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Programmes: GAW-CH and GCOS-CH

GAW (Global Atmosphere Watch) and GCOS (Global Climate Observing System) are two international programmes. They aim to secure long-term observations of the chemical composition of the atmosphere and the entire climate system and to ensure that the generated data is accessible. Coordinated by the Swiss GAW/GCOS Office at MeteoSwiss, various national institutions in Switzerland are implementing these programmes through their activities.


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The international programmes – History, Goals and Implementation


The World Meteorological Organization (WMO) formally established the international Global Atmosphere Watch programme (GAW) in 1989, as an important contribution to the monitoring of the implementation of the Vienna Convention for the Protection of the Ozone Layer and the Montreal Protocol on Substances that Deplete the Ozone Layer.

Shortly thereafter, in 1992, a joint initiative of several institutions (WMO; Intergovernmental Oceanographic Commission of UNESCO, IOC; United Nations Environment Programme, UN Environment; International Science Council, ISC) established the Global Climate Observing System (GCOS) programme. The United Nations Framework Convention on Climate Change (UNFCCC) acknowledged the need for climate monitoring and explicitly requested all its parties to cooperate in systematic climate observation in the same year in 1992. For this reason, GCOS reports to UNFCCC.

Goals of GAW

GAW aims to provide high-quality observations and analyses of the chemical composition of the atmosphere. This is primarily important for monitoring the ozone layer and greenhouse gas concentrations. It is also of significance for monitoring urban air quality, which allows, for example, important conclusions about human health.

About 100 countries are participating in the GAW programme. The GAW network includes about 30 Global and over 400 Regional stations, as well as 100 additional stations from contributing networks. These stations carry out measurements in the areas of greenhouse gases, ozone, UV radiation, aerosols, reactive gases and precipitation chemistry. Several of these components in GAW also contribute to GCOS.

Under the leadership of WMO, various countries support GAW activities. These include national research programmes and international cooperations, as well as services such as Global and Regional quality assurance and calibration centres operated on behalf of WMO. The main task of these centres is to link observations to global reference standards: they ensure the compatibility of the various measurement networks by conducting comparative measurements and carrying out regular quality controls.

Goals of GCOS

The goal of GCOS is to provide systematic and high-quality climate observations. It is only thanks to long-time series of observations of variables such as glaciers or air temperature that it is possible to detect changes in the climate system.

There are National Focal Points for GCOS in over 130 countries. GCOS aims to ensure that all climate-related observations and information are systematically recorded and made available to all users.

An important part of GCOS is the specification of Essential Climate Variables (ECVs) that should be observed systematically. GCOS currently specifies 55 ECVs. The list of ECVs includes atmospheric, terrestrial and oceanic variables that contribute significantly to the characterisation of the Earth's climate system.

GCOS observations and analyses in combination with models allow the estimation of future climate. Such knowledge is crucial for informed decision-making on climate change mitigation and adaptation. In this way, GCOS contributes significantly to the work of the Intergovernmental Panel on Climate Change (IPCC).

Implementation of the programs

Both GAW and GCOS have strict requirements in terms of quality, comparability and availability of data. These requirements are set out in the Implementation Plans, which form the basis for both programmes. They include strategies, definitions, global requirements and standards for the systematic observation of the atmosphere and the entire climate system.

WMO published the first plan for GAW in 2001. WMO has updated the GAW Implementation Plan approximately every 7 years ever since. For GCOS, UNFCCC requires a periodic review of the implementation plan. The GCOS Implementation Plan was first published in 2004 and is updated every five to six years. A report on the specific requirements for observations/ECVs, e.g. the required spatial resolution, is released together with the GCOS Implementation Plan.

The current Implementation Plans for GAW and GCOS as well as the ECV requirements report are available on the WMO website.

National Implementation

The Swiss Programmes

GAW and GCOS are international programmes. However, based on the Implementation Plans, the programmes are put into practice on a national level. The implementation in Switzerland takes place in the framework of GAW Switzerland (GAW-CH) and GCOS Switzerland (GCOS-CH) and is facilitated by the common effort of various national partner institutions. Since the atmosphere is relevant to both programmes, some institutions play an active role in the implementation of GAW-CH as well as GCOS-CH. The Swiss GAW/GCOS Office at MeteoSwiss coordinates both programmes.


In 1994, the Federal Council decided that the Swiss Confederation shall participate in WMO’s GAW programme.  A number of institutions, most of them Swiss, contribute to monitoring numerous chemical components of the atmosphere within the framework of GAW-CH. Some of these institutions also operate international centres for quality assurance and calibration of observations from Global GAW stations. Additionally, they may support capacity building, for example, when measurements are carried out in other countries. Thanks to the GAW-CH community, Switzerland is one of the most active GAW members in the implementation of the international programme.

Among others, measuring stations conduct atmospheric observations, such as ozone, aerosols and atmospheric radiation. In Switzerland, the Jungfraujoch research station is one of 30 Global GAW stations. In addition, four of the approximately 400 Regional GAW stations are operated in Switzerland: in Arosa, Payerne, Rigi and Thalwil.

The international platform GAW Station Information System GAWSIS contains more detailed descriptions and information on all Swiss and international stations. MeteoSwiss operates GAWSIS and further develops it in close cooperation with WMO. The platform collects the metadata of all GAW stations worldwide and makes them centrally available. This is an important contribution to data storage and distribution.

Within the framework of GAW-CH, Swiss institutions operate four international centres for quality assurance and calibration (Global and Regional centres). Two centres at the Swiss Federal Laboratories for Materials Science and Technology (Empa) support countries where GAW is implemented in the areas of surface ozone, carbon monoxide, methane and carbon dioxide: The World Calibration Centre (WCC-Empa) and the GAW Quality Assurance/Scientific Activity Centre (QA/SAC Switzerland). The World Radiation Centre (PMOD/WRC) operates from the Physical Meteorological Observatory Davos. It provides calibrations in the fields of radiation and optical depth of the atmosphere. The Central Calibration Laboratory of the Swiss Federal Institute of Metrology METAS (CCL METAS) produces and validates reference gases for ten halogenated volatile organic compounds. It thus supports high-quality monitoring of these compounds.

International cooperation is another important aspect of the GAW programme. Capacity building promotes both knowledge transfer as well as the expansion of the global monitoring network to countries situated in geographical gaps of this network. Within the framework of GAW-CH, MeteoSwiss has been supporting regular ozone soundings in Nairobi (Kenya) since 1996. This includes quality analyses and regular training of the Kenyan Meteorological Service.


In 2002, the Federal Council decided on Switzerland's contribution to GCOS in connection with the ratification of the Kyoto Protocol and UNFCCC. Within the framework of GCOS-CH, various institutions carry out high-quality climate observations and make the data available to users.

Climate observation has a long tradition in Switzerland. The longest systematic climate observation series dates back to 1808 and consists of phenological data on the timing of the chestnut bud burst in Geneva. Today, numerous institutions measure high-quality data on 34 ECVs in the framework of GCOS-CH. The ECVs are continuously collected, processed and made publically available. The inventory report of the National Climate Observing System GCOS-CH provides an overview of the ECVs observed in Switzerland.

Next to climate observations, quality control, data storage and data distribution are equally important to make the data available to all interested users. Therefore, GCOS-CH includes three international data centres operated by Swiss institutions. The World Glacier Monitoring Service (WGMS), based at the University of Zurich, collects standardised observations on glacier fluctuations. The Global Energy Balance Archive (GEBA) database at ETH Zurich collects information on energy fluxes measured at the Earth's surface. In addition, the Euro-Climhist database at the University of Bern provides historical climate data from the Middle Ages to the present day.

The data collected in the framework of GCOS-CH are the foundation for climate services in Switzerland and are therefore essential. In this way, GCOS-CH also supports the activities of the Swiss federal network for climate services - National Center for Climate Services (NCCS).

29 national partner institutions implement GAW-CH and GCOS-CH through joint efforts. This ensures high-quality and systematic monitoring of the atmosphere and the climate system, as well as the operation of international data, quality assurance, and calibration centres. The national partner institutions include universities, research institutes and other federal offices. Together, they all pursue the goal of collecting, regulating, processing, archiving, and making available continuous and high-quality atmospheric and climate observations.

The Swiss GAW/GCOS Office at the Federal Office of Meteorology and Climatology MeteoSwiss coordinates atmospheric and climate observations in Switzerland in support of the national partner institutions. Based on two Federal Council decisions, MeteoSwiss has been fulfilling this role for GAW-CH since 1994 and for GCOS-CH since 2006.

As the national coordination office, the Swiss GAW/GCOS Office has the following responsibilities:

On a national level:

  • Identifies time series at risk of interruption and takes the necessary steps to ensure their long-term continuation
  • Takes the necessary steps to ensure the continued operation of international data and calibrations centres in Switzerland whose future is at risk
  • Coordinates the implementation of the GCOS Implementation Plan, the GCOS Switzerland Strategy and the GAW Implementation Plan under the guidance of the Swiss GAW/GCOS Scientific Steering Committee (GCOS Switzerland Strategy 2017–2026)
  • Provides support and assistance to the Swiss GAW/GCOS Scientific Steering Committee
  • Coordinates the National Partner Institutions, for example, by organising national coordination meetings
  • Compiles, updates and maintains an inventory report of the National Climate Observing System that identifies and summarises the valuable series of climatic measurements, and the international data and calibration centres operated by Swiss institutions (National Climate Observing System)

On a international level:

  • Acts as the single point of contact for the international GAW and GCOS Secretariats
  • Facilitates the exchange with national GAW and GCOS coordinators of other countries and with other international institutions
  • Reports to the UNFCCC through the compilation of reports on national climate observation
  • Participates in the annual UNFCCC Conference of the Parties (COP) as member of the national delegation


Do not hesitate to contact the Swiss GAW/GCOS Office via the following e-mail address if you have any questions:

By coordinating the two programmes at the national level, MeteoSwiss is acting in accordance with its legal mandate: the Ordinance on Meteorology and Climatology (MetV), Articles 4 and 5.

In carrying out its coordination activities, the Swiss GAW/GCOS Office is under the leadership of an independent steering committee (Swiss GAW/GCOS Scientific Steering Committee).

In its function as an independent steering body, the Swiss GAW/GCOS Scientific Steering Committee is, among other things, responsible for the following:

  • Monitoring and guiding the implementation of the programmes based on the GAW Implementation Plan, the GCOS Implementation Plan and the GCOS Switzerland Strategy
  • Selecting projects that contribute to the respective Implementation Plans to be supported by MeteoSwiss in the framework of GAW-CH and GCOS-CH (see: GAW-CH and GCOS-CH supported activities)
  • Seeking and promoting synergies with other national and international activities

The Steering Committee currently consists of seven members covering a wide range of expertise related to atmospheric and climate sciences:

  • Prof. Dr. Thomas Stocker (Chair, University of Bern)
  • Dr. Brigitte Buchmann (Empa)
  • Dr. Jörg Klausen (MeteoSwiss)
  • Prof. Dr. Christoph Schär (ETH Zurich)
  • Prof. Dr. Julia Schmale (EPFL)
  • Prof. Dr. Jan Seibert (University of Zürich)
  • Vacant

Meeting Documents (SSC, national GAW-CH/GCOS-CH meetings,...)