TY - JOUR
T1 - Intercomparison of O2/N2ratio scales among AIST, NIES, TU, and SIO based on a round-robin exercise using gravimetric standard mixtures
AU - Aoki, Nobuyuki
AU - Ishidoya, Shigeyuki
AU - Tohjima, Yasunori
AU - Morimoto, Shinji
AU - Keeling, Ralph F.
AU - Cox, Adam
AU - Takebayashi, Shuichiro
AU - Murayama, Shohei
N1 - Funding Information:
Financial support. This research has been supported by the
Funding Information:
Acknowledgements. We thank the Global Environmental Forum (GEF) staff for their work in collecting the air samples at the Hateruma station. Andrew Manning of the University of East Anglia coordinated the GOLLUM cylinder comparison program and supported the data acquisition. Our research has been financially supported by the Global Environmental Research Co-ordination System from Ministry of the Environment of Japan (METI1454, METI1953) and the JSPS KAKENHI under grant number 19K05554.
Publisher Copyright:
© 2021 Nobuyuki Aoki et al.
PY - 2021/9/24
Y1 - 2021/9/24
N2 - A study was conducted to compare the δ(O2/N2) scales used by four laboratories engaged in atmospheric δ(O2/N2) measurements. These laboratories are the Research Institute for Environmental Management Technology, Advanced Industrial Science and Technology (EMRI/AIST); the National Institute for Environmental Studies (NIES); Tohoku University (TU); and Scripps Institution of Oceanography (SIO). Therefore, five high-precision standard mixtures for the O2 molar fraction gravimetrically prepared by the National Metrology Institute of Japan, AIST (NMIJ/AIST) with a standard uncertainty of less than 5 per meg (0.001‰) were used as round-robin standard mixtures. EMRI/AIST, NIES, TU, and SIO reported the analyzed values of the standard mixtures on their own δ(O2/N2) scales, and the values were compared with the δ(O2/N2) values gravimetrically determined by NMIJ/AIST (the NMIJ/AIST scale). The δ(O2/N2) temporal drift in the five standard mixtures during the intercomparison experiment from May 2017 to March 2020 was corrected based on the δ(O2/N2) values analyzed before and after the laboratory measurements by EMRI/AIST. The scales are compared based on offsets in zero and span. The relative span offsets of EMRI/AIST, TU, NIES, and SIO scales against the NMIJ/AIST scale were-0.11%±0.10%,-0.10%±0.13%, 3.39%±0.13%, and 0.93%±0.10%, respectively. The largest offset corresponded to a 0.30Pgyr-1 decrease and increase in global estimates for land biospheric and oceanic CO2 uptakes based on trends in atmospheric CO2 and δ(O2/N2). The deviations in the measured δ(O2/N2) values on the laboratory scales from the NMIJ/AIST scale are 65.8±2.2, 425.7±3.1, 404.5±3.0, and 596.4±2.4 per meg for EMRI/AIST, TU, NIES, and SIO, respectively. The difference between atmospheric δ(O2/N2) values observed at Hateruma Island (HAT; 24.05 N, 123.81 E), Japan, by EMRI/AIST and NIES were reduced from-329.3±6.9 to-6.6±6.8 per meg by converting their scales to the NMIJ/AIST scale.
AB - A study was conducted to compare the δ(O2/N2) scales used by four laboratories engaged in atmospheric δ(O2/N2) measurements. These laboratories are the Research Institute for Environmental Management Technology, Advanced Industrial Science and Technology (EMRI/AIST); the National Institute for Environmental Studies (NIES); Tohoku University (TU); and Scripps Institution of Oceanography (SIO). Therefore, five high-precision standard mixtures for the O2 molar fraction gravimetrically prepared by the National Metrology Institute of Japan, AIST (NMIJ/AIST) with a standard uncertainty of less than 5 per meg (0.001‰) were used as round-robin standard mixtures. EMRI/AIST, NIES, TU, and SIO reported the analyzed values of the standard mixtures on their own δ(O2/N2) scales, and the values were compared with the δ(O2/N2) values gravimetrically determined by NMIJ/AIST (the NMIJ/AIST scale). The δ(O2/N2) temporal drift in the five standard mixtures during the intercomparison experiment from May 2017 to March 2020 was corrected based on the δ(O2/N2) values analyzed before and after the laboratory measurements by EMRI/AIST. The scales are compared based on offsets in zero and span. The relative span offsets of EMRI/AIST, TU, NIES, and SIO scales against the NMIJ/AIST scale were-0.11%±0.10%,-0.10%±0.13%, 3.39%±0.13%, and 0.93%±0.10%, respectively. The largest offset corresponded to a 0.30Pgyr-1 decrease and increase in global estimates for land biospheric and oceanic CO2 uptakes based on trends in atmospheric CO2 and δ(O2/N2). The deviations in the measured δ(O2/N2) values on the laboratory scales from the NMIJ/AIST scale are 65.8±2.2, 425.7±3.1, 404.5±3.0, and 596.4±2.4 per meg for EMRI/AIST, TU, NIES, and SIO, respectively. The difference between atmospheric δ(O2/N2) values observed at Hateruma Island (HAT; 24.05 N, 123.81 E), Japan, by EMRI/AIST and NIES were reduced from-329.3±6.9 to-6.6±6.8 per meg by converting their scales to the NMIJ/AIST scale.
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U2 - 10.5194/amt-14-6181-2021
DO - 10.5194/amt-14-6181-2021
M3 - Article
AN - SCOPUS:85116345011
SN - 1867-1381
VL - 14
SP - 6181
EP - 6193
JO - Atmospheric Measurement Techniques
JF - Atmospheric Measurement Techniques
IS - 9
ER -