Physikalisch-Meteorologisches
Observatorium Davos, World Radiation
Center (PMOD/WRC)
The PMOD/WRC is the World Radiation Center of the World Meteorological
Organisation,
And is signatory of the Mutual Recognition Arrangement by the Committee
of Weights and Measures (CIPM MRA).
PMOD/WRC
PMOD/WRC
World Radiation Center
Absolute radiometry
(ARS)
Infrared radiometry
(IRS)
Optical depth
WORCC
UV radiometry
(WCC-UV)
EMRP-ENV03 “Solar UV”
http://projects.pmodwrc.ch/env03/
o Enhance the reliability of spectral solar UV radiation measured at the Earth surface
o Develop new techniques and devices for traceability better than 2% (now 5%) and for
cost-effective array-spectroradiometer in UV monitoring networks
o Intercomparison Campaigns and Workshops
Primary Irradiance Standard
Transfer Standard
Reference Spectroradiometer
End-User Devices
Calibrated UV Network
o Project Coordination: Julian Gröbner, Davos
o Duration:
2011 - 2014
o Total Budget:
3.9 M€
o 8 Partners EU-NMI; 2 Industry; 2 Universities; > 3 Collaborators (Stakeholders)
Traceability chain for spectral irradiance Wm-2nm-1
Cryogenic radiometer 0.01%
Detector
Source
cw-Laser Sources
Si-trap detector + aperture
Spectrally tuneable source
Filter Radiometer
Blackbody + aperture ~0.3%
Spectroradiometer
Spectral irradiance
standard ~1-3%
Portable transfer
standard (used for
stability check) ~4%
Gröbner & Sperfeld, Metrologia, 2006
Spectroradiometer ~5%
Validation of the QASUME irradiance reference at PTB
Blackbody BB3200pg at PTB
QASUME Validation at PTB in 2004 and 2013
±1.2%
Gröbner J., and P. Sperfeld, Direct traceability
of the portable QASUME irradiance scale to the
primary irradiance standard of the PTB,
Metrologia, 42, 134—139, 2005.
UV Quality Assurance Program
Quality site audit with the QASUME reference spectroradiometer
Status 2002 - 2013
•63 site visits
•34 sites
•>150 spectroradiometer intercomparisons
Ny Ålesund, Spitzbergen, 2009
QASUME
RBCC-E, 2005-2013
Gröbner et al., Appl. Opt. 2005
Gröbner et al., Metrologia, 2006
http://www.pmodwrc.ch/euvc/euvc.php?topic=qasume_audit
RBCC-E @ El Arenosillo
“The sunny place”
1999, 2005, 2007, 2009, 2011, 2013
2005
Daily ratios to QASUME: The ideal case
Brewer cosine error
Brewer cosine error
Single Brewer Stray light
Brewer Temperature dependency
6%
Temp. coefficient
-0.3 %/K
Summary from 6th RBCC-E (2011)
Wavelength scale
What needs to be addressed?
 Temperature dependency
 Absolute calibration
 Wavelength dispersion
 Single Brewer Stray Light
 Angular Response
 Apply Correction,
or better:
 Entrance optic
modification
Spectral solar UV Intercomparison at Davos &
Final ENV03 Workshop,
7-16 July 2014
International Pyrheliometer
Comparison (IPC) 2010
Presentations, Guidelines, Publications can be found at the
project web-site: http://projects.pmodwrc.ch/env03/