-relaties

KW - grenslaag

KW - mathematical models

KW - evapotranspiration

KW - precipitation

KW - soil energy relations

KW - boundary layer

M3 - internal PhD, WU

SN - 9789058086174

PB - S.n.

CY - S.l.

ER -