SIMULATING THE GLOBAL TRANSPORT OF NITROGEN-OXIDES EMISSIONS FROM AIRCRAFT

With the atmosphere general circulation model ECHAM the passive transp ort of NO(x) emitted from global subsonic air traffic and the NO(x) co ncentration change due to these emissions are investigated. The source of NO(x) is prescribed according to an aircraft emission data base. T he sink of NO(x) is parameterized as an exponential decay process with globally constant life-time. Simulations in perpetual January and Jul y modes are performed. Both the resulting mean and the standard deviat ion of the NO, mass mixing ratio are analysed. In January horizontal d ispersion is more pronounced and vertical mixing is smaller than in Ju ly. In both cases the resulting quasi-stationary fields of the mass mi xing ratio display a pronounced zonal asymmetry. The variability accou nts up to 30% of the mean field.