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NO 48
Acronym MRI
Name Meteorological Research Institute
Address 1 Department of Climate and Geochemistry Research
Address 2 Meteorological Research Institute
Address 3 1-1 Nagamine, Tsukuba, 305-0052, Japan
Country/Territory Japan
Website https://www.mri-jma.go.jp/index_en.html


Name Kazuhiro Tsuboi
Prefix Mr.
Email ktsuboi@mri-jma.go.jp
Organization No 48
Organization acronym MRI
Organization name Meteorological Research Institute
Organization country/territory Japan
Address 1 1-1, Nagamine
Address 2 Tsukuba
Address 3 Ibaraki 305-0052
Country/territory Japan
Tel +81-29-853-8720
Fax +81-29-853-8728
Last updated date 2023-08-30

 Background observation
 9999-12-31 00:00:00 - 9999-12-31 23:59:59: Shimadzu
GC-14A equipped with an FID and a data processor Shimadzu C-R4A(Gas chromatography (FID))
 9999-12-31 00:00:00 - 9999-12-31 23:59:59: 1.5 (m)
 3 hours
 The accuracy of the concentrations of some reference gases was in the range of ±1.5%, which was certified by the Chemical Inspection & Testing Institute (Japan). Since August 1996, the accuracy of those has been in the range of ±1.0%, which has been certified by the manufacturer itself.
In 1991, both laboratories of MRI and NOAA/CMDL determined the concentration of CH4 in NOAA cylinder #30507, filled with dried natural air at Niwot Ridge in 1988. MRI determined the CH4 mixing ratio in dry air to be 1749.2 (±2.7) ppb, while NOAA/CMDL measured the same cylinder as 1731.6 (±1.3) ppb on the so-called "Rasmussen-scale". There is a small, but significant offset between the two calibration scales.
Mixed gases of 1.7-1.8 ppm CH4 in pure air (Takachiho) are used as the reference gas.
 Technically false values caused by malfunction of the equipment are removed. In cases where the peak area of a reference signal (110000-120000 arbitrary unit) differ from both former and latter ones exceeding 500 (0.4%), the data is rejected.
 The outdoor air is drawn at 1.5m above the ground into a gas sampling loop(10ml).
A reference gas and a sample air are measured in series. This set of measurements is repeated automatically in every three hours (2,5,8,11,14,17,20 and 23h). The sample air is dried by an electroic cooler and a tube filled with magnesium perchlorate (6-14 mesh). The sample size is 10ml. Methane is separated on a 1m Porapack N precut column and a 1m Active Carbon main column at 60 °C.
Seasonal variability and long-term trend. To obtain the long-term trend, monthly mean value is calculated from the daily minimum values or the values obtained at 14h. Around 14h, surface air is vertically well mixed on average, and the possibility of the direct pollution from local sources such as paddy field is rather small.

This dataset was submitted to WDCGG by Michio Hirota on 2007/11.
Dr. Hirota retired from Japan Meteorological Agency in 2008.
 Wind direction: 1
 Wind speed: 1
 Relative humidity: 1
 Precipitation amount: 0
 Air pressure: 0
 Air temperature: 1
 Dew point temperature: 0
 Sea water temperature: 0
 Sea surface water temperature: 0
 Sea water salinity: 0
 Sea surface water salinity: 0
Meteorological data may remain as first provided, even when greenhouse gas data are updated.
 The file was made using the former WDCGG data file.
No DOI available

 Related information

Format Text (WDCGG Data Format Table, WDCGG Meteorological Data Format Table), NetCDF
Relation List (Is Part Of) All CH4 data contributed to WDCGG by GAW stations and mobiles by 2023-09-13
All CH4 data contributed to WDCGG by GAW stations and mobiles by 2022-09-07
All CH4 data contributed to WDCGG by GAW stations and mobiles by 2021-08-27
All CH4 data contributed to WDCGG by GAW stations and mobiles by 2020-09-28
All CH4 data contributed to WDCGG by GAW stations and mobiles by 2019-09-19
All CH4 data contributed to WDCGG by GAW stations and mobiles by 2018-10-25
Geolocation Point
Latitude (north: +; south: -) 36.0581
Longitude (east: +; west: -) 140.1258

 GAW Data Policy

"For Scientific purposes, access to these data is unlimited and provided without charge. By their use you accept that an offer of co-authorship will be made through personal contact with the data providers or owners whenever substantial use is made of their data. In all cases, an acknowledgement must be made to the data providers or owners and to the data centre when these data are used within a publication."

 Citation format

This format is an example of the WDCGG standard citation.
Please follow the citation format which the data providers or owners indicate.
Kazuhiro Tsuboi (MRI), Atmospheric CH4 at Tateno (Tsukuba) by Meteorological Research Institute , dataset published as CH4_TKB_ surface-insitu_MRI_data1 at WDCGG, ver. 2021-10-15-1330 (Reference date*: YYYY/MM/DD)

* As the reference date, please indicate the date you downloaded the files.


1  Hirota, M., H. Muramatsu, Y. Makino, M. Ikegami, and K. Tsutsumi, 1989: Gas-chromatographic measurement of atmospheric methane in Japan, Atmos. Environ., 23, 1835-1839.
2  Hirota, M., T. Aoki, Y. Makino, and S. Murayama, 1991: Atmospheric methane concentration between Tokyo and Syowa Station, Antarctica, Bull. Chem. Soc. Japan, 1991, 358-360.