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Supplementary material to “Volatile Organic Compounds in the Global Atmosphere”
29 December 2009
D. Helmig, Institute of Arctic and Alpine Research, University of Colorado, Boulder
J. Bottenheim, Environment Canada, Toronto, Ontario, Canada
I. E. Galbally, Marine and Atmospheric Research, Commonwealth Scientific and Industrial Research Organisation, Aspendale, Victoria, Australia
A. Lewis, National Center for Atmospheric Science, York, UK
M. J. T. Milton, National Physical Laboratory, Teddington, UK
S. Penkett, University of East Anglia, Norwich, UK
C. Plass-Duelmer, Deutscher Wetterdienst, Hohenpeissenberg, Germany
S. Reimann, Swiss Federal Laboratories for Materials Testing and Research (Empa), Dübendorf, Switzerland
P. Tans, Earth Systems Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado
S. Thiel, Forschungszentrum Karlsruhe, Garmisch-Partenkirchen, Germany
Citation:
Helmig, D., J. Bottenheim, I. E. Galbally, A. Lewis, M. J. T. Milton, S. Penkett, C. Plass-Duelmer, S. Reimann, P. Tans, and S. Thiel (2009), Volatile organic compounds in the global atmosphere, Eos Trans. AGU, 90(52), 513–514. [Full Article (pdf)]
Figure 1
Location of sites currently participating in the GAW-VOC program. Stations with in-situ measurement programs are indicated by diamonds, flask sampling sites are denoted by asterisk. See Supplemental Materials Section Table 1 and http://www.esrl.noaa.gov/gmd/dv/site/site_table.html for explanation of the station abbreviation codes.
Table 1
Table of contributing GAW-VOC sites with station 3-letter code, station full name, coordinates, and elevation. Locations are broken up in two sub sections, with one for in-situ sites, and one for flask sites.
The World Meteorological Organization (WMO) - Global Atmospheric Watch (GAW) Initiatives
A WMO-sponsored workshop in 1995 (GAW Report #111) was the first corner stone towards a new global VOC initiative. The meeting report identified VOC classes of interest, measurement approaches, and desired components for a global monitoring program. Motivated by the growing interest for global VOC data and progress made in VOC measurement techniques, a second workshop hosted by WMO-GAW in Geneva, 2006 (GAW Report #171), resulted in the final definition of the global VOC program, with identification of 17 particular target VOC of interest, and implementation of a measurement program of a subset of these VOC that can be measured with current techniques in the background atmosphere. GAW was identified as providing stewardship for implementation and coordination of the measurement activities performed by participating laboratories, and to encourage existing global VOC measurement platforms to contribute to GAW. A third meeting of interested scientists took place in Duebendorf, Switzerland, in July 2008, to present updates and report progress on calibration and data quality topics. The next meeting is scheduled for June 2010.
These activities have led to the establishment of the WMO-GAW VOC program incorporating ~50 surface sites. Essential components are 1. surface stations with regular, in-situ measurements of VOC, 2. VOC analyses in samples collected within existing flask sampling networks for wide geographical coverage, and 3. a concerted calibration and data quality control effort. In-situ surface measurements are limited to eight stations at this time, as current measurements rely on gas chromatography (GC) systems, which are complex and labor intensive to maintain. For the flask sampling component, the program essentially builds upon existing EMEP (European Monitoring and Evaluation Programme) activities and the greenhouse gas sampling by the US NOAA Earth System Research Laboratory — Global Cooperative Air Sampling Network. In the latter program, nine VOC species (ethane, propane, iso-butane, n-butane, iso-pentane, n-pentane, isoprene, benzene, toluene) are currently analyzed in the sample portion that remains in the flasks after completion of analyses of greenhouse gases and of CO2 and methane stable isotopic ratios. Pairs of samples are typically collected on a weekly schedule, and ~3000 samples per year are analyzed by an automated GC system at the University of Colorado's Institute of Arctic and Alpine Research (INSTAAR).
One of the principal activities of GAW-VOC is the operation of a World Calibration Center (WCC) at the Forschungszentrum Karlsruhe – Garmisch-Partenkirchen, Germany, and the implementation of Central Calibration Laboratories (CCL) to maintain a traceable VOC calibration scale, and to provide calibration standards to the GAW-VOC stations. The national institutes collaborating with standard preparation are the National Physical Laboratory — NPL (UK), the National Institute of Standards and Technology - NIST (USA), the Netherlands Measurements Institute - NMI (NL), and the Korea Research Institute of Standards and Science - KRISS (ROK). The WCC coordinates quality assurance and quality control activities, acts as interface between the CCL and the stations, and performs measurement system comparisons (Rappenglück et al., 2006) and audits of participating stations (http://imk-ifu.fzk.de/wcc-voc/).
In addition, WMO-GAW has provided guidance in defining data formats, and in retrieving, organization, and publication of existing data. VOC data are submitted to the World Data Centre for Greenhouse gases (http://gaw.kishou.go.jp/wdcgg/). Regular VOC training courses for GAW station staff to improve analytical performance and in turn data quality are incorporated into the GAW-Training and Education Center (GAW-TEC) training series (http://www.schneefernerhaus.de/e-gawtec.htm). It is envisaged to increase the number of VOC-trainees in the future, further widening the GAW-VOC network.
References
WMO Report No. 111. WMO-BMBF workshop on VOC establishment of a World calibration/instrument intercomparison facility for VOC to serve the WMO global atmospheric watch (GAW) program, Garmisch-Partenkirchen, Germany, 1995.
WMO Report No. 171. A WMO/GAW Expert Workshop on Global Long-Term Measurements of Volatile Organic Compounds. Geneva, Switzerland, 2007.
B. Rappenglück et al., The first VOC intercomparison exercise within the Global Atmosphere Watch (GAW), Atmos. Environ. 40, 7508–7527, 2006.
D. Helmig, University of Colorado, Boulder, USA;
J. Bottenheim, Environment Canada, CA;
I.E. Galbally CSIRO Marine and Atmospheric Research, Australia;
A. Lewis, University of York, U.K.;
M.J.T. Milton, National Physical Laboratory, U.K.;
S. Penkett, University of East Anglia, Norwich, U.K.;
C. Plass-Duelmer, Deutscher Wetterdienst, Hohenpeissenberg, Germany;
K. Read, University of York, U.K.;
S. Reimann, Empa, Switzerland;
R. Steinbrecher, Forschungszentrum Karlsruhe, Germany;
P. Tans, NOAA-ESRL, Boulder, USA;
S. Thiel, Forschungszentrum Karlsruhe, Germany