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 3, MARCH 1997
Special section: J. Geophys. Res., 101(D22), Dec.
20, 1996. Contains 35 papers on the 1993 summer intensive phase of the North
Atlantic Regional Experiment (NARE). Listed here are an introductory paper, and
two others which particularly emphasize the global implications of NARE findings
on tropospheric ozone.
"North Atlantic Regional Experiment 1993 Summer Intensive: Foreword,"
F.C. Fehsenfeld (Aeronomy Lab., NOAA, 325 Broadway, Boulder CO 80303), M.
Trainer et al., 28,869-28,875. NARE was established to study how the continents
that rim the North Atlantic are affecting tropospheric composition on a global
scale. Preliminary studies had shown that anthropogenic influences are very
significant contributors to the ozone budget, and the focus of the 1993 NARE
intensive was to investigate ozone, its precursors and its photochemical
coproducts in the near-continent region of North America and Europe. American
activities were complemented by the European project Oxidizing Capacity of the
"Three-Dimensional View of the Large-Scale Tropospheric Ozone
Distribution over the North Atlantic Ocean during Summer," P. Kasibhatla
(Sch. Earth & Atmos. Sci., Georgia Inst. Technol., Atlanta GA 30332), H.
Levy II et al., 29,305-29,316. Tests the performance of a global chemical
transport model by comparing simulations to observations taken during the NARE
campaign. Then compares present-day and preindustrial simulations to show that
anthropogenic NOx emissions have significantly perturbed tropospheric ozone
levels over most of the North Atlantic, and that present-day ozone levels are at
least twice as high as corresponding preindustrial levels.
"Transport of Ozone Precursors from the Arctic Troposphere to the North
Atlantic Region," R.E. Honrath (Dept. Civil Eng., Michigan Technological
Univ., Houghton MI 49931; e-mail: email@example.com), A.J. Hamlin, J.T. Merrill,
29,335-29,351. Combines atmospheric trajectories with field measurements to show
how ozone precursors are transported from the industrialized middle latitudes to
the Arctic. From there they move southward again under conditions conducive to
ozone formation. This process contributes to ozone formation in the North
Atlantic and perhaps other remote areas in the midlatitudes.
"Climatology and Trends of Tropospheric Ozone over the Eastern
Pacific Ocean: The Influences of Biomass Burning and Tropospheric Dynamics,"
J.H. Kim (Earth System Sci. Div., NASA/Marshall Space Flight Ctr., Huntsville AL
35812; e-mail: firstname.lastname@example.org), Geophys. Res. Lett., 23(25),
3723-3726, Dec. 15, 1996.
Analyzes tropospheric ozone climatology derived from satellite measurements
in conjunction with meteorological and biomass-burning data. In the latitude
band 2° N-22° S, ozone shows strong seasonal variation that is well
correlated with the biomass burning season over southern tropical South America.
Positive trends over the 14 years analyzed are strongest in the tropical
"Could Cloud-to-Cloud Discharges Be as Effective as Cloud-to-Ground
Discharges in Producing NOx?" L. Gallardo (Dept. Meteor., Stockholm Univ.,
106 91 Stockholm, Swed.; e-mail: email@example.com), V. Cooray, Tellus,
48B, 641-651, Nov. 1996.
Global models of tropospheric ozone and oxidized nitrogen usually assume
that cloud-to-cloud discharges are several times less effective (per discharge)
than cloud-to-ground discharges in producing nitrogen oxides. The authors claim
that the two are similar, and use a global 3-D climatological tracer model to
demonstrate this assertion. They also show the sensitivity of the two species to
the vertical distribution of lightning source assumed.
"Observations of Near-Zero Ozone Concentrations Over the Convective
Pacific: Effects on Air Chemistry," D. Kley, P.J. Crutzen et al., Science,
274(5285), 230-233, Oct. 11, 1996.
Measurements made over the equatorial Pacific showed ozone levels frequently
below 10 nanomoles per mole both in the marine boundary layer and between 10 km
and the tropopause. These results emphasize the enormous variability of tropical
tropospheric ozone and hydroxyl concentrations. They also imply a convective
short circuit of marine gaseous emissions, such as dimethyl sulfide, between the
sea surface and the upper troposphere, leading, for instance, to sulfate
"Changes in Surface Ozone Amount and Its Diurnal and Seasonal
Patterns, from 1954-55 to 1991-93, Measured at Ahmedabad (23° N), India,"
M. Naja (Physical Res. Lab., Navrangpura, Ahmedabad 380 009, India (e-mail:
firstname.lastname@example.org), S. Lal, Geophys. Res. Lett., 23(1), 81-84,
Jan. 1, 1996.
Despite the crucial role of ozone as a greenhouse gas and in the production
of OH radicals, there are few systematic, long-term measurements in the tropics.
The measurements presented here show a linear increase of 1.45% per year in
average ozone between the two periods analyzed; background concentrations
increased by 0.49% per year.
"Unexpectedly Low Ozone Concentration in Midlatitude Tropospheric
Ice Clouds: A Case Study," J. Reichardt (GKSS-Forschungszentrum Geesthacht,
Postfach 1160, 21494 Geesthacht, Ger.; e-mail: jens.reichardt@ gkss.de), A.
Ansmann et al., Geophys. Res. Lett., 23(15), 1929-1932, July 15,
Raman lidar measurements of ozone, water vapor, and cirrus optical
properties made in the early stages of a long-term program show pronounced ozone
minima in the presence of ice cloud layers. Results warrant an extensive study
of the possible influence on tropospheric ice clouds on the upper tropospheric
"More Worries About Pollution," Nature, 381(6582),
451, June 6, 1996.
This editorial argues for the importance of tropospheric ozone to climate
change, and for the need to overcome institutional and political barriers to
fund monitoring stations in the developing world for this and other species.
"Concentrations of Tropospheric Ozone from 1979 to 1992 over
Tropical Pacific South America from TOMS Data," Y. Jiang, Y.L. Yung (Div.
Glaciol. & Planetary Sci., Calif. Inst. Technol., Pasadena CA 91125), Science,
272(5262), 714-716, May 3, 1996.
Satellite measurements indicate that tropospheric ozone increased by 1.48 ±
0.40 percent per year over South America and the surrounding oceans. An increase
in biomass burning in the Southern Hemisphere can account for this trend.
"A Tropospheric Ozone-Lightning Climate Feedback," R. Toumi
(Dept. Phys., Imperial College, London SW7 2BZ, UK), J.D. Haigh, K.S. Law, Geophys.
Res. Lett., 23(9), 1037-1040, May 1, 1996.
Tropospheric ozone is an important greenhouse gas, and one of its major
sources in the upper troposphere are the nitrogen oxides produced by lightning.
Recent work has shown that lightning frequency may be very sensitive to changes
in the surface temperature. Experiments with a two-dimensional atmospheric model
described here show the possibility of a positive climate feedback mechanism
through ozone production by lightning.
Two items in Atmos. Environ., 30(10/11), May 1996:
"Radiative Forcing Due to Increased Tropospheric Ozone Concentrations,"
S. Chalita (Service d'Aéronomie du CNRS, Univ. Paris, 6 Pl. Jussieu,
Boite 102, 75252 Paris, Cedex 05, France), D.A. Hauglustaine et al., 1641-1646.
To determine their radiative forcing impact, pre-industrial and present-day
tropospheric ozone concentrations are simulated by a 3-D chemical transport
model in conjunction with a general circulation model. Ozone forcing is
regionally heterogeneous with a marked interhemispheric difference; it peaks
over the Northern Hemisphere continents in summer and locally reaches more than
1 W m-2. Changes in concentration in the high troposphere have about 10 times
more radiative impact than those in the planetary boundary layer. A 10% per
decade growth rate of ozone in the future implies an increase of 2 W m-2.
"The Role of Anthropogenic Emissions of NOx on Tropospheric Ozone over
the North Atlantic Ocean: A Three-Dimensional, Global Model Study," C.S.
D.D. Parrish (Aeron. Lab., NOAA, 325 Broadway, Boulder CO 80303) et al.,
1739-1749. The model is run with a baseline scenario and one in which North
American fossil fuel NOx emissions are reduced 50%. The NOx reduction produces a
30% reduction in the total mass of tropospheric ozone exported from North
America to the North Atlantic Ocean.
"The Impact of Man-Made and Natural NOx Emissions on Upper
Tropospheric Ozone: A Two-Dimensional Model Study," A. Strand (Geophys.
Inst., Univ. Bergen, Allégaten 70, N-5007 Bergen, Norway), O. Hov, ibid.,
30(8), 1291-1303, Apr. 1996.
Used a comprehensive 2-D zonally averaged chemistry-transport model to
evaluate the relative contributions to upper tropospheric NOx of lightning,
rapid vertical transport from the boundary layer, and aircraft emissions. The
impact of all three sources on upper tropospheric ozone was significant. For
July conditions, about half the ozone produced chemically at this level in the
northern mid-latitudes is anthropogenic; at other latitudes NOx from lightning
appears to be the dominant ozone precursor.
"Impacts of Increased Anthropogenic Emissions in Asia on
Tropospheric Ozone and Climate. A Global 3-D Model Study," T. Berntsen
(Inst. Geophys., Univ. Oslo, POB 1022, Blindern, 0315 Oslo, Norway), I.S.A.
Isaksen et al., Tellus, 48B(1), 13-32, Feb. 1996.
Asia was selected for study because its emissions are rapidly increasing,
and there is a large potential for future increases. A doubling of NOx emission
leads to ozone increases up to 30% in the upper troposphere. Increased
tropospheric ozone causes a positive radiative forcing of about 0.5 W m-2, which
is 30-50% of the estimated negative radiative forcing due to the direct effect
of sulfate aerosols.
"Subsonic Aircraft and Ozone Trends," A.E. Jones (Brit.
Antarctic Survey, High Cross, Madingley Rd., Cambridge CB3 0ET, UK), K.S. Law,
J.A. Pyle, J. Atmos. Chem., 23(1), 89-105, Jan. 1996.
Describes calculations of the impact that subsonic aircraft may already have
had on the atmosphere during the 1980s, using a 2-D chemical-radiative transport
model. Results show a significant increase in upper tropospheric ozone
over the period. They do not show any contribution to lower stratospheric ozone
loss, but they do highlight the sensitivity of the governing reactions at that
altitude to NOx concentrations. With the projected increasing trend of subsonic,
high altitude aircraft, the influence of their NOx emissions on lower
stratospheric ozone must be considered seriously.
Two items in J. Geophys. Res., 101(D1), Jan. 20, 1996:
"Three-Dimensional Model Studies of the Effect of NOx Emissions from
Aircraft on Ozone in the Upper Troposphere over Europe and the North Atlantic,"
F. Flatoy (Geophys. Inst., Univ. Bergen, Allégaten 70, N-5007 Bergen,
Norway), O. Hov, 1401-1422, Jan. 20, 1996. A mesoscale chemistry transport model
is coupled to a numerical weather prediction model to show that air traffic
emissions significantly increase the concentrations of NOx as well as the
formation of ozone over the Atlantic Ocean and central Europe.
"Atmospheric Impact of NOx Emissions by Subsonic Aircraft: A
Three-Dimensional Model Study," G.P. Brasseur (NCAR, POB 3000, Boulder CO
80307), J.-F. Müller, C. Granier, 1423-1428. Calculations suggest that the
world's fleet of subsonic aircraft has enhanced the abundance of nitrogen oxides
in the upper troposphere by up to 20-35%, and has increased ozone there by 4% in
summer and 1% in winter. On the basis of current growth scenarios in aviation,
by the year 2050 ozone could be enhanced by 7% in summer over the entire
Northern Hemisphere, although the uncertainty in this estimate is large.
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