TY - JOUR
T1 - Impact of model structure and parameterization on Penman-Monteith type evaporation models
AU - Ershadi, A.
AU - McCabe, M. F.
AU - Evans, J. P.
AU - Wood, Eric F.
N1 - Funding Information:
Funding for this research was provided via an Australian Research Council (ARC) Linkage ( LP0989441 ) and Discovery ( DP120104718 ) project, together with a top-up scholarship to support Dr Ali Ershadi from the National Centre for Groundwater Research and Training (NCGRT) in Australia during his PhD. Research reported in this publication was also supported by the King Abdullah University of Science and Technology (KAUST) . We thank the FLUXNET site investigators for allowing the use of their meteorological data. This work used eddy-covariance data acquired by the FLUXNET community and in particular by the AmeriFlux (U.S. Department of Energy, Biological and Environmental Research, Terrestrial Carbon Program: DE-FG02-04ER63917 and DE-FG02-04ER63911) and OzFlux programs. We acknowledge the financial support to the eddy-covariance data harmonization provided by CarboEuropeIP , FAO-GTOS-TCO , iLEAPS , Max Planck Institute for Biogeochemistry , National Science Foundation , University of Tuscia , Université Laval and Environment Canada and US Department of Energy and the database development and technical support from Berkeley Water Centre, Lawrence Berkeley National Laboratory, Microsoft Research eScience, Oak Ridge National Laboratory, University of California – Berkeley, University of Virginia. Data supplied by T. Kolb, School of Forestry, Northern Arizona University, for the US-Fuf site was supported by grants from the North American Carbon Program/USDA NRI ( 2004-35111-15057 ; 2008-35101-19076 ), Science Foundation Arizona ( CAA 0-203-08 ), and the Arizona Water Institute . Matlab scripts for automatic extraction of NDVI time series at towers were provided by Dr Tristan Quaife, University College London via the web portal at http://daac.ornl.gov/MODIS/MODIS-menu/modis_webservice.html .
Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2015/6/1
Y1 - 2015/6/1
N2 - The impact of model structure and parameterization on the estimation of evaporation is investigated across a range of Penman-Monteith type models. To examine the role of model structure on flux retrievals, three different retrieval schemes are compared. The schemes include a traditional single-source Penman-Monteith model (Monteith, 1965), a two-layer model based on Shuttleworth and Wallace (1985) and a three-source model based on Mu et al. (2011). To assess the impact of parameterization choice on model performance, a number of commonly used formulations for aerodynamic and surface resistances were substituted into the different formulations. Model response to these changes was evaluated against data from twenty globally distributed FLUXNET towers, representing a cross-section of biomes that include grassland, cropland, shrubland, evergreen needleleaf forest and deciduous broadleaf forest. Scenarios based on 14 different combinations of model structure and parameterization were ranked based on their mean value of Nash-Sutcliffe Efficiency. Results illustrated considerable variability in model performance both within and between biome types. Indeed, no single model consistently outperformed any other when considered across all biomes. For instance, in grassland and shrubland sites, the single-source Penman-Monteith model performed the best. In croplands it was the three-source Mu model, while for evergreen needleleaf and deciduous broadleaf forests, the Shuttleworth-Wallace model rated highest. Interestingly, these top ranked scenarios all shared the simple lookup-table based surface resistance parameterization of Mu et al. (2011), while a more complex Jarvis multiplicative method for surface resistance produced lower ranked simulations. The highly ranked scenarios mostly employed a version of the Thom (1975) formulation for aerodynamic resistance that incorporated dynamic values of roughness parameters. This was true for all cases except over deciduous broadleaf sites, where the simpler aerodynamic resistance approach of Mu et al. (2011) showed improved performance.Overall, the results illustrate the sensitivity of Penman-Monteith type models to model structure, parameterization choice and biome type. A particular challenge in flux estimation relates to developing robust and broadly applicable model formulations. With many choices available for use, providing guidance on the most appropriate scheme to employ is required to advance approaches for routine global scale flux estimates, undertake hydrometeorological assessments or develop hydrological forecasting tools, among many other applications. In such cases, a multi-model ensemble or biome-specific tiled evaporation product may be an appropriate solution, given the inherent variability in model and parameterization choice that is observed within single product estimates.
AB - The impact of model structure and parameterization on the estimation of evaporation is investigated across a range of Penman-Monteith type models. To examine the role of model structure on flux retrievals, three different retrieval schemes are compared. The schemes include a traditional single-source Penman-Monteith model (Monteith, 1965), a two-layer model based on Shuttleworth and Wallace (1985) and a three-source model based on Mu et al. (2011). To assess the impact of parameterization choice on model performance, a number of commonly used formulations for aerodynamic and surface resistances were substituted into the different formulations. Model response to these changes was evaluated against data from twenty globally distributed FLUXNET towers, representing a cross-section of biomes that include grassland, cropland, shrubland, evergreen needleleaf forest and deciduous broadleaf forest. Scenarios based on 14 different combinations of model structure and parameterization were ranked based on their mean value of Nash-Sutcliffe Efficiency. Results illustrated considerable variability in model performance both within and between biome types. Indeed, no single model consistently outperformed any other when considered across all biomes. For instance, in grassland and shrubland sites, the single-source Penman-Monteith model performed the best. In croplands it was the three-source Mu model, while for evergreen needleleaf and deciduous broadleaf forests, the Shuttleworth-Wallace model rated highest. Interestingly, these top ranked scenarios all shared the simple lookup-table based surface resistance parameterization of Mu et al. (2011), while a more complex Jarvis multiplicative method for surface resistance produced lower ranked simulations. The highly ranked scenarios mostly employed a version of the Thom (1975) formulation for aerodynamic resistance that incorporated dynamic values of roughness parameters. This was true for all cases except over deciduous broadleaf sites, where the simpler aerodynamic resistance approach of Mu et al. (2011) showed improved performance.Overall, the results illustrate the sensitivity of Penman-Monteith type models to model structure, parameterization choice and biome type. A particular challenge in flux estimation relates to developing robust and broadly applicable model formulations. With many choices available for use, providing guidance on the most appropriate scheme to employ is required to advance approaches for routine global scale flux estimates, undertake hydrometeorological assessments or develop hydrological forecasting tools, among many other applications. In such cases, a multi-model ensemble or biome-specific tiled evaporation product may be an appropriate solution, given the inherent variability in model and parameterization choice that is observed within single product estimates.
KW - Aerodynamic resistance
KW - Evaporation
KW - Evapotranspiration
KW - Latent heat flux
KW - Penman-Monteith
KW - Surface resistance
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U2 - 10.1016/j.jhydrol.2015.04.008
DO - 10.1016/j.jhydrol.2015.04.008
M3 - Article
AN - SCOPUS:84928136088
SN - 0022-1694
VL - 525
SP - 521
EP - 535
JO - Journal of Hydrology
JF - Journal of Hydrology
ER -