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  • 1
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    Infrared line intensities of chlorine monoxide (1986)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Absolute infrared line intensities of several ClO lines in the rotational-vibrational (1-0) band were measured using infrared heterodyne spectroscopy near 12 microns. A measurement technique using combined ultraviolet absorption and infrared line measurements near 9.5 microns and 12 microns permitted an accurate determination of the column densities of O3 and ClO in the absorption cell and thus improved ClO line intensities. Results indicate ClO line and band intensities approximately 2.4 times lower than previous experimental results. Effects of possible failure of local thermodynamic equilibrium conditions in the absorption cell and the implication of the results for stratospheric ClO measurements in the infrared are discussed.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 91; 2735-274
    Format: text
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  • 2
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    Stratospheric ozone measurement with an infrared heterodyne spectrometer (1978)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: Measurements of a stratospheric ozone concentration profile are made by detecting infrared absorption lines with a heterodyne spectrometer. The infrared spectrometer is based on a line-by-line tunable CO2 lasers, a liquid-nitrogen cooled HgCdTe photomixer, and a 64-channel spectral line receiver. The infrared radiation from the source is mixed with local-oscillator radiation. The difference frequency signal in a bandwidth above and below the local-oscillator frequency is detected. The intensity in each sideband is found by subtracting sideband contributions. It is found that absolute total column density is 0.32 plus or minus 0.02 cm-atm with a peak mixing ratio at about 24 km. The (7,1,6)-(7,1,7) O3 line center frequency is identified as 1043.1772/cm. Future work will involve a number of ozone absorption lines and measurements of diurnal variation. Completely resolved stratospheric lines may be inverted to yield concentration profiles of trace constituents and stratospheric gases.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 5; Apr. 197
    Format: text
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  • 3
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    Stratospheric sounding by infrared heterodyne spectroscopy (1979)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: Intensity profiles of infrared spectral lines of stratospheric constituents can be fully resolved with a heterodyne spectrometer of sufficiently high resolution (approximately 5 MHz = 0.000167 kaysers at 10 microns). The constituents' vertical distributions can then be evaluated accurately by analytic inversion of the measured line profiles. Estimates of the detection sensitivity of a heterodyne receiver are given in terms of minimum detectable volume mixing ratios of stratospheric constituents, indicating a large number of minor constituents which can be studied. Stratospheric spectral line shapes and the resolution required to measure them are discussed in light of calculated synthetic line profiles for some stratospheric molecules in a model atmosphere. The inversion technique for evaluation of gas concentration profiles is briefly described, and applications to synthetic lines of O3, CO2, CH4, and N2O are given. Some recent heterodyne measurements of CO2 and O3 absorption lines are analytically inverted, and the vertical distributions of the two gases are determined.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 84; June 1
    Format: text
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  • 4
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    Stratospheric ozone measurement with an infrared heterodyne spectrometer (1978)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: A stratospheric ozone absorption line in the 10 micron band was measured and resolved completely, using an infrared heterodyne spectrometer with a spectral resolution of 5 MHz. The vertical concentration profile of stratospheric ozone was obtained through an analytical inversion of the measured spectra line profile. The absolute total column density was 0.32 plus or minus 0.02 cm-atm with a peak mixing ratio occurring at approximately 24 km. The (7,1,6) - (7,1,7) O3 line center frequency was found to be 1043.1772 plus or minus 0.00033 cm/1 or 420 plus or minus 10 MHz higher than the P(24) CO2 laser line frequency.
    Keywords: GEOPHYSICS
    Type: WMO Geophys. Aspects and Consequences of Changes in the Composition of the Stratosphere; p 99-101
    Format: text
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  • 5
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    Is there any chlorine monoxide in the stratosphere? (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: A ground-based search for stratospheric 35-ClO was carried out using an infrared heterodyne spectrometer in the solar absorption mode. Lines due to stratospheric HNO3 and tropospheric OCS were detected at about 0.2 percent absorptance levels, but the expected 0.1 percent lines of ClO in this same region were not seen. We find that stratospheric ClO is at least a factor of seven less abundant than is indicated by in situ measurements, and we set an upper limit of 2.3 x 10 to the 13th molecules/sq cm at the 95 percent confidence level for the integrated vertical column density of ClO. Our results imply that the release of chlorofluorocarbons may be significantly less important for the destruction of stratospheric ozone (O3) than is currently thought. Previously announced in STAR as N83-27518
    Keywords: GEOPHYSICS
    Type: Science (ISSN 0036-8075); 221; July 15
    Format: text
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  • 6
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    Is there any chlorine monoxide in the stratosphere? (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A ground based search for the 856.50137/cm R(9.5) and for the 859.76765 R(12.5) transitions of stratospheric (Cl-35)O was made in the solar absorption mode using an infrared heterodyne spectrometer. Lines due to stratospheric HNO3 and tropospheric OCS were detected, at about 0.3% absorption levels. The expected lines of ClO in this same region were not detected, even though the optical depth of the ClO lines should be on the order of 0.2% using currently accepted ClO abundances. These infrared measurements suggest that stratospheric ClO is at least a factor of 7 less abundant than is indicated by indirect in situ fluorescence measurements, and the upper limit of 2.4x10 to the 13th power molecules/sq cm to the integrated column density of ClO is a factor of over 4 less than is indicted by microwave measurements. Results imply that the release of fluorocarbon precursors of ClO may be significantly less important for the destruction of stratospheric ozone than was previously thought.
    Keywords: GEOPHYSICS
    Type: NASA-TM-83939 , NAS 1.15:83939
    Format: application/pdf
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  • 7
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    Stratospheric sounding by infrared heterodyne spectroscopy (1978)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Intensity profiles of infrared spectral lines of stratospheric constituents can be fully resolved with a heterodyne spectrometer of sufficiently high resolution. The constituents' vertical distributions can then be evaluated accurately by analytic inversion of the measured line profiles. Estimates of the detection sensitivity of a heterodyne receiver are given in terms of minimum detectable volume mixing ratios of stratospheric constituents, indicating a large number of minor constituents which can be studied. Stratospheric spectral line shapes, and the resolution required to measure them are discussed in light of calculated synthetic line profiles for some stratospheric molecules in a model atmosphere. The inversion technique for evaluation of gas concentration profiles is briefly described and applications to synthetic lines of O3, CO2, CH4 and N2O are given.
    Keywords: GEOPHYSICS
    Type: NASA-TM-78066
    Format: application/pdf
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  • 8
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    Stratospheric ozone measurement with an infrared heterodyne spectrometer (1978)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A stratospheric ozone absorption line in the 10 microns band was measured and resolved completely, using an infrared heterodyne spectrometer with spectral resolution of 5 MHz (0.000167 cm to -1 power). The vertical concentration profile of stratospheric ozone was obtained through an analytical inversion of the measured spectral line profile. The absolute total column density was 0.34 cm atm with a peak mixing ratio occurring at approximately 24 km. The (7,1,6) to (7,1,7) O3 line center frequency was found to be 1043.1775 + or - 0.00033 cm to toe -1 power, or 430 + or - 10 MHz higher than the P(24) CO2 laser line frequency.
    Keywords: GEOPHYSICS
    Type: NASA-TM-78067
    Format: application/pdf
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  • 9
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    Is there any chlorine monoxide in the stratosphere? (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A ground-based search for stratospheric 35-ClO was carried out using an infrared heterodyne spectrometer in the solar absorption mode. Lines due to stratospheric HNO3 and tropospheric OCS were detected at about 0.2% absorptance levels, but the expected 0.1% lines of ClO in this same region were not seen. We find that stratospheric ClO is at least a factor of seven less abundant than is indicated by in situ measurements, and we set an upper limit of 2.3x10 to the 13th molecules/sq cm at the 95% confidence level for the integrated vertical column density of ClO. Our results imply that the release of chlorofluorocarbons may be significantly less important for the destruction of stratospheric ozone (O3) than is currently thought.
    Keywords: GEOPHYSICS
    Type: NASA-TM-85026 , NAS 1.15:85026
    Format: application/pdf
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