Global Atmosphere Watch
The Global Atmosphere Watch (GAW) programme of the World Meteorological Organization (WMO) is a partnership involving 80 countries, which provides reliable scientific data and information on the chemical composition of the atmosphere, its natural and anthropogenic change, and helps to improve the understanding of interactions between the atmosphere, the oceans and the biosphere.
The network of global GAW stations

One of the core tasks of the GAW programme is the coordination of the activities and data of currently 32 Global, more than 400 Regional atmospheric monitoring stations, and around 100 Contributing stations operated by contributing networks to produce data that are relevant to air pollution and climate change.

The GAW monitoring programme targets six classes of variables (i.e. ozone, UV radiation, greenhouse gases, aerosols, selected reactive gases and precipitation chemistry). Each of the six variable groups is supported by a Scientific Advisory Group and so called GAW Central Facilities (Quality Assurance/Science Activity Centres, Central Calibration Laboratories, World and Regional Calibration Centres and World Data Centres) responsible for quality control, scientific guidance and technical details of the global network.

GAW at Empa
The Swiss Federal Laboratories for Materials Science and Technology (Empa) have been designated by WMO to operate two Central Facilites: the World Calibration Centre for Surface Ozone, Carbon Monoxide, Methane and Carbon Dioxide (WCC-Empa), and a Quality Assurance/Scientific Activity Centre (QA/SAC Switzerland).  Funding for both activities by MeteoSwiss is greatfully acknowledged.
Conceptual GAW quality assurance system
GAW data from all over the globe need to be consistent, traceable to common reference scales, of known and adequate quality, and require appropriate documentation. Meeting these quality objectives is essential to properly address the spatial and temporal variability of atmospheric composition in order to allow for retrieving robust averages, detecting regional gradients and long-term trends, and for verification of models and satellite retrievals. To achieve these goals, an elaborate quality management framework was developed for GAW in line with WMO’s overarching guidelines. World Calibration Centres and Quality Assurance/Scientific Activity Centres play central roles in GAW’s quality assurance and quality control system.
Mission Statement

The mission of WCC-Empa and QA/SAC Switzerland is to improve and maintain the quality and public access of surface ozone, carbon monoxide, methane and carbon dioxide data measured at Global Atmosphere Watch stations, primarily through system and performance audits at GAW stations, inter-comparison and calibration of instrumentation, one-to-one training and workshops, as well as continuous operational and strategic support for the GAW programme, in order to contribute to the scientific basis of our understanding of climate change.

From 2011 to 2016, the GAW team at Empa was also involved in the CATCOS (Capacity Building and Twinning for Climate Observing Systems) project funded by the Swiss Agency for Development and Cooperation (SDC) with MeteoSwiss as the coordinating partner. Within CATCOS, Empa was responsible for the implementation of greenhouse gas observation capabilities in Vietnam, Chile and Kyrgyzstan & associated twinning / support. To ensure sustainability of the implementation beyond the end of the project, reduced twinning & support is still provided through WCC-Empa and QA/SAC Switzerland activities.

From fall 2022 to fall 2025, some QA/SAC Switzerland activities in Africa, and in patricular in Kenya, are also supported through the KADI (Knowledge and Climate Services from an African Observation and Data Research Infrastructure) project. KADI is funded by the European Commission's Horizon Europe programme, The Swiss contribution to supported by the State Secretariat for Education, Research and Innovation (SERI). KADI aims at improving the knowledge about climate change in Africa, at developing tools to combat its negative consequences, and at providing concepts for developing science-based climate services in Africa. Ultimately, first steps should be taken towards a pan-African climate observation research infrastructure. QA/SAC Switzerland is mainly involved in a pilot on lessons learned from existing long-term atmospheric and ecosystem observations.

GAW Station Support
Click here to access a variety of useful documents like checklists, videos, webinars, presentations, technical tutorials, instrument recommendations, scientific talks/papers, and audit documents.

more about ...

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

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

GAW Station Support

WMO/GAW Glossary of QA/QC-Related Terminology

CATCOS Webpage @ Empa




GAWSIS (GAW Station Information System


The Global Atmosphere Watch Programme: 25 Years of Global Coordinated Atmospheric Composition Observations and Analyses

GAW Report No. 228: WMO Global Atmosphere Watch (GAW) Implementation Plan: 2016-2023

GAW Report No. 255: 20th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases and Related Measurement Techniques (GGMT-2019)

GAW Report No. 242: 19th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases and Related Measurement Techniques (GGMT-2017)
Link to GGMT-2017 meeting web page

GAW Report No. 229: 18th WMO/IAEA Meeting on Carbon Dioxide, Other Greenhouse Gases and Related Measurement Techniques (GGMT-2015)

WMO Report No. 1215: Low-cost sensors for the measurement of atmospheric composition: overview of topic and future applications (2018)

Technical advice note on lower cost air pollution sensors