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Global Climate Change Digest
A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999
FROM VOLUME 1, NUMBER 5, NOVEMBER 1988
"European Sources of Halocarbons and Nitrous Oxide: Update 1986,"
M. Prather (NASA/GSFC, Inst. Space Studies, 2880 Broadway, New York NY 10025 ),
J. Atmos. Chem., 6(4), 375-406, May 1988.
Semi-continuous measurements of CFCl3, CF2Cl2, CCl4, CH3CCl3 and N2O were
made at Adrigole, Ireland as part of the Atmospheric Lifetime Experiment (ALE).
This paper extends previous work on the relative enhancements of trace gases
during pollution episodes and presents 1) unambiguous identification of elevated
levels of N2O concurrent with halocarbon pollution events, 2) detection of
trends in emission of CH3CCl3, 3) discovery of seasonal variations in emission
of CF2Cl2, CCl4 and CH3CCl3, 4) characterization of typical summer and winter
pollution episodes, and 5) identification of weather patterns over Europe that
are associated with high concentrations of CFCs at Adrigole. The source of
nitrous oxide correlated with halocarbons is 0.8 Tg(N)/yr from Europe alone and
represents approximately 10% of the global stratospheric loss.
"Antarctic Ozone: Meteoric Control of HNO3," M.J. Prather
(Goddard Inst. Space Studies, NASA/GSFC, 2880 Broadway, New York NY 10025), J.M.
Rodriguez, Geophys. Res. Letters, 15(1), 1-4, Jan. 1988.
Ablation of meteoroids provides a source of alkalinity for stratospheric
aerosols. The largest concentrations of meteoric material in the stratosphere
occur in the Antarctic spring in amounts sufficient to neutralize parts per
billion of acidic vapor, remove nitric acid from the gas phase and bond it as
metal nitrates in the aerosol phase. Removal of nitric acid vapor allows
increased catalytic loss from chlorine and bromine. This is a critical link in
the photochemical depletion of ozone.
"Comparison of Total Ozone Amounts Derived from Satellite and
Ground-Based Measurements," W.G. Planet (Nat. Environ. Satellite, Data &
Info. Svc., NOAA), ibid., 5-8.
Presents results of qualitative comparisons of the data sets from TOVS, SBUV
and the Dobson systems over the period 1978-1986. The global trends of the data
show qualitative agreement until mid-1984, when the data diverge with the
TOVS-derived data showing higher values. After 1984 there is a drift apart,
especially of the TOVS and SBUV data records, which is clearly evident in the
north and south temperate zones. There is overall qualitative agreement between
the TOVS measurements and the Dobson data record.
"Isotopic Fractionation in Ozone Decomposition," S.K.
Bhattacharya (Dep. Chem., B-017, Univ. Calif., La Jolla CA 92093), M.H.
Thiemens, ibid., 9-12.
Provides measurements of the isotopic fractionation during O3 destruction,
which complement details previously obtained for the O3 production process. The
fractionation magnitude is required for modeling the steady-state isotopic
composition of stratospheric ozone.
"Laboratory Studies of Sticking Coefficients and Heterogeneous
Reactions Important in the Antarctic Stratosphere," M.T. Leu (MS 183-301
Jet Propulsion Lab., Calif. Inst. Tech., Pasadena CA 91109), ibid.,
Measured sticking coefficients of H2O, HCl, Cl2 and HNO3 on ice, and
heterogeneous reactions of ClONO2 with ice or HCl/ice. With HCl present in ice,
the reaction probability of ClONO2 is greatly enhanced, while molecular chlorine
was found to be the major gas phase product. Nitric acid, another reaction
product, remained in the solid phase. Results should be a major factor in
producing observed springtime ozone depletion.
"Airborne Lidar Observations of Arctic Polar Stratospheric Clouds:
Indications of Two Distinct Growth Stages," L.R. Poole (NASA Langley Res.
Ctr., Atmos. Sci. Div., Hampton VA 23665), M.P. McCormick, ibid., 21-23.
Observations show two distinct PSC growth stages delineated by the
frost-point temperature. Results at 2-6 ° K above the frost point indicate a
stage of significant particle growth such as proposed in models of PSC formation
by co-deposition of HNO3 and H2O vapors. Results near frost point show the
formation of larger crystalline particles.
"A Ground-Based Intercomparison of NO, NOx, and NOy Measurement
Techniques," F.C. Fehsenfeld (Aeronomy Lab, NOAA, Boulder CO 80307), R.R.
Dickerson et al., J. Geophys. Res., 92(D12), 14,710-14,722, Dec.
Simultaneous atmospheric measurements were made in a field intercomparison
of instruments involving two currently employed techniques of NOx and NOy
measurement. Conclusions drawn from results are 1) the two NO instruments agreed
on NO mixing ratios that were measured during the daytime hours over a range
from the limits of detection to 35 ppbv, 2) the two NOy instruments gave similar
estimates of NOy in ambient air over a wide range of mixing ratios (0.4-10
ppbv), 3) the ferrous sulfate converter used for NOx detection showed a
significant interference from NPN and PAN.
"Atmospheric Infrared Emission of ClONO2 Observed by a Balloon-Borne
Fourier Spectrometer," S.T. Massie (NCAR, Boulder CO 80307), J.A. Davidson
et al., ibid., 14,806-14,814.
Spectral simulations were used in an analysis incorporating line-by-line
calculations and new ClONO2 cross sections to determine the mixing ratios of
ClONO2. The inferred mixing ratios of ClONO2 are 1.3 + or - 0.45 ppb and 0.98 +
or - 0.35 ppb at 14 and 34 mbar. Comparisons with observations taken near 0300
LT at a latitude of 35 ° N show agreement at 14 mbar, but the ClONO2 mixing
ratio at 34 mbar is larger than the model prediction.
Comment and reply on "An Intercomparison of Nitrogen-Containing
Species in Nimbus 7 LIMS and SAMS Data," ibid., 14,869.
"An Important Uncertainty in Coupled Chlorine-Carbon Dioxide Studies
of Atmospheric Ozone Modification," R.S. Ekman (Dept. Phys., Cambridge
Univ., UK), J.D. Haigh, J.A. Pyle, Nature, 329(6140), 616-619,
Oct. 15, 1987.
Presents calculations of the effect on stratospheric ozone of increased
amounts of CO2 and Cl compounds. Changes in the kinetic data used in the two
dimensional model have led to significant differences in the calculated ozone
modification. The lower stratosphere now plays a more crucial role in the
vertically integrated ozone depletion. Uncertainties in the thermal response of
the lower stratosphere may represent a significant limitation in current ability
to predict future states of the middle atmosphere.
"Antarctic Stratospheric Chemistry of Chlorine Nitrate, Hydrogen
Chloride, and Ice: Release of Active Chlorine," M.J. Molina (Jet Propulsion
Lab., Calif. Inst. Tech., Pasadena CA 91109), T-L. Tso et al., Science,
238(4831), 1253-1257, Nov. 27, 1987.
The reaction rate between atmospheric HCl and ClONO2 is greatly enhanced in
the presence of ice particles. Cl2 is released into the gas phase in a few
milliseconds while HNO3 remains in the condensed phase. This reaction releases
photolytically active chlorine from its most abundant reservoir species,
promotes the formation of HNO3 and removes NO2 from the gas phase. This
establishes the necessary conditions for the efficient catalytic destruction of
ozone by halogenated free radicals.
"Reactions of Chlorine Nitrate with Hydrogen Chloride and Water at
Antarctic Stratospheric Temperatures," M.A. Tolbert (Chem. Phys. Lab., SRI
Internat., Menlo Pk CA 94025), M.J. Rossi et al., ibid., 1258-1260.
Results of laboratory studies of heterogeneous reactions important to ozone
depletion, performed on surfaces that simulate polar stratospheric clouds, show
that the reaction of ClONO2 on ice and of certain mixtures of HNO3 and ice
proceed rapidly. Also nearly all of the HCl in the bulk of the ice can react
with ClONO2 on the ice surface. The gaseous products, HOCl, Cl2O and Cl2 could
all photolyze to produce active chlorine for ozone depletion. The formation of
condensed-phase HNO3 could also serve as a sink for odd nitrogen species that
would otherwise scavenge the active chlorine, adding further to ozone depletion.
"Tropospheric Latitudinal Distributions of CF2Cl2, CFCl3, N2O,
CH3CCl3 and CCl4 Over the Remote Pacific Ocean," D.C. DeLorey (Lab. Atmos.
Res., Washington State Univ., Pullman WA 99164), D.R. Cronn, J.C. Farmer, Atmos.
Environ., 22(7), 1481-1494, 1988.
These trace gas latitudinal distributions were used to calculate Northern
and Southern Hemisphere mean concentrations, annual time trends, total
atmospheric burdens, and lifetimes. Normalizing these hemispheric annual time
trends with the October-November 1980 mean hemispheric concentrations shows
CH3CCl3 mean hemispheric concentrations increased the fastest at about 9% yr-1,
while N2O increased the slowest at about 0.3% yr-1. The October-November 1980
trace gas total atmospheric burdens were: 5.81 Mton for CF2Cl2, 3.95 Mton for
CFCl3, 2.47 Mton for CH3CCl3, 3.50 Mton for CCl4, and 2283 Mton for N2O. The
atmospheric lifetimes obtained for CF2Cl2, CFCl3 and CH3CCl3 were 174 + or - 89,
202 + or - 149, and 14.5 + or - 2.2 yr, respectively.
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Index of Abbreviations