Yukio Terao

Earth System Division, National Institute for Environmental Studies (NIES)

NIES

Email: cgerdb_admin(at)nies.go.jp

Elevation: 30 m

Sampling height: 8 m above ground

Flask samples were collected from June 2012 in Comilla, Bangladesh. Inlets were mounted at 8 m above ground level (on top of the 5 m tower on the roof of the one-storey weather station building) in CLA. Air samples were collected once a week (usually on Wednesdays) at 14:00 LT into a 1.5 L Pyrex flask with two stopcocks sealed with Viton O-rings via a sampling line. The sampling line contained a diaphragm pump and a freezer for dehumidification by a glass trap. The sampling flow rate was approximately 2 L min⁻¹, and the sample was passed through a −30 ℃ cooler and pressurized to 0.25 MPa after 10 min flushing through the sampling tube and flask. The sampled flasks were packed in a cardboard box and transported to the laboratory of the Center for Global Environmental Research (CGER), National Institute for Environmental Studies, Japan (NIES) (transportation period: 3–7 d), for analyses.

After the mole fraction analysis, we used the remaining air inside the flask for analysis of δ13C-CO₂ and δ18O-CO₂. The air was introduced into two traps sequentially (−100 and −197 ℃), which trapped H₂O and CO₂, respectively. Finally, CO₂ was sealed in a glass tube. Air δ13C-CO₂ and δ18O-CO₂ were measured by MT-252 using the working standard CO₂ gas which was prepared in our laboratory.

The sample was injected into the analytical system 3 times per one sample, and the working standard gases were analyzed after every 6 samples. Values of δ13C-CO₂ and δ18O-CO₂ were reported against the VPDB scale using working standard gases which were calibrated with the NIES Atmospheric Reference CO₂ for Isotopic Studies (NARCIS).

[GCMD_Platform]

In Situ Land-based Platforms > Ground Stations

[GCMD_Science]

Atmosphere > Atmospheric Chemistry > Carbon and Hydrocarbon Compounds > Atmospheric Carbon Dioxide

[Free keywords]

Comilla, Bangladesh, Indo-Gangetic Plain, Paddies field, Oxygen Isotopic Ratio of Carbon Dioxide, NIES, Flask sampling

[2022/03/01]

Dataset was created. ver.2022.0.

Hitoshi Mukai

Center for Climate Change Adaptation, NIES

Yukio Terao

Earth System Division, NIES

Shohei Nomura^*1, Toshinobu Machida^*1, Motoki Sasakawa^*1, M. Kawser Ahmed^*2, Prabir K. Patra^*3

^*1 Earth System Division, NIES
^*2 University of Dhaka
^*3 Research Institute for Global Change, JAMSTEC

CC BY 4.0 (Creative Commons Attribution 4.0 International)

When this data set is referred to in publications, it should be cited in the following format.

Terao, Y., Nomura, S., Mukai, H., Machida, T., Sasakawa, M., Ahmed, M. K., and Patra, P. K. (2022), Oxygen Isotopic Ratio (O18/O16) of Carbon Dioxide at Comilla, Bangladesh, ver.xxxx.x ^*1, NIES, DOI:10.17595/20220301.016. (Reference date^*2: YYYY/MM/DD)

^*1 The version number is indicated in the data file.

^*2 As the reference date, please indicate the date you downloaded the files.

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