Impact of aircraft emissions on tropospheric and stratospheric ozone. Part I: chemistry and 2-D model results

Abstract The impact of air-traffic-induced NOx and water vapor emissions on the chemical composition of the global troposphere and stratosphere is investigated for current conditions (1991) and a future scenario (2015). The NOx dependence of ozone chemistry is studied using photochemical steady-state calculations for a typical upper tropospheric chemical composition. These calculations demonstrate that above a critical NOx mixing ratio of about 0.3 ppbv, additional NOx emitted by aircraft can actually decrease the net ozone production, whereas below this value there is the commonly accepted increase in ozone production. Subsequently, we assess the impact of aircraft emissions on photochemical ozone production using the Mainz two-dimensional photochemical model including effects of heterogeneous chemistry in the lower stratosphere. Based on not well-represented convection, 2-D models generally underestimate background values of NOx in the free troposphere, hence overestimate the ozone increase caused by subsonic aircraft. In particular, convection might shift the NOx mixing ratio above the critical 0.3 ppbv level. To correctly reproduce the impact of this non-linear relation on ozone, a 3-D model calculation is essential, especially for mid-latitude summer, where significant convection take place. For northern winters, where due to weak convection the 2-D calculations are most appropriate, current aircraft emissions are calculated to yield a tropospheric ozone increase of about 3% and little effect on stratospheric ozone. For the case of installation of 500 commercial supersonic transport in the year 2015 (flight altitude 18–21 km, cruise speed Mach 2.4, emission index 15 g NO2 kg-1 fuel), ozone decreases of 3% in the lower polar stratosphere are predicted leading to decreases in ozone columns by up to 1.5%.

[1]  Paul J. Crutzen,et al.  Increase in the PSC‐formation probability caused by high‐flying aircraft , 1991 .

[2]  D. R. Hanson,et al.  Differences in the reactivity of type I polar stratospheric clouds depending on their phase , 1996 .

[3]  Richard S. Stolarski,et al.  The Atmospheric Effects of Stratospheric Aircraft: a First Program Report , 1992 .

[4]  M. Pitts,et al.  Polar stratospheric cloud climatology based on Stratospheric Aerosol Measurement II observations from 1978 to 1989 , 1994 .

[5]  Henry Hidalgo,et al.  The tropospheric and stratospheric composition perturbed by NO x emissions of high‐altitude aircraft , 1977 .

[6]  Paul J. Crutzen,et al.  The origin of ozone in the troposphere , 1978, Nature.

[7]  Ø. Hov,et al.  Three‐dimensional model studies of the effect of NO x emissions from aircraft on ozone in the upper troposphere over Europe and the North Atlantic , 1996 .

[8]  F. Deidewig,et al.  The ANCAT/EC global inventory of NOx emissions from aircraft , 1997 .

[9]  Ø. Hov,et al.  A two‐dimensional zonally averaged transport model including convective motions and a new strategy for the numerical solution , 1993 .

[10]  Robert Sausen,et al.  Estimations of global no, emissions and their uncertainties , 1997 .

[11]  G. Visconti,et al.  High‐speed civil transport impact: Role of sulfate, nitric acid trihydrate, and ice aerosols studied with a two‐dimensional model including aerosol physics , 1993 .

[12]  D. Weisenstein,et al.  Effects on stratospheric ozone from high‐speed civil transport: Sensitivity to stratospheric aerosol loading , 1993 .

[13]  Ulrich Schumann,et al.  The impact of nitrogen oxides emissions from aircraft upon the atmosphere at flight altitudes—results from the aeronox project , 1997 .

[14]  David John Lary,et al.  Diffuse radiation, twilight, and photochemistry — I , 1991 .

[15]  P. Crutzen,et al.  A two-dimensional photochemical model of the atmosphere: 1. Chlorocarbon emissions and their effect on stratospheric ozone , 1983 .

[16]  R. Derwent,et al.  Two-dimensional model studies of the impact of aircraft exhaust emissions on tropospheric ozone , 1982 .

[17]  R. V. Dorland,et al.  Greenhouse effects of aircraft emissions as calculated by a radiative transfer model , 1995 .

[18]  D. Wuebbles,et al.  Nitrogen oxides from high-altitude aircraft: An update of potential effects on ozone , 1989 .

[19]  Paul J. Crutzen,et al.  A two‐dimensional photochemical model of the atmosphere: 2. The tropospheric budgets of the anthropogenic chlorocarbons CO, CH4, CH3Cl and the effect of various NO x sources on tropospheric ozone , 1983 .

[20]  P. Crutzen.  The influence of nitrogen oxides on the atmospheric ozone content , 1970 .

[21]  David R. Hanson,et al.  Laboratory studies of the nitric acid trihydrate: Implications for the south polar stratosphere , 1988 .

[22]  D. Fahey,et al.  Observations of denitrification and dehydration in the winter polar stratospheres , 1990, Nature.

[23]  M. Molina,et al.  Chemical kinetics and photochemical data for use in stratospheric modeling , 1985 .

[24]  Modelling the Chemistry and Micro-Physics of the Cold Stratosphere , 1994 .

[25]  X. Tie,et al.  Model study of polar stratospheric clouds and their effect on stratospheric ozone , 1996 .

[26]  D. Fahey,et al.  The 1995 scientific assessment of the atmospheric effects of stratospheric aircraft , 1995 .

[27]  D. Rind,et al.  Modeled impacts of stratospheric ozone and water vapor perturbations with implications for high‐speed civil transport aircraft , 1995 .

[28]  J. J. Barnett,et al.  Middle Atmosphere Reference Model Derived from Satellite Data , 1985 .

[29]  H. Johnston.  Reduction of Stratospheric Ozone by Nitrogen Oxide Catalysts from Supersonic Transport Exhaust , 1971, Science.

[30]  James M. Russell,et al.  The Halogen Occultation Experiment , 1993 .

[31]  P. Crutzen,et al.  Scenarios of possible changes in atmospheric temperatures and ozone concentrations due to man's activities, estimated with a one-dimensional coupled photochemical climate model , 1988 .

[32]  J. Pyle,et al.  Future aircraft and global ozone , 1991, Nature.

[33]  A. Douglass,et al.  Effects of a polar stratospheric cloud parameterization on ozone depletion due to stratospheric aircraft in a two‐dimensional model , 1994 .