Measurements of the carbon and hydrogen isotopes of atmospheric methane at Izaña, Tenerife: Seasonal cycles and synoptic‐scale variations

Bergamaschi, P.; Bräunlich, Maya; Marik, Thomas; Brenninkmeijer, Carl A. M.

doi:10.1029/1999jd901176

Cited by 82 publications

(130 citation statements)

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“…The calculated atmospheric values can be compared with the current, global measured atmospheric measured values for d 13 CH 4 of K47.1‰ (Miller et al 2002) and dD-CH 4 of K86‰ (Whalen 1993;Quay et al 1999;Bergamaschi et al 2000). The difference between the measured atmospheric and calculated atmospheric estimates is relatively small for d 13 CH 4 (0.3‰), but larger (9‰) for dD-CH 4 .…”

Section: Source-sink Components Of Modern Global Methane Inventorymentioning

confidence: 96%

Constraining past global tropospheric methane budgets with carbon and hydrogen isotope ratios in ice

Whiticar

Schaefer

2007

Phil. Trans. R. Soc. A.

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Upon closer inspection, the classical view of the synchronous relationship between tropospheric methane mixing ratio and Greenland temperature observed in ice samples reveals clearly discernable variations in the magnitude of this response during the Late Pleistocene (!50 kyr BP). During the Holocene this relationship appears to decouple, indicating that other factors have modulated the methane budget in the past 10 kyr BP. The d 13 CH 4 and dD-CH 4 of tropospheric methane recorded in ice samples provide a useful constraint on the palaeomethane budget estimations. Anticipated changes in palaeoenvironmental conditions are recorded as changes in the isotope signals of the methane precursors, which are then translated into past global d 13 CH 4 and dD-CH 4 signatures. We present the first methane budgets for the late glacial period that are constrained by dual stable isotopes. The overall isotope variations indicate that the Younger Dryas ( YD) and Preindustrial Holocene have methane that is 13 C-and 2 H-enriched, relative to Modern. The shift is small for d 13 CH 4 (approx. 1‰) but greater for dD-CH 4 (approx. 9‰). The YD d 13 CH 4 -dD-CH 4 record shows a remarkable relationship between them from 12.15 to 11.52 kyr BP. The corresponding C-and H-isotope mass balances possibly indicate fluctuating emissions of thermogenic gas. This d 13 CH 4 -dD-CH 4 relationship breaks down during the YD-Preboreal transition. In both age cases, catastrophic releases of hydrates with Archaeal isotope signatures can be ruled out. Thermogenic clathrate releases are possible during the YD period, but so are conventional natural gas seepages.

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Section: Source-sink Components Of Modern Global Methane Inventorymentioning

confidence: 96%

Constraining past global tropospheric methane budgets with carbon and hydrogen isotope ratios in ice

Whiticar

Schaefer

2007

Phil. Trans. R. Soc. A.

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“…Sample air is measured against reference air that is processed in the GC-IRMS system in the same manner as a sample. The IMAU δ 13 C-CH 4 standard scale is based on a set of assigned values for 13 firn air samples measured at Max Planck Institute for Chemistry (MPIC;Bräunlich et al, 2001) and they are ultimately referenced to a CO 2 gas produced from NBS-19 (Röckmann, 1998;Bergamaschi et al, 2000). The δD-CH 4 standard scale is based on a set of reference gases originally produced at the MPIC (see Sect.…”

Section: Imaumentioning

confidence: 99%

“…The MPIC has reported δ 13 C-CH 4 and δD-CH 4 measurements at a baseline station (Bergamaschi et al, 2000) and for firn air samples (Bräunlich et al, 2001) based on an offline DI-IRMS measurement for δ 13 C-CH 4 (Bergamaschi et al, 2000) and a tunable diode laser-based absorption spectrometer (TDLAS) for δD-CH 4 (Bergamaschi et al, 1994). Some firn air measurements by Bräunlich et al (2001) were performed by using a GC-IRMS system at the Laboratory of Glaciology and Geophysics of the Environment.…”

Section: Mpicmentioning

confidence: 99%

“…3.2, the δ 13 C-CH 4 and δD-CH 4 standard scales of MPIC are based on that of IMAU. For the δ 13 C-CH 4 DI-IRMS measurement, the CH 4 -derived CO 2 was measured against a working standard (pure CO 2 ) that was calibrated against NBS-19 on a DI-IRMS system (Röckmann, 1998;Bergamaschi et al, 2000). The MPIC δD-CH 4 scale is based on measurements of standard gases at the Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover, Germany.…”

Section: Mpicmentioning

confidence: 99%

“…3 and Table 1). Besides analysis by mass spectrometry, laser-based spectroscopy has also been developed for atmospheric δ 13 C-CH 4 and δD-CH 4 measurements (Bergamaschi et al, 2000;Eyer et al, 2016), but detailed discussion on the technique is beyond the scope of this study.…”

Section: Introductionmentioning

confidence: 99%

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Interlaboratory comparison of δ13C and δD measurements of atmospheric CH4 for combined use of data sets from different laboratories

et al. 2018

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Abstract. We report results from a worldwide interlaboratory comparison of samples among laboratories that measure (or measured) stable carbon and hydrogen isotope ratios of atmospheric CH 4 (δ 13 C-CH 4 and δD-CH 4 ). The offsets among the laboratories are larger than the measurement reproducibility of individual laboratories. To disentangle plausible measurement offsets, we evaluated and critically assessed a large number of intercomparison results, some of which have been documented previously in the literature. The results indicate significant offsets of δ 13 C-CH 4 and δD-CH 4 measurements among data sets reported from different laboratories; the differences among laboratories at modern atmospheric CH 4 level spread over ranges of 0.5 ‰ for δ 13 C-CH 4 and 13 ‰ for δD-CH 4 . The intercomparison results summarized in this study may be of help in future attempts to harmonize δ 13 C-CH 4 and δD-CH 4 data sets fromPublished by Copernicus Publications on behalf of the European Geosciences Union. 1208T. Umezawa et al.: Interlaboratory comparison of δ 13 C and δD measurements of CH 4 different laboratories in order to jointly incorporate them into modelling studies. However, establishing a merged data set, which includes δ 13 C-CH 4 and δD-CH 4 data from multiple laboratories with desirable compatibility, is still challenging due to differences among laboratories in instrument settings, correction methods, traceability to reference materials and long-term data management. Further efforts are needed to identify causes of the interlaboratory measurement offsets and to decrease those to move towards the best use of available δ 13 C-CH 4 and δD-CH 4 data sets.

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Gas transport properties of 6FDA‐durene/1,3‐phenylenediamine (mPDA) copolyimides

Chung

Lin

Vora

2001

J of Applied Polymer Sci

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ABSTRACT:The gas transport properties of He, H 2 , O 2 , N 2 , and CO 2 for 6FDA-durene, 6FDA-mPDA, and their copolyimides have been investigated as a function of the composition, pressure, and temperature. The permeabilities, diffusion coefficients, and solubility coefficients follow the simple additional rules and Arrihenuis relationships for 6FDA-durene/mPDA polyimides. The permeability decreases with an increase in pressure except He, and in the kinetic diameters of the penetrant molecules with the order of He, CO 2 , O 2 , and N 2 . The diffusion coefficients of O 2 , N 2 , and CO 2 increase with increasing pressure and temperature. Interestingly, for these polyimides, the diffusion coefficient of O 2 is larger than that of CO 2 . This may be caused by the strong quadrupole moment of the CO 2 molecules or the difficulty in estimating the accurate diameter of CO 2 molecules. The solubility coefficients decrease in the order of inherent condensability of the penetrant gases, namely CO 2 , O 2 , and N 2 . In addition, WAXD results show that 6FDA-durene/mPDA polyimides are amorphous. The presence of a single glass transition temperature for these copolyimides indicates that these polyimides can be assumed to be random copolymers. They have excellent thermal stability exhibiting degradation temperature in a range of 493 to 548°C.

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Measurements of the carbon and hydrogen isotopes of atmospheric methane at Izaña, Tenerife: Seasonal cycles and synoptic‐scale variations

Cited by 82 publications

References 61 publications

Constraining past global tropospheric methane budgets with carbon and hydrogen isotope ratios in ice

Constraining past global tropospheric methane budgets with carbon and hydrogen isotope ratios in ice

Interlaboratory comparison of <i>δ</i><sup>13</sup>C and <i>δ</i>D measurements of atmospheric CH<sub>4</sub> for combined use of data sets from different laboratories

Gas transport properties of 6FDA‐durene/1,3‐phenylenediamine (mPDA) copolyimides

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Measurements of the carbon and hydrogen isotopes of atmospheric methane at Izaña, Tenerife: Seasonal cycles and synoptic‐scale variations

Cited by 82 publications

References 61 publications

Constraining past global tropospheric methane budgets with carbon and hydrogen isotope ratios in ice

Constraining past global tropospheric methane budgets with carbon and hydrogen isotope ratios in ice

Interlaboratory comparison of &lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;13&lt;/sup&gt;C and &lt;i&gt;δ&lt;/i&gt;D measurements of atmospheric CH&lt;sub&gt;4&lt;/sub&gt; for combined use of data sets from different laboratories

Gas transport properties of 6FDA‐durene/1,3‐phenylenediamine (mPDA) copolyimides

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Interlaboratory comparison of <i>δ</i><sup>13</sup>C and <i>δ</i>D measurements of atmospheric CH<sub>4</sub> for combined use of data sets from different laboratories