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The present data set is a set of continuous observational data of background CO2 mixing ratios in the vicinity of 20°N in the Western Pacific Ocean facing East Asia, measured on Hateruma Island, Okinawa Prefecture, Japan. Hateruma Island is a small island with a diameter of approx. 5 km. Because it is subjected to very small influence from local terrestrial ecosystem and/or anthropogenic CO2 emissions, the daily variations are small and the CO2 mixing ratios observed here can therefore be regarded as representative of the sub-tropics in the East Asian region. The Hateruma data reflects the influence from the Pacific Ocean in summer and from the Asian continent in winter, located downwind from each region, respectively.
Description
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Supervisor
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Release date
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2014/05/19
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Temporal coverage
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1993/01/01 - 2022/12/31
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Data provider
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NIES
Email: cgerdb_admin(at)nies.go.jp |
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DOI
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File format
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Data volume
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13.2MB
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Version
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Ver.1.5 (Last updated: 2023/06/30)
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Language
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English
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Data Set
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Parameters
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CO2 mixing ratios
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Time resolution
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1 hour (60 minutes preceding the hour)
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Precision
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0.05 ppm
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Observation period
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From 1993 (ongoing)
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Location
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24.06069°N, 123.80939°E
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Altitude
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Elevation: 10m;
Sampling height: 37m above ground Altitude: 47m |
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Measurement method
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Air is sampled at a height of 37 m above ground by a sampling inlet mounted on a steel monitoring tower through a stainless tube to a ground-based observation room using a diaphragm pump. The sampled air is led into a measuring line where it goes through primary dehumidification at -45 °C and secondary dehumidification at -70 °C, after which the mixing ratios are determined using a measuring equipment (NDIR).
Every 3 hours, 4 cylinders of standard gases are measured and the CO2 mixing ratios are calibrated. Calibration of the standard gases is carried out using the NIES09 standard gas series developed by NIES. Please refer to the webpage "GHGs Monitoring at Hateruma Island and Cape Ochi-ishi" for pictures of the measuring equipment. |
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Calculation method
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First, CO2 mixing ratio values measured at 1-second intervals are averaged over 5 seconds, and then 12 such 5-second averages are averaged to produce an average mixing ratio value over a 1-minute period. The hourly values are then calculated by averaging all the 1-minute values in that hour.
The calibrated CO2 mixing ratio values are the time-weighted average values calculated from the calibration curve right before and after the measurements. |
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Keywords
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[GCMD_Platform]
In Situ Land-based Platforms > GROUND STATIONS
[GCMD_Science]
Atmosphere > Atmospheric Chemistry > Carbon and Hydrocarbon Compounds > Carbon Dioxide
[Free keywords]
Greenhouse gases, carbon dioxide, CO2, global warming, Hateruma, continuous observations, infrared analyzer
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Update history
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[2023/06/30]
A new data set for the period between November 2022 and December 2022 has been added. Ver.1.5.
[2023/02/08]A new data set of the period between October 2020 and October 2022 has been added. Supplementary dataset Ver.1.4 is identical to the previous version (Ver.1.2). Ver. 1.4.
[2021/11/09]A new data set of the CO2 measured by for the NDIR for the period between May 2020 and September 2021 has been added. Supplementary dataset Ver.1.3 is identical to the previous version (Ver.1.2). Ver. 1.3.
[2020/10/09]A new data set for the period between January 2014 and April 24, 2020 has been added. Since the CO2 data weren't often obtained due to the malfunction of the NDIR after December 2019, the CO2 data after December 2019 measured by a cavity ring-down spectroscopy (CRDS) analyzer have been added as a supplementary data set. Ver.1.2.
[2016/09/01]A new data set for the period between January 2011 and December 2013 has been added. The data between January 2008 and December 2013 have been corrected for biases. (The biases are arisen from a decrease in mixing ratios due to the use of copper pipes in the measurement equipment. The correction has been made using a function based on the difference with respect to the time series from bottled samples). The Conditions and Terms of Use have been revised as well. Ver.1.1.
[2013/07/26]The data from 1993 to 2010 have been compiled in NASA Ames Format 1001. Ver.1.0.
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Contributors
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Project manager
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Data manager
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Shigeru Hashimoto (*1), Keiichi Katsumata (*1), Toshinobu Machida (*1), Noritsugu Tsuda(*2)
(*1) CGER, NIES (*2) Global Environmental Forum |
Reference Information
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Supplementary data set
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References
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Zeng, JY, Nakajima, H., Matsunaga, T., Mukai, H., Hiraki, K., Yokota, Y. (2012), Linking Carbon Dioxide Variability at Hateruma Station to East Asia Emissions by Bayesian Inversion, Lagrangian Modeling of the Atmosphere (edited by Lin, J., Brunner, D., Gerbig, C., Stohl, A., Luhar, A., Webley, P.), Geophysical Monograph Series, 200, 163-172, doi:10.1029/2012GM001245.
Tohjima, Y., Mukai, H., Hashimoto, S., Patra, PK. (2010), Increasing synoptic scale variability in atmospheric CO2 at Hateruma Island associated with increasing East-Asian emissions, Atmos. Chem. Phys., 10, 453-462, doi:10.5194/acp-10-453-2010.
Mukai, H., Katsumoto, M., Ide, R., Machida, T., Fujinuma, Y., Nojiri,Y., Inagaki, M., Oda, N., Watai, T. (2001), Characterization of atmospheric CO2 observed at two-background air monitoring stations (Hateruma and Ochi-ishi) in Japan, Sixth International Carbon Dioxide Conference Extend Abstract, 1, 108-111, Organizing Committee of Sixth International Carbon Dioxide Conference, Sendai, Japan.
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Terms and Conditions of Use*
*By accessing or using the Service you agree to be bound by these Terms. If you disagree with any part of the terms then you may not access the Service.
The author of this data set (hereafter "Author") agrees to the use of this data set by person(s) wishing to use the data (hereafter "User") as stipulated in the Terms and Conditions below.
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Scope of consent
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The User may re-distribute the data to third party without any change or transformation of the data, and may publish new intellectual products (hereafter "Products") based on this data set.
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Conditions for distribution
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The User shall not accept any compensation for the re-distribution of the data of this data set to a third party.
In the event that the User re-distributes the data of this data set to a third party, the same Terms and Conditions apply also to the re-distributed data set. When the User re-distributes the data of this data set to a third party, the User is obliged to inform the third party about the URL of the original data set, the Terms and Conditions of Use, and the fact that the data set is continuously updated by the Author. |
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Use of the latest version
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Unless special reason exists, the User shall use the latest version of this data set.
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Citation policy
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When publishing any Products based on the present data set, it must be clearly stated that the present data set was used.
However, the Author may request the User to delete the citation from the Product. In that case, the User shall comply with the request within reasonable extent. |
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Citation format
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When this data set is referred to in publications, it should, as a general rule, be made in the following format.
Mukai et al. (2014), Continuous observational data of atmospheric CO2 mixing ratios on Hateruma Island, Ver. x.x (*1), Center for Global Environmental Research, National Institute for Environmental Studies, DOI:10.17595/20160901.001. (Reference date: YYYY/MM/DD)(*2)
However, if the citation format is otherwise determined by the submission guidelines of the journal, the journal submission guidelines are to be followed.(*1) The version number is indicated in the name of each data file. (*2) As the reference date, please describe the date you downloaded the files. |
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Utilization reporting
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Re-distribution of the data or release of Products derived from the data set, shall be reported to the Data Provider without delay.
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Error reporting
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Any error in the data set, or the suspicion thereof, should be immediately reported to the Data Provider.
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Disclaimer
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The Author and the Data Provider shall not have any liability or responsibility whatsoever for any damage that may arise from the use of this data set, and the User must not imply that any guarantee is provided by the Author or the Data Provider. Any injury or loss arising from the use of this data set is solely the responsibility of the User.
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Advisory Service
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Advisory service
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If you need scientific advice or expert opinion regarding the contents or scientific validity of this data set or Products derived from it, we can provide an advisory service based on an individual contract, different from the above one.
Depending on the extent of the help required, we can offer collaboration and/or supervision of the work based on the present data set. If you want to use our advisory service, contact the Data Provider. |