long wave radiation parameterisations

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DESCRIPTION

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

TRANSCRIPT

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

Outline

•  NewAge-JGrass hydrological system

•  NewAge-LWRB package

•  Models Applications (LWRB; SWRB+LWRB+SWE)

Interpola+

on!

Tools!

Energy!

Balance!

Water!

Balance!

Automa+

c!Calibra+o

n!NewAge-JGrass hydrological system

Forme;a!et.!al,!2014!

Interpola+

on!

Tools!

Energy!

Balance!

Water!

Balance!

Automa+

c!Calibra+o

n!

Forme;a!et.!al,!2014!

Forme;a!et.!al,!2013!

W/m2!

NewAge-JGrass hydrological system

Interpola+

on!

Tools!

Energy!

Balance!

Water!

Balance!

Automa+

c!Calibra+o

n!

Forme;a!et.!al,!2011!

Forme;a!et.!al,!2014!

Forme;a!et.!al,!2013!

W/m2!

NewAge-JGrass hydrological system

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

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!

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

NewAge-LWRB package

Downwelling Upwelling

NewAge-LWRB

Model Parameters

NewAge-LWRB package

Downwelling Upwelling

NewAge-LWRB

Model Parameters In

put

Dat

a

Raster Maps (dem, sky view factor) Meteorological Forcing data

!!!!!!!!!!Time Series or Raster Maps of LWRB (total, in and out)

Out

put

Dat

a

NewAge-LWRB package

Downwelling

Depends on Atmospheric emissivity

L↓ = εa ⋅σ ⋅Ta4

εa = εcls − 0.035 ⋅z

1000#

$%

&

'(

)

*+

,

-.⋅ 1+ a ⋅cb( )

Upwelling

Depends on Soil emissivity

L↑ = εs ⋅σ ⋅Ts4

NewAge-LWRB package: model formulation

Downwelling

Depends on Atmospheric emissivity

L↓ = εa ⋅σ ⋅Ta4

εa = εcls − 0.035 ⋅z

1000#

$%

&

'(

)

*+

,

-.⋅ 1+ a ⋅cb( )

10 clear sky emissivity formulations

Downwelling

Depends on Atmospheric emissivity

L↓ = εa ⋅σ ⋅Ta4

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

Downwelling

Depends on Atmospheric emissivity

L↓ = εa ⋅σ ⋅Ta4

εa = εcls − 0.035 ⋅z

1000#

$%

&

'(

)

*+

,

-.⋅ 1+ a ⋅cb( )

Could correction

NewAge-LWRB package: model formulation

NewAge-LWRB package: Multistep Luca Calibration

NewAge-LWRB package: Multistep Luca Calibration

Step

0

Separate Clear and cloud periods

TA!Shortwave!Measured!Shortwave!

CI=MEAS/TA!

NewAge-LWRB package: Multistep Luca Calibration

Step

1

εa = εcls − 0.035 ⋅z

1000#

$%

&

'(

)

*+

,

-.⋅ 1+ a ⋅cb( )

Step

0

Separate Clear and cloud periods

Estimate Clear LW parameters using clear periods

NewAge-LWRB package: Multistep Luca Calibration

Step

1

Step

2

εa = εcls − 0.035 ⋅z

1000#

$%

&

'(

)

*+

,

-.⋅ 1+ a ⋅cb( )

Step

0

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

Study Area: 6 Ameriflux stations

NewAge-LWRB package: Model Results in station 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$11$

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

Mass!Balance!

Precipita+on!form!

Mel+ng!

Freezing!

DegreeUDay!(C1)! CazorziUDella!Fontana!(C2)! Hock!Model!(C3)!

NewAge-LWRB package coupled with NewAge-SWE models

SWE Model simulation with daily and hourly time step

Application on the Cache la Poudre basin (CO, USA)

SWE Model simulation with daily and hourly time step

Application on the Cache la Poudre basin (CO, USA)

SWE Model simulation in distributed mode for model C2

Application on the Cache la Poudre basin (CO, USA)

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

Thanks for your attention

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