Atmospheric CO2 mole fraction data of CONTRAIL-CME

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This data set contains CO2 mole fractions observed by Continuous CO2 Measuring Equipment (CME) onboard commercial aircraft under the CONTRAIL (Comprehensive Observation Network for TRace gases by AIrLiner) project. The project started in 2005 with two Boeing 747-400 aircraft and three 777-200ER aircraft operated by Japan Airlines (JAL) between Japan and Europe, Asia, Australia, Hawaii and North America. As of 2017, eight 777-200ER and two 777-300ER aircraft are used for the CME observation. The mole fraction values are obtained from 10-second average values of the CME signals for the ascending and descending portion of the flight and from 1-minute averages for the cruise.


Toshinobu Machida*1(ORCID iD, Kentaro Ishijima*2, Yosuke Niwa*1(ORCID iD, Kazuhiro Tsuboi*2, Yousuke Sawa*2,*3, Hidekazu Matsueda*2,*4, Motoki Sasakawa*1
*1 Earth System Division, National Institute for Environmental Studies (NIES)
*2 Meteorological Research Institute
*3 Now at Atmosphere and Ocean Department, Japan Meteorological Agency
*4 Dokkyo University
Release date
Temporal coverage
2005/11/05 - 2021/12/31
Data provider
Email: cgerdb_admin(at)
File format
Data volume
1.98 GB
ver.2023.1.0 (Last updated: 2023/07/25)
Publications using this dataset

Data Set

Atmospheric CO2 mole fraction
0.2 ppm
Observation period
From 2005 (ongoing)
Measurement method
Sample air is drawn by a diaphragm pump from an intake port connected to the air conditioning duct of the aircraft and introduced into an NDIR (LI-COR, LI-840) of the CME. Water vapor is removed from the sample air by a membrane dryer (Nafion Dryer) and magnesium perchlorate.
Calculation method
Sample air is continuously introduced to the NDIR except for time periods when the line is switched to standard gases. Two standard gases (CO2 in air), whose CO2 mole fractions are traceable to the NIES 09 scale, are introduced into the NDIR every 10-15 min during the ascent or descent portion of the flight and every 20-60 min during the cruise. The standard gases flow for 50 seconds and the last 10-second signals are averaged for the calculation. Sample air signals are averaged every 10 and 60 seconds for the ascent/descent and cruising portion of the flight, respectively. The CO2 mole fraction of sample air is calculated based on the signals of the standard gases taken before and after the sample signals. Sample measurements are corrected for the time lag of about 40 seconds between the intake of outside air and the measurement in the NDIR.
Aircraft > AIRCRAFT
Atmosphere > Atmospheric Chemistry > Carbon and Hydrocarbon Compounds > Carbon Dioxide
[Free keywords]
Carbon Dioxide, CO2, Aircraft, B747-400, B777-200ER, B777-300ER
Update history
Data are extended to the end of 2021. ver.2023.1.0.
Data are extended to the end of 2020. ver.2022.1.0.
Data are extended to the end of 2019. Motoki Sasakawa joined the creators. ver.2021.1.0.
Data of wind speed/direction and static air temperature are added. Data are extended to the end of 2017. Kentaro Ishijima and Kazuhiro Tsuboi joined the creators. ver.2020.1.0.
The data for 2016 are added. Some data are slightly modified by data review. ver.2019.1.0.
Data for 2005-2015 are released. ver.2017.1.0.


The observations of the CONTRAIL project are conducted under great support from Japan Airlines, JAMCO and the JAL Foundation. The CONTRAIL project has been financially supported by the research funds of the Global Environmental Research Coordination System (MOE0653, MOE1151, MOE1652, MOE2151) and the Environment Research and Technology Development Fund (JPMEERF20142001) from Ministry of the Environment of Japan.


Machida, T., H. Matsueda, Y. Sawa, Y. Nakagawa, K. Hirotani, N. Kondo, K. Goto, N. Nakazawa, K. Ishikawa and T. Ogawa (2008), Worldwide measurements of atmospheric CO2 and other trace gas species using commercial airlines, J. Atmos. Oceanic Technol., 25(10), 1744-1754, doi:10.1175/2008JTECHA1082.1.

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Citation format
When this data set is referred to in publications, it should be cited in the following format.
Machida, T., K. Ishijima, Y. Niwa, K. Tsuboi, Y. Sawa, H. Matsueda and M. Sasakawa (2018), Atmospheric CO2 mole fraction data of CONTRAIL-CME, ver.x.x.x *1, Center for Global Environmental Research, NIES, DOI:10.17595/20180208.001, (Reference date*2: YYYY/MM/DD)
*1 The version number is indicated in the name of each data file.
*2 As the reference date, please indicate the date you downloaded the files.
When generally referring to the CONTRAIL-CME CO2 data, please also cite Machida et al. (2008). Furthermore, the User is encouraged to cite relevant paper(s) listed at
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