Stratospheric N2O, CF2Cl2, and CFCl3 composition studies utilizing in situ cryogenic, whole air sampling methods

Gallagher, Charles C.; Forsberg, Charles A.; Fieri, Robert V.

doi:10.1029/jc088ic06p03798

Cited by 17 publications

(6 citation statements)

References 25 publications

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“…Resonance fluorescence has been used to provide point values of these species abundances [Anderson, 1980], but the experimental method is not suitable for inclusion on the sample platform with the other experiments primarily because nitric oxide is used in the technique. (The nitric oxide content of our samples has been measured in a separate program [Gallagher et al, 1985].) Microwave [Waters et al, 1979] and optical [Menzies, 1979] methods have been used to determine C10 but cannot provide values specific to the point where the cryogenic and filter samplings occur.…”

Section: Identification Of Major Stratospheric Chlorine Speciesmentioning

confidence: 99%

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Total chlorine content in the lower stratosphere

Gallagher¹,

Forsberg²,

Mason³

et al. 1985

J. Geophys. Res.

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A cryogenic whole air sampler and a filter sampler were used, simultaneously, on a balloon platform to capture and preserve all significant stratospheric chlorine species with the exception of Cl and ClO at altitudes of 15, 20, 25, and 30 km. The whole air samples were analyzed by gas chromatography to determine mixing ratios of CF2Cl2, CFCl3, CH3Cl, CH3CCl3, and CCl4. Liquid extractions of the filter samples were analyzed for acidic and particulate chlorine content using neutron activation and wet chemistry techniques. Summation of the contributions from the major species produced total chlorine mixing ratios that decreased from 2.6 ppbv at 15 km to 2.2–2.5 ppbv for the higher altitudes. Omission of Cl and ClO introduced about a 3–7% error at 25–30 km and negligible error at 15 and 20 km. The combined contributions of all other omitted species introduced 1–2% error to the total chlorine values for all altitudes investigated. The increase in total acidic species content with increasing altitude correlates with the decrease in the mixing ratios of the chlorine species of tropospheric origin.

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Section: Identification Of Major Stratospheric Chlorine Speciesmentioning

confidence: 99%

“…Approximately one-mole whole air samples were obtained at three altitudes per balloon flight using a liquid helium cooled dewar containing three 2-L-volume chambers (trisampler) [Gallagher et al, 1981. The sampling valves are remotely activated.…”

Section: Sampling Programmentioning

confidence: 99%

Total chlorine content in the lower stratosphere

Gallagher¹,

Forsberg²,

Mason³

et al. 1985

J. Geophys. Res.

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“…The intake tubing undergoes a thorough cleaning prior to launch day and is then encased in polyethylene which is pulled away at launch. A trickle flow of helium is maintained through the tubing from the encasement until shortly prior to launch [Gallagher et al, 1981.…”

Section: Concern Arose In the Early 1970's That Anthropogenic Influenmentioning

confidence: 99%

“…Oxides of nitrogen from the exhausts of supersonic transports [Johnston, 1971] and photodissociation of fluorocarbons as they diffuse upward [Molina and RowlandThe intake tubing undergoes a thorough cleaning prior to launch day and is then encased in polyethylene which is pulled away at launch. A trickle flow of helium is maintained through the tubing from the encasement until shortly prior to launch [Gallagher et al, 1981.…”

mentioning

confidence: 99%

Nitric oxide and nitrogen dioxide content of whole air samples obtained at altitudes from 12 to 30 km

Gallagher¹,

Forsberg²,

Pieri³

et al. 1985

J. Geophys. Res.

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Whole air samples were obtained in the stratosphere using a liquid helium‐cooled cryosampler mounted on a balloon platform. Approximately 1 g mol of sample was obtained at each of three altitudes per balloon flight and was maintained at 4 K until desorption just prior to analysis. Samples were obtained at six altitudes ranging from 12 to 30 km and at five latitudes from 9° to 64°N. Nitric oxide and the sum of nitric oxide and nitrogen dioxide content of the samples were determined using two chemiluminescence analyzers. Results from flights conducted between 1977 and 1981 are correlated with atmospheric motions and other significant variables and evaluated in terms of both one‐ and two‐dimensional models of the stratosphere.

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“…The measured values are consistent with the model calculation, though the measurements are sparse and data points are rather scattered. At least, our values were within the range of many values measured over mid-latitude of the northern hemisphere (Pierotti and Rasmussen, 1977;Fabian et al, 1979Fabian et al, , 1981Goldan et al, 1980;Vedder et at., 1981;Gallagher et at., 1983). Annual increases in the stratospheric mixing ratios of these compounds could not be observed due to the experimental uncertainties.…”

Section: Reference Gasmentioning

confidence: 99%