Application of the Versatile Soil Moisture Budget Model to Estimate Evaporation from Prairie Grassland

Jackson, J. F.; Xu, Ligang

doi:10.4296/cwrj3502187

Cited by 29 publications

(42 citation statements)

References 29 publications

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“…Daily evapotranspiration was then calculated using the adjusted mean daytime latent heat flux. Comparison with daily ET estimates for the WNC site derived using the methodology of Hayashi et al (2010) suggest that our ET estimates probably represent the high end of the expected range. Hayashi et al (2010) used three methods for estimating daily ET.…”

Section: Validation: Data and Methodologymentioning

confidence: 78%

“…Comparison with daily ET estimates for the WNC site derived using the methodology of Hayashi et al (2010) suggest that our ET estimates probably represent the high end of the expected range. Hayashi et al (2010) used three methods for estimating daily ET. The first estimate (deemed to be the lower bound) was calculated without forcing energy closure (i.e., unadjusted latent heat flux).…”

Section: Validation: Data and Methodologymentioning

confidence: 78%

“…The data were then compared for 17 days for which we could calculate the daily ET estimate using all of the aforementioned methods at WNC. Careful comparison between the daytime ET estimates using our methodology and that of Hayashi et al (2010) suggest that, on average, our daytime ET estimates may be 5% to 7% too high. This equates to about 0.2 mm to 0.3 mm of ET per day.…”

Section: Validation: Data and Methodologymentioning

confidence: 90%

“…The average closure rate was 0.78 which is similar to the closure rate reported by Su et al (2005) for EC measurements made over a soybean crop. Hayashi et al (2010) estimated the uncertainty associated with calculating daytime ET estimates to be 10-15%, using the EC system at Spy Hill farm, located 10 km south of the WNC site. Mo et al (2008) reported that the overall accuracy of eddy covariance fluxes is between 10 and 20% (e.g., Santaren et al, 2007).…”

Section: Water Vapour Concentrationmentioning

confidence: 99%

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Validation of ET Estimates from the Canadian Prairie Agrometeorological Model for Contrasting Vegetation Types and Growing Seasons

Brimelow¹,

Hanesiak²,

Raddatz³

2010

Canadian Water Resources Journal

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Abstract:The objective of this study was to establish the ability of the prairie agrometeorological model (PAMII) to simulate daily evapotranspiration (ET). Specifically, modelled ET estimates from PAMII were validated using daily ET estimates from eddy-covariance systems at West Nose Creek (barley field located northwest of Calgary, Alberta) and a FluxNet site (short-grass prairie located west of Lethbridge, Alberta). Additionally, PAMII was validated for three contrasting growing seasons at the grassland site to establish the model's ability to quantify the effect of different growth conditions on ET. PAMII performed well and was able to capture the day-to-day variability of the ET at both sites. PAMII successfully captured the increase (decrease) in accumulated growing season ET for the wet (dry) growing seasons at the short-grass prairie site. Moreover, the optimal reference minimum stomatal resistance term was significantly lower for the barley crop (50 s m ). At the grassland site the optimal stomatal resistance term varied markedly depending on the growing conditions; the optimal value for the wet year was 60 s m -1 compared to 90 s m -1 for the dry year. That is, no single value worked best for all years, and our findings caution against using a single value for the reference minimum stomatal resistance. In summary, PAMII captured the salient features of the ET variability at both sites and for contrasting at the grassland site. However, our research has identified several areas where future versions of the PAMII model might be improved.Résumé : La présente étude avait pour objectif d'établir la capacité du modèle agrométéorologique des Prairies (PAMII) de simuler l'évapotranspiration quotidienne (ET). Spécifiquement, les estimations de l'évapotranspiration modélisées, tirées du modèle PAMII, ont été validées à l'aide des estimations de l'évapotranspiration quotidienne des systèmes de covariance des turbulences à West Nose Creek (champ d'orge situé au nord-ouest de Calgary, en Alberta) et à un site FluxNet (prairie à herbes courtes située à l'ouest de Lethbridge, en Alberta). De plus, PAMII a été validé pour trois saisons de croissance différentes dans la prairie afin d'établir la capacité du modèle à quantifier l'effet de différentes conditions de croissance sur l'évapotranspiration. PAMII a donné de bons résultats et a su capter la variabilité quotidienne de ). Au site de la prairie, la durée de la résistance stomatique optimale variait de façon marquée, selon les conditions de croissance; la valeur optimale pour l'année humide était de 60 s m -1 comparativement à 90 s m -1 pour l'année sèche. En conclusion, aucune valeur unique n'a donné de résultats supérieurs pour toutes les années et nos constatations nous incitent à la prudence quant à l'utilisation d'une valeur unique pour la résistance stomatique minimale de référence. En résumé, le modèle PAMII a capté les traits saillants de la variabilité de l'évapotranspiration aux deux sites, faisant également ressortir les contrastes saisonniers au site de...

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Section: Validation: Data and Methodologymentioning

confidence: 78%

Section: Validation: Data and Methodologymentioning

confidence: 78%

Section: Validation: Data and Methodologymentioning

confidence: 90%

Section: Water Vapour Concentrationmentioning

confidence: 99%

See 2 more Smart Citations

Validation of ET Estimates from the Canadian Prairie Agrometeorological Model for Contrasting Vegetation Types and Growing Seasons

Brimelow¹,

Hanesiak²,

Raddatz³

2010

Canadian Water Resources Journal

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“…Only rarely has the error originating from the post-closure method been reported in the literature. Hayashi et al (2010) used the arithmetic average of raw flux and Bowen ratio-adjusted fluxes as a measure of uncertainty. Falge et al (2005) as well as Spank et al (2013) plotted the difference between LE-adjusted and non-adjusted flux data as a grey band to indicate the postclosure method error of the latent heat flux measurements.…”

Section: Introductionmentioning

confidence: 99%

On the use of the post-closure methods uncertainty band to evaluate the performance of land surface models against eddy covariance flux data

et al. 2015

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Abstract. The energy balance of eddy covariance (EC) flux data is normally not closed. Therefore, at least if used for modelling, EC flux data are usually post-closed, i.e. the measured turbulent fluxes are adjusted so as to close the energy balance. At the current state of knowledge, however, it is not clear how to partition the missing energy in the right way. Eddy flux data therefore contain some uncertainty due to the unknown nature of the energy balance gap, which should be considered in model evaluation and the interpretation of simulation results. We propose to construct the post-closure methods uncertainty band (PUB), which essentially designates the differences between non-adjusted flux data and flux data adjusted with the three post-closure methods (Bowen ratio, latent heat flux (LE) and sensible heat flux (H ) method). To demonstrate this approach, simulations with the NOAH-MP land surface model were evaluated based on EC measurements conducted at a winter wheat stand in southwest Germany in 2011, and the performance of the Jarvis and Ball-Berry stomatal resistance scheme was compared. The width of the PUB of the LE was up to 110 W m −2 (21 % of net radiation). Our study shows that it is crucial to account for the uncertainty in EC flux data originating from lacking energy balance closure. Working with only a single post-closing method might result in severe misinterpretations in model-data comparisons.

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Land‐use comparison of depression‐focussed groundwater recharge in the Canadian prairies

Morgan

Cey

2021

Hydrological Processes

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In the cold semiarid Canadian prairies, groundwater recharge is focussed under numerous topographic depressions, in which snowmelt runoff converges. Agricultural land uses on the uplands surrounding the depressions affect snow accumulation, snowmelt infiltration, evapotranspiration (ET) and soil moisture dynamics, thereby influencing snowmelt runoff and depression-focussed recharge. The objective of this study is to compare the differences in hydrological processes under two common land uses in the Canadian prairies, namely grazed grass and annual crop, and examine how they affect groundwater recharge. A short-term (3 years) paired catchment study was used for detailed observation of hydrological processes in two depressions, supplemented by a longer-term (17 years) data set covering a larger scale to quantify the differences in snowmelt runoff between the two land uses. Compared to the grazed grassland, the cropland had a shorter and more intense period of ET, and root water uptake restricted to the shallower (top 0-80 cm) soil zone. The amount of snowmelt runoff was greater in the grazed grassland primarily due to a higher amount of snow accumulation, which was dictated by differences in topography. This finding was contrary to previous studies in the Canadian prairies that indicated substantially smaller snowmelt runoff in ungrazed grassland, but was consistent with the larger-scale remote sensing results, which showed only a marginal difference between grazed grasslands and croplands. Groundwater recharge rates were estimated using the chloride mass balance method for the present condition using "modern" pore water containing tritium. The rates were similar between the grazed grassland and croplands, implying similarity in snowmelt runoff characteristics.These results suggest that groundwater recharge will continue to be focussed under depressions in the future, though the amount and seasonality of recharge may be influenced by warmer winters.

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Application of the Versatile Soil Moisture Budget Model to Estimate Evaporation from Prairie Grassland

Cited by 29 publications

References 29 publications

Validation of ET Estimates from the Canadian Prairie Agrometeorological Model for Contrasting Vegetation Types and Growing Seasons

Validation of ET Estimates from the Canadian Prairie Agrometeorological Model for Contrasting Vegetation Types and Growing Seasons

On the use of the post-closure methods uncertainty band to evaluate the performance of land surface models against eddy covariance flux data

Land‐use comparison of depression‐focussed groundwater recharge in the Canadian prairies

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