| Project/Area Number |
62460048
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Space and upper atmospheric physics
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
FUKUNISHI Hiroshi Tohoku University, Fuculty of Science, 理学部, 教授 (90099937)
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| Co-Investigator(Kenkyū-buntansha) |
OKANO Shoichi Tohoku University, Fuculty of Science, 理学部, 助手 (10004483)
MORIOKA Akira Tohoku University, Fuculty of Science, 理学部, 助教授 (50004479)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 1988: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1987: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | ozone / heterodyne spectroscopy / tunable diode laser / infrared spectroscopy / 大気吸収 / テヘロダイン分光 / 半導体レーザー |
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| Research Abstract |
1. Development of a laser heterodyne spectrometer A laser heterodyne spectrometer using a tunable diode laser as a local oscillator has been developed for remote sounding of atmospheric trace gases. The spectral resolution of the tunable diode laser heterodyne spectrometer (TDLHS) is either 0.0013cm^<-1> (40MHz) or 0.0027CM^<-1> (80MHz) and the signa-to-noise ratio of the obtained solar absorption spectra is 300 - 600. These performance of the TDLHS has been realized by using (1) lenses with diffraction limited quality for an exact alignment of signal beam and local oscillator beam, and (2) a diode laser which can operate at liquid nitrogen temperature (77K) for high stability of the laser frequency, and by improving (3) isolation of the reflected local oscillator laser beam.
2. Data analysis and results Vertical profiles of volume mixing ratio for both ozone and nitrous oxide were inverted from the observed spectra. The accuracy of the retrieved volume mixing ratio is 2-7% and the vertical resolution is 4-6km, depending on the altitude. The results for ozone were compared with the data obtained by Dobson spectro-photometers and an ozonesonde, and the results for nitrous oxide were compared with the data obtained by sampling method. Both comparison showed good coincidence.
3. Future plan Measurements of trace constituents related to ozone chemistry will be carried out by the TDLHS with further improved resolution of 0.0007cm^<-1> (20MHz) in order to increase the upper bound of ozone remote sounding.
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