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1996 Fiscal Year Final Research Report Summary

A New Measuring method for effluence gas flux into atmosphere with a laser

Research Project

Project/Area Number 07650496
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 計測・制御工学
Research InstitutionOkayama University

Principal Investigator

KOGA Ryuji  Okayama University, Faculty of Engineering, Professor, 工学部, 教授 (20027147)

Co-Investigator(Kenkyū-buntansha) KAGAWA Naoki  Fukuyama Unversity, Faculty of Engineering, Lecturer, 工学部, 講師 (80258300)
MING Wang  Okayama University, Graduate School of Natural Science and Technologies, Assista, 大学院・自然科学研究科, 助手 (60253019)
Project Period (FY) 1995 – 1996
Keywordsscintillation / methane gas / infrared absorption spectrum / effluence / DSP / atmospheric concentration flux / lead-salt diode laser / temporal resolution
Research Abstract

Propagation of laser beam in open atmosphere is heavily suffered from the fluctuation of atmospheric constituent, density and temperature. Quantity of methane gas penetrating through the ground surface is governed by the production rate under the ground as well as by the chemica activity at the ground surface.
This group measured temporal variation of absorption for for the 7 micron meter band laserbeam using a lead-salt diode laser. They there found that the spectra of the absorption signal below 1 Hz correspond to atmosheric methane density, and that beyond 10Hz to the scintillation. In other words, one can measure methane density independent from the scintillation if the absorption line is spectrally scanned within a few milli-seconds. A test equipment was build and outdoor measurement was conducted.
The equipment fully utilize the DSP (Digital Signal Processor) LSI,which allows the systm temporal resolution as short as 4 milli-seconds to spectrally scan a methane absorption line. A clear spectrum of methane was actually measured being not smeared by scintillation, which would not be able to achieve with a scheme that employ a long temporal integration.
This results assures the possibility to further develop an apparatus to measure gas effluence flux into open atmosphere.

  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] N.Kagawa: "Calculation of PSDF of scintillation for 7μm band TDL beam around water vapor line" Infrared Physics and Technology. 37. 13-19 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] N.Kagawa: "Flutuation spectra for An Infraved Laser Beam Propagating Horizantally in the Open Atmosphere" Proc.SPIE. 2815. 138-144 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] R.Koga: "Quick Scanning TDL Speotrometry for atmospheric trace gas manitoring with Anti-scintillation pertormance" Proc.SPIE. 2834. 142-147 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] N.Kagawa, O.Wada and Ryuji Koga: "Calculation of PSDF of scintillatin for 7 mu m band TDL beam around water vapor line" Infrared Physics and Technology. Vol.37. 13-19 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N.Kagawa, Osami Wada and Ryuji Koga: "Fluctuation Spectra for An Infrared Laser Beam Propagating Horizontally in The Open Atmosphere" Proc.SPIE-the Society of Photo-Optical instrumentation Engineers. Vol.2815. 138-144

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Ryuji Koga, Osami Wada, Ming Wang, and Naoki Kagawa: "Quick scanning TDL spectrometry for atmospheric trace gas monitoring with anti-scintillation performance" Proc.SPIE-the Society of Photo-Optical instrumentation Engineers. Vol.2834. 142-147

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

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Published: 1999-03-09  

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