Japan Meteorological Agency (JMA)
Methane Reference Gas Intercomparison in the 5th Round
In the 5th round intercomparison, the methane reference gases (Cylinder number: CPB13002, CPB13003) prepared in Japan in 2014 were circulated in the order of Asia (2014-2016), the South-West Pacific (2018) and Japan (2018-2019). The measurement results of the methane reference gases are summarized in Table 1.

Table 1. Results of Methane Reference Gas Intercomparison in the 5th Round

Laboratory and Location Date of
Measurement		 Cylinder No. CPB13002 Cylinder No. CPB13003 Scale Measu-
rement
Info
Mole
fraction (ppb)		 SD
(ppb)		 U
(ppb)		 N Mole
fraction (ppb)		 SD
(ppb)		 U
(ppb)		 N
Asia 2014-2016
JMA
Headquarters, Tokyo		 Jul. 2, 2014 1738.0 0.8 - 10 1897.2 1.0 - 10 WMO X2004A PDF
KMA
Anmyeon-do, Rep. of Korea		 Mar. 16, 2015 1738 0.48 - 1 1897.26 0.48 - 1 WMO X2004A PDF
IITM
Pune, India		 Jul. 14, 2015 to
Jan. 1, 2016		 1738 ** 31.67 - 4 1874 ** 2.61 - 5 WMO X2004A PDF
JMA
Headquarters, Tokyo		 Nov. 7, 2016 1738.3 1.9 - 10 1897.7 1.8 - 10 WMO X2004A PDF
South-West Pacific 2018
JMA
Headquarters, Tokyo		 Jan. 10, 2018 1738.31 0.03 0.09 5 1897.17 0.07 0.09 5 WMO X2004A Link
CSIRO
Aspendale, Australia		 Feb. 6, 2018 to
Mar. 05, 2018		 1737.69 2.48 0.29 138 1897.27 2.55 0.31 135 WMO X2004A
NIWA
Wellington, New Zealand		 Apr. 11, 2018 1736.85 1.27 0.40 37 1896.33 1.29 0.40 38 WMO X2004A
NOAA/ESRL(GC/FID)
Boulder, U.S.A.		 Jun. 15, 2018 to
Jul. 24, 2018		 1738.75 0.31 0.5 3 1901.25 0.54 0.5 4 WMO X2004A
NOAA/ESRL(CRDS)
Boulder, U.S.A.		 Jun. 27, 2018 to
Jul. 23, 2018		 1737.33 0.04 0.1 4 1896.96 0.04 0.1 4 WMO X2004A
JMA
Headquarters, Tokyo		 Sep. 5, 2018 1738.33 0.10 0.09 5 1897.09 0.05 0.09 5 WMO X2004A
Japan 2018-2019
JMA
Headquarters, Tokyo		 Sep. 5, 2018 1738.33 0.10 - 5 1897.09 0.05 - 5 WMO X2004A LINK
JAMSTEC
Yokosuka, Japan		 Oct. 18, 2018 to
Oct. 22, 2018		 1738.69 0.27 - 2 1897.35 0.30 - 2 WMO X2004A
TU
Sendai, Japan		 Nov. 23, 2018 to
Nov. 26, 2018		 1739.6 1.4 - 26 1898.5 2.3 - 28 TU 1987 scale
AIST
Tsukuba, Japan		 Dec. 18, 2018 to
Dec. 19, 2018		 1741.4 0.88 - 16 1899.9 1.52 - 17 AIST scale
NIES
Tsukuba, Japan		 Feb. 26, 2019 to
Mar. 4, 2019		 1739.85 0.93 - 17 1900.87 1.37 - 17 NIES 94 CH4 scale
MRI
Tsukuba, Japan		 Mar. 27, 2019 1739.3 0.1 - 3 1900.2 0.0 - 3 MRI scale
JMA
Headquarters, Tokyo		 Apr. 5, 2019 1738.34 0.03 - 5 1897.11 0.04 - 5 WMO X2004A
SD: Standard deviation; N: Number of measurements; U: Measurement uncertainty  
**: Reference value  

Table 2. Information on Participants

Participant (WEB Site) Country
Japan Meteorological Agency (JMA) Japan
China Meteorological Administration (CMA) China
Korea Meteorological Administration (KMA) Rep. of Korea
Indian Institute of Tropical Meteorology (IITM) India
Commonwealth Scientific and Industrial Research Organisation (CSIRO) Australia
National Institute of Water & Atmospheric Research Ltd. (NIWA) New Zealand
National Oceanic and Atmospheric Administration/Earth System Research Laboratory (NOAA/ESRL) U.S.A.
Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Japan
Tohoku University (TU) Japan
National Institute of Advanced Industrial Science and Technology (AIST) Japan
National Institute for Environmental Studies (NIES) Japan
Meteorological Research Institute (MRI) Japan