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Determination of the isotopic composition of atmospheric methane and its application in the AntarcticA procedure for establishing the C-13/C-12 ratio and the C-14 abundance in the atmospheric methane is discussed. The method involves air sample collection, measurement of the methane mixing ratio by gas chromotography followed by quantitative conversion of the methane in the air samples to CO2 and H2O, and analysis of the resulting CO2 for the C-13/C-12 ratio by stable isotope ratio mass spectrometry and measurement of C-14 content by accelerator mass spectrometry. The carbon isotropic composition of methane in air collected at Baring Head, New Zealand, and in air collected on aircraft flights between New Zealand and Antarctica is determined by the method, and no gradient in the composition between Baring Head and the South Pole station is found. As the technique is refined, and more data is gathered, small seasonal and long-term variations in C-13 are expected to be resolved.
Document ID
19910066691
Document Type
Reprint (Version printed in journal)
Authors
Lowe, David C. (Department of Scientific and Industrial Research Lower Hutt, New Zealand)
Brenninkmeijer, Carl A. M. (Department of Scientific and Industrial Research Nuclear Sciences Group, Lower Hutt, New Zealand)
Tyler, Stanley C. (NCAR, Atmospheric Chemistry Div., Boulder CO, United States)
Dlugkencky, Edward J. (NOAA, Climate Monitoring and Diagnostics Laboratory; Cooperative Institute for Research in Environmental Sciences, Boulder CO, United States)
Date Acquired
August 14, 2013
Publication Date
August 20, 1991
Publication Information
Publication: Journal of Geophysical Research
Volume: 96
ISSN: 0148-0227
Subject Category
GEOPHYSICS
Funding Number(s)
CONTRACT_GRANT: NASA ORDER W-16184
Distribution Limits
Public
Copyright
Other