発表論文

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

著者
Umezawa T., Brenninkmeijer C. A. M., Röckmann T., van der Veen C., Tyler S. C., Fujita R., Morimoto S., Aoki S., Sowers T., Schmitt J., Bock M., Beck J., Fischer H., Michel S. E., Bruce H. Vaughn B. H., Miller J. B., White J. W. C., Brailsford G., Schaefer H., Sperlich P., Brand W. A., Rothe M., Blunier T., Lowry D., Fisher R. E., Nisbet E. G., Rice A. L., Bergamaschi P., Veidt C., Levin I. (2018) Interlaboratory comparison of δ13C and δD measurements of atmospheric CH4 for combined use of data sets from different laboratories. Atmos. Meas. Tech., 11, 1207-1231, doi.org/10.5194/amt-11-1207-2018.
雑誌名
Atmos. Meas. Tech., 11, 1207-1231
DOI
10.5194/amt-11-1207-2018
概要

We report results from a worldwide inter-laboratory comparison of samples among laboratories that measure (or measured in the past) stable carbon and hydrogen isotope ratios of atmospheric CH413C-CH4 and δD-CH4). 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 δ13C-CH4 and δD-CH4 measurements among datasets reported from different laboratories; the differences among laboratories at modern atmospheric CH4 level spread over ranges of 0.5‰ for δ13C-CH4 and 13‰ for δD-CH4. The intercomparison results summarized in this study may be of help for future attempts to harmonize δ13C-CH4 and δD-CH4 datasets from different laboratories in order to jointly incorporate them into modelling studies. However, establishing such a merged dataset, which includes δ13C-CH4 and δD-CH4 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 inter- laboratory measurement offsets and to decrease those towards the best use of available δ13C-CH4 and δD-CH4 datasets.