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1995 Fiscal Year Final Research Report Summary

DEVELOPMENT OF OPEN PATH METHANE SENSOR

Research Project

Project/Area Number 06558076
Research Category

Grant-in-Aid for Developmental Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field Environmental dynamic analysis
Research InstitutionOKAYAMA UNIVERSITY

Principal Investigator

OHTAKI Eiji  OKAYAMA UNIV.ENVIRON.SCI.AND TECH.PROFESSOR, 環境理工学部, 教授 (40033120)

Co-Investigator(Kenkyū-buntansha) TORIGOE Hiroshi  ADVANET CO.LTD,RESEARCHER, 研究開発部, 研究員
SAZAKI Susumu  ADVANET CO.LTD,PRINCIPAL RESEARCHER, 研究開発部, 主任研究員
TSUKAMOTO Osamu  OKAYAMA UNIV.SCIENCE,ASSOC.PROFESSOR, 理学部, 助教授 (40027298)
Project Period (FY) 1994 – 1995
KeywordsEDDY CORRELATION METHOD / AERODYNAMIC METHOD / METHANE / METHANE FLUX
Research Abstract

Methane is an important trace gas in the atmosphere because its high potential to absorb the outgoing longwave radiation. The absorbing potential is about 20 times that of carbon dioxide. It is well known that the methane concentration in the atmosphere is increasing. The major source of this increasing methane concentration has been assumed to be human activities associated with rice cultivation and animal husbandry. The eddy correlation technique is the most promising method to measure methane flux in the atmosphere. However, this technique requires a fast response and high resolution instrument for methane measurement.
A prototype fast response CH4 instrument with open sensing path is developed in the present study. Results of the laboratory and fild test are summarized as follows : (1) The sensitivity of the instrument is about 15.6 ppm per volt. The measuring frequency is 30 Hz. (2) The noise-limited sensitivity is about 0.6 ppm peak-to-peak in CH4 concentration. (3) The sensitivity is practically invariant with a possible change in the adjustment of the optical system. (4) Preliminary test shows that the instrument is feasible for measurements of CH4 flux by the eddy correlation technique under field conditions. However, the present instrument suffers from several limitations. Most serious problem is the inadequate oscillation of He-Ne laser. In order to reduce the noise level of the instrument, further effort is required to control the oscillation of He-Ne laser.

  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] 大滝英治: "海水中の二酸化炭素濃度(pCo_2)測定器の開発" 海の研究. 3. 413-418 (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ohtaki, E.: "Open path methane sensor" Proc. of the UK/JAPAN Workshop. 75-84 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ohtaki, E.: "Carbondioxide in surface seawaters of western tropical Pacific Ocean" J. Meteorol. Soc. Japan. 73. 631-637 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Liu, X.: "Eddy correlation measurements of carbon dioxide flux over coastal sea Surface" Bull. Disas. Prev. Res. Inst. Kyoto Univ.45. 17-25 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ohtaki, E.: "Development of measuring instrument of pCO_2 in seawater." Umi no Kenkyu. 3 (in Japanese). 413-418 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Ohtaki, E.: "Open path methane sensor." Proceedings of the Uk/Japan Workshop of Controlling Methane and the Nitrogen Cycle on Farms. 75-84 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Ohtaki, E.: "Carbon dioxide in surface seawaters of western tropical Pacific Ocean." J.Meteorol.Soc.Japan. 73. 631-637 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Liu.X.: "Eddy correlation measurements of carbon dioxide flux over coastal sea surface." Bull.Disas.Prev.Res.Inst.Kyoto Univ.45. 17-25 (1995)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1997-03-04  

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