POTENTIAL IMPACT ON STRATOSPHERIC OZONE DUE TO EMISSION OF HYDROCARBONS FROM HIGH-ALTITUDE AIRCRAFT

A two-dimensional chemical/dynamical model is used to assess the sensi tivities on the stratospheric ozone due to emission of hydrocarbons (H Cs) from various high-altitude aircraft (including proposed further Hi gh Speed Civil Transports, HSCT) under different partitioning of HCs ( HCs as CH4 or HCs as C2H6) and different sulfate aerosol loadings (bac kground aerosol or large volcanic aerosol). The model calculation sugg ests that the emission of HCs increases stratospheric ozone, but the m agnitudes of increase vary with different situations. The further prop osed HSCT has relatively small emission of HCs. Thus, the impact on st ratospheric ozone due to HC emission is small (less than 0.1% increase in total ozone). In some type of aircraft engines which were proposed by the Climate Impact Assessment Program (CIAP) in 1975, the HC emiss ion is about 20 x larger than the HSCT emission; moreover, these aircr aft could produce a important increase on stratospheric ozone, especia lly after a large volcanic eruption, such as Mt. Pinatubo (Philippines in June, 1991).