Traceability for atmospheric total column ozone ATMOZ A Joint Research Project within the European Metrology Research Programme (EMRP) Julian Gröbner & JRP consortium Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union
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Traceability for atmospheric total column ozone ATMOZ · Traceability for atmospheric total column ozone ATMOZ A Joint Research Project within the European Metrology Research Programme
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Traceability for atmospheric total column ozone
ATMOZ
A Joint Research Project within the European
Metrology Research Programme (EMRP)
Julian Gröbner & JRP consortium
Physikalisch-Meteorologisches Observatorium Davos, World
Radiation Center
The EMRP is jointly funded by the EMRP
participating countries within EURAMET and the
European Union
The European Metrology Research Programme (EMRP)
The EMRP
• supports the collaboration of European metrology institutes, industrial organisations
and academia through Joint Research Projects (JRPs).
• is jointly funded by the EMRP participating countries and the European Union with a
total budget of 400 M€.
The European Metrology Research Programme (EMRP)
The EMRP
• supports the collaboration of European metrology institutes, industrial organisations
and academia through Joint Research Projects (JRPs).
• is jointly funded by the EMRP participating countries and the European Union with a
total budget of 400 M€.
Provides access to know-how and
infrastructure from the metrology community
PMOD/WRC
Solar radiometry
(SRS) since 1971
Infrared radiometry
(IRS) since 2004
UV radiometry
(WCC-UV)
since 2005
Optical depth
WORCC since 1996
World Radiation Center
The Physikalisch-Meteorologisches Observatorium
Davos and World Radiation Center (PMOD/WRC)
The 2 Worlds of PMOD/WRC
The PMOD/WRC is designated Institute of METAS for solar irradiance:
Signatory of the CIPM MRA
Implementation of a Quality System according to ISO 17025
Holder of 2 CMC's for solar irradiance and 4 CMC's for solar UV
The PMOD/WRC is designated World Radiation Center by the WMO:
operates instruments representing radiation quantities accepted as world reference standards by the WMO
Calibrates meteorological radiation instruments
Provides traceable measurements to SI
EMRP-ENV59 “ATMOZ”
o Provide traceability of total column ozone to 1%,
o Radiometric characterisation of Dobson and Brewer
spectrophotometers,
o Development of array-based solar UV
spectroradiometers,
o Improved and consistent ozone absorption x-sections,
o Comprehensive uncertainty budget incorporating
instrumental and atmospheric uncertainties
o Project Coordination: PMOD/WRC,
Julian Gröbner
o Duration: 10/2014 – 9/2017
o Total Budget: 2.5 M€
o 9 Partners NMI-DI, Industry, Universities
Present
A traceable and harmonized Global Total Column Ozone Network
Stakeholders and Collaborators
What are the main challenges?
DOBSON
1) Seasonal total ozone differences between
Brewer and Dobson in Arosa, Switzerland.
10 DU
3) Eventual phase-out of Dobson (Brewer) requires
introduction of new total ozone measuring instruments
Brewer, 1973
A comprehensive uncertainty assessment of total column ozone measurements
from Dobson and Brewer spectrophotometers has not been made so far.
Scarnato et al., 2009 Redondas et al., 2014
2) Dobson spectroscopy (slit functions and wavelength
*excluding regions with s<10-23 cm2/molecule (365 – 410 nm and longer than 950 nm) and 305-320 nm **excluding regions near 380 nm and longer than 800 nm ***discrete wavelengths
Overview on uncertainties in ozone absorption x-sections
• Different sources can provide slightly different versions (e.g. Bass-Paur modified for ground and satellite retrievals
• Single wavelength measurements can be very helpful because of high accuracy
• Reported uncertainties can be underestimated or incomplete
Courtesy Mark Weber
How to address these issues?
1) Radiometric characterisation of current reference ozone spectroradiometers
• Dobson 083 – World standard (NOAA)
• Dobson 064 / 074 – Regional Standards RA VI (DWD, CHMI)