long wave radiation parameterisations
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 evapotranspirationTRANSCRIPT
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