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A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999
FROM VOLUME 3, NUMBER 6, JUNE 1990
STRATOSPHERIC OZONE CHEMISTRY
"Observations of Denitrification and Dehydration in the Winter Polar
Stratospheres," D.W. Fahey (Aeronomy Lab., NOAA, Boulder CO 80303), K.K.
Kelly et al., Nature, 344(6264), 321-324, Mar. 22, 1990.
Argues that Arctic denitrification can be explained by the selective growth
and sedimentation of aerosol particles rich in nitric acid. Because reactive
nitrogen species moderate the destruction of ozone by chlorine-catalyzed
reactions, by sequestering chlorine in reservoir species such as ClONO2, the
possibility of the removal of reactive nitrogen without dehydration should be
allowed for in attempts to model ozone depletion in the Arctic.
"A Comparison of Solar Mesosphere Explorer and Stratosphere Aerosol
and Gas Experiment II Ozone Densities Near the Stratopause," D.W. Rusch
(LASP, Univ. Colo., Boulder CO 80309), R.T. Clancy et al., J. Geophys. Res.,
95(D4), 3533-3537, Mar. 20, 1990.
Compares ozone measurements made by two instruments at 1.0 mbar for the time
period October 1984 to December 1986. These instruments agree to within 5% at
all latitudes considered in the comparison. Results support the accuracy and
precision of each instrument and the accuracy of ozone trends derived over the
1982-1986 period from Solar Mesosphere Explorer data.
"Laboratory Studies on the Stratospheric NOx Production Rate,"
G.D. Greenblatt (R/E/AL2/NOAA, 325 Broadway, Boulder CO 80303), A.R.
Ravishankara, ibid., 3539-3547.
Measured yields showed excellent agreement with NO yields predicted from a
model using previously measured rate parameters. The results of this experiment
reduced the most probable uncertainty in the yield of NO from near 80% to less
"The Role of Chlorine Chemistry in Antarctic Ozone Loss:
Implications of New Kinetic Data," J.M. Rodriguez (Atmos. Environ. Res.
Inc., 840 Memorial Dr., Cambridge MA 02139), M.K.W. Ko, N.D. Sze, Geophys.
Res. Lett., 17(3), 255-258, Mar. 1990.
New kinetic data, yielding a slower formation rate and larger absorption
cross sections of Cl2O2, are incorporated into a photochemical model to reassess
the role of chlorine chemistry in the ozone reductions derived from Antarctic
TOMS observations during 1987. Ozone reductions calculated from chlorine
catalytic cycles are still consistent with observed decreases in column ozone
between August and October 1987 in the vortex core.
"Effects of Initial Active Chlorine Concentrations on the Antarctic
Ozone Spring Depletion," G.S. Henderson (Dept. Geol., Univ. Toronto,
Toronto, Ont. M5S 3B1, Can.), W.F.J. Evans, J.C. McConnell, J. Geophys. Res.,
95(D2), 1899-1908, Feb. 20, 1990.
Presents the results of further numerical experiments, conducted with a
one-dimensional photochemical model, to investigate the effects of the initial
conditions for Clx (all forms of odd chlorine) upon the depletion of O3 during
the austral spring. The main O3 loss is due to formation and photolysis of
Cl2O2. The depth of the O3 minimum in spring appears to be related to the
vertical extent of the region chemically processed by polar stratospheric
clouds, as well as to the absolute levels of active Clx.
"Ozone and Temperature Profiles Over McMurdo Station Antarctica in
the Spring of 1989," T. Deshler (Dept. Phys., Univ. Wyoming, Laramie WY
82071), D.J. Hofmann et al., Geophys. Res. Lett., 17(2),
151-154, Feb. 1990.
Thirty-nine soundings of pressure, temperature and O3 using balloon-borne
sensors were conducted from August 23 to October 30, 1989. Compared to 1986 and
1988 the stratosphere was colder and ozone depletion worse.
"Ozone Depletion in the Arctic Vortex at Alert During February 1989,"
W.F.J. Evans (Atmos. Environ. Serv., 4905 Dufferin St., Downsview, Ont. M3H 5T4,
Can.), ibid., 167-170.
Reports a series of 15 measurements of ozone profiles within the winter
polar vortex, most of which show a depleted layer. Comparison of the late
February and late January ozone profiles indicates that the depletion was due to
a process which may have occurred while the polar air was partially in sunlight.
The depletion may have started at high altitudes above 22 km and moved downwards
during February in a manner similar to the process in September in the
"Large Stratospheric Sudden Warming in Antarctic Late Winter and
Shallow Ozone Hole in 1988," H. Kanzawa (Nat. Inst. Polar Res., 1-9-10
Kaga, Itabashi-ku, Tokyo 173, Japan), S. Kawaguchi, Geophys. Res. Lett.,
17(1), 77-80, Jan. 1990. Describes the behavior of stratospheric
temperatures and total ozone mainly over the Syowa Station in 1988, and compares
them to the past 22-year trend. The data show that dynamics plays an essential
role in many aspects of the Antarctic ozone hole.
"ER-2 Mountain Wave Encounter Over Antarctica: Evidence for
Blocking," J.T. Bacmeister (Dept. Earth Sci., Johns Hopkins Univ.,
Baltimore MD 21218), M.R. Schoeberl et al., ibid., 81-84. Reasonable
agreement between a three-dimensional linear model of orographically forced
gravity waves and observations is obtained if the effects of low-level flow
blocking are taken into account.
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