Abstract

Measurements of 13CH4/12CH4 and 12CH3D/12CH4 ratios in atmospheric methane (CH4) sources provide important information about the global CH4 budget as well as about CH4 production and consumption processes occurring within the various sources. As an alternative to the conventional mass spectrometer (MS) technique, which requires conversion of CH4 to CO2 and H2, we have developed a tunable diode laser absorption spectrometer (TDLAS), which permits rapid direct measurements of the 13CH4/12CH4 and 12CH3D/12CH4 ratios. An intercomparison between TDLAS and MS techniques for samples from natural wetlands, landfills, and natural gas sources resulted in a mean deviation of Δδ13C = 0.44‰ and ΔδD = 5.1‰. In the present system the minimum mixing ratios required are 50 parts in 106 by volume (ppmv) CH4 (sample size 2 μmol CH4) for direct δ13C measurements and 2000 ppmv (sample size 80 μmol CH4) for direct δD measurements. These mixing-ratio limits are adequate for most CH4 source characterization studies without requiring sample preconcentration.

© 1994 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. R. A. Rasmussen, M. A. K. Khalil, “Atmospheric methane in the recent and ancient atmospheres: concentrations, trends, and interhemispheric gradient,” J. Geophys. Res. 89, 11599–11605 (1984).
    [CrossRef]
  2. D. R. Blake, F. S. Rowland, “Continuing worldwide increase in tropospheric methane, 1978 to 1987,” Science 239, 1129–1131 (1988).
    [CrossRef] [PubMed]
  3. D. M. Etheridge, G. I. Pearman, P. J. Fraser, “Changes in tropospheric methane between 1841 and 1978 from a high accumulation-rate Antarctic ice core,” Tellus 44, 282–294 (1992).
    [CrossRef]
  4. J. Lelieveld, P. J. Crutzen, C. Brühl, “Climate effects of atmospheric methane,” Chemosphere 26, 739–768 (1993).
    [CrossRef]
  5. R. J. Cicerone, R. S. Oremland, “Biogeochemical aspects of atmospheric methane,” Global Biogeochem. Cycles 2, 299–327 (1988).
    [CrossRef]
  6. C. M. Stevens, A. Engelkemeir, “Stable carbon isotopic composition of methane from natural and anthropogenic sources,” J. Geophys. Res. 93, 725–733 (1988).
    [CrossRef]
  7. M. Wahlen, N. Tanaka, R. Henry, B. Deck, J. Zeglen, J. S. Vogel, J. Southon, A. Shemesh, R. Fairbanks, W. Broecker, “Carbon-14 in methane sources and in atmospheric methane: the contribution from fossil carbon,” Science 245, 286–290 (1989).
    [CrossRef] [PubMed]
  8. M. R. Manning, D. C. Lowe, W. Melhuish, R. Spaarks, G. Wallace, C. A. M. Brenninkmeijer, R. C. McGill, “The use of radiocarbon measurements in atmospheric studies,” Radio-carbon 32, 37–58 (1990).
  9. P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
    [CrossRef]
  10. S. C. Tyler, “The global methane budget,” in Microbial Production and Consumption of Greenhouse Gases: Methane, Nitrogen Oxides, and Halomethanes, J. E. Rogers, W. B. Whitman, eds. (American Society for Microbiology, Washington, D.C., 1991), pp. 7–38.
  11. Usually the stable isotope ratios are expressed in the δ notationδ=(RsampleRstandard-1)1000(‰),where Rsample, Rstandard are the 13C/12C (or D/H, i.e., 2H/1H) ratios of the sample and a standard, respectively. Generally the PeeDee Belemnite (PDB) standard is used for 13C/12C ratios,12 whereas D/H ratios are referenced to the standard mean ocean water (SMOW) standard.13
  12. H. Craig, “Isotopic standards for carbon and oxygen and correction factors for mass-spectrometric analysis of carbon dioxide,” Geochim. Cosmochim. Acta 12, 133–149 (1957).
    [CrossRef]
  13. R. Hagemann, G. Nief, E. Roth, “Absolute isotopic scale for deuterium analysis of natural waters, absolute D/H ratio for SMOW,” Tellus 22, 712–715 (1970).
    [CrossRef]
  14. M. J. Whiticar, E. Faber, M. Schoell, “Biogenic methane formation in marine and freshwater environments: CO2 reduction vs. acetate fermentation—isotope evidence,” Geochim. Cosmochim. Acta 50, 693–709 (1986).
    [CrossRef]
  15. M. Wahlen, “The global methane cycle,” Ann. Rev. Earth Planet. Sci. 21, 407–426 (1993).
    [CrossRef]
  16. R. A. Burke, T. R. Barber, W. M. Sackett, “Seasonal variations of stable hydrogen and carbon isotope ratios of methane in subtropical freshwater sediments,” Global Biogeochem. Cycles 6, 125–138 (1992).
    [CrossRef]
  17. D. D. Coleman, J. B. Risatti, M. Schoell, “Fractionation of carbon and hydrogen isotopes by methane-oxidizing bacteria,” Geochim. Cosmochim. Acta 45, 1033–1037 (1981).
    [CrossRef]
  18. R. A. Burke, T. R. Barber, W. M. Sackett, “Methane flux and stable hydrogen and carbon isotope composition of sedimentary methane from the Florida Everglades,” Global Biogeochem. Cycles 2, 329–340 (1988).
    [CrossRef]
  19. M. J. Whiticar, “A geochemical perspective of natural gas and atmospheric methane,” Org. Geochem. 16, 531–547 (1990).
    [CrossRef]
  20. I. Levin, P. Bergamaschi, H. Dörr, D. Trapp, “Stable isotopic signature of methane from major sources in Germany,” Chemosphere 26, 161–177 (1993).
    [CrossRef]
  21. P. Bergamaschi, “Messungen der 13CH4/12CH4- und 12CH3D/12CH4-Verhältnisse an Proben atmosphärischer Methanquellen mittels Diodenlaserabsorptionsspektrospkopie,” Ph.D. dissertation (Universität Heidelberg, Heidelberg, Germany, 1993).
  22. W. D. Hermichen, H. Schütze, “Zur Bedeutung der molekularen Diffusion für die Stoff- und Isotopentrennung bei der Bildung und Zerstörung von Erdgaslagerstätten,” Isotopenpraxis 23, 285–289 (1987).
    [CrossRef]
  23. E. J. Mroz, “Deuteromethanes: potential fingerprints of the sources of atmospheric methane,” Chemosphere 26, 45–53 (1993).
    [CrossRef]
  24. R. Bösinger, “Isotopenmessungen an atmosphärischem und quellnahem Methan,” Ph.D. dissertation (Universität Heidelberg, Heidelberg, Germany, 1990).
  25. D. C. Lowe, C. A. M. Brenninkmeijer, “Determination of the isotopic composition of atmospheric methane and its application in the Antarctic,” J. Geophys. Res. 96, 15455–15467 (1991).
    [CrossRef]
  26. I. Dumke, E. Faber, J. Poggenburg, “Determination of stable carbon and hydrogen isotopes of light hydrocarbons,” Anal. Chem. 61, 2149–2154 (1989).
    [CrossRef]
  27. C. R. Webster, R. D. May, “In situ stratospheric measurements of CH4, 13CH4, N2O, and OC18O using the BLISS tunable diode laser spectrometer,” Geophys. Res. Lett. 19, 45–48 (1992).
    [CrossRef]
  28. W. W. Wong, “Comparison of infrared and mass-spectrometric measurements of carbon-13/carbon-12 ratios,” Int. J. Appl. Radiat. Isot. 36, 997–999 (1985).
    [CrossRef] [PubMed]
  29. J. F. Becker, T. B. Sauke, M. Loewenstein, “Stable isotope analysis using diode laser spectroscopy,” Appl. Opt. 31, 1921–1927 (1992).
    [CrossRef] [PubMed]
  30. M. Wahlen, T. Yoshinari, “Oxygen isotope ratios in N2O from different environments,” Nature (London) 313, 780–782 (1985).
    [CrossRef]
  31. P. S. Lee, R. F. Majkowski, “High resolution infrared diode laser spectroscopy for isotope analysis—measurement of isotopic carbon monoxide,” Appl. Phys. Lett. 48, 619–621 (1986).
    [CrossRef]
  32. S. M. Anderson, J. Morton, K. Mauersberger, “Laboratory measurements of ozone isotopomers by tunable diode laser absorption spectroscopy,” Chem. Phys. Lett. 156, 175–180 (1989).
    [CrossRef]
  33. M. Schupp, P. Bergamaschi, G. W. Harris, P. J. Crutzen, “Development of a tunable diode laser absorption spectrometer for measurements of the 13C/12C ratio in methane,” Chemosphere 26, 13–22 (1993).
    [CrossRef]
  34. M. Schupp, “Entwicklung und Demonstration einer laserspektroskopischen Methode zur Messung des Kohlenstoffisoto-penverhältnisses in Methan,” Ph.D. dissertation (Universität Mainz, Mainz, Germany, 1992).
  35. M. Schupp, P. Bergamaschi, G. W. Harris, “Measurements of the 13C/12C ratio in methane using a tunable diode laser absorption spectrometer,” in Monitoring of Gaseous Pollutants by Tunable Diode Lasers, R. Grisar, H. Böttner, M. Tacke, G. Restelli, eds. (Kiuwer, Dordrecht, The Netherlands, 1992), pp. 343–352.
  36. A. Fried, B. Henry, J. R. Drummond, “Tunable diode laser ratio measurements of atmospheric constituents by employing dual fitting analysis and jump scanning,” Appl. Opt. 32, 821–827 (1993).
    [CrossRef] [PubMed]
  37. C. R. Webster, R. T. Menzies, E. D. Hinkley, “Infrared laser absorption: theory and applications,” in Laser Remote Chemical Analysis, R. M. Measures, ed. (Wiley, New York, 1988), pp. 163–272.
  38. The subscript indicates the measurement method: mass spectrometry (MS) or TDLAS; the superscript indicates the scale to which the δ values are referred (PDB, SMOW, reference). The measured gas (sample, reference, calibration) is identified within the parentheses.
  39. L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
    [CrossRef]
  40. R. A. Toth, L. R. Brown, R. H. Hunt, L. S. Rothman, “Line parameters of methane from 2385 to 3200 cm−1,” Appl. Opt. 20, 932–935 (1981).
    [CrossRef] [PubMed]
  41. We define the mean deviation Δδ 13C (ΔδD) asΔδ={1n∑i=1n[δMS(i)-δTDLAS(i)]2}1/2.This provides a better measure of the comparison than the slopes and intercepts of the regression lines, which in all cases were insignificantly different from unity and zero.
  42. L. S. Rothman, R. R. Gamache, A. Goldman, L. R. Brown, R. A. Toth, H. M. Pickett, R. L. Poynter, J.-M. Flaud, C. Camy-Peyret, A. Barbe, N. Husson, C. P. Rinsland, M. A. H. Smith, “The hitran database: 1986 edition,” Appl. Opt. 26, 4058–4097 (1987).
    [CrossRef] [PubMed]

1993 (6)

J. Lelieveld, P. J. Crutzen, C. Brühl, “Climate effects of atmospheric methane,” Chemosphere 26, 739–768 (1993).
[CrossRef]

M. Wahlen, “The global methane cycle,” Ann. Rev. Earth Planet. Sci. 21, 407–426 (1993).
[CrossRef]

I. Levin, P. Bergamaschi, H. Dörr, D. Trapp, “Stable isotopic signature of methane from major sources in Germany,” Chemosphere 26, 161–177 (1993).
[CrossRef]

E. J. Mroz, “Deuteromethanes: potential fingerprints of the sources of atmospheric methane,” Chemosphere 26, 45–53 (1993).
[CrossRef]

M. Schupp, P. Bergamaschi, G. W. Harris, P. J. Crutzen, “Development of a tunable diode laser absorption spectrometer for measurements of the 13C/12C ratio in methane,” Chemosphere 26, 13–22 (1993).
[CrossRef]

A. Fried, B. Henry, J. R. Drummond, “Tunable diode laser ratio measurements of atmospheric constituents by employing dual fitting analysis and jump scanning,” Appl. Opt. 32, 821–827 (1993).
[CrossRef] [PubMed]

1992 (5)

J. F. Becker, T. B. Sauke, M. Loewenstein, “Stable isotope analysis using diode laser spectroscopy,” Appl. Opt. 31, 1921–1927 (1992).
[CrossRef] [PubMed]

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

C. R. Webster, R. D. May, “In situ stratospheric measurements of CH4, 13CH4, N2O, and OC18O using the BLISS tunable diode laser spectrometer,” Geophys. Res. Lett. 19, 45–48 (1992).
[CrossRef]

R. A. Burke, T. R. Barber, W. M. Sackett, “Seasonal variations of stable hydrogen and carbon isotope ratios of methane in subtropical freshwater sediments,” Global Biogeochem. Cycles 6, 125–138 (1992).
[CrossRef]

D. M. Etheridge, G. I. Pearman, P. J. Fraser, “Changes in tropospheric methane between 1841 and 1978 from a high accumulation-rate Antarctic ice core,” Tellus 44, 282–294 (1992).
[CrossRef]

1991 (2)

P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
[CrossRef]

D. C. Lowe, C. A. M. Brenninkmeijer, “Determination of the isotopic composition of atmospheric methane and its application in the Antarctic,” J. Geophys. Res. 96, 15455–15467 (1991).
[CrossRef]

1990 (2)

M. J. Whiticar, “A geochemical perspective of natural gas and atmospheric methane,” Org. Geochem. 16, 531–547 (1990).
[CrossRef]

M. R. Manning, D. C. Lowe, W. Melhuish, R. Spaarks, G. Wallace, C. A. M. Brenninkmeijer, R. C. McGill, “The use of radiocarbon measurements in atmospheric studies,” Radio-carbon 32, 37–58 (1990).

1989 (3)

M. Wahlen, N. Tanaka, R. Henry, B. Deck, J. Zeglen, J. S. Vogel, J. Southon, A. Shemesh, R. Fairbanks, W. Broecker, “Carbon-14 in methane sources and in atmospheric methane: the contribution from fossil carbon,” Science 245, 286–290 (1989).
[CrossRef] [PubMed]

I. Dumke, E. Faber, J. Poggenburg, “Determination of stable carbon and hydrogen isotopes of light hydrocarbons,” Anal. Chem. 61, 2149–2154 (1989).
[CrossRef]

S. M. Anderson, J. Morton, K. Mauersberger, “Laboratory measurements of ozone isotopomers by tunable diode laser absorption spectroscopy,” Chem. Phys. Lett. 156, 175–180 (1989).
[CrossRef]

1988 (4)

R. J. Cicerone, R. S. Oremland, “Biogeochemical aspects of atmospheric methane,” Global Biogeochem. Cycles 2, 299–327 (1988).
[CrossRef]

C. M. Stevens, A. Engelkemeir, “Stable carbon isotopic composition of methane from natural and anthropogenic sources,” J. Geophys. Res. 93, 725–733 (1988).
[CrossRef]

D. R. Blake, F. S. Rowland, “Continuing worldwide increase in tropospheric methane, 1978 to 1987,” Science 239, 1129–1131 (1988).
[CrossRef] [PubMed]

R. A. Burke, T. R. Barber, W. M. Sackett, “Methane flux and stable hydrogen and carbon isotope composition of sedimentary methane from the Florida Everglades,” Global Biogeochem. Cycles 2, 329–340 (1988).
[CrossRef]

1987 (2)

W. D. Hermichen, H. Schütze, “Zur Bedeutung der molekularen Diffusion für die Stoff- und Isotopentrennung bei der Bildung und Zerstörung von Erdgaslagerstätten,” Isotopenpraxis 23, 285–289 (1987).
[CrossRef]

L. S. Rothman, R. R. Gamache, A. Goldman, L. R. Brown, R. A. Toth, H. M. Pickett, R. L. Poynter, J.-M. Flaud, C. Camy-Peyret, A. Barbe, N. Husson, C. P. Rinsland, M. A. H. Smith, “The hitran database: 1986 edition,” Appl. Opt. 26, 4058–4097 (1987).
[CrossRef] [PubMed]

1986 (2)

P. S. Lee, R. F. Majkowski, “High resolution infrared diode laser spectroscopy for isotope analysis—measurement of isotopic carbon monoxide,” Appl. Phys. Lett. 48, 619–621 (1986).
[CrossRef]

M. J. Whiticar, E. Faber, M. Schoell, “Biogenic methane formation in marine and freshwater environments: CO2 reduction vs. acetate fermentation—isotope evidence,” Geochim. Cosmochim. Acta 50, 693–709 (1986).
[CrossRef]

1985 (2)

W. W. Wong, “Comparison of infrared and mass-spectrometric measurements of carbon-13/carbon-12 ratios,” Int. J. Appl. Radiat. Isot. 36, 997–999 (1985).
[CrossRef] [PubMed]

M. Wahlen, T. Yoshinari, “Oxygen isotope ratios in N2O from different environments,” Nature (London) 313, 780–782 (1985).
[CrossRef]

1984 (1)

R. A. Rasmussen, M. A. K. Khalil, “Atmospheric methane in the recent and ancient atmospheres: concentrations, trends, and interhemispheric gradient,” J. Geophys. Res. 89, 11599–11605 (1984).
[CrossRef]

1981 (2)

D. D. Coleman, J. B. Risatti, M. Schoell, “Fractionation of carbon and hydrogen isotopes by methane-oxidizing bacteria,” Geochim. Cosmochim. Acta 45, 1033–1037 (1981).
[CrossRef]

R. A. Toth, L. R. Brown, R. H. Hunt, L. S. Rothman, “Line parameters of methane from 2385 to 3200 cm−1,” Appl. Opt. 20, 932–935 (1981).
[CrossRef] [PubMed]

1970 (1)

R. Hagemann, G. Nief, E. Roth, “Absolute isotopic scale for deuterium analysis of natural waters, absolute D/H ratio for SMOW,” Tellus 22, 712–715 (1970).
[CrossRef]

1957 (1)

H. Craig, “Isotopic standards for carbon and oxygen and correction factors for mass-spectrometric analysis of carbon dioxide,” Geochim. Cosmochim. Acta 12, 133–149 (1957).
[CrossRef]

Anderson, S. M.

S. M. Anderson, J. Morton, K. Mauersberger, “Laboratory measurements of ozone isotopomers by tunable diode laser absorption spectroscopy,” Chem. Phys. Lett. 156, 175–180 (1989).
[CrossRef]

Barbe, A.

Barber, T. R.

R. A. Burke, T. R. Barber, W. M. Sackett, “Seasonal variations of stable hydrogen and carbon isotope ratios of methane in subtropical freshwater sediments,” Global Biogeochem. Cycles 6, 125–138 (1992).
[CrossRef]

R. A. Burke, T. R. Barber, W. M. Sackett, “Methane flux and stable hydrogen and carbon isotope composition of sedimentary methane from the Florida Everglades,” Global Biogeochem. Cycles 2, 329–340 (1988).
[CrossRef]

Becker, J. F.

Bergamaschi, P.

M. Schupp, P. Bergamaschi, G. W. Harris, P. J. Crutzen, “Development of a tunable diode laser absorption spectrometer for measurements of the 13C/12C ratio in methane,” Chemosphere 26, 13–22 (1993).
[CrossRef]

I. Levin, P. Bergamaschi, H. Dörr, D. Trapp, “Stable isotopic signature of methane from major sources in Germany,” Chemosphere 26, 161–177 (1993).
[CrossRef]

M. Schupp, P. Bergamaschi, G. W. Harris, “Measurements of the 13C/12C ratio in methane using a tunable diode laser absorption spectrometer,” in Monitoring of Gaseous Pollutants by Tunable Diode Lasers, R. Grisar, H. Böttner, M. Tacke, G. Restelli, eds. (Kiuwer, Dordrecht, The Netherlands, 1992), pp. 343–352.

P. Bergamaschi, “Messungen der 13CH4/12CH4- und 12CH3D/12CH4-Verhältnisse an Proben atmosphärischer Methanquellen mittels Diodenlaserabsorptionsspektrospkopie,” Ph.D. dissertation (Universität Heidelberg, Heidelberg, Germany, 1993).

Blake, D. R.

D. R. Blake, F. S. Rowland, “Continuing worldwide increase in tropospheric methane, 1978 to 1987,” Science 239, 1129–1131 (1988).
[CrossRef] [PubMed]

Bösinger, R.

R. Bösinger, “Isotopenmessungen an atmosphärischem und quellnahem Methan,” Ph.D. dissertation (Universität Heidelberg, Heidelberg, Germany, 1990).

Brenninkmeijer, C. A. M.

D. C. Lowe, C. A. M. Brenninkmeijer, “Determination of the isotopic composition of atmospheric methane and its application in the Antarctic,” J. Geophys. Res. 96, 15455–15467 (1991).
[CrossRef]

M. R. Manning, D. C. Lowe, W. Melhuish, R. Spaarks, G. Wallace, C. A. M. Brenninkmeijer, R. C. McGill, “The use of radiocarbon measurements in atmospheric studies,” Radio-carbon 32, 37–58 (1990).

Broecker, W.

M. Wahlen, N. Tanaka, R. Henry, B. Deck, J. Zeglen, J. S. Vogel, J. Southon, A. Shemesh, R. Fairbanks, W. Broecker, “Carbon-14 in methane sources and in atmospheric methane: the contribution from fossil carbon,” Science 245, 286–290 (1989).
[CrossRef] [PubMed]

Brown, L. R.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

L. S. Rothman, R. R. Gamache, A. Goldman, L. R. Brown, R. A. Toth, H. M. Pickett, R. L. Poynter, J.-M. Flaud, C. Camy-Peyret, A. Barbe, N. Husson, C. P. Rinsland, M. A. H. Smith, “The hitran database: 1986 edition,” Appl. Opt. 26, 4058–4097 (1987).
[CrossRef] [PubMed]

R. A. Toth, L. R. Brown, R. H. Hunt, L. S. Rothman, “Line parameters of methane from 2385 to 3200 cm−1,” Appl. Opt. 20, 932–935 (1981).
[CrossRef] [PubMed]

Brown, T. A.

P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
[CrossRef]

Brühl, C.

J. Lelieveld, P. J. Crutzen, C. Brühl, “Climate effects of atmospheric methane,” Chemosphere 26, 739–768 (1993).
[CrossRef]

Burke, R. A.

R. A. Burke, T. R. Barber, W. M. Sackett, “Seasonal variations of stable hydrogen and carbon isotope ratios of methane in subtropical freshwater sediments,” Global Biogeochem. Cycles 6, 125–138 (1992).
[CrossRef]

R. A. Burke, T. R. Barber, W. M. Sackett, “Methane flux and stable hydrogen and carbon isotope composition of sedimentary methane from the Florida Everglades,” Global Biogeochem. Cycles 2, 329–340 (1988).
[CrossRef]

Camy-Peyret, C.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

L. S. Rothman, R. R. Gamache, A. Goldman, L. R. Brown, R. A. Toth, H. M. Pickett, R. L. Poynter, J.-M. Flaud, C. Camy-Peyret, A. Barbe, N. Husson, C. P. Rinsland, M. A. H. Smith, “The hitran database: 1986 edition,” Appl. Opt. 26, 4058–4097 (1987).
[CrossRef] [PubMed]

Chris Benner, D.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

Cicerone, R. J.

R. J. Cicerone, R. S. Oremland, “Biogeochemical aspects of atmospheric methane,” Global Biogeochem. Cycles 2, 299–327 (1988).
[CrossRef]

Coleman, D. D.

D. D. Coleman, J. B. Risatti, M. Schoell, “Fractionation of carbon and hydrogen isotopes by methane-oxidizing bacteria,” Geochim. Cosmochim. Acta 45, 1033–1037 (1981).
[CrossRef]

Craig, H.

H. Craig, “Isotopic standards for carbon and oxygen and correction factors for mass-spectrometric analysis of carbon dioxide,” Geochim. Cosmochim. Acta 12, 133–149 (1957).
[CrossRef]

Crutzen, P. J.

J. Lelieveld, P. J. Crutzen, C. Brühl, “Climate effects of atmospheric methane,” Chemosphere 26, 739–768 (1993).
[CrossRef]

M. Schupp, P. Bergamaschi, G. W. Harris, P. J. Crutzen, “Development of a tunable diode laser absorption spectrometer for measurements of the 13C/12C ratio in methane,” Chemosphere 26, 13–22 (1993).
[CrossRef]

Deck, B.

M. Wahlen, N. Tanaka, R. Henry, B. Deck, J. Zeglen, J. S. Vogel, J. Southon, A. Shemesh, R. Fairbanks, W. Broecker, “Carbon-14 in methane sources and in atmospheric methane: the contribution from fossil carbon,” Science 245, 286–290 (1989).
[CrossRef] [PubMed]

Dörr, H.

I. Levin, P. Bergamaschi, H. Dörr, D. Trapp, “Stable isotopic signature of methane from major sources in Germany,” Chemosphere 26, 161–177 (1993).
[CrossRef]

Drummond, J. R.

Dumke, I.

I. Dumke, E. Faber, J. Poggenburg, “Determination of stable carbon and hydrogen isotopes of light hydrocarbons,” Anal. Chem. 61, 2149–2154 (1989).
[CrossRef]

Engelkemeir, A.

C. M. Stevens, A. Engelkemeir, “Stable carbon isotopic composition of methane from natural and anthropogenic sources,” J. Geophys. Res. 93, 725–733 (1988).
[CrossRef]

Etheridge, D. M.

D. M. Etheridge, G. I. Pearman, P. J. Fraser, “Changes in tropospheric methane between 1841 and 1978 from a high accumulation-rate Antarctic ice core,” Tellus 44, 282–294 (1992).
[CrossRef]

Faber, E.

I. Dumke, E. Faber, J. Poggenburg, “Determination of stable carbon and hydrogen isotopes of light hydrocarbons,” Anal. Chem. 61, 2149–2154 (1989).
[CrossRef]

M. J. Whiticar, E. Faber, M. Schoell, “Biogenic methane formation in marine and freshwater environments: CO2 reduction vs. acetate fermentation—isotope evidence,” Geochim. Cosmochim. Acta 50, 693–709 (1986).
[CrossRef]

Fairbanks, R.

M. Wahlen, N. Tanaka, R. Henry, B. Deck, J. Zeglen, J. S. Vogel, J. Southon, A. Shemesh, R. Fairbanks, W. Broecker, “Carbon-14 in methane sources and in atmospheric methane: the contribution from fossil carbon,” Science 245, 286–290 (1989).
[CrossRef] [PubMed]

Farwell, G. W.

P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
[CrossRef]

Flaud, J.-M.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

L. S. Rothman, R. R. Gamache, A. Goldman, L. R. Brown, R. A. Toth, H. M. Pickett, R. L. Poynter, J.-M. Flaud, C. Camy-Peyret, A. Barbe, N. Husson, C. P. Rinsland, M. A. H. Smith, “The hitran database: 1986 edition,” Appl. Opt. 26, 4058–4097 (1987).
[CrossRef] [PubMed]

Fraser, P. J.

D. M. Etheridge, G. I. Pearman, P. J. Fraser, “Changes in tropospheric methane between 1841 and 1978 from a high accumulation-rate Antarctic ice core,” Tellus 44, 282–294 (1992).
[CrossRef]

Fried, A.

Fung, I.

P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
[CrossRef]

Gamache, R. R.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

L. S. Rothman, R. R. Gamache, A. Goldman, L. R. Brown, R. A. Toth, H. M. Pickett, R. L. Poynter, J.-M. Flaud, C. Camy-Peyret, A. Barbe, N. Husson, C. P. Rinsland, M. A. H. Smith, “The hitran database: 1986 edition,” Appl. Opt. 26, 4058–4097 (1987).
[CrossRef] [PubMed]

Gammon, R. H.

P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
[CrossRef]

Goldman, A.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

L. S. Rothman, R. R. Gamache, A. Goldman, L. R. Brown, R. A. Toth, H. M. Pickett, R. L. Poynter, J.-M. Flaud, C. Camy-Peyret, A. Barbe, N. Husson, C. P. Rinsland, M. A. H. Smith, “The hitran database: 1986 edition,” Appl. Opt. 26, 4058–4097 (1987).
[CrossRef] [PubMed]

Grootes, P. M.

P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
[CrossRef]

Hagemann, R.

R. Hagemann, G. Nief, E. Roth, “Absolute isotopic scale for deuterium analysis of natural waters, absolute D/H ratio for SMOW,” Tellus 22, 712–715 (1970).
[CrossRef]

Harris, G. W.

M. Schupp, P. Bergamaschi, G. W. Harris, P. J. Crutzen, “Development of a tunable diode laser absorption spectrometer for measurements of the 13C/12C ratio in methane,” Chemosphere 26, 13–22 (1993).
[CrossRef]

M. Schupp, P. Bergamaschi, G. W. Harris, “Measurements of the 13C/12C ratio in methane using a tunable diode laser absorption spectrometer,” in Monitoring of Gaseous Pollutants by Tunable Diode Lasers, R. Grisar, H. Böttner, M. Tacke, G. Restelli, eds. (Kiuwer, Dordrecht, The Netherlands, 1992), pp. 343–352.

Henry, B.

Henry, R.

M. Wahlen, N. Tanaka, R. Henry, B. Deck, J. Zeglen, J. S. Vogel, J. Southon, A. Shemesh, R. Fairbanks, W. Broecker, “Carbon-14 in methane sources and in atmospheric methane: the contribution from fossil carbon,” Science 245, 286–290 (1989).
[CrossRef] [PubMed]

Hermichen, W. D.

W. D. Hermichen, H. Schütze, “Zur Bedeutung der molekularen Diffusion für die Stoff- und Isotopentrennung bei der Bildung und Zerstörung von Erdgaslagerstätten,” Isotopenpraxis 23, 285–289 (1987).
[CrossRef]

Hinkley, E. D.

C. R. Webster, R. T. Menzies, E. D. Hinkley, “Infrared laser absorption: theory and applications,” in Laser Remote Chemical Analysis, R. M. Measures, ed. (Wiley, New York, 1988), pp. 163–272.

Hunt, R. H.

Husson, N.

Khalil, M. A. K.

R. A. Rasmussen, M. A. K. Khalil, “Atmospheric methane in the recent and ancient atmospheres: concentrations, trends, and interhemispheric gradient,” J. Geophys. Res. 89, 11599–11605 (1984).
[CrossRef]

King, S. L.

P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
[CrossRef]

Lee, P. S.

P. S. Lee, R. F. Majkowski, “High resolution infrared diode laser spectroscopy for isotope analysis—measurement of isotopic carbon monoxide,” Appl. Phys. Lett. 48, 619–621 (1986).
[CrossRef]

Lelieveld, J.

J. Lelieveld, P. J. Crutzen, C. Brühl, “Climate effects of atmospheric methane,” Chemosphere 26, 739–768 (1993).
[CrossRef]

Levin, I.

I. Levin, P. Bergamaschi, H. Dörr, D. Trapp, “Stable isotopic signature of methane from major sources in Germany,” Chemosphere 26, 161–177 (1993).
[CrossRef]

Loewenstein, M.

Lowe, D. C.

D. C. Lowe, C. A. M. Brenninkmeijer, “Determination of the isotopic composition of atmospheric methane and its application in the Antarctic,” J. Geophys. Res. 96, 15455–15467 (1991).
[CrossRef]

M. R. Manning, D. C. Lowe, W. Melhuish, R. Spaarks, G. Wallace, C. A. M. Brenninkmeijer, R. C. McGill, “The use of radiocarbon measurements in atmospheric studies,” Radio-carbon 32, 37–58 (1990).

Majkowski, R. F.

P. S. Lee, R. F. Majkowski, “High resolution infrared diode laser spectroscopy for isotope analysis—measurement of isotopic carbon monoxide,” Appl. Phys. Lett. 48, 619–621 (1986).
[CrossRef]

Malathy Devi, V.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

Manning, M. R.

M. R. Manning, D. C. Lowe, W. Melhuish, R. Spaarks, G. Wallace, C. A. M. Brenninkmeijer, R. C. McGill, “The use of radiocarbon measurements in atmospheric studies,” Radio-carbon 32, 37–58 (1990).

Massie, S. T.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

Mauersberger, K.

S. M. Anderson, J. Morton, K. Mauersberger, “Laboratory measurements of ozone isotopomers by tunable diode laser absorption spectroscopy,” Chem. Phys. Lett. 156, 175–180 (1989).
[CrossRef]

May, R. D.

C. R. Webster, R. D. May, “In situ stratospheric measurements of CH4, 13CH4, N2O, and OC18O using the BLISS tunable diode laser spectrometer,” Geophys. Res. Lett. 19, 45–48 (1992).
[CrossRef]

McGill, R. C.

M. R. Manning, D. C. Lowe, W. Melhuish, R. Spaarks, G. Wallace, C. A. M. Brenninkmeijer, R. C. McGill, “The use of radiocarbon measurements in atmospheric studies,” Radio-carbon 32, 37–58 (1990).

Melhuish, W.

M. R. Manning, D. C. Lowe, W. Melhuish, R. Spaarks, G. Wallace, C. A. M. Brenninkmeijer, R. C. McGill, “The use of radiocarbon measurements in atmospheric studies,” Radio-carbon 32, 37–58 (1990).

Menzies, R. T.

C. R. Webster, R. T. Menzies, E. D. Hinkley, “Infrared laser absorption: theory and applications,” in Laser Remote Chemical Analysis, R. M. Measures, ed. (Wiley, New York, 1988), pp. 163–272.

Morton, J.

S. M. Anderson, J. Morton, K. Mauersberger, “Laboratory measurements of ozone isotopomers by tunable diode laser absorption spectroscopy,” Chem. Phys. Lett. 156, 175–180 (1989).
[CrossRef]

Mroz, E. J.

E. J. Mroz, “Deuteromethanes: potential fingerprints of the sources of atmospheric methane,” Chemosphere 26, 45–53 (1993).
[CrossRef]

Nief, G.

R. Hagemann, G. Nief, E. Roth, “Absolute isotopic scale for deuterium analysis of natural waters, absolute D/H ratio for SMOW,” Tellus 22, 712–715 (1970).
[CrossRef]

Oremland, R. S.

R. J. Cicerone, R. S. Oremland, “Biogeochemical aspects of atmospheric methane,” Global Biogeochem. Cycles 2, 299–327 (1988).
[CrossRef]

Pearman, G. I.

D. M. Etheridge, G. I. Pearman, P. J. Fraser, “Changes in tropospheric methane between 1841 and 1978 from a high accumulation-rate Antarctic ice core,” Tellus 44, 282–294 (1992).
[CrossRef]

Perrin, A.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

Pickett, H. M.

Poggenburg, J.

I. Dumke, E. Faber, J. Poggenburg, “Determination of stable carbon and hydrogen isotopes of light hydrocarbons,” Anal. Chem. 61, 2149–2154 (1989).
[CrossRef]

Poynter, R. L.

Quay, P. D.

P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
[CrossRef]

Rasmussen, R. A.

R. A. Rasmussen, M. A. K. Khalil, “Atmospheric methane in the recent and ancient atmospheres: concentrations, trends, and interhemispheric gradient,” J. Geophys. Res. 89, 11599–11605 (1984).
[CrossRef]

Rinsland, C. P.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

L. S. Rothman, R. R. Gamache, A. Goldman, L. R. Brown, R. A. Toth, H. M. Pickett, R. L. Poynter, J.-M. Flaud, C. Camy-Peyret, A. Barbe, N. Husson, C. P. Rinsland, M. A. H. Smith, “The hitran database: 1986 edition,” Appl. Opt. 26, 4058–4097 (1987).
[CrossRef] [PubMed]

Risatti, J. B.

D. D. Coleman, J. B. Risatti, M. Schoell, “Fractionation of carbon and hydrogen isotopes by methane-oxidizing bacteria,” Geochim. Cosmochim. Acta 45, 1033–1037 (1981).
[CrossRef]

Roth, E.

R. Hagemann, G. Nief, E. Roth, “Absolute isotopic scale for deuterium analysis of natural waters, absolute D/H ratio for SMOW,” Tellus 22, 712–715 (1970).
[CrossRef]

Rothman, L. S.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

L. S. Rothman, R. R. Gamache, A. Goldman, L. R. Brown, R. A. Toth, H. M. Pickett, R. L. Poynter, J.-M. Flaud, C. Camy-Peyret, A. Barbe, N. Husson, C. P. Rinsland, M. A. H. Smith, “The hitran database: 1986 edition,” Appl. Opt. 26, 4058–4097 (1987).
[CrossRef] [PubMed]

R. A. Toth, L. R. Brown, R. H. Hunt, L. S. Rothman, “Line parameters of methane from 2385 to 3200 cm−1,” Appl. Opt. 20, 932–935 (1981).
[CrossRef] [PubMed]

Rowland, F. S.

D. R. Blake, F. S. Rowland, “Continuing worldwide increase in tropospheric methane, 1978 to 1987,” Science 239, 1129–1131 (1988).
[CrossRef] [PubMed]

Sackett, W. M.

R. A. Burke, T. R. Barber, W. M. Sackett, “Seasonal variations of stable hydrogen and carbon isotope ratios of methane in subtropical freshwater sediments,” Global Biogeochem. Cycles 6, 125–138 (1992).
[CrossRef]

R. A. Burke, T. R. Barber, W. M. Sackett, “Methane flux and stable hydrogen and carbon isotope composition of sedimentary methane from the Florida Everglades,” Global Biogeochem. Cycles 2, 329–340 (1988).
[CrossRef]

Sauke, T. B.

Schmidt, F. H.

P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
[CrossRef]

Schoell, M.

M. J. Whiticar, E. Faber, M. Schoell, “Biogenic methane formation in marine and freshwater environments: CO2 reduction vs. acetate fermentation—isotope evidence,” Geochim. Cosmochim. Acta 50, 693–709 (1986).
[CrossRef]

D. D. Coleman, J. B. Risatti, M. Schoell, “Fractionation of carbon and hydrogen isotopes by methane-oxidizing bacteria,” Geochim. Cosmochim. Acta 45, 1033–1037 (1981).
[CrossRef]

Schupp, M.

M. Schupp, P. Bergamaschi, G. W. Harris, P. J. Crutzen, “Development of a tunable diode laser absorption spectrometer for measurements of the 13C/12C ratio in methane,” Chemosphere 26, 13–22 (1993).
[CrossRef]

M. Schupp, P. Bergamaschi, G. W. Harris, “Measurements of the 13C/12C ratio in methane using a tunable diode laser absorption spectrometer,” in Monitoring of Gaseous Pollutants by Tunable Diode Lasers, R. Grisar, H. Böttner, M. Tacke, G. Restelli, eds. (Kiuwer, Dordrecht, The Netherlands, 1992), pp. 343–352.

M. Schupp, “Entwicklung und Demonstration einer laserspektroskopischen Methode zur Messung des Kohlenstoffisoto-penverhältnisses in Methan,” Ph.D. dissertation (Universität Mainz, Mainz, Germany, 1992).

Schütze, H.

W. D. Hermichen, H. Schütze, “Zur Bedeutung der molekularen Diffusion für die Stoff- und Isotopentrennung bei der Bildung und Zerstörung von Erdgaslagerstätten,” Isotopenpraxis 23, 285–289 (1987).
[CrossRef]

Shemesh, A.

M. Wahlen, N. Tanaka, R. Henry, B. Deck, J. Zeglen, J. S. Vogel, J. Southon, A. Shemesh, R. Fairbanks, W. Broecker, “Carbon-14 in methane sources and in atmospheric methane: the contribution from fossil carbon,” Science 245, 286–290 (1989).
[CrossRef] [PubMed]

Smith, M. A. H.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

L. S. Rothman, R. R. Gamache, A. Goldman, L. R. Brown, R. A. Toth, H. M. Pickett, R. L. Poynter, J.-M. Flaud, C. Camy-Peyret, A. Barbe, N. Husson, C. P. Rinsland, M. A. H. Smith, “The hitran database: 1986 edition,” Appl. Opt. 26, 4058–4097 (1987).
[CrossRef] [PubMed]

Southon, J.

M. Wahlen, N. Tanaka, R. Henry, B. Deck, J. Zeglen, J. S. Vogel, J. Southon, A. Shemesh, R. Fairbanks, W. Broecker, “Carbon-14 in methane sources and in atmospheric methane: the contribution from fossil carbon,” Science 245, 286–290 (1989).
[CrossRef] [PubMed]

Spaarks, R.

M. R. Manning, D. C. Lowe, W. Melhuish, R. Spaarks, G. Wallace, C. A. M. Brenninkmeijer, R. C. McGill, “The use of radiocarbon measurements in atmospheric studies,” Radio-carbon 32, 37–58 (1990).

Steele, L. P.

P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
[CrossRef]

Stevens, C. M.

C. M. Stevens, A. Engelkemeir, “Stable carbon isotopic composition of methane from natural and anthropogenic sources,” J. Geophys. Res. 93, 725–733 (1988).
[CrossRef]

Stutsman, J.

P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
[CrossRef]

Tanaka, N.

M. Wahlen, N. Tanaka, R. Henry, B. Deck, J. Zeglen, J. S. Vogel, J. Southon, A. Shemesh, R. Fairbanks, W. Broecker, “Carbon-14 in methane sources and in atmospheric methane: the contribution from fossil carbon,” Science 245, 286–290 (1989).
[CrossRef] [PubMed]

Tipping, R. H.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

Toth, R. A.

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

L. S. Rothman, R. R. Gamache, A. Goldman, L. R. Brown, R. A. Toth, H. M. Pickett, R. L. Poynter, J.-M. Flaud, C. Camy-Peyret, A. Barbe, N. Husson, C. P. Rinsland, M. A. H. Smith, “The hitran database: 1986 edition,” Appl. Opt. 26, 4058–4097 (1987).
[CrossRef] [PubMed]

R. A. Toth, L. R. Brown, R. H. Hunt, L. S. Rothman, “Line parameters of methane from 2385 to 3200 cm−1,” Appl. Opt. 20, 932–935 (1981).
[CrossRef] [PubMed]

Trapp, D.

I. Levin, P. Bergamaschi, H. Dörr, D. Trapp, “Stable isotopic signature of methane from major sources in Germany,” Chemosphere 26, 161–177 (1993).
[CrossRef]

Tyler, S. C.

S. C. Tyler, “The global methane budget,” in Microbial Production and Consumption of Greenhouse Gases: Methane, Nitrogen Oxides, and Halomethanes, J. E. Rogers, W. B. Whitman, eds. (American Society for Microbiology, Washington, D.C., 1991), pp. 7–38.

Vogel, J. S.

M. Wahlen, N. Tanaka, R. Henry, B. Deck, J. Zeglen, J. S. Vogel, J. Southon, A. Shemesh, R. Fairbanks, W. Broecker, “Carbon-14 in methane sources and in atmospheric methane: the contribution from fossil carbon,” Science 245, 286–290 (1989).
[CrossRef] [PubMed]

Wahlen, M.

M. Wahlen, “The global methane cycle,” Ann. Rev. Earth Planet. Sci. 21, 407–426 (1993).
[CrossRef]

M. Wahlen, N. Tanaka, R. Henry, B. Deck, J. Zeglen, J. S. Vogel, J. Southon, A. Shemesh, R. Fairbanks, W. Broecker, “Carbon-14 in methane sources and in atmospheric methane: the contribution from fossil carbon,” Science 245, 286–290 (1989).
[CrossRef] [PubMed]

M. Wahlen, T. Yoshinari, “Oxygen isotope ratios in N2O from different environments,” Nature (London) 313, 780–782 (1985).
[CrossRef]

Wallace, G.

M. R. Manning, D. C. Lowe, W. Melhuish, R. Spaarks, G. Wallace, C. A. M. Brenninkmeijer, R. C. McGill, “The use of radiocarbon measurements in atmospheric studies,” Radio-carbon 32, 37–58 (1990).

Webster, C. R.

C. R. Webster, R. D. May, “In situ stratospheric measurements of CH4, 13CH4, N2O, and OC18O using the BLISS tunable diode laser spectrometer,” Geophys. Res. Lett. 19, 45–48 (1992).
[CrossRef]

C. R. Webster, R. T. Menzies, E. D. Hinkley, “Infrared laser absorption: theory and applications,” in Laser Remote Chemical Analysis, R. M. Measures, ed. (Wiley, New York, 1988), pp. 163–272.

Whiticar, M. J.

M. J. Whiticar, “A geochemical perspective of natural gas and atmospheric methane,” Org. Geochem. 16, 531–547 (1990).
[CrossRef]

M. J. Whiticar, E. Faber, M. Schoell, “Biogenic methane formation in marine and freshwater environments: CO2 reduction vs. acetate fermentation—isotope evidence,” Geochim. Cosmochim. Acta 50, 693–709 (1986).
[CrossRef]

Wilbur, D. O.

P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
[CrossRef]

Wong, W. W.

W. W. Wong, “Comparison of infrared and mass-spectrometric measurements of carbon-13/carbon-12 ratios,” Int. J. Appl. Radiat. Isot. 36, 997–999 (1985).
[CrossRef] [PubMed]

Yoshinari, T.

M. Wahlen, T. Yoshinari, “Oxygen isotope ratios in N2O from different environments,” Nature (London) 313, 780–782 (1985).
[CrossRef]

Zeglen, J.

M. Wahlen, N. Tanaka, R. Henry, B. Deck, J. Zeglen, J. S. Vogel, J. Southon, A. Shemesh, R. Fairbanks, W. Broecker, “Carbon-14 in methane sources and in atmospheric methane: the contribution from fossil carbon,” Science 245, 286–290 (1989).
[CrossRef] [PubMed]

Anal. Chem. (1)

I. Dumke, E. Faber, J. Poggenburg, “Determination of stable carbon and hydrogen isotopes of light hydrocarbons,” Anal. Chem. 61, 2149–2154 (1989).
[CrossRef]

Ann. Rev. Earth Planet. Sci. (1)

M. Wahlen, “The global methane cycle,” Ann. Rev. Earth Planet. Sci. 21, 407–426 (1993).
[CrossRef]

Appl. Opt. (4)

Appl. Phys. Lett. (1)

P. S. Lee, R. F. Majkowski, “High resolution infrared diode laser spectroscopy for isotope analysis—measurement of isotopic carbon monoxide,” Appl. Phys. Lett. 48, 619–621 (1986).
[CrossRef]

Chem. Phys. Lett. (1)

S. M. Anderson, J. Morton, K. Mauersberger, “Laboratory measurements of ozone isotopomers by tunable diode laser absorption spectroscopy,” Chem. Phys. Lett. 156, 175–180 (1989).
[CrossRef]

Chemosphere (4)

M. Schupp, P. Bergamaschi, G. W. Harris, P. J. Crutzen, “Development of a tunable diode laser absorption spectrometer for measurements of the 13C/12C ratio in methane,” Chemosphere 26, 13–22 (1993).
[CrossRef]

I. Levin, P. Bergamaschi, H. Dörr, D. Trapp, “Stable isotopic signature of methane from major sources in Germany,” Chemosphere 26, 161–177 (1993).
[CrossRef]

E. J. Mroz, “Deuteromethanes: potential fingerprints of the sources of atmospheric methane,” Chemosphere 26, 45–53 (1993).
[CrossRef]

J. Lelieveld, P. J. Crutzen, C. Brühl, “Climate effects of atmospheric methane,” Chemosphere 26, 739–768 (1993).
[CrossRef]

Geochim. Cosmochim. Acta (3)

D. D. Coleman, J. B. Risatti, M. Schoell, “Fractionation of carbon and hydrogen isotopes by methane-oxidizing bacteria,” Geochim. Cosmochim. Acta 45, 1033–1037 (1981).
[CrossRef]

H. Craig, “Isotopic standards for carbon and oxygen and correction factors for mass-spectrometric analysis of carbon dioxide,” Geochim. Cosmochim. Acta 12, 133–149 (1957).
[CrossRef]

M. J. Whiticar, E. Faber, M. Schoell, “Biogenic methane formation in marine and freshwater environments: CO2 reduction vs. acetate fermentation—isotope evidence,” Geochim. Cosmochim. Acta 50, 693–709 (1986).
[CrossRef]

Geophys. Res. Lett. (1)

C. R. Webster, R. D. May, “In situ stratospheric measurements of CH4, 13CH4, N2O, and OC18O using the BLISS tunable diode laser spectrometer,” Geophys. Res. Lett. 19, 45–48 (1992).
[CrossRef]

Global Biogeochem. Cycles (4)

R. A. Burke, T. R. Barber, W. M. Sackett, “Methane flux and stable hydrogen and carbon isotope composition of sedimentary methane from the Florida Everglades,” Global Biogeochem. Cycles 2, 329–340 (1988).
[CrossRef]

R. A. Burke, T. R. Barber, W. M. Sackett, “Seasonal variations of stable hydrogen and carbon isotope ratios of methane in subtropical freshwater sediments,” Global Biogeochem. Cycles 6, 125–138 (1992).
[CrossRef]

R. J. Cicerone, R. S. Oremland, “Biogeochemical aspects of atmospheric methane,” Global Biogeochem. Cycles 2, 299–327 (1988).
[CrossRef]

P. D. Quay, S. L. King, J. Stutsman, D. O. Wilbur, L. P. Steele, I. Fung, R. H. Gammon, T. A. Brown, G. W. Farwell, P. M. Grootes, F. H. Schmidt, “Carbon isotopic composition of atmospheric CH4: fossil and biomass burning source strengths,” Global Biogeochem. Cycles 5, 25–47 (1991).
[CrossRef]

Int. J. Appl. Radiat. Isot. (1)

W. W. Wong, “Comparison of infrared and mass-spectrometric measurements of carbon-13/carbon-12 ratios,” Int. J. Appl. Radiat. Isot. 36, 997–999 (1985).
[CrossRef] [PubMed]

Isotopenpraxis (1)

W. D. Hermichen, H. Schütze, “Zur Bedeutung der molekularen Diffusion für die Stoff- und Isotopentrennung bei der Bildung und Zerstörung von Erdgaslagerstätten,” Isotopenpraxis 23, 285–289 (1987).
[CrossRef]

J. Geophys. Res. (3)

D. C. Lowe, C. A. M. Brenninkmeijer, “Determination of the isotopic composition of atmospheric methane and its application in the Antarctic,” J. Geophys. Res. 96, 15455–15467 (1991).
[CrossRef]

R. A. Rasmussen, M. A. K. Khalil, “Atmospheric methane in the recent and ancient atmospheres: concentrations, trends, and interhemispheric gradient,” J. Geophys. Res. 89, 11599–11605 (1984).
[CrossRef]

C. M. Stevens, A. Engelkemeir, “Stable carbon isotopic composition of methane from natural and anthropogenic sources,” J. Geophys. Res. 93, 725–733 (1988).
[CrossRef]

J. Quant. Spectrosc. Radiat. Transfer (1)

L. S. Rothman, R. R. Gamache, R. H. Tipping, C. P. Rinsland, M. A. H. Smith, D. Chris Benner, V. Malathy Devi, J.-M. Flaud, C. Camy-Peyret, A. Perrin, A. Goldman, S. T. Massie, L. R. Brown, R. A. Toth, “The hitran molecular database: editions of 1991 and 1992,” J. Quant. Spectrosc. Radiat. Transfer 48, 469–507 (1992).
[CrossRef]

Nature (London) (1)

M. Wahlen, T. Yoshinari, “Oxygen isotope ratios in N2O from different environments,” Nature (London) 313, 780–782 (1985).
[CrossRef]

Org. Geochem. (1)

M. J. Whiticar, “A geochemical perspective of natural gas and atmospheric methane,” Org. Geochem. 16, 531–547 (1990).
[CrossRef]

Radio-carbon (1)

M. R. Manning, D. C. Lowe, W. Melhuish, R. Spaarks, G. Wallace, C. A. M. Brenninkmeijer, R. C. McGill, “The use of radiocarbon measurements in atmospheric studies,” Radio-carbon 32, 37–58 (1990).

Science (2)

M. Wahlen, N. Tanaka, R. Henry, B. Deck, J. Zeglen, J. S. Vogel, J. Southon, A. Shemesh, R. Fairbanks, W. Broecker, “Carbon-14 in methane sources and in atmospheric methane: the contribution from fossil carbon,” Science 245, 286–290 (1989).
[CrossRef] [PubMed]

D. R. Blake, F. S. Rowland, “Continuing worldwide increase in tropospheric methane, 1978 to 1987,” Science 239, 1129–1131 (1988).
[CrossRef] [PubMed]

Tellus (2)

D. M. Etheridge, G. I. Pearman, P. J. Fraser, “Changes in tropospheric methane between 1841 and 1978 from a high accumulation-rate Antarctic ice core,” Tellus 44, 282–294 (1992).
[CrossRef]

R. Hagemann, G. Nief, E. Roth, “Absolute isotopic scale for deuterium analysis of natural waters, absolute D/H ratio for SMOW,” Tellus 22, 712–715 (1970).
[CrossRef]

Other (9)

S. C. Tyler, “The global methane budget,” in Microbial Production and Consumption of Greenhouse Gases: Methane, Nitrogen Oxides, and Halomethanes, J. E. Rogers, W. B. Whitman, eds. (American Society for Microbiology, Washington, D.C., 1991), pp. 7–38.

Usually the stable isotope ratios are expressed in the δ notationδ=(RsampleRstandard-1)1000(‰),where Rsample, Rstandard are the 13C/12C (or D/H, i.e., 2H/1H) ratios of the sample and a standard, respectively. Generally the PeeDee Belemnite (PDB) standard is used for 13C/12C ratios,12 whereas D/H ratios are referenced to the standard mean ocean water (SMOW) standard.13

R. Bösinger, “Isotopenmessungen an atmosphärischem und quellnahem Methan,” Ph.D. dissertation (Universität Heidelberg, Heidelberg, Germany, 1990).

P. Bergamaschi, “Messungen der 13CH4/12CH4- und 12CH3D/12CH4-Verhältnisse an Proben atmosphärischer Methanquellen mittels Diodenlaserabsorptionsspektrospkopie,” Ph.D. dissertation (Universität Heidelberg, Heidelberg, Germany, 1993).

We define the mean deviation Δδ 13C (ΔδD) asΔδ={1n∑i=1n[δMS(i)-δTDLAS(i)]2}1/2.This provides a better measure of the comparison than the slopes and intercepts of the regression lines, which in all cases were insignificantly different from unity and zero.

M. Schupp, “Entwicklung und Demonstration einer laserspektroskopischen Methode zur Messung des Kohlenstoffisoto-penverhältnisses in Methan,” Ph.D. dissertation (Universität Mainz, Mainz, Germany, 1992).

M. Schupp, P. Bergamaschi, G. W. Harris, “Measurements of the 13C/12C ratio in methane using a tunable diode laser absorption spectrometer,” in Monitoring of Gaseous Pollutants by Tunable Diode Lasers, R. Grisar, H. Böttner, M. Tacke, G. Restelli, eds. (Kiuwer, Dordrecht, The Netherlands, 1992), pp. 343–352.

C. R. Webster, R. T. Menzies, E. D. Hinkley, “Infrared laser absorption: theory and applications,” in Laser Remote Chemical Analysis, R. M. Measures, ed. (Wiley, New York, 1988), pp. 163–272.

The subscript indicates the measurement method: mass spectrometry (MS) or TDLAS; the superscript indicates the scale to which the δ values are referred (PDB, SMOW, reference). The measured gas (sample, reference, calibration) is identified within the parentheses.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (8)

Fig. 1
Fig. 1

FTIR spectra from 2800 to 3200 cm−1 (resolution 0.02 cm−1). Top, CH4 at natural isotopic composition (i.e., ~98.8% 12CH4); middle, 13CH4; bottom, 12CH3D.

Fig. 2
Fig. 2

TDLAS spectra. Top, natural CH413C = −27.8‰); bottom, pure 13CH4. Possible 13CH4/12CH4 line pairs are indicated by the arrows.

Fig. 3
Fig. 3

Optical setup of the TDLAS instrument. See text for abbreviations.

Fig. 4
Fig. 4

δ 13C measurement at the 3007.145-cm−1/3007.078-cm−1 (12CH4) line pair: simultaneously recorded 2f spectra of (middle) a sample and (bottom) the reference gas (ref). The fits carried out according to Eqs. (2) and (3) are also shown in the sample spectrum, with the vertical lines marking the corresponding fit boundaries. However, at the scale used in the figure the fits cannot be distinguished from the recorded spectrum; the residuals of the fits are shown at the top (scale × 10).

Fig. 5
Fig. 5

Direct (modulation-broadened) absorption spectrum (sample), recorded simultaneously with the 2f spectra shown in Fig. 4. A parabolic fit is laid through three spectral intervals (marked by the vertical lines). The arrows indicate the derived total laser power at the (2f) line centers.

Fig. 6
Fig. 6

Illustration of the automated White-cell-filling procedure.

Fig. 7
Fig. 7

Intercomparison between TDLAS and MS; δ13C measurements for various samples from natural wetlands and landfills. The mean deviation is Δδ13C = 0.44‰.

Fig. 8
Fig. 8

Intercomparison between TDLAS and MS δD measurements for various landfill and natural gas samples (n = 5); the mean deviation is.ΔδD = 5.1‰. In addition, the intercomparison between TDLAS measurements with the two different standard 12CH3D/12CH4 line pairs is shown; the mean deviation is Δ.δD = 2.6‰. A is the line pair at 3042.345 cm−1/3042.221 cm−1, and B is the line pair at 3044.289 cm−1/3044.170 cm−1.

Tables (3)

Tables Icon

Table 1 13CH4 Line Pairs of Comparable Intensities (from hitran 92a)

Tables Icon

Table 2 12CH3D/12CH4 Line Pairs (from hitran 92)

Tables Icon

Table 3 Two Examples of 13CH4/12CH4 Line Pairs from the R Brancha (from hitran 92b)

Equations (11)

Equations on this page are rendered with MathJax. Learn more.

Δ δ Δ T Δ E k T 2 1000 ( ) ,
spec sample ( i ) = a 0 spec ref ( i ) + a 1 + a 2 i ,
spec sample ( i ) = b 0 spec ref ( i ) + b i + b 2 i .
δ = ( b 0 a 0 γ - 1 ) 1000 ,
γ = ( p sample ( i 16 ) - z sample ) [ p ref ( i 17 ) - z ref ] [ p sample ( i 17 ) - z sample ) [ p ref ( i 16 ) - z ref ] ,
Δ I I 0 = 1 - exp ( - od ) = od - 1 2 od 2 + 1 6 od 3 - + .
m = m ref l ref l WC p total , WC p sample , WC p total , ref p total , WC ln [ 1 - ( Δ I / I 0 ) WC ] ln [ 1 - ( Δ I / I 0 ) ref ] β ,
α = δ MS PDB / SMOW ( cal ) - δ MS PDB / SMOW ( ref ) δ TDLAS ref ( cal ) [ 1 + δ MS PDB / SMOW ( ref ) 1000 ] .
δ TDLAS PDB / SMOW ( sample ) = δ MS PDB / SMOW ( ref ) + α [ 1 + δ MS PDB / SMOW ( ref ) 1000 ] × δ TDLAS ref ( sample ) .
δ = ( R sample R standard - 1 ) 1000 ( ) ,
Δ δ = { 1 n i = 1 n [ δ MS ( i ) - δ TDLAS ( i ) ] 2 } 1 / 2 .

Metrics