February 28, 2007
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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 3, NUMBER 8, AUGUST 1990
STRATOSPHERIC OZONE CHEMISTRY
"Heterogeneous Reactions on Nitric Acid Trihydrate," S.B. Moore
(Jet Propulsion Lab., Calif. Inst. Technol., Pasadena CA 91109), L.F. Keyser et
al., Nature, 345(6273), 333-335, May 24, 1990.
Reports the first direct measurements of the reaction probabilities at
stratospheric temperatures for two important heterogeneous reactions on nitric
acid trihydrate (NAT). Calculates the sticking coefficients and solubilities of
HCl and NAT, which are important in modeling physical-chemical processes in the
stratosphere. Results show that the conversion of the chlorine reservoir species
can occur within a few days of the first appearance of type I polar
stratospheric clouds during the polar winter.
"Spatial Variation of Ozone Depletion Rates in the Springtime
Antarctic Polar Vortex," Y.L. Yung (Div. Geol. Plan. Sci., Calif. Inst.
Technol., Pasadena CA 91125), M. Allen et al., Science, 721-724, May 11,
An area mapping technique, designed to filter out synoptic perturbations of
the Antarctic polar vortex such as distortion or displacement away from the
pole, was applied to the Nimbus-7 TOMS data. The concentrations of ClO required
to account for the observed loss of O3 are higher than those previously
reported. However, the O3 loss rates could be larger than deduced because of
underestimates of total O3 by TOMS near the terminator. These uncertainties
suggest that in early spring, closer to the vortex center, there may be even
larger ClO concentrations than have yet been detected.
"Comparison of Stratospheric Ozone Profiles and Their Seasonal
Variations as Measured by Lidar and Strato-spheric Aerosol and Gas Experiment
During 1988," I.S. McDermid (Jet Propulsion Lab., Wrightwood CA 92397),
S.M. Godin et al., J. Geophys. Res., 95(D5), 5605-5612, Apr. 20,
Presents the data obtained during the first full year of operation of the
lidar and compares them with SAGE II measurements and with the proposed CIRA
reference atmosphere ozone model. Seasonal variations, observed by the two
instruments and indicated by the reference model between 25 km and 50 km, are in
"Uptake of HCl Molecules by Aqueous Sulfuric Acid Droplets as a
Function of Acid Concentration," L.R. Watson (Geophys. Lab., Hanscom Air
Force Base, Bedford MA 01731), J.M. Van Doren et al., ibid., 5631-5638.
Measures the uptake of HCl at 283 K. Results are in good accord with
calculations based on the decrease in the solubility of HCl with increasing
H2SO4 mole fraction. Indicates that mass accommodation coefficients are large
enough to show that the HCl content of stratospheric aerosols will be determined
entirely by this solubility.
"Heterogeneous Reactions on Model Polar Strato-spheric Cloud
Surfaces: Reaction of N2O5 on Ice and Nitric Acid Trihydrate," M.A. Quinlan
(Dept. Chem., Univ. Calif., Berkeley CA 94720), C.M. Reihs et al., J. Phys.
Chem., 94(8), 3255-3260, Apr. 19, 1990.
Used a Knudsen cell flow reactor in a laboratory study of the heterogeneous
reaction of N2O5. N2O5 was quantitatively converted to HNO3 on ice surfaces at
188 K. On initially pure ice surfaces, a gradual increase in the N2O5 uptake
efficiency was observed up to a maximum value near 0.03.
"Photodissociation of OClO: REMPI Study of Primary Photofragments,"
E. Rühl (Dept. Chem., Univ. Colorado, Boulder CO 80309), A. Jefferson, V.
Vaida, ibid., 94(7), 2990-2994, Apr. 5, 1990.
Investigates the photochemistry of OClO of samples in the collision-free
conditions of a molecular jet. Assesses in situ formed photolysis
products, outlines the photochemical mechanism of OClO, and explains the
implications of the revised picture of OClO photoreactivity with regard to
stratospheric ozone depletion.
"Stratospheric Ozone Depletion at Northern Midlatitudes after Major
Volcanic Eruptions," H. Jäger (Fraunhofer Inst. Atmos. Environ. Res.,
D-8100 Garmisch-Partenkirchen, FRG), K. Wege, J. Atmos. Chem., 10,
Analyzes ozone variations measured at Hohenpeissenberg with respect to
dynamic transport variations related to the quasibiennial oscillation. Results
show that the 1985 ozone minimum is a transport effect, but that at 17 to 20 km
in 1982-1983, 30 to 40% of the deficiency was probably related to the aerosol
perturbation of the lower stratosphere following the April 1982 eruption of the
Mexican volcano El Chichón.
"Kinetics of the Reactions of CF2ClO2 Radicals with Nitrogen Dioxide,"
S.B. Moore (Dept. Chem. Eng., Univ. Minn., Minneapolis MN 55455), R.W. Carr,
ibid., 94(4), 1393-1400, Feb. 22, 1990.
Reports the determination by flash photolysis with time-resolved mass
spectrometry of the room temperature rate constant for the reaction CF2ClO2 +
NO2 + M yields CF2ClO2NO2 + M. Concludes that this reaction must certainly
occur in the stratosphere and play a role in the rate of Cl release from
halocarbons present there.
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