Impact of future subsonic aircraft NOx emissions on the atmospheric composition

The effect of future subsonic aircraft emissions on the chemical compositio n of the atmosphere is investigated by means of the coupled dynamic-chemica l circulation model ECHAM3/CHEM. Present (1992) and future (2015 and 2050) atmospheric compositions are simulated with three sets of time slice experi ments. Expected changes of the sea surface temperatures (SST), surface emis sions of CFCs, greenhouse gases (GHG), and NOx (=NO+NO2) are prescribed. Mo del results show future increases in NOx and O-3 due to aircraft NOx emissi ons, which scale almost linearily with the magnitude of the emission. The c alculated climate change reduces the NOx concentration as well as its incre ase due to aircraft emissions by more than 10% at flight altitude in 2015. However, the aircraft induced ozone perturbation decreases only slightly wh en climate change is regarded.