Quality Assurance/Scientific Activity Centre (QA/SAC Switzerland)

The GAW Quality Assurance/Scientific Activity Centre (QA/SAC Switzerland), funded by MeteoSwiss and Empa, was established in 2000. Being closely linked to the World Calibration Centre also hosted by Empa, the QA/SAC mainly focuses on surface ozone, carbon monoxide, methane and carbon dioxide measurements but is also broader in scope and provides technical and scientific support in general.

The main tasks of QA/SAC Switzerland are

  • science activities fostering steady analytical progress,
  • training, twinning, and capacity building, e.g. through GAWTEC,
  • contribution to GAW outreach,
  • networking / cooperation with other programmes / projects in line with the GAW strategy.
  • previous QA/SAC activities also focussed on the development and operation of the GAW Station Information System (GAWSIS); this task was recently transferred to MeteoSwiss
Science activities
QA/SAC’s science activities have two main foci. Scientific data analysis in collaboration with other GAW station operators world-wide (see also the twinning activities below) and a steady analytical assessment of the available state-of-the-art and cutting edge instrumentation for ground-based in-situ monitoring.
The latter includes
  • evaluation of novel measurement techniques and their performance improvement
  • assessment of their applicability for long-term monitoring purposes, e.g. through long-term side-by-side intercomparisons
  • dissemination of know-how to the GAW community through publications and presentations at conferences
Twinning and capacity building

Twinning is one of the core activities of QA/SAC Switzerland since the early beginning. The main twinning stations are Assekrem (Algeria), Bukit Koto Tabang (Indonesia) and Mt. Kenya (Kenya). These stations were established in the mid-1990ies under the WMO/UNDOP/GEF programme. It was recognized that a continuous support is key to maintaining high-precision observations in line with the GAW requirements after the end of the initial programme.

QA/SAC also supports many other stations. In general, successful twinning has many aspects, such as

  • advice for instrument selection and operation
  • technical support / advice to set up measurement capabilities
  • regular on-site training (along with WCC-Empa)
  • remote support / trouble shooting
  • facilitating the provision of spare parts
  • support for quality control, data processing and data submission
  • support for (research) proposal writing
  • support for scientific data analysis and publication
teaching at a GAWTEC course

QA/SAC Switzerland has been a partner of the GAW Training and Education Center (GAWTEC) for a long time. GAWTEC, a German contribution to GAW, provides technical guidance through twice yearly training courses, where QA/SAC Switzerland is regularly involved in teaching.

GAW outreach
QA/SAC Switzerland is engaged in the prepa-ration of strategic documents for the GAW.
An active participation in writing GAW reports and the promotion of the use of GAW data strive for an appropriate release of best practices and a good visibility of the GAW activities within and outside the GAW community.

Recent contributions to GAW reports were e.g. made to GAW Report No. 192 (Guidelines for the Measurement of Atmospheric Carbon Monoxide), GAW Report No. 195 (WMO/GAW Expert Workshop on Global Long-term Measurements of Nitrogen Oxides and Recommendations for GAW Nitrogen Oxides Network), the GAW Report No. 209 (Guidelines for Continuous Measurements of Ozone in the Troposphere) and GAW Report No. 213 17th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases and Related Tracers Measurement Techniques (GGMT-2013).


QA/SAC’s cooperation with other programmes, e.g. by sharing expert knowledge, aims at fostering the synergies between GAW and those programmes. Examples are the Integrated Carbon Observation System (ICOS), the Integrated non-CO2 Greenhouse gas Observation System  (InGOS) and the Aerosol, Clouds, and Trace Gases Research Network  (ACTRIS).

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

more about...

Global Atmosphere Watch: Introduction

WCC-Empa (World Calibration Centre for Surface Ozone, Carbon Monoxide, Methane and Carbon Dioxide)

QA/SAC Switzerland (Quality Assurance/Scientific Activity Centre)

CATCOS webpage @ Empa



GAW Activity Report: GAW Activity Report for WMO RA VI (1998-2002)

GAW Report No. 143: Global Atmosphere Watch Measurements Guide

GAW Report No. 166: Joint WMO-GAW / ACCENT Workshop on the Global Tropospheric Carbon Monoxide Observations Systems, Quality Assurance and Applications, EMPA, Dübendorf, Switzerland, 24-26 October 2005.  Editor: Jörg Klausen (WMO TD No. 1335)

GAW Report No. 172: Strategy for the Implementation of the Global Atmosphere Watch Programme, 2008-2015

GAW Report No. 192: Guidelines for the Measurement of Atmospheric Carbon Monoxide

GAW Report No. 195: WMO/GAW Expert Workshop on Global Long-term Measurements of Nitrogen Oxides and Recommendations for GAW Nitrogen Oxides Network

GAW Report No. 209: Guidelines for Continuous Measurements of Ozone in the Troposphere

GAW Report No. 213: 17th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases and Related Tracers Measurement Techniques (GGMT-2013)

Questionnaire: Audit Gases

SOP: Audit Gases

meetings / workshops

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