BibTex format
@article{Dasgupta:2025:10.5194/amt-18-6591-2025,
author = {Dasgupta, B and Menoud, M and van, der Veen C and Levin, I and Veidt, C and Moossen, H and Englund, Michel S and Sperlich, P and Morimoto, S and Fujita, R and Umezawa, T and Platt, S and Zwaaftink, CG and Myhre, CL and Fisher, R and Lowry, D and Nisbet, EG and France, J and Woolley, Maisch C and Brailsford, G and Moss, R and Goto, D and Pandey, S and Houweling, S and Warwick, N and Röckmann, T},
doi = {10.5194/amt-18-6591-2025},
journal = {Atmospheric Measurement Techniques},
pages = {6591--6607},
title = {Harmonisation of methane isotope ratio measurements from different laboratories using atmospheric samples},
url = {http://dx.doi.org/10.5194/amt-18-6591-2025},
volume = {18},
year = {2025}
}
RIS format (EndNote, RefMan)
TY - JOUR
AB - <jats:p>Abstract. Establishing interlaboratory compatibility among measurements of stable isotope ratios of atmospheric methane (δ13C-CH4 and δD-CH4) is challenging. Significant offsets are common because laboratories have different ties to the VPDB or SMOW-SLAP scales. Umezawa et al. (2018) surveyed numerous comparison efforts for CH4 isotope measurements conducted from 2003 to 2017 and found scale offsets of up to 0.5 ‰ for δ13C-CH4 and 13 ‰ for δD-CH4 between laboratories. This exceeds the World Meteorological Organisation Global Atmospheric Watch (WMO-GAW) network compatibility targets of 0.02 ‰ and 1 ‰ considerably. We employ a method to establish scale offsets between laboratories using their reported CH4 isotope measurements on atmospheric samples. Our study includes data from eight laboratories with experience in high-precision isotope ratio mass spectrometry (IRMS) measurements for atmospheric CH4. The analysis relies exclusively on routine atmospheric measurements conducted by these laboratories at high-latitude stations in the Northern and Southern Hemispheres, where we assume each measurement represents sufficiently well-mixed air at the latitude for direct comparison. We use two methodologies for interlaboratory comparisons: (I) assessing differences between time-adjacent observation data and (II) smoothing the observed data using polynomial and harmonic functions before comparison. The results of both methods are consistent, and with a few exceptions, the overall average offsets between laboratories align well with those reported by Umezawa et al. (2018). This indicates that interlaboratory offsets remain robust over multi-year periods. The evaluation of routine measurements allows us to calculate the interlaboratory offsets from hundreds, in some cases thousands of measurements. Therefore, the uncertainty in the mean inter
AU - Dasgupta,B
AU - Menoud,M
AU - van,der Veen C
AU - Levin,I
AU - Veidt,C
AU - Moossen,H
AU - Englund,Michel S
AU - Sperlich,P
AU - Morimoto,S
AU - Fujita,R
AU - Umezawa,T
AU - Platt,S
AU - Zwaaftink,CG
AU - Myhre,CL
AU - Fisher,R
AU - Lowry,D
AU - Nisbet,EG
AU - France,J
AU - Woolley,Maisch C
AU - Brailsford,G
AU - Moss,R
AU - Goto,D
AU - Pandey,S
AU - Houweling,S
AU - Warwick,N
AU - Röckmann,T
DO - 10.5194/amt-18-6591-2025
EP - 6607
PY - 2025///
SP - 6591
TI - Harmonisation of methane isotope ratio measurements from different laboratories using atmospheric samples
T2 - Atmospheric Measurement Techniques
UR - http://dx.doi.org/10.5194/amt-18-6591-2025
UR - https://doi.org/10.5194/amt-18-6591-2025
VL - 18
ER -