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 9, NUMBER 9, SEPTEMBER 1996
OZONE DEPLETION: CHEMISTRY & DYNAMICS
Geophys. Res. Lett., 23(17), Aug. 15, 1996. Contains 32 papers
on the ATLAS (Atmospheric Laboratory for Applications and Science) space shuttle
missions, with the following introduction:
"The Atlas Series of Shuttle Missions," J.A. Kaye (Office of
Mission to Planet Earth, NASA, Washington DC 20546; e-mail:
firstname.lastname@example.org), T.L. Miller, 2285-2288. These missions, conducted in
March 1992, April 1993 and November 1994, made measurements of solar (total and
spectrally resolved) irradiance, atmospheric temperatures, and trace gas
concentrations. The missions complemented other programs, such as NASA's Upper
Atmosphere Research Satellite, which contained similar instruments and could
make "correlative measurements." Topics covered in the papers include
ozone in the high-latitude stratosphere, the latitudinal distribution and
seasonal variation of water vapor and ClO, trace gas transport in the Arctic
vortex, tracers in the vortex, trends of trace gases in the lower stratosphere,
and nitrogen compounds in the stratosphere.
"The Potential of
Cirrus Clouds for Heterogeneous Chlorine Activation," S. Borrmann (Inst.
Atmos. Phys., Becherweg 21, Univ. Mainz, D-55099 Mainz, Ger.; e-mail:
email@example.com), S. Solomon et al., Geophys. Res. Lett.,
23(16), 2133-2136, Aug. 1, 1996.
Using ER-2 data (from the Airborne Arctic Stratospheric Expeditions) taken
during ascents and descents through layers of cirrus clouds, studied
heterogeneous reactions of ClONO2 with H1O, of HOCl and ClONO2 with HCl, and
their potential role for activation of Cl near the tropopause and the potential
effects on ozone there. Found considerable potential of cirrus clouds for Cl
activation. If ClONO2 and HCl are present, they are likely to be quickly
converted to active Cl by cirrus clouds.
Observations of Organic and Inorganic Chlorine in the Stratosphere: The Role of
HClO4 Production on Sulfate Aerosols," L. Jaeglé (Dept. Earth &
Planetary Sci., Pierce Hall, Harvard Univ., 29 Oxford St., Cambridge MA 02138;
e-mail: firstname.lastname@example.org), Y.L. Yung et al., Geophys. Res. Lett., 23(14),
1749-1752, July 1, 1996.
Between 15 to 20 km, the sum of measured HCl, ClONO2 and HOCl could not
account for all the inorganic Cl. The new species measured, HClO4, could bring
to closure this budget deficiency. This also confirms laboratory measurements
that the reaction of ClO radicals on H1SO4 produces small amounts of perchloric
"Chemical Loss of
Polar Vortex Ozone Inferred from UARS MLS Measurements of ClO During the Arctic
and Antarctic Late Winters of 1993," I.A. MacKenzie (Dept. Meteor., Univ.
Edinburgh, Edinburgh, EH9 3JZ Scotland), R.S. Harwood et al., J. Geophys.
Res., 101(D9), 14,505-14,518, June 20, 1996.
Used a computationally cheap, and easily initialized photochemical model
with UARS MLS measurements of ClO to calculate ozone destruction rates within
polar vortices due to ClO + ClO, ClO + BrO, and ClO + O catalytic cycles. Test
integrations gave good agreement with more detailed model calculations. The
estimated chemical destruction on isentropic surfaces in the lower stratosphere
is broadly similar to the observed change in ozone distribution, implying that
the change is dominated by chemical destruction.
Two related items in
Science, 272(5268), June 14, 1996:
"Polar Clouds and Sulfate Aerosols," M.A. Tolbert (Dept. Chem.,
Univ. Colorado, Boulder CO 80309; e-mail: email@example.com), 1597. Discusses
how the theoretical work of the following article helps explain why type I PSCs
form over and over throughout the winter, and what questions remain.
"Melting of H1SO4¨4H1O Particles upon Cooling: Implications for
Polar Stratospheric Clouds [PSC]," T. Koop (M. Planck Inst. Chem., POB
3060, D-55020 Mainz, Ger.), K.S. Carslaw, 1638-1641. Solid PSC can form on
sulfuric acid tetrahydrate (SAT) nuclei, but laboratory experiments have shown
that PSC nucleation on SAT is strongly hindered. Proposes a PSC formation
mechanism in which SAT particles melt upon cooling in the presence of HNO3 to
form liquid HNO3-H1SO4-H1O droplets, 2-3 K above the ice frost point. This
offers a PSC formation temperature that is defined by the ambient conditions and
sets a temperature limit below which PSCs should form.
"Is It Possible
to 'Repair' the Ozone Holes?" I.L. Karol' (Voyeykov Main Observatory,
Russia), A.A. Kiselev, V.A. Frol'kis, Atmos. & Oceanic Phys., 31(1),
113-115, June 1995. English Edition.
Used a radiative-photochemical model to estimate the intensity and optimum
altitude needed for an ozone source to increase total column ozone under
conditions of the Arctic and Antarctic ozone holes. The ozone source considered
is not related to any particular project nor does it depend on any particular
method of generation. The calculated required injection is so large as to be
unrealistic at the current level of technical development.
Simulation of the Dynamical Response of the Arctic Vortex to Aerosol-Associated
Chemical Perturbations in the Lower Stratosphere," X. Zhao (Dept. Atmos.
Sci., Univ. California, Los Angeles CA 90095), R.P. Turco et al., Geophys.
Res. Lett., 23(12), 1525-1528, June 1, 1996.
Used a general circulation model coupled to a stratospheric photochemistry
model to study the effect on the Arctic polar vortex of ozone depletion
catalyzed by volcanic aerosols. Model results show that temperatures may be
depressed as much as 3-7 K in late March in the lower stratosphere at northern
middle and high latitudes, owing to ozone-radiation-dynamics feedback. The
simulations demonstrate the close coupling between the dynamics and chemistry in
this region, and the complexity of analyzing cause and effect
"Model Study of
Polar Stratospheric Clouds [PSCs] and Their Effect on Stratospheric Ozone. 2.
Model Results," X. Tie (NCAR, POB 3000, Boulder CO 80307), G.P. Brasseur et
al., J. Geophys. Res., 101(D7), 12,575-12,584, May 20, 1996.
Used the model described in Part 1 to study the effect of heterogeneous
reactions on PSC surfaces on stratospheric ozone. Calculations show that these
reactions are the likely cause of the ozone decrease from 1980 to 1990 in the
Antarctic and the Arctic. Also demonstrates that the future density of Arctic
PSCs could be enhanced by the potential emission of water vapor and nitrogen
species by high altitude aircraft, which could in turn lead to a maximum of
ozone depletion of 10% at northern high latitudes in winter.
"Decline in the
Tropospheric Abundance of Halogen from Halocarbons: Implications for
Stratospheric Ozone Depletion," S.A. Montzka (CMDL, NOAA 325 Broadway,
Boulder CO 80303), J.H. Butler et al., Science, 272(5266),
1318-1322, May 31, 1996.
Previous studies have shown that tropospheric chlorine attributable to
anthropogenic halocarbons peaked near the beginning of 1994 and has started to
decrease. The authors have estimated the effect of this trend on stratospheric
ozone, concluding that the amount of reactive chlorine and bromine there will
reach a maximum between 1997 and 1999. Concentrations will decline thereafter if
limits outlined in the adjusted and amended Montreal Protocol are not exceeded
in future years.
J. Geophys. Res., J.C. Gille, S.T. Massie, W.G. Mankin, Eds., 101(D6),
April 30, 1996.
Contains 46 papers that evaluate the quality of the data collected between
15 and 100 km altitude by the Upper Atmosphere Research Satellite (UARS). The
success of UARS data validation rests on several foundations. There was
enthusiastic support and involvement of the instrument principal investigators
in planning and evaluation. Early planning, budgeting and staffing for
correlative measurements were essential. Time and effort were taken to refine
and improve algorithms, to acquire correlative measurements and supply them to
"The Role of
Aerosol Variations in Anthropogenic Ozone Depletion at Northern Midlatitudes,"
S. Solomon (Aeronomy Lab., NOAA, 325 Broadway, Boulder CO 80303), R.W. Portmann
et al., J. Geophys. Res., 101(D3), 6713-6727, Mar. 20, 1996.
Quantifies the role of volcanic stratospheric aerosols in ozone depletion by
using satellite measurements of aerosol extent as input to a two-dimensional
dynamical-chemical model. The model simulated the effects of heterogeneous ozone
chemistry at northern midlatitudes over the last 15 years, a time period that
included major volcanic eruptions. Results show that interannual and decadal
changes in aerosols likely played a substantial role, along with trends in
anthropogenic Cl and Br, in triggering the observed ozone losses. The timing and
magnitude of future ozone losses in the area of investigation are likely to be
strongly dependent on volcanic aerosol variations, as well as on future Cl and
Br loading. The results also underscore the potential importance of any future
source of particles, such as supersonic aircraft emissions.
Vertical Column Abundances Above the Jungfraujoch Station, 1986-1994: Long-Term
Trend and Winter-Spring Enhancements," C.P. Rinsland (Atmos. Sci. Div.,
NASA-Langley Res. Ctr., Hampton VA 23681), R. Zander et al., ibid., 101(D2),
3891-3899, Feb. 20, 1996.
Solar absorption spectra show a regular, long-term increase in ClONO2, and
in general reflect a linear rate of increase and 1Ő uncertainty equal to
4.0% ± 0.7% per year referenced to 1990.
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Index of Abbreviations