WCC-Empa was established in 1996, assuming worldwide responsibility for surface ozone, carbon monoxide and methane inter-comparisons at global GAW stations. In 2010, WCC-Empa was also assigned to extend its activities towards carbon dioxide.

The goals of the WCC-Empa are

• To ensure that measurements are fully traceable to the designated GAW reference
• To assist stations with regards to instrument and/or measurement problems
• To improve technical know-how at stations through on-site training

through

• Regular system and performance audits at global GAW stations including inter-comparison measurements with traveling standards.
• Maintaining laboratory and traveling standards for surface ozone, carbon monoxide, methane and carbon dioxide.
• Ensuring traceability of the WCC-Empa laboratory standards trough regular inter-comparisons with the corresponding GAW Central Calibration Laboratories.

WCC-Empa measurements are traceable to

• NIST Standard Reference Photometer SRP#2 (surface ozone)
• NOAA/ESRL WMO-2000 carbon monoxide scale
• NOAA/ESRL NOAA04 methane scale
• NOAA/ESRL WMO X2007 carbon dioxide scale

Achievements

Benefits of WCC-Empa audits include

• Improved data quality
• Increased data availability
• Improved technical know-how of station operators
• Increased awareness and acceptance of the GAW programme

WCC-Empa Audits

• 2008
  Barrow (O₃, CO and CH₄)
  Danum Valley (O₃)
  Bukit Koto Tabang   (O₃ and CO)
  
• 2007
  Pallas, Finland   (O₃, CO and CH₄)
  Assekrem, Algeria   (O₃ and CO)
  Bukit Koto Tabang   (O₃ and CO)
  
• 2006
  Mt. Kenya   (O₃ and CO)
  Zugspitze- Schneefernerhaus, Germany   (O₃, CO and CH₄)
  Hohenpeissenberg, Germany   (O₃, and CO)
  Jungfraujoch, Switzerland   (O₃, CO and CH₄)
  Cape Point, South Africa (O₃, CO and CH₄)
  
• 2005
  Mt. Kenya   (O₃ and CO)
  Mace Head, Ireland   (O₃, CO and CH₄)
  Ny Alesund, Norway   (O₃, CO and CH₄)
  Ryori, Japan   (O₃, CO and CH₄)
  
• 2004
  Bukit Koto Tabang   (O₃ and CO)
  Alert, Canada   (O₃, CO and CH₄)
  Mt. Waliguan, China   (O₃, CO and CH₄)
  Izaña, Spain   (O₃, CO and CH₄)
  
• 2003
  Assekrem, Algeria   (O₃)
  Pallas, Finland   (O₃, and CO)
  Mauna Loa, USA   (O₃, CO and CH₄)
  Ushuaia, Argentina   (O₃ and CO)
  
• 2002
  Mt. Kenya, Kenya   (O₃)
  Cape Point, South Africa   (O₃, CO and CH₄)
  Mace Head, Ireland   (O₃, CO and CH₄)
  Cape Grim, Australia  (O₃, CO and CH₄)
  
• 2001
  Zugspitze, Germany   (O₃, CO and CH₄)
  Bukit Koto Tabang, Indonesia   (O₃)
  Ny Alesund, Norway   (O₃, CO and CH₄)
  Arembepe, Brazil   (O₃)
  
• 2000
  Mt. Kenya, Kenya   (O₃)
  Izaña, Spain   (O₃ and CO)
  Mt. Waliguan, China   (O₃ and CO)
  
• 1999
  Jungfraujoch, Switzerland   (O₃ and CO)
  Bukit Koto Tabang, Indonesia   (O₃)
  
• 1998
  Izaña, Spain   (O₃)
  Mace Head, Ireland   (O₃ and CO)
  Sonnblick, Austria    (O₃ and CO)
  Cape Point, South Africa   (O₃ and CO)
  Usuhaia, Argentinia   (O₃ and CO)
  
• 1997
  Cape Point, South Africa   (O₃)
  Ny Alesund, Norway   (O₃)
  Zugspitze, Germany   (O₃)
  Pallas-Sodankylä , Finland (O₃)
  Hohenpeissenberg, Germany   (O₃)
  
• 1996
  Zugspitze, Germany   (O₃)
  Mace Head, Ireland   (O₃)
  Izaña, Spain   (O₃)

Further Information
Please direct questions and/or comments about GAW activities of Empa to Brigitte Buchmann (Head of section), or Christoph Zellweger (WCC-Empa), or Martin Steinbacher (QA/SAC Switzerland).