Concerning the Relationship between Evapotranspiration and Soil Moisture

Wetzel, Peter J.; Chang, J. L.

doi:10.1175/1520-0450(1987)026<0018:ctrbea>2.0.co;2

Cited by 198 publications

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“…These parameters define the maximum water stock available for the crop which controls the plant transpiration. The wilting point and the rooting depth are two cropdependent parameters which can lead to large variations in time of the root-zone water reservoir over the crop succession (Wetzel and Chang, 1987;Verhoef and Egea, 2014).…”

Section: S Garrigues Et Al: Evaluation Of Land Surface Model Simulamentioning

confidence: 99%

Evaluation of land surface model simulations of evapotranspiration over a 12-year crop succession: impact of soil hydraulic and vegetation properties

Garrigues

Olioso

Calvet

et al. 2015

Hydrol. Earth Syst. Sci.

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Abstract. Evapotranspiration has been recognized as one of the most uncertain terms in the surface water balance simulated by land surface models. In this study, the SURFEX/ISBA-A-gs (Interaction Sol-BiosphereAtmosphere) simulations of evapotranspiration are assessed at the field scale over a 12-year Mediterranean crop succession. The model is evaluated in its standard implementation which relies on the use of the ISBA pedotransfer estimates of the soil properties. The originality of this work consists in explicitly representing the succession of crop cycles and inter-crop bare soil periods in the simulations and assessing its impact on the dynamics of simulated and measured evapotranspiration over a long period of time. The analysis focuses on key parameters which drive the simulation of ET, namely the rooting depth, the soil moisture at saturation, the soil moisture at field capacity and the soil moisture at wilting point. A sensitivity analysis is first conducted to quantify the relative contribution of each parameter on ET simulation over 12 years. The impact of the estimation method used to retrieve the soil parameters (pedotransfer function, laboratory and field methods) on ET is then analysed. The benefit of representing the variations in time of the rooting depth and wilting point is evaluated. Finally, the propagation of uncertainties in the soil parameters on ET simulations is quantified through a Monte Carlo analysis and compared with the uncertainties triggered by the mesophyll conductance which is a key above-ground driver of the stomatal conductance.This work shows that evapotranspiration mainly results from the soil evaporation when it is continuously simulated over a Mediterranean crop succession. This results in a high sensitivity of simulated evapotranspiration to uncertainties in the soil moisture at field capacity and the soil moisture at saturation, both of which drive the simulation of soil evaporation. Field capacity was proved to be the most influencing parameter on the simulation of evapotranspiration over the crop succession. The evapotranspiration simulated with the standard surface and soil parameters of the model is largely underestimated. The deficit in cumulative evapotranspiration amounts to 24 % over 12 years. The bias in daily daytime evapotranspiration is −0.24 mm day −1 . The ISBA pedotransfer estimates of the soil moisture at saturation and at wilting point are overestimated, which explains most of the evapotranspiration underestimation. The use of field capacity values retrieved from laboratory methods leads to inaccurate simulation of ET due to the lack of representativeness of the soil structure variability at the field scale. The most accurate simulation is achieved with the average values of the soil properties derived from the analysis of field measurements of soil moisture vertical profiles over each crop cycle. The representation of the variations in time of the wilting point and the maximum rooting depth over the crop succession has litPublished by Copernicus Publica...

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Section: S Garrigues Et Al: Evaluation Of Land Surface Model Simulamentioning

confidence: 99%

Evaluation of land surface model simulations of evapotranspiration over a 12-year crop succession: impact of soil hydraulic and vegetation properties

Garrigues

Olioso

Calvet

et al. 2015

Hydrol. Earth Syst. Sci.

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“…where T max i is the maximum rate of transpiration sustainable given the moisture status of soil layer i, q i is the relative fraction of root area within layer i, and T p is the potential transpiration [41]. Based in part on observed leaf area index (LAI) magnitudes, T p is calculated following the Jarvis-type approach presented in [28].…”

Section: Land Surface Modelingmentioning

confidence: 99%

“…Fractional vegetation covers (f v ) were derived using (2) and TM NDVI observations. Since typical internal plant resistances (r p ) for crops vary between 5.0 · 10 8 and 1.0 · 10 9 s [41], an averaged value of 7.5 · 10 8 s was used for corn and soybean.…”

Section: Model Parametersmentioning

confidence: 99%

Upscaling of field-scale soil moisture measurements using distributed land surface modeling

Crow

Ryu

Famiglietti

2005

Advances in Water Resources

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Accurate coarse-scale soil moisture information is required for robust validation of current-and next-generation soil moisture products derived from spaceborne radiometers. Due to large amounts of land surface and rainfall heterogeneity, such information is difficult to obtain from existing ground-based networks of soil moisture sensors. Using ground-based field data collected during the Soil Moisture Experiment in 2002 (SMEX02), the potential for using distributed modeling predictions of the land surface as an upscaling tool for field-scale soil moisture observations is examined. Results demonstrate that distributed models are capable of accurately capturing a significant level of field-scale soil moisture heterogeneity observed during SMEX02. A simple soil moisture upscaling strategy based on the merger of ground-based observations with modeling predictions is developed and shown to be more robust during SMEX02 than upscaling approaches that utilize either field-scale ground observations or model predictions in isolation.

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“…LOUMAGNE et al, 1996). L'évaporation de la couche globale E g se décompose entre l'évaporation du sol nu, E sd , calculée en se basant sur le concept d'éva-poration limite (WETZEL et al, 1987) et la transpiration des plantes E veg qui se déduit de l'évaporation potentielle suivant une relation empirique validée dans le cadre de l'expérience Hapex-Mobilhy (OTTLE et VIDAL-MADJAR, 1994). L'éva-poration de la couche de surface, E s , se décompose entre l'évaporation du sol nu, une partie assez faible (20 %) de la transpiration des plantes estimée d'après la répartition racinaire verticale, et le contenu en eau de la couche superficielle, Ws qui est un facteur limitant pour l'évaporation.…”

Section: Schematlc Diagram Of the Gr4j Modelunclassified

Assimilation de données d'humidité des sols pour la prévision de crues : comparaison d'un modèle pluie-débit conceptuel et d'un modèle intégrant une interface sol-végétation-atmosphère

Weisse¹,

Oudin²,

Loumagne³

2005

rseau

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SUMMARYImproving the accuracy of rainfall-runoff models and in particular their performances in flood prédiction is a key point of continental hydrology. Methods hâve been developed to improve flood prédiction in hydrology based on a better compliance of the model with current observations prior to its use in forecasting mode. This opération has been termed updating in hydrology and assimilation in meteorology. The fundamental idea is that if model prédictions diverge from observations at a given time, there is little chance that future estimations will approach correct values. The improvement then cornes from a correction of the trajectory of the model based on observations during the period preceding the day vvhen a prédiction into the immédiate or long-term future is desired. This can be dealt with by a correction of model parameters, which is usually called "parameter updating".The inability of rainfall-runoff models to produce correct streamflow values generally translates into parameter uncertainty. Parameter calibration is the means used by a model structure to adjust to a given set of data. Therefore, a parameter updating methodology seems to be a natural way to amend errors in streamflow values. In this paper, a spécifie methodology of parameter updating is presented. The main feature of this method is that it does not carry out updating by référence only to récent streamflow observations, as classic procédures do, but also to soil moisture measurements, which can be retrieved daily from TDR (Time Domain Reflectometry) probes. Indeed, it

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Concerning the Relationship between Evapotranspiration and Soil Moisture

Cited by 198 publications

References 0 publications

Evaluation of land surface model simulations of evapotranspiration over a 12-year crop succession: impact of soil hydraulic and vegetation properties

Evaluation of land surface model simulations of evapotranspiration over a 12-year crop succession: impact of soil hydraulic and vegetation properties

Upscaling of field-scale soil moisture measurements using distributed land surface modeling

Assimilation de données d'humidité des sols pour la prévision de crues : comparaison d'un modèle pluie-débit conceptuel et d'un modèle intégrant une interface sol-végétation-atmosphère

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