THE GLOBAL ATMOSPHERE WATCH PROGRAMME 25 YEARS OF GLOBAL COORDINATED ATMOSPHERIC COMPOSITION OBSERVATIONS AND ANALYSES WMO-No. 1143 WMO-No. 1143 © World Meteorological Organization, 2014 The right of publication in print, electronic and any other form and in any language is reserved by WMO. Short extracts from WMO publications may be reproduced without authorization, provided that the complete source is clearly indicated. Editorial correspondence and requests to publish, reproduce or translate this publication in part or in whole should be addressed to: Chairperson, Publications Board World Meteorological Organization (WMO) 7 bis, avenue de la Paix Tel.: +41 (0) 22 730 84 03 P.O. Box 2300 Fax: +41 (0) 22 730 80 40 CH-1211 Geneva 2, Switzerland E-mail: [email protected] ISBN 978-92-63-11143-2 Cover illustrations: The two photos show the changes in ozone observations from 1957 (International Geophysical Year) until now. On the left, Dobson instruments are being calibrated at the Tateno station in Japan before they are deployed to their individual stations. On the right, Dobson instruments have been set up for a modern intercomparison study. The spectrophotometers are the same, but the measurement and calibration process are now monitored by computers. NOTE The designations employed in WMO publications and the presentation of material in this publication do not imply the expression of any opinion what- soever on the part of WMO concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or products does not imply that they are endorsed or recommended by WMO in preference to others of a similar nature which are not mentioned or advertised. The findings, interpretations and conclusions expressed in WMO publications with named authors are those of the authors alone and do not neces- sarily reflect those of WMO or its Members. CONTENTS 1. History and background 2 2. Long-term objectives and applications 3 3. Organizational structure 4 4. Observations 5 5. Quality assurance 6 6. Focal areas 8 6.1 Ozone 8 6.2 Greenhouse gases 10 6.3 Reactive gases 12 6.4 Atmospheric wet deposition 15 6.5 Ultraviolet radiation 18 6.6 Aerosols 19 6.7 The GAW Urban Research Meteorology and Environment project 23 7. Global Atmosphere Watch data management 27 8. Training 35 9. Global Atmosphere Watch publications 36 10. The future of the Global Atmosphere Watch 37 Acknowledgements 40 References 41 List of abbreviations 43 1. HISTORY AND BACKGROUND Scientific curiosity drove the early observation of spectrophotometer network to measure total atmospheric constituents. But those observations atmospheric ozone. raised many questions: To what extent were the observed increases in certain trace chemicals In the late 1960s, the Background Air Pollution connected to human activities? What human Monitoring Network (BAPMoN) was established, consequences would there be if the increase focusing on precipitation chemistry, aerosol and continued unabated? carbon dioxide measurements. The Network included regional and background stations and In the 1950s, the World Meteorological a WMO World Data Centre in the United States Organization (WMO) launched a programme of America. on atmospheric chemistry and the meteoro- logical aspects of air pollution that transformed During the 1970s, three important atmospheric those early sporadic measurements into regular issues were addressed: (i) the threat of chloro- observations. The new programme soon deter- fluorocarbons (CFCs) to the ozone layer, (ii) the mined that adequate gathering of such data – and acidification of lakes and forests in large parts analysis of its anthropogenic impact on a global of North America and Europe, caused princi- scale – would require that all measurements be pally by the conversion of sulphur dioxide into expressed in the same units and on the same sulphuric acid by precipitation processes in the scale, so that measurements performed by dif- atmosphere, and (iii) global warming caused by ferent countries could be comparable. the build-up of greenhouse gases in the atmo- sphere. Each of these issues is now the subject The first steps towards reaching this objec- of international treaties or conventions. The tive were made during the 1957 International initial development of these agreements and the Geophysical Year. The World Meteorological subsequent assessments of the mitigation mea- Organization began developing standard pro- sures they contain rely heavily on the information cedures for uniform ozone observations and derived from the WMO atmospheric composition established the Global Ozone Observing System observations and analysis programme. (GO3OS), which involved ozonesonde intercom- parisons, preparation of the ozone bulletins In 1989, the two observing networks, BAPMoN and ozone assessments, and support of the and GO3OS, were consolidated into the cur- Ozone Data Centre in Toronto, Canada (later rent WMO Global Atmosphere Watch (GAW) to become the World Ozone and Ultraviolet Programme. As the networks evolved and grew, Radiation Data Centre). The Organization also so did the community involved in atmospheric coordinated the Dobson, and later Brewer, composition observations and analysis. Evolution of the GAW greenhouse gas community: group photos of the 1st meeting of greenhouse gas experts in the Scripps Institution of Oceanography, United States, in 1975 (this page) and the 17th meeting in Beijing, China, from 10–14 June 2013 (opposite page) 2 2. LONG-TERM OBJECTIVES AND APPLICATIONS The GAW Programme is driven by the need data can provide important information. These to understand the variability and trends in the application areas include: composition of the global atmosphere and the related physical parameters, and to assess the • Assessment of the health impacts of air pol- consequences thereof. The foremost challenges lution through health indices it needs to address are: • Air quality forecasting • Emission verifications using inverse modelling • Stratospheric ozone depletion and the increase techniques of ultraviolet (UV) radiation • Assessment of atmospheric composition • Changes in the weather and climate related changes and impacts on climate to human influence on atmospheric composi- • Eutrophication tion, particularly greenhouse gases, ozone • Ecosystem services and aerosols • Attribution of the sources of atmospheric • Risk reduction of air pollution on human health species and issues related to atmospheric deposition and the long-range transport of air pollution The GAW Programme is implemented by WMO Members and supported by the international Many of these challenges have socio-economic scientific community. Together, WMO Members consequences affecting weather, climate, human and scientists around the world perform long- and ecosystem health, water supply and qual- term observations of the chemical composition ity, and agricultural production. Advancing and selected physical characteristics of the atmo- the scientific understanding to address these sphere on a global scale, paying special attention challenges remains critical. At the same time, to quality assurance and quality control of the GAW increasingly focuses on service delivery data and providing integrated products and in a number of application areas where GAW services of relevance to users. 3 3. ORGANIZATIONAL STRUCTURE The GAW Programme addresses six classes 4) The Programme is administered and managed of variables: ozone, UV radiation, greenhouse by the WMO Secretariat with the support of gases, aerosols, selected reactive gases and the Integrated Global Atmospheric Chemistry precipitation chemistry. For these variables, Observations (IGACO) office (for ozone- and GAW acts as a “steward of global coordination”, UV-related issues). supporting all components needed for a rational observing system. 5) General guidance of the Programme, its structural review, the selection of priorities, The organizational structure of the GAW implementation and other leadership activities Programme is outlined in Figure 1, which shows are conducted by the Environmental Pollution the various building blocks of the Programme. and Atmospheric Chemistry Scientific Steering Committee (EPAC SSC) under the WMO Com- 1) The global observing networks that deliver mission for Atmospheric Sciences (CAS). Each high-quality measurements constitute the of the six GAW focus groups has a Scientific core of the Programme. Advisory Group (SAG). An additional SAG exists for the GAW Urban Research Meteorology and 2) Observational data and data products are Environment (GURME) project. Data exchange used in a number of applications, and support issues and near real-time chemical data delivery and contribute to other systems, programmes are coordinated by respective expert teams and research projects. Several data prod- (the Expert Team on World Data Centres (ET- ucts are used to underpin international WDC), and the Expert Team on Near Real-time conventions. Chemical Data Transfer (ET-NRT CDT)). 3) Support for ensuring and controlling the The GAW activities are undertaken by WMO quality of observations and for data and Members with a substantial contribution by metadata management is provided by National Meteorological and Hydrological Services the institutions that act as GAW central (NMHSs). Many research institutes and univer- facilities. They play different roles in the sities contribute to and support the Programme