Global Atmosphere Watch (GAW)

Logo des Programms GAW und der WMO OMMClick to enlarge
GAW Programme and WMO OMM logo
Source: WMO OMM

The Global Atmosphere Watch (GAW) Programme of the World Meteorological Organisation, UNO/WMO is a system of global monitoring of the atmosphere. It consists of a worldwide measuring network of observation stations and scientific infrastructure.

Global Atmosphere Watch

The aim of GAW is to take high-quality measurements of the chemical composition of the atmosphere, aerosols, and physical parameters. The collected data are widely available to the scientific community and are used to improve the scientific understanding of the changes of the chemical and physical state of the atmosphere in respect to climate change, to research atmospheric trends, improve forecast models, for the near surface calibration of satellite measurements and for consultation purposes of mitigation policies and evaluation of climate policy programmes (e.g, Montreal Protocol or Kyoto Protocol). And last not least Global Atmosphere Watch is the essential measurement program for the Global Climate Observing System (GCOS) of the UN/WMO.


25th anniversary

In 2014 the Global Atmosphere Watch programme has its 25th anniversary. The official celebration will be at the CACGP / 13th IGAC Quadrennial Symposium/Conference which will take place on 22-26 September 2014 in Natal, Brazil

GAWTEC celebrates 10th anniversary – Global Atmosphere Watch Training & Education Centre of the UNO/WMO (GAW)

The milestone anniversary was celebrated in the Schneefernerhaus environmental research station in October 2011. The objective of the GAWTEC programme is to use high-quality measurements to gain information about the background atmospheric concentrations of trace substances that can impact and change the climate.

The permanent staff of the more than 500 GAW measuring stations around the world have regularly attended training seminars on the Zugspitze for ten years. Up to now more than 290 participants from 56 countries have come to two-week courses on the Zugspitze to learn about greenhouse gases, aerosols and other climate change trace chemicals. The internationally acclaimed training programme is sponsored by the Federal Environment Agency and the Land Bavaria. There will continue to be two training courses per year in the future.

Quality-assured time series for VOC - Background concentrations in the northern hemisphere are on the decline

The WCC-VOC in collaboration with other researchers from the Global Atmosphere Watch Programme (GAW) have completed the first quality-assured long-term time analysis of volatile organic hydrocarbons. Initial trends at the Hohenpeissenberg GAW station show a slight decline in a few of the anthropogenic emissions of VOC from 1998 to 2009.

Global Atmosphere Watch Training & Education Centre (GAWTEC) celebrates 10th anniversary: a group of persons standing in front of a house
Global Atmosphere Watch Training & Education Centre (GAWTEC) celebrates 10th anniversary
Source: Umweltbundesamt

The GAW Global stations

The map shows the location of the GAW Global stations. Global stations are situated in remote regions with very low background levels of air pollutants and no anthropogenic influence. They have a large area of representativeness and measure a broad range of atmospheric pollutants over decades. In addition, there are more than 600 GAW regional stations and contributing stations with measurement programmes that usually depend on regional needs. Regional stations are representative for a smaller region and provide data applied for regional issues. The GAWSIS Information System provides an overview of the global measurement network of GAW stations.

there are many GAW Global stations all around the globe
Map showing the location of the GAW Global stations
Source: WMO GAW Secretary

GAW Activities in Germany

Activities for the GAW monitoring programme in Germany consist of a co-operation of the German Weather Service, the Federal Environment Agency and a number of research institutes.

The Global station Zugspitze/Hohenpeissenberg consists of the two platforms Zugspitze and Hohenpeissenberg and is operated by the Federal Environment Agency Germany and the German Weather Service. At platform Zugspitze the Federal Environment Agency measures at the Environmental Research Station Schneefernerhaus greenhouse gases, aerosols and chemical reactive atmospheric trace gases. The German Weather Service measures synoptic data, radiation and radioactivity at the Zugspitze summit (2960 m a.s.l.) and at Schneefernerhaus. The measurement program of platform Hohenpeissenberg operated by the German Weather Service includes e.g. reactive atmospheric trace substances, aerosols, ozone profiles, radiation parameters and precipitation. For details on the measurement programs please refer to the respective websites.

The station Zugspitze/Hohenpeissenberg provides the data for central Europe. The next GAW Global Stations are situated in the northwest at the west coast of Ireland, in the north in Finland at the polar circle, in the east at Mount Waliguan in China and in the south in Tamanrasset/Sahara and in Izana on Tenerife/Canary Islands, and in the west on the Jungfraujoch in Switzerland.

The stations on the Hoher Sonnblick in Austria (3100 m a.s.l.), on the Jungfraujoch (3580 m a.s.l.) in Switzerland, and on  Hoher Peissenberg (1000 m a.s.l. )Hohenpeissenberg and Zugspitze (2670 m a.s.l.) in Germany, cooperate through the DACH German-Austrian-Swiss and Italian  working programme  for the joint evaluation of regionally and globally relevant time series and detection and analysis of atmospheric changes in this region.

Measurement activities of the Federal Environment Agency (UBA) at platform Zugspitze

The measurement programme of the Federal Environment Agency includes greenhouse gases and chemically reactive atmospheric trace substances.

  • Greenhouse Gases: Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O), Sulfur hexa fluoride (SF6), and halogenated climate forcing trace gases
  • Reactive Trace Gases: Ozone (O3), Nitrogen oxides (NO, NO2, NOX, NOy), Peroxy Acetic Nitric Anhydride (PAN), Carbon monoxide (CO), Volatile organic carbons ( < C5) and (>= C5)
  • Aerosols: Fine and ultrafine particles, size ranges of fraction concentrations from 10 to 800nm and from 1µm to 20µm, PM10 Beta Absorption, PM10 Mass.

The GAW regional station of Schauinsland is located on a mountain by the same name in the southern Black Forest, about 10 kilometres southeast of Freiburg. Due to its elevation of 1205 metres at the eastern rim of the Upper Rhine Rift, it often lies above the ground-level mixing layer which allows for detection of both long-range transported, and locally influenced, air masses. The station acts as a regional station in the GAW network. Its mainly monitors the greenhouse gases CO, CO2, CH4, N2O, SF6, and the chemically reactive gases ozone, NOx , NO, NO2, PAN, VOC and aerosols, PM10, PM2,5, size ranges of fraction concentrations from 10 to 800 nm.

The GAW regional station Neuglobsow is located in northern Brandenburg, at the southeastern edge of the Brandenburg-Mecklenburg Lake District, right on the southeastern shore of the Stechlinsee lake. The air masses monitored are typical for the eastern region of northern Germany. One of the station’s uses is to serve as a regional station for GAW and monitor the greenhouse gases CO2, CH4, and the reactive gases ozone, NO, NO2.

Quality assurance activities in Germany

The main purpose of quality assurance at GAW is to enable comparability of measurement data over several decades and to grant the fulfillment of the GAW data quality objectives at the same time. This is the only way to derive meaningful data on chemicals such as carbon dioxide and nitrous oxide that are identified in the Kyoto Protocol.

Scientific Advisory Groups (SAGs) define data quality objectives (DQOs) and develop Standard Operating Procedures (SOPs) which incorporate the guidelines and recommendations that govern all issues in the area of quality assurance. These recommendations are published in GAW Reports.

The Federal Environment Agency (UBA) has managed one of the five QA/SAC (Quality Assurance / Science Activity Centres) worldwide since 2000. Other QA/SAC have been established in the United States of America, Japan, Switzerland and China. In addition to the central laboratories, these centres are crucial to the quality assurance activities of GAW.
The UBA is responsible for implementation of the quality assurance measures relevant to atmospheric measurements in three topic areas:

  • Aerosols (physical properties)
  • nitrous oxide (dinitrogen oxide, N2O)
  • Volatile Organic Compounds, VOC.

Special centralized institutions known as World Calibration Centres (WCC) have been set up under GAW which handle these topic areas. They are funded by QA/SAC Germany. The WCC conduct round-robin tests in their own laboratories and global monitoring activities at selected measuring stations.

The WCC Aerosols is managed by the Institute for Tropospheric Research (IfT) Leipzig.  The WCC-N2O and WCC-VOC were established at the Karlsruhe Institute of Technology (KIT), (Institute of Meteorology and Climate Research Atmospheric Environmental Research – IMK-IFU) in Garmisch-Partenkirchen:

A major part of QA/SAC Germany is the GAW Training and Education Centre GAWTEC, which is located at the Schneefernerhaus Environmental Research Station (UFS). The Federal Environment Agency and the Bavarian State Ministry of the Environment and Public Health have provided funding since 2001. Between 2001 and end 2014, the Centre hosted 26 training courses with 297 participants from 62 countries.

Workshop QA/SAC Germany

Further national QA activities within GAW include the World Calibration Centre for Ozone Sondes run by the Research Centre Jülich.

6 persons standing in front of the UBA office building Langen
Participants of the QA/SAC Workshop 2014 in Langen
Source: Umweltbundesamt

Research structure of GAW and contribution of the Federal Environment Agency to GAW

The Federal Environment Agency operates the German Quality Assurance/Science Activity Centre (QA/SAC Germany) as well as a global station and two regional stations. It also funds three World Calibration Centres for nitrous oxide, volatile organic compounds (VOC) and physical aerosols.

Data processing

In keeping with the specific data quality requirements, all data processing steps starting from the acquisition of raw data in the time range of seconds to the production of quality-assured half hour mean values have to be performed at the station. A special software system for data collection and quality assurance at GAW stations was developed in a project commissioned by the Federal Environment Agency under the Environmental Research Plan of the German Environment Ministry. In order to facilitate international standardisation of data processing at GAW stations, developed software components are available to GAW stations free of charge. For further information please refer to „Standardized and automated data quality assurance at GAW Stations: concept, methods and tools“.


Atmospheric peroxyacetyl nitrate (PAN): a global budget and source attribution
E. V. Fischer, D. J. Jacob, R. M. Yantosca, M. P. Sulprizio, D. B. Millet, J. Mao, F. Paulot, H. B. Singh, A. Roiger, L. Ries, R.W. Talbot, K. Dzepina, S. Pandey Deolal; Atmospheric Chemistry and Physics (Impact Factor: 4.88). 03/2014; 14:2679-2698. DOI:10.5194/acp-14-2679-2014.

Nitrogen deposition along differently exposed slopes in the Bavarian Alps
Manfred Kirchner, Wolfgang Fegg, Horst Römmelt, Michael Leuchner, Ludwig Ries, Ralf Zimmermann, Bernd Michalke, Markus Wallasch, Jürgen Maguhn, Theresa Faus-Kessler, Gert Jakoi, Helmholtz Zentrum München, Cooperation Group "Comprehensive Molecular Analytics", Ingolstaedter Landstrasse 1, D-85764 Neuherberg, Germany. Science of The Total Environment (Impact Factor: 3.26). 11/2013; 470-471C:895-906. DOI:10.1016/j.scitotenv.2013.10.036.

Dafit - a new workflow oriented approach for time efficient data preparation, validation and flagging of time series data from environmental monitoring
L.Ries. In: Proceedings of the 27th conference on Environmental informatics – Informatics for Environmental Protection, Sustainable Development and Risk Management, Part II, pp. 651-656, Shaker Verlag, 2013, Aachen, 938.p, ISBN 979.3-8440-1676-5.

Altitudinal temperature lapse rates in an Alpine valley: trends and the influence of season and weather patterns
Manfred Kirchner, Theresa Faus-Kessler, Gert Jakobi, Michael Leuchner, Ludwig Ries, Hans-Eckhart Scheel, Peter Suppan, International Journal of Climatology 03/2013; 33(3):539-555.

Number Size Distributions and seasonality of Submicron Particles in Europe 2008–2009
A. Asmi, A. Wiedensohler, P. Laj, A.-M. Fjaeraa, K. Sellegri, W. Birmili, E. Weingartner, U. Baltensperger, V. Zdimal, N. Zikova, [...], G. Deleeuw, B. Henzing, R.M. Harrison, D. Beddows, C. O’Dowd, H. Flentje, K.Weinhold, F. Meinhardt, L. Ries, M. Kulmala; Atmospheric Chemistry and Physics,01/2011; 11:5505-5538.

Influences of the 2010 Eyjafjallajokull volcanic plume on air quality in the northern Alpine region
K Schaefer, W Thomas, A Peters, L Ries, F Obleitner, J Schnelle-Kreis, W Birmili, J Diemer, W Fricke, W Junkermann, [...], H Flentje, S Gilge, H E Wichmann, F Meinhardt, R Zimmermann, K Weinhold, J Soentgen, C Muenkel, C Freuer, J Cyrys; Atmospheric Chemistry and Physics, 01/2011; 11(16):8555-8575.

Measurement and simulation of the 16/17 April 2010 Eyjafjallajokull volcanic ash layer dispersion in the northern Alpine region
S Emeis, R Forkel, W Junkermann, K Schaefer, H Flentje, S Gilge, W Fricke, M Wiegner, V Freudenthaler, S Gross, L Ries, F Meinhardt, W Birmili, C Muenkel, F Obleitner, P Suppan
Atmospheric Chemistry and Physics 01/2011; 11(6):2689-2701.

A case of transatlantic aerosol transport detected at the Schneefernerhaus Observatory (2650 m) on the northern edge of the Alps
Wolfram Birmili, Tina Obel, And E Sonntag, Ludwig Ries, Ralf Sohmer, Stefan Gilge, Ingeborg Levin, Andreas Stohl; Meteorologische Zeitschrift, Bd. 9, Heft 6, 01/2011; 19:591-600.

Temporal and spatial structure of a volcanic ash cloud: ground-based remote sensing and numerical modeling
Klaus Schäfer, Wolfram Birmili, Josef Cyrys, Stefan Emeis, Renate Forkel, Stefan Gilge, Christoph Münkel, Mike Pitz, Ludwig Ries, Peter Suppan; Proc SPIE 10/2010;

Continuous aerosol observations in the German Ultrafine Aerosol Network (GUAN)
W. Birmili, K. Weinhold, S. Nordmann, A. Wiedensohler, G. Spindler, K. Müller, H. Herrmann, T. Gnauk, M. Pitz, J. Cyrys, H. Flentje, C. Nickel, T. A. J. Kuhlbusch, G. Löschau, F. Meinhardt, A. Schwerin, L. Ries, H. Gerwig, K. Wirtz; International Aerosol Conference 2010, Helsinki, Finland; 08/2010

Spatial structure and dispersion of the 16/17 April 2010 volcanic ash cloud over Germany
Emeis S, Junkermann W, Schäfer K, Forkel R, Suppan P, Flentje H, Gilge S, Fricke W, Wiegner M, Freudenthaler V, Groß S, Ries L, Meinhardt F, Münkel C, Obleitner F Atmospheric Chemistry and Physics 01/2010;

Ozone, carbon monoxide and nitrogen oxides time series at four alpine GAW mountain stations in central Europe
Gilge S, Plass-Duelmer C, Fricke W, Kaiser A, Ries L, Buchmann B, Steinbacher M., Atmospheric Chemistry and Physics, 01/2010;

Transport of nitrogen oxides, carbon monoxide and ozone to the Alpine Global Atmosphere Watch stations Jungfraujoch (Switzerland), Zugspitze and Hohenpeissenberg (Germany), Sonnblick (Austria) and Mt. Krvavec (Slovenia)
August Kaiser, Helfried Scheifinger, Wolfgang Spangl, Andrea Weiss, Stefan Gilge, Wolfgang Fricke, Ludwig Ries, Danijel Cemas, Brigita Jesenovec Atmospheric Environment 41 (2007) 9273–9287

How to Keep the Quality Chain, Work Flow-Oriented Data Processing for Global Atmosphere Watch Measurement Stations.
L.Ries,  pp. 109-112,
In: Environmental Informatics and Systems Research. Vol. 2 Workshop and application papers. Eds. Olgierd Hryniewicz, Jan Studzinski, Anna Szediw. Shaker Verlag, 2007, Aachen, 292 p.

Final Report on CarboEurope ‚Cucumber‘ Intercomparison Programme
Manning A.C., Jordan A., Levin I., et. Al., 2008

Atmospheric aerosol measurements in the German Ultrafine Aerosol Network (GUAN) Part 1: Soot and particle number size distributions
W. Birmili, K. Weinhold, S. Nordmann, A. Wiedensohler, G. Spindler, K. Müller, H. Herrmann, T. Gnauk, M. Pitz, J. Cyrys, H. Flentje, C. Nickel, T. A. J. Kuhlbusch, G. Löschau, D. Haase, F. Meinhardt, A. Schwerin, L. Ries, K. Wirtz, Gefahrstoffe – Reinhaltung  Luft, 69(4), 2009, S. 137-145.

Observation and origin of organochlorine compounds and polycyclic aromatic hydrocarbons in the free troposphere over central Europe.
Gerhard Lammel, Jana Klánová, Jiří Kohoutek, Roman Prokeš, Ludwig Ries and Andreas Stohl, Environmental Pollution, Article in Press, 2009

Feine und ultrafeine Aerosolpartikeln an der GAW-Station Schneefernerhaus/Zugspitze
Birmili, W.; Ries, L.; Sohmer, R.; Anastou, A.; Sonntag, A.; König, K.; Levin, I. , Gefahrstoffe- Reinhaltung der Luft 1-2/2009, Seite 31-35

The data for greenhouse gases and reactive gases are transferred to the World Data Centre for Greenhouse Gases (WDCGG) in Japan. Data on aerosols is submitted to the World Data Centre for Aerosols.

Current WDCGG newsletter on development greenhouse gases.


Dr. Ludwig Ries (ludwig [dot] ries [at] uba [dot] de), German Federal Environment Agency (GAW measurements at platform Zugspitze, QA/SAC Germany)

Dr. Holger Gerwig (holger [dot] gerwig [at] uba [dot] de), German Federal Environment Agency (QA/SAC Germany)

Dr. Christian Plass-Duelmer (Christian [dot] plass-duelmer [at] dwd [dot] de), German Weather Service (GAW measurements at platform Hohenpeissenberg, GAW contact person Germany)

Mirella Glor (m [dot] glor [at] schneefernerhaus [dot] de), Environmental Research Station Schneefernerhaus (GAW Training and Education Centre)

Participating research institutes

Research Centre Jülich:
World Calibration Centre for Ozone Sondes

Alfred-Wegener-Institute Bremerhaven (AWI):
Global Station Neumayer/Antarktis

Leibniz Institute for Tropospheric Research (IfT):
World Calibration Centre for Aerosol Physics

Research Centre Karlsruhe, IMK-IFU
World Calibration Centre for Volatile Organic Compounds
Wold Calibration Centre for Nitrous Oxide

further article pages
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