Development and evaluation of a suite of isotope reference gases for methane
in air
-
Published:2016-08-12
Issue:8
Volume:9
Page:3717-3737
-
ISSN:1867-8548
-
Container-title:Atmospheric Measurement Techniques
-
language:en
-
Short-container-title:Atmos. Meas. Tech.
Author:
Sperlich Peter, Uitslag Nelly A. M., Richter Jürgen M., Rothe Michael, Geilmann Heike, van der Veen Carina, Röckmann ThomasORCID, Blunier ThomasORCID, Brand Willi A.
Abstract
Abstract. Measurements from multiple laboratories have to be related to unifying and traceable reference material in order to be comparable. However, such fundamental reference materials are not available for isotope ratios in atmospheric methane, which led to misinterpretations of combined data sets in the past. We developed a method to produce a suite of synthetic CH4-in-air standard gases that can be used to unify methane isotope ratio measurements of laboratories in the atmospheric monitoring community. Therefore, we calibrated a suite of pure methane gases of different methanogenic origin against international referencing materials that define the VSMOW (Vienna Standard Mean Ocean Water) and VPDB (Vienna Pee Dee Belemnite) isotope scales. The isotope ratios of our pure methane gases range between −320 and +40 ‰ for δ2H–CH4 and between −70 and −40 ‰ for δ13C–CH4, enveloping the isotope ratios of tropospheric methane (about −85 and −47 ‰ for δ2H–CH4 and δ13C–CH4 respectively). Estimated uncertainties, including the full traceability chain, are < 1.5 ‰ and < 0.2 ‰ for δ2H and δ13C calibrations respectively. Aliquots of the calibrated pure methane gases have been diluted with methane-free air to atmospheric methane levels and filled into 5 L glass flasks. The synthetic CH4-in-air standards comprise atmospheric oxygen/nitrogen ratios as well as argon, krypton and nitrous oxide mole fractions to prevent gas-specific measurement artefacts. The resulting synthetic CH4-in-air standards are referred to as JRAS-M16 (Jena Reference Air Set – Methane 2016) and will be available to the atmospheric monitoring community. JRAS-M16 may be used as unifying isotope scale anchor for isotope ratio measurements in atmospheric methane, so that data sets can be merged into a consistent global data frame.
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference57 articles.
1. Anicich, V. G.: Evaluated bimolecular ion-molecule gas phase kinetics of positive ions for use in modeling planetary atmospheres, cometary comae, and interstellar clouds, J. Phys. Chem. Ref. Data, 22, 1469–1569, 1993. 2. Assonov, S. S. and Brenninkmeijer, C. A. M.: A new method to determine the 17O isotopic abundance in CO2 using oxygen isotope exchange with a solid oxide, Rapid Commun. Mass Sp., 15, 2426–2437, 2001. 3. Behrens, M., Schmitt, J., Richter, K. U., Bock, M., Richter, U. C., Levin, I., and Fischer, H.: A gas chromatography/combustion/isotope ratio mass spectrometry system for high-precision δ13C measurements of atmospheric methane extracted from ice core samples, Rapid Commun. Mass Sp., 22, 3261–3269, 2008. 4. Bergamaschi, P., Schupp, M., and Harris, G. W.: High-precision direct measurements of 13CH4/12CH4 and 12CH3D/12CH4 ratios in atmospheric methane sources by means of a long-path tunable diode-laser absorption spectrometer, Appl. Optics, 33, 7704–7716, 1994. 5. Bergamaschi, P., Bräunlich, M., Marik, T., and Brenninkmeijer, C. A. M.: Measurements of the carbon and hydrogen isotopes of atmospheric methane at Izana, Tenerife: Seasonal cycles and synoptic-scale variations, J. Geophys. Res.-Atmos., 105, 14531–14546, 2000.
Cited by
22 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|