Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center (PMOD/WRC)

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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).
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PMOD/WRC
PMOD/WRC
World Radiation Center
Absolute radiometry (ARS)
Infrared radiometry (IRS)
Optical depth WORCC
UV radiometry (WCC-UV)
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EMRP-ENV03 Solar UV
http//projects.pmodwrc.ch/env03/

• Enhance the reliability of spectral solar UV
  radiation measured at the Earth surface
• Develop new techniques and devices for
  traceability better than 2 (now 5) and for
  cost-effective array-spectroradiometer in UV
  monitoring networks
• Intercomparison Campaigns and Workshops

End-User Devices
Calibrated UV Network
Transfer Standard
Reference Spectroradiometer
Primary Irradiance Standard

• Project Coordination Julian Gröbner, Davos
• Duration 2011 - 2014
• Total Budget 3.9 M
• 8 Partners EU-NMI 2 Industry 2 Universities gt
  3 Collaborators (Stakeholders)

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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
Spectroradiometer 5
Gröbner Sperfeld, Metrologia, 2006
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Validation of the QASUME irradiance reference at
PTB
Blackbody BB3200pg at PTB
QASUME Validation at PTB in 2004 and 2013
Gröbner J., and P. Sperfeld, Direct traceability
of the portable QASUME irradiance scale to the
primary irradiance standard of the PTB,
Metrologia, 42, 134139, 2005.
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UV Quality Assurance Program

• Quality site audit with the QASUME reference
  spectroradiometer

• Status 2002 - 2013
• 63 site visits
• 34 sites
• gt150 spectroradiometer intercomparisons

Ny Ålesund, Spitzbergen, 2009
QASUME
Gröbner et al., Appl. Opt. 2005 Gröbner et al.,
Metrologia, 2006
http//www.pmodwrc.ch/euvc/euvc.php?topicqasume_a
udit
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RBCC-E _at_ El ArenosilloThe sunny place

• 1999, 2005, 2007, 2009, 2011, 2013

2005
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Daily ratios to QASUME The ideal case
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Brewer cosine error
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Brewer cosine error
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Single Brewer Stray light
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Brewer Temperature dependency
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Summary from 6th RBCC-E (2011)
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Wavelength scale
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What needs to be addressed?

• Temperature dependency
• Absolute calibration
• Wavelength dispersion
• Single Brewer Stray Light
• Angular Response
• Apply Correction,
• or better
• Entrance optic modification

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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/
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UV Quality Assurance Program

• Quality site audit with the QASUME reference
  spectroradiometer

• Status 2002 - 2013
• 63 site visits
• 34 sites
• gt150 spectroradiometer intercomparisons

http//www.pmodwrc.ch/euvc/euvc.php?topicqasume_a
udit
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QASUME irradiance reference stability 2004 to
2012
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QASUME irradiance reference

• Based on 7 transfer standards directly calibrated
  against the primary irradiance normal of the
  Physikalisch-Technische Bundesanstalt (PTB), in
  Germany.

PTB
Transfer standard 1000 W FEL lamp
Transfer standard 1000 W FEL lamp
Transfer standard 1000 W FEL lamp

EUVC/QASUME
250 W portable lamp
Portable QASUME irradiance reference
250 W portable lamp
250 W portable lamp

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Spectral UV irradiance site audit procedure
PMOD/WRC
Measuring Station
Spectroradiometer Brewer163
QASUME
Quality Assurance
Regular intercomparisons
Portable QASUME reference spectroradiometer
Local Spectroradiometer
QASUME irradiance reference traceable to PTB
Audit report and calibration certificate sent to
local operator and published on
www.pmodwrc.ch/euvc/euvc.html
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Comparison of spectroradiometers
QASUME
TEST
matSHIC

• Same wavelength scale
• Uniform slit width (1 nm default)

Ratio TEST/QASUME
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Wavelength scale