Synopsis Back to Top
In 2004, NOAA's Global Monitoring Division in collaboration with the Atmospheric Research Laboratory at the Institute of Arctic and Alpine Research at the University of Colorado, Boulder, began a program for measurements of Volatile Organic Compounds (VOC) in air samples collected at remote locations around the globe. This program is one of the core components of the World Meteorological Organization (WMO) Global Atmospheric Watch (GAW) program for Volatile Organic Compounds. The objectives and approaches of this program have been detailed in these reports:
Establishment of a World Calibration/Instrument Intercomparison for VOC to Serve the WMO Global Atmosphere Watch (GAW) Programme. WMO-BMBF Workshop on VOC. World Meteorological Organization Global Atmosphere Watch Report No. 111, 1996.Helmig, D., Bottenheim J., Galbally I. E., Lewis A., Milton M. J. T., Penkett S., Plass-Duelmer C., Reimann S., Tans P., and Theil S. (2009) Volatile Organic Compounds in the Global Atmosphere. Eos Trans. AGU, 90(52), Feature.
Global Network Back to Top
in a pair
Detailed Sampling Site Information.
Analytical Procedure Back to Top
The analytical procedure is based on extraction of ~ 500 ml of air from the flask samples onto a two-stage Peltier-cooled micro-adsorbent trap after drying of the sample air to a dewpoint of -30ºC. After thermal desorption VOC are separated by gas chromatography on an Alumina PLOT column. Quantification is done by flame ionization detection. A series of 3-5 gravimetrically prepared standards is used for calibration of the detector response. Flask analyses are automated with a series of 12 sample flasks being bracketed by blank and standard runs each. More details and extensive tests on the analytical procedure were published by Pollmann et al., 2006 and Pollman et al., 2008. Our laboratory was audited by the World Calibration Center for Volatile Organic Gases in 2008 and 2011 and found to meet all quality criteria defined by the WMO-GAW program for Reactive Gases on both occasions.
Collection of whole air samples into a network flask on top of the Pico Mountain, Azores, site.
The analytical system for VOC analysis from the NOAA Cooperative Network Cabon Cycle flasks. The photograph shows a series of 12 flasks mounted on the flask manifold with the gas chromatograph instrument to the left.
Included Compounds Back to Top
Flask In-Situ Comparisons Back to Top
At two sites, i.e. the German Weather Service Hohenpeissenberg Observatory and at Summit, Greenland, parallel VOC measurements are being conducted with flask sample collection and by in-situ monitoring at the site with a GC system. These observations allow evaluation and quality control of the of bi-weekly flask sample collection with the much higher resolution in-situ measurements. These measurements are continuing and further analyses and evaluations are ongoing.
Eight month comparison of propane quantification results from flasks and in-situ measurements at Hohenpeissenberg Observatory (DWD).
Eight month comparison of isoprene quantification results from flaks and in-situ measurements at Hohenpeissenberg Observatory (DWD).
Two year comparison of ethane quantification results from in-situ measurements and NOAA/INSTAAR bi-weekly flask samples from Summit, Greenland.
Results of Spacial and Seasonal Distribution Back to Top
3D Presentations of ethane, propane, butane, and pentane global distribution.
Global distribution of ethane (C2H6) from 2004-2011.
Global distribution of propane (C3H8) from 2004-2011.
Global distribution of iso-butane (i-C4H10) from 2004-2011.
Global distribution of n-butane (n-C4H10) from 2004-2011.
Global distribution of i-pentane (i-C5H12) from 2004-2011.
Global distribution of n-pentane (n-C5H12) from 2004-2011.
Data Products and Policy Back to Top
After completion of all calibration and quality control steps, final data are reported to the NOAA GMD data portal and from there they are released to the World Data Centre of Greenhouse Gases in Tokyo approximately 18-24 months after sample collection. Data from this program are for public use in scientific research. We request that the Program Principal Investigator (D. Helmig) be contacted to discuss intentions to utilize these data in scientific publication for possible consideration of co-authorship.
Publications Resulting From This Program Back to Top
Simpson I.J., Andersen M.P.S., Meinardi S., Bruhwiler L., Blake N.J., Helmig D., Rowland F.S., and Blake D.R. (2012) Long-term decline of global atmospheric ethane concentrations and implications for methane. Nature 488, 490-494.
Pozzer A., Pollmann J., Taraborrelli D., Jöckel P., Helmig D., Tans P., Hueber J., and Lelieveld J. (2010) Observed and simulated global distribution and budget of atmospheric C2-C5 alkanes. Atmos. Chem. Phys. 10, 4403-4422.
Helmig, D., Bottenheim J., Galbally I. E., Lewis A., Milton M. J. T., Penkett S., Plass-Duelmer C., Reimann S., Tans P., Theil S. (2009) Volatile Organic Compounds in the Global Atmosphere. Eos Trans. AGU, 90(52), Feature.
Pollmann J., Helmig D., Hueber J., Plass-Duelmer C., and Tans P. (2008) Sampling, storage, and analysis of C2-C7 non-methane hydrocarbons from the US National Oceanic and Atmospheric Administration Cooperative Air Sampling Network glass flasks. J. Chromatogr., 1188, 75-87.
Pollmann J., Helmig D., Hueber J., Tanner D., and Tans P. (2006) Evaluation of adsorbent materials for cryogen-free trapping-one stage-GC analysis of atmospheric C2-C6 non-methane hydrocarbons. J. Chrom., 1134, 1-15.
Recognition Back to Top
World Calibration Centre for Volatile Organic Compounds (WCC-VOC)
NOAA ESRL Global Monitoring Division
World Data Centre for Greenhouse Gases
Contact Information Back to Top
Institute of Arctic and Alpine Research
University of Colorado
Boulder, CO 80305, USA
001 303 492-2509