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

And is signatory of the Mutual Recognition Arrangement by the Committee of

Weights and Measures (CIPM MRA).

The PMOD/WRC is the World Radiation Center of the World Meteorological Organisation,

PMOD/WRC

PMOD/WRC

Absolute radiometry (ARS)

Infrared radiometry (IRS)

Optical depth WORCC

UV radiometry (WCC-UV)

World Radiation Center

EMRP-ENV03 “Solar UV”http://projects.pmodwrc.ch/env03/

o Enhance the reliability of spectral solar UV radiation measured at the Earth surfaceo 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 - 2014o Total Budget: 3.9 M€o 8 Partners EU-NMI; 2 Industry; 2 Universities; > 3 Collaborators (Stakeholders)

Cryogenic radiometer 0.01%Cryogenic radiometer 0.01%

Spectral irradiance standard ~1-3%

Spectral irradiance standard ~1-3%

cw-Laser Sources cw-Laser Sources

Si-trap detector + apertureSi-trap detector + aperture

Filter Radiometer Filter Radiometer

Blackbody + aperture ~0.3% Blackbody + aperture ~0.3%

Detector

Source

SpectroradiometerSpectroradiometer

Spectrally tuneable source Spectrally tuneable source

Spectroradiometer ~5%Spectroradiometer ~5%

Traceability chain for spectral irradiance Wm-2nm-1

Portable transfer standard (used for stability check) ~4%

Portable transfer standard (used for stability check) ~4%

Gröbner & Sperfeld, Metrologia, 2006

Validation of the QASUME irradiance reference at PTBBlackbody BB3200pg at PTB

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.

QASUME Validation at PTB in 2004 and 2013

±1.2%

Quality site audit with the QASUME reference spectroradiometer

UV Quality Assurance Program

Status 2002 - 2013•63 site visits•34 sites•>150 spectroradiometer intercomparisons

http://www.pmodwrc.ch/euvc/euvc.php?topic=qasume_audit

Ny Ålesund, Spitzbergen, 2009

RBCC-E, 2005-2013

QASUME

Gröbner et al., Appl. Opt. 2005Gröbner et al., Metrologia, 2006

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 ResponseApply Correction, or better:Entrance optic

modification

Presentations, Guidelines, Publications can be found at the project web-site: http://projects.pmodwrc.ch/env03/

Spectral solar UV Intercomparison at Davos & Final ENV03 Workshop,

7-16 July 2014

International Pyrheliometer Comparison (IPC) 2010