Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
Quality controlled data base of the COPS surface energy balance network
Thomas Foken, Rafael Eigenmann Dept. Micrometeorology, University of Bayreuth
www.bayceer.uni-bayreuth.de/mm
7th COPS Workshop 27th-29th October 2008, Strasbourg
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
Content
• Energy balance group: an overview• Turbulence data processing• Turbulence quality control:
– Part 1: Turbulence flux calculation– Part 2: Footprint analysis– Part 3: Internal boundary layer evaluation
• WDCC data base • Conclusion
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
Energy balance network
• Organisation: http://www.bayceer.uni-bayreuth.de/COPS/
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
Energy balance network - WEB
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
Turbulence data processing with TK2
Processing steps and applied flux corrections:– Calculation of averages, variances and covariances for
30 min averaging intervals– Correction of a time delay between different sensors
by cross correlation– Spike test– Cross-wind correction– Planar fit coordinate rotation– Correction of spectral loss– Conversion of buoyancy into sensible heat flux– WPL correction
(Vickers and Mahrt, 1997)
(Wilczak et al., 2001)
(Moore, 1986)
(Schotanus et al., 1983; Liu et al., 2001)
(Webb et al., 1980; Fuehrer and Friehe, 2002; Liebethal and Foken, 2003, 2004)
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
EC-data quality checkTest on steady state conditions
iiM
j jj
jjNjjNi
yxyx
yxyxyx
''''
''
1
11
1
i ijj
jjNM
ii jjjNM
yxyxyx 11
1''
(Foken and Wichura, 1996, Foken et al. 2004)
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
EC-data quality check Test on developed turbulence
(Foken and Wichura, 1996, Foken et al. 2004)
21
*
,, cwvuLzcu
21
*
cT
LzcT
parameter z/L c1 c2
σW/u* 0 > z/L > -0,032-0,032 > z/L
1,32,0
01/8
σu/u* 0 > z/L > -0,032-0,032 > z/L
2,74,15
01/8
σT/T* 0,02 < z/L < 10,02 > z/L > -0,062-0,062 > z/L > -1
-1 > z/L
1,40,51,01,0
-1/4-1/2-1/4-1/3
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
quality class steady state integral turbulence charactersitics
1 1 1–2 2 2 1–2 3 1–2 3–4 4 3–4 1–2 5 1–4 3–5 6 5 ≤ 5 7 ≤ 6 ≤ 6 8 ≤ 8 ≤ 8 9 one parameter 9 9
EC-data quality check Overall flagging of data
(Foken and Wichura, 1996, Foken et al. 2004)
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
quality class steady state integral turbulence charactersitics
1 1 1–2 2 2 1–2 3 1–2 3–4 4 3–4 1–2 5 1–4 3–5 6 5 ≤ 5 7 ≤ 6 ≤ 6 8 ≤ 8 ≤ 8 9 one parameter 9 9
EC-data quality check Overall flagging of data
good
moderate
bad
do not use
(Foken and Wichura, 1996, Foken et al. 2004)
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
Turbulence data quality (I)
• Post-field quality control
– Steady state test– Test for integral turbulence
characteristics
combined flag (1 to 9)
will be uploaded to the WDCC
data base within a flux NetCDF-file
Classes 1-3: suitable for fundamental researchClasses 4-6: only for monthly or annual sumsClasses 7-8: rough orientationClass 9: data should always be rejected
(Foken et al., 2004; Foken and Wichura, 1996)
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
Accuracy of surface fluxes
Eddy-covariance measurements according to recent findings (EBEX-2000 in USA and LITFASS-2003 in Germany)
Sonic anemometer
quality class sensible heat flux latent heat flux
Type A,e.g. CSAT3
1-3 5% or 10 Wm-2 10% or 20 Wm-2
4-6 10% or 20 Wm-2 15% or 30 Wm-2
Type B,e.g. USA-1
1-3 10% or 20 Wm-2 15% or 30 Wm-2
4-6 15% or 30 Wm-2 20% or 40 Wm-2
Foken and Oncley (1995), Mauder et al. (2006)
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
-500
-400
-300
-200
-100
0
100
200
0 3 6 9 12 15 18 21 24UTC
ener
gy
in W
m-2
Sensible heat flux
Latent heat flux
Net radiation
Ground heat flux
Residual
Energy balance closure problem
Foken and Oncley (1995), Mauder et al. (2006), Oncley et al. (2007), Mauder and Foken (2006), Foken (2008)
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
-500
-400
-300
-200
-100
0
100
200
0 3 6 9 12 15 18 21 24UTC
ener
gy
in W
m-2
Sensible heat flux
Latent heat flux
Net radiation
Ground heat flux
Residual
Energy Balance Closure Problem
Foken and Oncley (1995), Mauder et al. (2006), Oncley et al. (2007), Mauder and Foken (2006), Foken (2008)
WHAT IS TO DO BY THE USER?
Distribute the residual according to the Bowen ratioto the sensible and latent heat flux
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
Stull (1988)
Internal Boundary Layers
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
• Internal boundary layers
• Flagging scheme for each 30 min flux value in the NetCDF-file
Condition Flag value Description
0az with x3.00 0 Measurement within new
equilibrium layer
10 az
with x3.00 and x5.01 1 Disturbance range
1az with x5.01 2 Measurement above new
equilibrium layer
Internal boundary layers
0
1
2
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
Footprint analysis
• Combination of the flux quality approach with a forward Lagrangian footprint model(Göckede et al., 2004, 2006; Foken et al., 2004; Rannik at al., 2003)
Spatial representativeness
(footprint climatology)
Spatial distribution of
quality flags
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
Internal boundary layer evaluation:Height of internal boundary layer
Footprint analysis: Flux contribution from the target land use
Turbulence data quality (II)
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
Supplementary FOOT file
• 6 pictures per station:– Land use information map (on which
your footprint analysis is based on):
– Footprint climatology:
– Spatial distribution of quality flags in relation to footprint climatology
for u*, QH, QE, CO2:
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
WDCC data base structure
• Each station comprises 2 data sets:
• And 1 supplementaryfile (FOOT)Land use information map, footprint analysis
• Additional information possible (e.g. TK2 manual, references …)
Meteorological (MET): Radiation and soil measurements
Flux data set (FLUX): Turbulent fluxes, footprint analysis, IBL
NEBT
UF1ETG
IMK1ETG
IMK2ETG
IMK3ETG
MF1ETG
MF2ETG
MF3ETG
UBT1ETG
UBT2T
UBT3ETG
UBT4ETG
UBN1ETG
UV1EG
IMK4T
IMK5T
IMK6T
IMK7T
IMK8T
MET
FLUX
FOOT
d
d
s
::
::
::
::
cops
cops_<EXP(4)>_<INSTRU (6)>_<PARA(6)>_ <FLAG(1)>
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
Conclusion
We will write a cook book for the user.
Thomas [email protected]
University of Bayreuth – Department of Micrometeorology www.bayceer.uni-bayreuth.de/mm
Bayreuth Center of Ecology and Environmental Research
Thank you for your attention !