Introduction to the WMO WDCGG
1. Global Atmosphere Watch (GAW)
The Global Atmosphere Watch (GAW) programme of WMO (http://www.wmo.int/gaw) coordinates
global atmospheric chemistry observations, analysis and scientific assessments related
to the changing composition of the Earth's atmosphere and its effects on weather, climate,
water and the environment. GAW is the lead programme for implementing recommendations of
the Global Climate Observing System (GCOS) on the essential climate variables (greenhouse gases,
ozone and aerosols). It is a major contributor to the Global Earth Observation System of
Systems (GEOSS) coordinating integrated global atmospheric chemistry observations and research
for greenhouse gases, ozone, aerosols, reactive gases and precipitation chemistry.
The mission of GAW is to:
These goals are pursued through:
reduce environmental risks to society and meet the requirements of
strengthen capabilities to predict climate, weather and air quality
contribute to scientific assessments in support of environmental policy
maintaining and applying global, long-term observations of the chemical
composition and selected physical characteristics of the atmosphere
emphasising quality assurance and quality control
delivering integrated products and services of relevance to users.
Global observations are archived and made available by GAW World Data Centres (WDC).
The purpose of the WDCs is to collect and archive processed GAW data, to make them
publicly available, and to provide support in the quality assurance, analysis and
interpretation of these data for scientific advances and policy decisions. The WDCs
are committed to align their operations to the needs of data submitters and data
2. History and objectives of the WDCGG
The WDCGG, one of the WDCs under WMO's GAW programme, has been
operating since October 1990 at the Japan Meteorological Agency (JMA).
Furthermore, under an agreement between the Global Climate Observing System (GCOS)
and WMO/GAW that considers the WMO/GAW global atmospheric CO2 and CH4 monitoring
network as a comprehensive network of GCOS, the WDCGG is charged with data
management and dissemination of value-added products on these species in order to
facilitate more reliable monitoring and data analysis.
The objectives of the WDCGG are to support scientific research, assessment and
correspondence policy for environmental issues such as global warming, ultimately to
contribute toward reducing societal environmental risks and to meet the requirements of
related environmental conventions.
3. Functions of the WDCGG
Since its establishment in 1990, the WDCGG has been principally working to achieve its
objectives. In addition, the WDCGG has improved its operation and functions
in accordance with GAW Strategic Plans. The current operations of the WDCGG are
composed of the following four functions:
To collect measurement data and associated metadata of greenhouse and related
trace gas species from various platforms of the GAW observation network
and relevant international research programmes
To archive the data of known quality for long-term use after validation
To make the archived data available to users via the Internet
To disseminate value-added products and user support information in order
to facilitate more reliable monitoring and data analysis.
Schematic diagram of the functions of the WDCGG and the flow of data
4. Archived parameters
The WDCGG archives measurement data for greenhouse and related
gases in the atmosphere and the ocean (77 gaseous species as of 31 December 2009).
The data are classified into six categories
according to the observation platforms or methods used (see WDCGG Data Submission
and Dissemination Guide).
Air observation at stationary platform
Air observation by mobile platforms (e.g. aircraft, ships, etc.)
Vertical profile observation of air (e.g. multi-height observation using a tower)
Hydrographic sampling observation by ships
Ice core observation
Observation of surface seawater and overlying air