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 4, NUMBER 7, JULY 1991
"Sensitivity of Stratospheric Ozone to Heterogeneous Chemistry on
Sulfate Aerosols," G. Pitari (Dip.to Fisica, Univ. L'Aquila, 67010 Coppito
L'Aquila, Italy), G. Visconti, Geophys. Res. Lett., 18(5),
833-836, May 1991.
Using a two-dimensional model, including a comprehensive chemical code for
homogeneous and heterogeneous reactions, both background and volcanic aerosols
have been taken into account according to different scenarios. Increase of total
Cl in the stratosphere causes a well-known O3 depletion by itself, but the
effects could be highly enhanced in the presence of a large amount of volcanic
Special Section: "CHEOPS III: An Ozone Research Campaign in
the Arctic Winter Stratosphere 1989/90," ibid., 18(4), Apr.
CHEOPS (CHEmistry of Ozone in the Polar Stratosphere) is a joint
German-French research project begun in 1987 and aimed at understanding the
composition of the lower Arctic stratosphere during the season when polar
stratospheric clouds are most likely. The nine papers in this section report
results of balloon-borne measurements (O3, NOy, HNO3, NO2, radicals, long-lived
species, PSC particles), ground-based observations of various chemical species,
and O3 observations by sondes and spectrophotometers.
"Stratospheric Aerosol and Gas Experiment II and ROCOZ-A Ozone
Profiles at Natal, Brazil: A Basis for Comparison with Other Satellite
Instruments," R.A. Barnes (Chemal Inc., POB 44, Wallops Island VA 23337),
L.R. McMaster et al., J. Geophys. Res., 96, D4, 7515-7530, Apr.
Geophys. Res. Lett., 18(4), Apr. 1991.
"Ozone Profiles at McMurdo Station, Antarctica, the Austral Spring of
1990," T. Deshler (Dept. Phys., Univ. Wyoming, Laramie WY 82071), D.J.
Hofmann, 657-660. Near record levels of O3 depletion were observed; on several
occasions the edge of the polar vortex was over McMurdo, when O3 above 20 km
"The 1990 Antarctic Ozone Hole as Observed by TOMS," P. Newman
(NASA-Goddard, Code 916, Greenbelt MD 20771), R. Stolarski et al., 661-664.
Satellite instruments indicate the 1990 Antarctic ozone hole matched the 1987
record for depth, duration and area, but the ozone hole breakup was the latest
yet recorded. Temperatures were below normal for late spring.
"NO2 Overnight Decay and Layer Height at Halley Bay, Antarctica,"
J.G. Keys (DSIR Phys. Sci., Lauder, N.Z.), B.G. Gardiner, 665-668. Calculations
based on ground-based measurements suggest photolysis of only small amounts of
N2O5 inside the cold core of the polar vortex, in agreement with the previously
proposed idea of N2O5 conversion to HNO3.
"CH4 and N2O Photochemical Lifetimes in the Upper Stratosphere: In Situ
Estimates Using SAMS Data," J.L. Stanford (Dept. Phys., Iowa State Univ.,
Ames IA 50011), J.R. Ziemke, 677-680. Upper stratospheric lifetimes are
estimated for the first time by investigating the time dependence of tracers
injected into high northern latitudes in late winter and their subsequent
photochemical decay in the dynamically quiescent summer stratosphere.
"Measuring Air from Polar Vortices," H.K. Roscoe (British
Antarctic Survey, Natural Environ. Res. Council, Madingley Rd., Cambridge CB3
0ET, UK), Nature, 350(6315), 197-198, Mar. 21, 1991. Proposes a
technique for using limb-sounding sensors to study ozone-destroying cells of
stratospheric air shed from the Arctic winter vortex.
J. Geophys. Res., 96(D3), Mar. 20, 1991.
"Tests of Stratospheric Models: The Reactions of Atomic Chlorine with
O3 and CH4 at Low Temperature," W.B. DeMore (Jet Propulsion Lab., Code
183-601, Pasadena CA 91109), 4995-5000. Experiments on the competitive
chlorination of O3/CH4 mixtures have been carried out at 197-217 K. Showed that
the absolute rate constants recommended by the NASA Panel for Data Evaluation
are accurate on a relative basis to within 15% at stratospheric temperatures.
"Ozone Loss Rates Calculated along ER-2 Flight Tracks," D.M.
Murphy (ERL, NOAA, 325 Broadway, Boulder CO 80303), 5045-5053. Local ozone loss
rates due to the ClO+ClO and BrO+ClO cycles are calculated using ClO, pressure
and temperature from in-situ aircraft measurements and representative BrO mixing
ratios, in a manner that allows one to look for patterns in the O3 loss rate
that may not be apparent in separate measurements of ClO, pressure and
"Three-Dimensional Simulations of Wintertime Ozone Variability in the
Lower Stratosphere," R.B. Rood (NASA-Goddard, Greenbelt MD 20771), A.R.
Douglass et al., 5055-5071. Modeled O3 fields are verified against satellite and
sonde measurements. By sampling the model with a limb-viewing satellite and then
Kalman filtering the "observations" of the model, shows that transient
subplanetary-scale features that are essential to the O3 budget are missed by
the satellite system.
"The Reaction Probabilities of ClONO2 and N2O5 on Polar Stratospheric
Cloud Materials," D.R. Hanson (NOAA, R/E/AL2, 325 Broadway, Boulder CO
80303), A.R. Ravishankara, 5081-5090. Some of the reaction probabilities
estimated differ from previous determinations because of the large reactant
concentrations used by others; implications for polar stratospheric Cl
activation are discussed.
"Satellite Ozone Comparisons: Effects of Pressure and Temperature,"
J.J. Olivero (Dept. Meteor., Penn. State Univ., Univ. Pk. PA 16802), R.A.
Barnes, 5091-5098. Comparisons using SAGE II and SBUV data indicate that modest
differences in vertical positioning can propagate into significant O3
differences in regions with strong vertical O3 gradients, particularly at 70
mbar in the tropics.
"On the Temperature Dependence of Polar Stratospheric Clouds,"
G. Fiocco (Dip.to Fisica, Univ. "La Sapienza," Pl. A. Moro 2, 00184
Roma, Italy), D. Fuà et al., Geophys. Res. Lett., 18(3),
424-427, Mar. 1991. The dependence of Antarctic lidar measurements on
temperature can be used to distinguish the pure nitric acid trihydrate from the
mixed ice-trihydrate phase in the composition of the PSC aerosol, and to provide
indication of particle sizes.
J. Geophys. Res., 96(D2), Feb. 20, 1991.
"Stratospheric Cloud Observations during Formation of the Antarctic
Ozone Hole in 1989," D.J. Hofmann (Dept. Phys., Univ. Wyoming, Laramie WY
82071), T. Deshler, 2897-2912. Describes continued measurements of PSC particle
size distributions, using a new particle counter with 0.5 micron radius size
resolution. A bimodal distribution was caused by small sulfate particles
(0.05-0.10 micron) and by nitric acid trihydrate condensation on larger
sulfate-layer particles (1.5-3.5 micron).
"Inferring the Abundances of ClO and HO2 from Spacelab 3 Atmospheric
Trace Molecule Spectroscopy Observations," M. Allen (Earth Sci. Div., Jet
Propulsion Lab., Pasadena CA 91109), M.L. Delitsky, 2913-2919. A simple
steady-state algebraic expression for ClO, utilizing the observed ClONO2:NO2
abundance ratio, approximates the ClO results of time-dependent photochemical
model calculations at sunset. A similar procedure applied to HO2 confirms for
the first time the procedure suggested previously by a number of authors of
deriving HOx abundances from observed fields of O3 and H2O.
"Ozone and Other Trace Gases in the Arctic and Antarctic Regions: Three
Dimensional Model Simulations," C. Granier (NCAR, POB 3000, Boulder CO
80307), G. Brasseur, 2995-3011. A comprehensive chemical-dynamical model of the
middle atmosphere reproduces important features noted during different
observation campaigns. Despite elevated concentration of active Cl at high
latitudes in the Northern Hemisphere in late winter, no ozone hole is produced
by the model, a conclusion which could be modified for very stable and cold
winters with delayed final warming.
Geophys. Res. Lett., 18(2), Feb. 1991.
"Balloon-Borne Observations of Backscatter, Frost Point and Ozone in
Polar Stratospheric Clouds at the South Pole," J.M. Rosen (Dept. Phys.,
Univ. Wyoming, Laramie WY 82071), N.T. Kjome, S.J. Oltmans, 171-174. The first
measurements of this type showed a large decrease in PSC backscatter above about
14 km before the stratosphere began to warm, consistent with the loss of
particles by sedimentation. No compelling evidence was found supporting earlier
claims that PSC layers are anti-correlated with O3 inside the vortex.
"An Estimate of the Antarctic Ozone Modulation by the QBO," E.
Mancini (Dip.to Fisica, Univ. L'Aquila, 67010 Coppito, L'Aquila, Italy), G.
Visconti et al., 175-178. Comparison of simulations by a two-dimensional model
with parameterization of Kelvin and Rossby-gravity wave forcing indicates a
QBO-induced temperature effect and its feedback on PSC with the activation of
Geophys. Res. Lett., 18(1), Jan. 1991.
"Rate Constants for the Gas Phase Reactions of the OH Radical with
CF3CF2CHCl2 (HCFC-225ca) and CF2ClCF2CHClF (HCFC-225cb)," Z. Zhang (Chem.
Kinetics Div., Nat. Inst. Standards Technol., Gaithersburg MD 20899), R. Liu et
"In Situ Measurements of Midlatitude ClO in Winter," S.W. Toohey
(Dept. Earth Sci., Harvard Univ., Cambridge MA 02128), W.H. Brune et al., 21-24.
Aircraft data collected from 38° N to 61° N show ClO enhancements
that coincide with a major warming of the polar vortex to the north. While the
relationship among chemical processes in the vortex and those at lower latitudes
is not clear, reactions involving ClO at the concentrations observed in the
midlatitudes may be responsible for the O3 decreases observed in the Northern
"The Influence of Polar Heterogeneous Processes on Reactive Chlorine at
Middle Latitudes: Three Dimensional Model Implications," A.R. Douglass
(Atmos. Chem., Code 916, NASA-Goddard, Greenbelt MD 20771), R.B. Rood et al.,
25-28. The chemistry and transport model reproduces basic features of the ClO
measurements, which were made on flights from Norway to California via Virginia
in Feb. 1989. This indicates that perturbed air within the polar vortex during
winter is not homogeneously mixed and that the flights were made through air
with the largest conversion of HCl to reactive chlorine that is seen at middle
"Spatial and Temporal Variability of the Extent of Chemically Processed
Stratospheric Air," J.A. Kaye (addr. immed. above), A.R. Douglass et al.,
29-32. Simulations using a 3-D chemistry-transport model for the winters of 1979
and 1989 show that chemically processed air may be identified over much of the
Arctic lower stratosphere from early January to late February, with HCl
depletions being larger in 1989 than in 1979. There is some evidence for
transport to midlatitudes of processed air.
"Total Ozone Measurements and Stratospheric Cloud Detection during the
AASE and the TECHNOPS Arctic Balloon Campaigns," L. Lef?vre (Météo
France, Ctr. Nat. Recherches Météor., 42 Ave. Coriolis, 31057
Toulouse Cedex, France), D. Cariolle, 33-36. Total O3 fields, calculated for
winter 1989 using the TOVS/HIRS2 infrared radiances, generally show good
agreement with TOMS O3 data. A major type II PSC event is identified in the TOVS
O3 field on January 31.
Geophys. Res. Lett., 17(12), Dec. 1990.
"Equilibrium Constant for the Reaction ClO + O2 [double arrow] ClO.O2,"
W.B. DeMore (Jet Propulsion Lab., 4800 Oak Grove Dr., Pasadena CA 91109),
2353-2355. Photolysis of Cl2/Cl2O/O2 mixtures at 197 K has been used to place an
upper limit on the equilibrium constant for the reaction at three orders of
magnitude below the current NASA recommendation.
"The Pressure Dependence of the Reaction between ClO and OClO at 226 K,"
A.D. Parr (Phys. Chem. Lab., S. Parks Rd., Oxford OX1 3QZ, UK), R.P. Wayne et
al., 2357-2360. The importance of the reaction is discussed in the context of
Antarctic ozone depletion, and an explanation for the unexpected behavior
observed in earlier studies of the OClO/NO2 system is given.
"Measurements of Arctic Total Ozone during the Polar Winter,"
J.B. Kerr (Atmos. Environ. Service, 4905 Dufferin St., Downsview, Ont. M3H 5T4,
Can.), C.T. McElroy et al., Atmos.-Ocean, 28(4), 383-392, Dec.
1990. Ground-based measurements were made during the polar night from three
Arctic stations in the winters of 1987-88 and 1988-89 with automated Brewer
ozone spectrophotometers using the moon as a light source.
"Measurement Intercomparison of the JPL and GSFC Stratospheric Ozone
Lidar Systems," I.S. McDermid (NASA-Goddard, Greenbelt MD 20771), S.M.
Godin et al., Appl. Optics, 29(31), 4671-4676, Nov. 1, 1990.
This first reported side-by-side intercomparison of two stratospheric ozone
lidar systems showed good agreement of the O3 profiles measured between 20-40 km
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