2-DIMENSIONAL ASSESSMENT OF THE IMPACT OF AIRCRAFT SULFUR EMISSIONS ON THE STRATOSPHERIC SULFATE AEROSOL LAYER

We have developed a two-dimensional sulphate aerosol model, which includes most of the important microphysical processes governing the formation and evolution of stratospheric sulphate particles. Simulations of the background aerosol layer shows that important aerosol properties (surface area density, optically active particle concentration, mass mixing ratio) are strongly latitude dependent. This model is used to investigate if the sulphur aircraft emissions may have caused die 60% increase in large aerosol particles observed over the 1979-1990 time period. Results suggest that although aircraft may represent a substantial source of sulphate below 20 km, the rise in air traffic is insufficient to account for the apparent trend in stratospheric aerosol particles.