Long wave radiation parameterisations

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This presentation deals with the parameterisation (modelling) of net long wave radiation. It is deemed useful for estimation of both snow cover evolution and evapotranspiration

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Long wave radiation parameterisations

  1. 1. Testing site-specific parameterizations of longwave radiation integrated in a GIS-based hydrological model Giuseppe Formetta1, Marialaura Bancheri2, Olaf David3 and Riccardo Rigon2 !! !1Dept. of Civil and Environmental Engineering, University of Calabria,Rende (CS),Italy 2Dept. of Civil and Environmental Engineering, University of Trento, 77 Mesiano St., 38123 Trento, Italy 3Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, Colorado, USA
  2. 2. Outline •  NewAge-JGrass hydrological system •  NewAge-LWRB package •  Models Applications (LWRB; SWRB+LWRB+SWE)
  3. 3. Interpola+on! Tools! Energy! Balance! Water! Balance! Automa+c! Calibra+on!NewAge-JGrass hydrological system Forme;a!et.!al,!2014!
  4. 4. Interpola+on! Tools! Energy! Balance! Water! Balance! Automa+c! Calibra+on! Forme;a!et.!al,!2014! Forme;a!et.!al,!2013! W/m2! NewAge-JGrass hydrological system
  5. 5. Interpola+on! Tools! Energy! Balance! Water! Balance! Automa+c! Calibra+on! Forme;a!et.!al,!2011! Forme;a!et.!al,!2014! Forme;a!et.!al,!2013! W/m2! NewAge-JGrass hydrological system
  6. 6. Interpola+on! Tools! Energy! Balance! Water! Balance! Automa+c! Calibra+on! Forme;a!et.!al,!2011! Forme;a!et.!al,!2014! Forme;a!et.!al,!2013! W/m2! NewAge-JGrass hydrological system
  7. 7. Interpola+on! Tools! Energy! Balance! Water! Balance! NewAge-JGrass hydrological system Automa+c! Calibra+on! Forme;a!et.!al,!2011! Forme;a!et.!al,!2014! Forme;a!et.!al,!2013! W/m2!
  8. 8. Longwave Radiation: why is important? LW is vitally important in determining the radiation budget, which, in turn, modulates the magnitude of the terms in the surface energy budget (e.g., evaporation, evapotransiration) (Todd and Duchon, 1998, J.A.M. ) ! Solar radiation is an important input for hydrological models e.g., Sinokrot and Stefan, 1993; Wigmosta et al., 1994; Kustas et al. ,1994; Cline et al., 1998; Pomeroy et al. , 2003 While shortwave radiation has often been considered the dominant energy source for snow melting, LW can match, or exceed, incoming shortwave radiation during cloudy periods (Müller 1985; Granger and Gray 1990; Duguay 1993; Ohmura, 2001; Sedlar and Hock, 2006) http://www.wunderground.com/blog/RickyRood Expensive to measure, and LW radiation measurement stations density is at least one of two order of magnitude lower that SW radiation
  9. 9. NewAge-LWRB package Downwelling Upwelling NewAge-LWRB Model Parameters
  10. 10. NewAge-LWRB package Downwelling Upwelling NewAge-LWRB Model ParametersInputData Raster Maps (dem, sky view factor) Meteorological Forcing data !!!!!!!!!! Time Series or Raster Maps of LWRB (total, in and out) OutputData
  11. 11. NewAge-LWRB package Downwelling Depends on Atmospheric emissivity L↓ =εa ⋅σ ⋅Ta 4 εa = εcls − 0.035⋅ z 1000 # $ % & ' ( ) * + , - .⋅ 1+ a⋅cb ( ) Upwelling Depends on Soil emissivity L↑ =εs ⋅σ ⋅Ts 4
  12. 12. NewAge-LWRB package: model formulation Downwelling Depends on Atmospheric emissivity L↓ =εa ⋅σ ⋅Ta 4 εa = εcls − 0.035⋅ z 1000 # $ % & ' ( ) * + , - .⋅ 1+ a⋅cb ( ) 10 clear sky emissivity formulations
  13. 13. Downwelling Depends on Atmospheric emissivity L↓ =εa ⋅σ ⋅Ta 4 εa = εcls − 0.035⋅ z 1000 # $ % & ' ( ) * + , - .⋅ 1+ a⋅cb ( ) Correction due to the elevation Swinbank (1963): the air column above the site decreases with elevation NewAge-LWRB package: model formulation
  14. 14. Downwelling Depends on Atmospheric emissivity L↓ =εa ⋅σ ⋅Ta 4 εa = εcls − 0.035⋅ z 1000 # $ % & ' ( ) * + , - .⋅ 1+ a⋅cb ( ) Could correction NewAge-LWRB package: model formulation
  15. 15. NewAge-LWRB package: Multistep Luca Calibration
  16. 16. NewAge-LWRB package: Multistep Luca Calibration Step0 Separate Clear and cloud periods TA!Shortwave! Measured!Shortwave! CI=MEAS/TA!
  17. 17. NewAge-LWRB package: Multistep Luca Calibration Step1 εa = εcls − 0.035⋅ z 1000 # $ % & ' ( ) * + , - .⋅ 1+ a⋅cb ( ) Step0 Separate Clear and cloud periods Estimate Clear LW parameters using clear periods
  18. 18. NewAge-LWRB package: Multistep Luca Calibration Step1Step2 εa = εcls − 0.035⋅ z 1000 # $ % & ' ( ) * + , - .⋅ 1+ a⋅cb ( ) Step0 εa = εcls − 0.035⋅ z 1000 # $ % & ' ( ) * + , - .⋅ 1+ a⋅cb ( ) Separate Clear and cloud periods Estimate Clear LW parameters using clear periods Estimate Clouds LW parameters using cloud periods
  19. 19. Study Area: 6 Ameriflux stations
  20. 20. NewAge-LWRB package: Model Results in station 101
  21. 21. 0! 0.2! 0.4! 0.6! 0.8! 1! 1! 2! 3! 4! 5! 6! 7! 8! 9! 10! KGE$ Models$ Sta.on$11$ 0! 0.2! 0.4! 0.6! 0.8! 1! 1! 2! 3! 4! 5! 6! 7! 8! 9! 10! KGE$ Models$ Sta.on$24$ 0! 0.2! 0.4! 0.6! 0.8! 1! 1! 2! 3! 4! 5! 6! 7! 8! 9! 10! KGE$ Models$ Sta.on$62$ 0! 0.2! 0.4! 0.6! 0.8! 1! 1! 2! 3! 4! 5! 6! 7! 8! 9! 10! KGE$ Models$ Sta.on$75$ 0! 0.2! 0.4! 0.6! 0.8! 1! 1! 2! 3! 4! 5! 6! 7! 8! 9! 10! KGE$ Models$ Sta.on$101$ 0! 0.2! 0.4! 0.6! 0.8! 1! 1! 2! 3! 4! 5! 6! 7! 8! 9! 10! KGE$ Models$ Sta.on$129$ Classic!formula+on! Op+mized!formula+on! NewAge-LWRB package: Clear-sky model results
  22. 22. Mass!Balance! Precipita+on!form! Mel+ng! Freezing! DegreeUDay!(C1)! CazorziUDella!Fontana!(C2)! Hock!Model!(C3)! NewAge-LWRB package coupled with NewAge-SWE models
  23. 23. SWE Model simulation with daily and hourly time step Application on the Cache la Poudre basin (CO, USA)
  24. 24. SWE Model simulation with daily and hourly time step Application on the Cache la Poudre basin (CO, USA)
  25. 25. SWE Model simulation in distributed mode for model C2 Application on the Cache la Poudre basin (CO, USA)
  26. 26. We are not providing “The Hydrological Model”, we are offering a strategy to choose, link and test different hydrological models built by components •  Compare, on the same platform different model structures to simulate the same physical process (LWRB, SWE) •  Investigate the model structure error using different model for a given calibration algorithm • Parameter optimization, using the same platform, for different hydrological processes Conclusions
  27. 27. Thanks for your attention

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