Impact of aircraft NOX emissions on tropospheric ozone calculated with a chemistry-general circulation model: Sensitivity to higher hydrocarbon chemistry

Abstract

A three-dimensional chemistry-general circulation model has been employed to estimate the impact of current aircraft NOx emissions on tropospheric ozone. The model contains a representation of higher hydrocarbon chemistry, implemented by means of the Carbon Bond Mechanism 4 (CBM4), in order to investigate the potential effect of higher hydrocarbons on aircraft-induced ozone changes. Aircraft NOx emissions increase background NOX (= NO + NO2 + NO3 + 2N2O5 + HNO 4) concentrations by 50-70 pptv in the upper troposphere over the Northern Hemisphere, and contribute up to 3 ppbv to upper tropospheric background ozone levels. When higher hydrocarbon chemistry is considered in the simulation, the aircraft-induced ozone perturbations are higher by ∼12% during summer and the aircraft-induced ozone production efficiency per NO x molecule increases by ∼20%, when compared to a simulation without higher hydrocarbon chemistry. Copyright 2002 by the American Geophysical Union.