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 10, NUMBER 1, JANUARY 1997
OZONE DEPLETION: DISTRIBUTION & TRENDS
"Recovery of Antarctic Ozone Hole," D.J. Hofmann (CMDL/NOAA,
325 Broadway, Boulder CO 80303; e-mail: email@example.com), Nature,
384(6606), 222-223, Nov. 21, 1996.
Detection of the first signs of healing of the ozone layer is important
because it will provide verification of the research that prompted the ban of
ozone-depleting substances under the Montreal Protocol. This detection may occur
early in the next century, and likely will first be observed over Antarctica
because springtime depletion there is large compared to natural variability.
Owing to their lower natural variability, suitable early ozone-healing
indicators will probably be the ozone-loss rate, and the amount of ozone
remaining in the 12-20 km altitude interval on Sep. 15 each year.
"Ozone and Aerosol Observed by Lidar in the Canadian Arctic During
the Winter of 1995/96," D.P. Donovan (Inst. for Space & Terrestrial
Sci., 4700 Keele St., N. York ON M3J 1P3, Can.), J.C. Bird et al., Geophys.
Res. Lett., 23(23), 3317-3320, Nov. 15, 1996.
Observations at Eureka showed substantial declines in ozone mixing ratios
and reductions in ozone levels of up to 40% between the 410 K and 580 K
isentropic levels. The correlation of ozone data with potential vorticity and
concurrent lidar observations of stratospheric aerosol is consistent with the
claim that significant chemical depletion did occur there.
"Polar Vortex Conditions During the 1995-96 Arctic Winter:
Meteorology and MLS Ozone," G.L. Manney (Jet Propulsion Lab., 4800 Oak
Grove Dr., Pasadena CA 91109; e-mail: firstname.lastname@example.org), M.L. Santee et
al., ibid., 23(22), 3203-3206, Nov. 1, 1996.
The winter stratosphere for this region and time period was colder than in
any of 17 previous winters. Consistent with the unusual cold and associated
chemical processes on polar stratospheric clouds (PSCs), satellite measurements
showed that ozone decreased throughout the vortex over an altitude range nearly
as large as is typical of the Southern Hemisphere. As in prior winters,
temperatures in 1996 rose above the PSC threshold, ending chemical processing in
the vortex much earlier than is usual in the Southern Hemisphere.
"Development of the Antarctic Ozone Hole," M.R. Schoeberl
(NASA-Goddard, Code 916, Greenbelt MD 20771), A.R. Douglass et al., J.
Geophys. Res., 101(D15), 20,909-20,924, Sep. 20, 1996.
Improves on previous model simulations of the ozone hole using a Lagrangian
chemical model, which simulates chemical reactions following air parcels as they
move. A benchmark simulation of HNO3, ClONO2, ClO and O3 for Sep. 17, 1992, is
in good agreement with UARS observations, and a simulation of the ozone column
for 1979-1994 shows quantitative agreement with the secular decline in Antarctic
ozone and the change in the area of the ozone hole as observed by TOMS. A
hypothetical doubling of the 1992 atmospheric Cl amount would expand the ozone
hole to the very edge of the polar vortex.
"Validation of NOAA-9 SBUV/2 Total Ozone Measurements During the
1994 Antarctic Ozone Hole," J.H. Lienesch (Natl. Environ. Satellite, Data &
Info. Service, NOAA, Washington DC 20233), W.G. Planet et al., Geophys. Res.
Lett., 23(19), 2593 2596, Sep. 15, 1996.
Measurements made by different satellites must be consistent. This article
describes calibration of the SBUV instruments on the NOAA-9 and NOAA-11
satellites. The agreement achieved makes possible a continuation of the
Antarctic measurements without a large instrument-related bias, and establishes
data from NOAA-9 as a suitable transition data set during the replacement of
NOAA-11 by NOAA-14.
"Estimating the Ozone Decline over Eurasia in 1973-1995 Using
Reevaluated Filter-Ozonometer Data," R.D. Bojkov (WMO, POB 5, CH-1211
Geneva 20, Switz.), V.E. Fioletov et al., Russian Meteor. & Hydrol.,
No. 9, 19-27, 1995.
This re-evaluation of routinely-made, ground-based measurements demonstrates
a strong ozone deficiency over the former USSR averaging up to 12% for
winter-spring and 5% for summer. This can not be explained by natural ozone
fluctuations or by instrumental error. For the winter-spring of 1995,
ground-based data were the only source of real-time information, demonstrating
the importance of the existence and continuation of ground-based measurements.
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