The international Global Atmosphere Watch programme (GAW) was launched in 1989, since when it has been making an important contribution to monitoring the composition of the atmosphere. GAW is a partnership of over 100 countries worldwide. MeteoSwiss coordinates the national GAW activities and operates Centres for Calibration and Quality Assurance, as well as a database of stations.
The aim of GAW is to provide high quality observation data and analyses of the chemical composition of the atmosphere and its physical properties. The programme supports a worldwide network of selected monitoring stations for measuring greenhouse gases, ozone, UV radiation, aerosols, reactive gases and precipitation chemistry. The GAW network includes 30 global and over 400 regional stations, as well as 100 additional stations from contributing networks. The climate-associated aspects of the GAW programme feed directly into the Global Climate Observing System (GCOS).
The GAW framework supports a diverse range of activities under the leadership of the World Meteorological Organization (WMO), including, for example, national research programmes and international cooperation. Furthermore, it provides services such as global and regional calibration centres, which are run on behalf of the WMO by the individual member countries.
The development and maintenance of the GAW network, knowledge transfer and research projects are dependent to a large extent on the initiatives of the member states. Switzerland plays an active role in this regard, having founded GAW-CH in 1994 as the country's contribution to the global GAW programme. The GAW-CH Office at MeteoSwiss is responsible for coordinating the GAW-related activities in Switzerland. Under its leadership, Switzerland has been continually expanding its contribution over the past few years, and has stepped up its cooperation with partner institutions. GAW-CH conducts long-term observations of the atmospheric composition, as well as undertaking research projects. In addition, it operates calibration and quality assurance centres and a station metadata portal on behalf of the WMO.