February 28, 2007
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A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999
FROM VOLUME 9, NUMBER 5, MAY 1996
OZONE DEPLETION: CHEMISTRY & DYNAMICS
"Evidence of Large Scale Ozone Depletion Within the Arctic Polar
Vortex 94/95 Based on Airborne LIDAR Measurements," M. Wirth (Inst. Phys.
der Atmos., Münchner Str. 20, 82230 Wessling, Ger.), Geophys. Res.
Lett., W. Renger, 23(8), 813-816, Apr. 15, 1996.
Measurements made during SESAME show that the ozone mixing ratio declined
from the beginning of February to mid-March by about 50% throughout the polar
vortex, in a sharply defined altitude band. Analysis shows that the decrease
cannot be attributed to dynamic transport.
Two related items in Nature, 379(6565), Feb. 8, 1996:
"Satellite Confirmation of the Dominance of Chlorofluorocarbons in the
Global Stratospheric Chlorine Budget," J.M. Russell III (NASA-Langley Res.
Ctr., Hampton VA 23681), M. Luo et al., 526-529. The present concentration of
ozone-destroying stratospheric chlorine is more than five times that expected
from known natural emissions from the oceans and from biomass burning, yet the
political sensitivity of the ozone depletion issue has generated a
re-examination of the evidence. This paper reports a four-year global time
series of satellite observations of hydrogen chloride and hydrogen fluoride in
the stratosphere, which shows conclusively that releases of CFCsrather
than other anthropogenic or natural emissions are responsible for the
recent global increases in stratospheric chlorine concentrations. The results
implicate CFCs beyond a reasonable doubt as dominating ozone depletion in the
"There's Safety in Numbers," W. Brune (Dept. Meteor., Pennsylvania
State Univ., Univ. Pk. PA 16802), 486-487. Discusses how the previous paper
strengthens the already powerful scientific case that underlies the Montreal
"The Effects of Tropical Cirrus Clouds on the Abundance of Lower
Stratospheric Ozone," A.E. Dessler (Code 916, NASA-Goddard, Greenbelt MD
20771), K. Minschwaner et al., J. Atmos. Chem., 23(2), 209-220,
Calculations show the significant effect of high cirrus clouds on the net
radiative heating of the tropical lower stratosphere, which influences the
amount of ozone calculated. Concludes that calculated ozone is sensitive to the
inclusion of clouds in models.
"Bromine-Chlorine Coupling in the Antarctic Ozone Hole," M.Y.
Danilin (Atmos. & Environ. Res. Inc., 840 Memorial Dr., Cambridge MA 02139),
N.-D. Sze et al., Geophys. Res. Lett., 23(2), 153-156, Jan. 15,
Model calculations show that ozone destruction by chlorine increases as
bromine levels decrease in the lower stratosphere. This finding has implications
for the control of anthropogenic compounds to reduce ozone loss. Further
modeling and measurements are needed to clarify this relationship.
"On the Relationship Between the Quasi-Biennial Oscillation, Total
Chlorine and the Severity of the Antarctic Ozone Hole," N. Butchart
(Meteor. Off., London Rd., Bracknell, Berkshire RG12 2SZ, UK), J. Austin, Quart.
J. Royal Meteor. Soc., 122, 183-217, Jan. 1996 (Part A).
Explores this relationship with a 3-D model of the dynamics and radiation of
the stratosphere and mesosphere, finding that the influence of the oscillation
is considerable. Makes the general conclusion that in the more sensitive
conditions of low chlorine levels, current models may oversimplify the
representation of heterogeneous processes, so we cannot be certain for what
future atmospheric conditions the ozone hole will disappear until models are
able to simulate accurately the historical onset of the hole.
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