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  • Stratospheric chlorine  (2)
  • HO2 -, NO2 +in situ data  (1)
  • NO2  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Pure and applied geophysics 116 (1978), S. 545-553 
    ISSN: 1420-9136
    Keywords: Chlorofluoromethanes ; Stratospheric chlorine ; Trace gas observation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Available data on halogenated molecules in the stratosphere will be reviewed. Presently vertical profiles of CFCl3 and CF2Cl2 in the stratosphere exist to 50 km altitude. Only measurements in the lower stratosphere are reported for the other major halocarbons, CCl4 and CH3Cl. Profiles of the product species ClO, Cl, HCl, and HF exist to about 35 km. Comparison with theoretical profiles from 1-D models shows generally good agreement except for ClO where the earliest measured concentrations exceed the calculated ones considerably.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Pure and applied geophysics 116 (1978), S. 575-582 
    ISSN: 1420-9136
    Keywords: Chlorofluoromethanes ; Stratospheric chlorine ; Oceanographic tracers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Depth profiles of the chlorofluoromethanes (CFM), CFCl3 and CF2Cl2, have been obtained together with tritium profiles from water samples collected in the Norwegian Sea between surface and 2800 m depth. CFM analysis was performed by vacuum extraction of the dissolved gases from 500 ml samples of seawater and subsequent gaschromatographic measurement. The CFM concentration decreases with depth to about 10 percent of surface concentration at depths below 2000 m. The same behaviour is found for the tritium content. From a correlation of the CFM and tritium concentration the upper limit of the preindustrial atmospheric CFM levels can be estimated to ≤5 percent of the present day concentrations.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of atmospheric chemistry 2 (1984), S. 191-202 
    ISSN: 1573-0662
    Keywords: Stratospheric photochemistry ; HO2 -, NO2 +in situ data ; vertical profiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Vertical profiles of stratospheric HO2 and NO2 concentrations were determined using matrix isolation and ESR. Up to 10 different samples per flight were collected in situ by a balloon borne cryosampler. Free radicals and trace constituents which are condensable at 68 K are trapped in a polycristalline H2O or D2O matrix. After collection, the samples are stored at a temperature below 83 K until they are analysed in the laboratory by X-band ESR spectroscopy at 4 K. The HO2 and NO2 were identified and calibrated by comparison with standard samples collected in the laboratory under typical stratospheric sampling conditions. From several flights over Southern France (44°N) we obtained two profiles of the stratospheric NO2 mixing ratio. One, from 21 October 1982, agrees well with previous measurements. The other, from 8 October 1981, is lower by one order of magnitude. The few HO2 data obtained around 35 km altitude agree with previous measurements. An isolated measurement at 17 km altitude is one order of magnitude higher than the model predicted HO2 concentration.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of atmospheric chemistry 3 (1985), S. 341-361 
    ISSN: 1573-0662
    Keywords: Peroxyradicals ; NO2 ; in-situ measurement ; matrix isolation ; electron spin resonance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract A cryogenic system for the airborne and ground based sampling of ambient radicals by matrix isolation is described. The trapped radicals, e.g., NO2 and RO2, are analyzed by ESR. The technique has been improved, mainly by addition of water vapor to the sampled air, to yield a collection efficiency of (90±10)% and a lower detection limit of about 20 ppt, but it still does not distinguish between the different RO2. Careful calibration reduced the measurement error (1 σ) to ±10% for NO2 and ±15% for HO2. Two diurnal variations of RO2 and NO2 at ground level and vertical profiles in the lower troposphere are presented.
    Type of Medium: Electronic Resource
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