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A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999

FROM VOLUME 10, NUMBER 3, MARCH 1997

PROFESSIONAL PUBLICATIONS...
TROPOSPHERIC OZONE

Item #d97mar24

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 Tropospheric Atmosphere.

"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: reh@mtu.edu), 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.

Item #d97mar25

"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: jaek@knuecc-sun.knue.ac.kr), 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 Southern Hemisphere.

Item #d97mar26

"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: laura@misu.su.se), 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.

Item #d97mar27

"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 particle formation.

Item #d97mar28

"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: manish@prl.ernet.in), 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.

Item #d97mar29

"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, 1996.

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 ozone budget.

Item #d97mar30

"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.

Item #d97mar31

"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.

Item #d97mar32

"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.

Item #d97mar33

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. Atherton,. .

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.

Item #d97mar34

"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.

Item #d97mar35

"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.

Item #d97mar36

"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.

Item #d97mar37

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.