Atmos. Chem. Phys. Discuss., 9, 2381-2415, 2009
www.atmos-chem-phys-discuss.net/9/2381/2009/
doi:10.5194/acpd-9-2381-2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Inter-comparison of four different carbon monoxide measurements techniques and evaluation of the long-term carbon monoxide time series of Jungfraujoch
C. Zellweger, C. Hüglin, J. Klausen, M. Steinbacher, M. K. Vollmer, and B. Buchmann
Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Air Pollution/Environmental Technology, 8600 Dübendorf, Switzerland

Abstract. The 12-year record (1996–2007) of continuous carbon monoxide (CO) measurements of the high-alpine site Jungfraujoch (JFJ), Switzerland, was investigated with a focus on trend analysis. To date this is one of the longest time series of continuous CO measurements in the free troposphere over Central Europe. A significant negative trend was observed at JFJ with a decrease of 21.4±0.3% in the investigated period, or an average annual decrease of 2.65±0.04 ppb/yr (1.78%/yr). These results were compared with emission inventory data reported to the Long-range Transboundary Air Pollution (LRTAP) Convention. It could be shown that long range transport significantly influences the CO levels observed at JFJ, with air masses of non-European origin contributing to at least a third to observed mixing ratios.

Such trend analysis and inter-comparison with emission inventories are only possible with data of known quality. To this end, the Non-dispersive Infrared Absorption (NDIR) technique used for CO measurements at JFJ was inter-compared over two months using three additional analytical techniques, namely Vacuum UV Resonance Fluorescence (VURF), gas chromatographic separation with a mercuric oxide reduction detector (GC/HgO), and gas chromatographic separation followed by reduction on a nickel catalyst and analysis by a flame ionization detector (GC/FID). The agreement among all techniques was better than 2% for one-hourly averages which confirmed the suitability of the NDIR method for CO measurements even at remote sites.


Citation: Zellweger, C., Hüglin, C., Klausen, J., Steinbacher, M., Vollmer, M. K., and Buchmann, B.: Inter-comparison of four different carbon monoxide measurements techniques and evaluation of the long-term carbon monoxide time series of Jungfraujoch, Atmos. Chem. Phys. Discuss., 9, 2381-2415, doi:10.5194/acpd-9-2381-2009, 2009.
 
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