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Field evaluation of the Maximum Entropy Production model

Field evaluation of the Maximum Entropy Production model. WWOSC 2014 Montréal, Canada. Morais A., Parent A.C., Anctil F., and Music B. Université Laval, Département de génie civil et de génie des eaux. Hydrological modelling with conceptual models. Why Maximum Entropy Production model?.

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Field evaluation of the Maximum Entropy Production model

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  1. Field evaluation of the Maximum Entropy Production model WWOSC 2014 Montréal, Canada MoraisA., Parent A.C., Anctil F., and Music B. Université Laval, Département de génie civil et de génie des eaux

  2. Hydrological modelling with conceptual models Why Maximum Entropy Production model?

  3. Hydrological modelling with conceptual models Why Maximum Entropy Production model? • Non-stationary climate

  4. Why Maximum Entropy Production model?

  5. Why Maximum Entropy Production model? Potential evapotranspiration based on empiricalrelationships that does not close the energy budget Is there a simple modelthat would include the energy budget closure and provide evapotranspiration for use with conceptual models and a non-stationary climate?

  6. Outline • Model description • Methodology • Results • Conclusion

  7. The Maximum Entropy Model: Model derivedfromthermodynamics(Wang and Bras 2012) • « Maximization of the of the transpiration/evaporation rate and the correspondingheat fluxes under the constraint of Rn is the mostpropable and macroscopicallyreproduciblethermodynamicprocessamong all possible partition of energy fluxes. » (Wang and Bras, 2007) • Based on the theory of maximum entropy production of Dewar (2005) • With constraint of surface energy balance: EvaporationTranspiration :

  8. Transpiration Equations of the 2 models: Evaporation

  9. The Canadian Land Surface Scheme (CLASS) • Sophistic 1 D physical Land surface Scheme for use in atmospheric models • Good reference since the model is well known and has been validated for a variety of land type. • CLASS is only used as a comparison toolfor the evaluation of the MEP model, if the MEP model gives similar outputs we will gain more confidence in his application.

  10. Models Experimental data Field evaluation • Two micro-meteorological stations located in a potatofield, St-Ubalde, Qc (N46 45',W72 20') • Complete season: June 6th – October 8th 2013 (125 days) • Observations of latent (Lv) and sensible (Ls) heat fluxes derived from the eddy covariance method Maximum Entropy Production model (MEP) from Wang and Bras 2012 Canadian Land Surface Scheme3.5(CLASS) fromVershegy 1992

  11. Meteorological inputs • Rain gauge CS700,Campbell SCI Precipitation (pr) • Pyranometer SP-Lite, Kipp&ZonenGlobal radiation at the surface (rs) • Net radiometer NR-Lite, Kipp &ZonenNet radiation at the surface (rn) • Barometer 06103,R.M. Young Atmospheric pressure (ps) • Heatflux plates HFP01SC, Hukse FluxSoilheatflux (G) • IRGA LI-7500, LI-COR Water vapour and air temperature (qa, ta) • 3-D sonic anemometer CSAT3, Campbell SCI 2m wind speed in 3D (v) ** rl : Downwellinglongwave radiation North American RegionalReanalysis(Available via the Web site: http://www.resarch.noaa.gov)

  12. How to distinguishbetweenevaporation and transpiration? The leaf area index (LAI)

  13. Two indices to represent the LAI :fg : Ground fraction fc : Canopy fraction fg = (1-fc) fc = fg =1 fc = 0 fg = 0 fc = 1 Baresoil and crops ETR = (fg*E) + (fc*T) 100% crops ETR = T 100% Baresoil ETR = E

  14. Energy budget

  15. Evapotranspiration and energy components

  16. Latent heat flux

  17. Sensible heat flux

  18. Ground heat flux

  19. Conclusion • MEP gave encouraging results for use as an alternative evapotranspiration model • Advantage of only requiring a few meteorological inputs and physiological parameters • A simple and general model which may fit for global scales

  20. Merci pour votre attention!Thank you for your attention!

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