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.