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  • 1
    Electronic Resource
    Electronic Resource
    The vertical distribution of trace gases in the stratosphere (1975)
    Springer
    Pure and applied geophysics 113 (1975), S. 389-402 
    Details
    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Summary New measurements on the stratospheric distribution of H2, CH4, CO and N2O are presented and used to demonstrate the natural variability of the trace gas concentrations. The present CH4 and H2 measurements and data from older balloon flights are combined to give average vertical profiles. These profiles are compared with water vapor data from various authors to see if the vertical decrease in CH4 is matched by a corresponding increase in H2O. By comparing the average measured profiles to those predicted by a one-dimensional chemical model, profiles of the vertical eddy diffusion coefficientk z are deduced. Generally, a barrier in the low stratosphere and increasing transport in middle and upper stratosphere seem required to match theoretical and experimental profiles. The limitations of the calculatedk z are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01592926
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  • 2
    Electronic Resource
    Electronic Resource
    Depth profiles of chlorofluoromethanes in the Norwegian sea (1978)
    Springer
    Pure and applied geophysics 116 (1978), S. 575-582 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01636910
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  • 3
    Electronic Resource
    Electronic Resource
    The concentration of molecular H2 and CH4 in the stratosphere (1973)
    Springer
    Pure and applied geophysics 106-108 (1973), S. 1352-1360 
    Details
    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Stratospheric profiles of CH4 and H2 over eastern Texas have been derived up to 31 km altitude from air samples collected aboard a balloon and analyzed by gas chromatography. For H2, contamination during flight and measurement presented a problem which has been resolved only recently. The earlier profiles require corrections which are rather large for the highest altitudes. The three profiles indicate an increase of the H2 concentration in the lower stratosphere from about 0.5 p.p.m. per volume at the tropopause to about 0.8 p.p.m. at around 27 km altitude. Above that altitude the H2 concentration decreases again. An air sample collected between 44 and 62 km by a rocket-borne cryogenic sampler had an H2 concentration of 0.4 p.p.m. The five CH4 profiles showed a decrease in CH4 concentration with altitude generally with a steeper gradient directly above the tropopause and a weaker gradient at higher altitudes reaching 0.9 p.p.m. at 30 km altitude. The CH4 concentration in the rocket sample was 0.25 p.p.m., in good agreement with the gradient obtained from the balloon samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00881090
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  • 4
    Electronic Resource
    Electronic Resource
    Sources and sinks of atmospheric methane (1978)
    Springer
    Pure and applied geophysics 116 (1978), S. 452-464 
    Details
    ISSN: 1420-9136
    Keywords: Trace gases ; Atmosphere ; Sources and Sinks ; Methane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract In 1972 average mixing ratio of methane in the troposphere was 1.41 ppm and 1.3 ppmv for the northern and southern hemisphere, respectively, which corresponds to a total amount of 4×1015 g of CH4 present in the atmosphere. Most is of recent biologic origin.14C analyses show that no more than 20 percent is released by fossil sources. The various ecosystems producing CH4 are discussed and the total annual production is estimated to lie between 5.5×1014 g/yr and 11×1014 g/yr. The corresponding turnover times for atmospheric CH4 range from 4 to 7 yrs. The destruction of CH4 takes place mainly in the troposphere, most probably through the reaction of CH4 + OH ↠ CH3 + H2O. About 10 percent of the CH4 is destroyed in the stratosphere. The CH4 cycle contributes on the order of 1 percent to the atmospheric carbon cycle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01636899
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  • 5
    Electronic Resource
    Electronic Resource
    Measurements of free radicals in the atmosphere by matrix isolation and electron paramagnetic resonance (1978)
    Springer
    Pure and applied geophysics 116 (1978), S. 530-536 
    Details
    ISSN: 1420-9136
    Keywords: Electron paramagnetic resonance ; Free radicals ; Matrix isolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract With some special adaptations the technique of matrix isolation followed by detection through electron paramagnetic resonance (EPR) can also be used for the measurement of atmospheric radical concentrations. A light weight cryogenic sampling device has been constructed. It uses condensation of atmospheric CO2 or H2O at 77 K for matrix formation and trapping of the radicals. The sampler has been flown on a balloon for stratospheric sampling. First data on stratospheric, HO2 and NO2 at 32 km altitude have been obtained on a flight on 8 August 1976 and will be reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01636905
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  • 6
    Electronic Resource
    Electronic Resource
    The vertical distribution of CFM and related species in the stratosphere (1978)
    Springer
    Pure and applied geophysics 116 (1978), S. 545-553 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF01636907
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  • 7
    Electronic Resource
    Electronic Resource
    A Peak in the Tritium Content of Atmospheric Hydrogen following the Accident at Windscale (1966)
    [s.l.] : Nature Publishing Group
    Nature 209 (1966), S. 903-904 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] In view of the time of onset and the brief duration of the tritium peak it seems far more likely that the tritiated hydrogen was released during the reactor accident at Windscale on October 10 and 11, 1957. Since the samples were taken two days apart, the initial rise in Fig. 1 is not well defined, ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/209903a0
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  • 8
    Electronic Resource
    Electronic Resource
    Physical Sciences: Krypton-85 in the Troposphere (1971)
    [s.l.] : Nature Publishing Group
    Nature 233 (1971), S. 614-615 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The raw krypton samples were purified by removal of the oxygen in a magnesium furnace, and their activity was measured in a small gas proportional counter, of sensitive volume 11 cm3, surrounded by a lead shield 10 cm thick; a plastic scintillator was used as an anticoincidence counter. The ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/233614a0
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  • 9
    Electronic Resource
    Electronic Resource
    Der atmosphärische Kreislauf von Methan (1979)
    Springer
    Naturwissenschaften 66 (1979), S. 307-311 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Notes: Abstract Present methane concentrations in the northern troposphere average 1.65 ppm. Most CH4 is of recent biogenic origin. 14C analyses indicate that no more than 10% is released by fossil sources. The various CH4-producing ecosystems are described and the total annual production is estimated to lie between 5.9×1014 and 9.3×1014 g/y. CH4 is destroyed through photochemical oxidation mainly in the troposphere. In this process CH2O, H2, and CO are produced as intermediates. Tropospheric CH4 provides an important source of stratospheric water vapor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00441273
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  • 10
    Electronic Resource
    Electronic Resource
    An improved method of measuring tropospheric NO2 and RO2 by matrix isolation and electron spin resonance (1985)
    Springer
    Journal of atmospheric chemistry 3 (1985), S. 341-361 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00122523
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