A Lagrangian estimate of aircraft effluent lifetime

摘要: The lifetime of aircraft exhaust is estimated using multiyear diabatic trajectory integrations United Kingdom Meteorological Office and Goddard Space Flight Center (GSFC) Data Assimilation winds. Instantaneous January parcel releases in the midlatitude stratosphere at 19, 16, 14, 13, 11 km are compared. first two cases correspond to proposed flight altitudes high-speed supersonic aircraft. last subsonic altitudes. Parcels descending below 250 hPa eliminated as would occur when effluent reaches troposphere. After a transient adjustment period total number parcels most experiments decays exponentially with decay (lifetime) about 1 year. This longest-lived eigenmode discussed by Prather [1996]. Our 1-year shorter than 1.5 year GSFC two-dimensional (2-D) model for same release, but good agreement 1.13 3-D lifetime. We also find that slightly longer southern hemisphere northern. Both 13 mostly within stratospheric middle world rapidly leave stratosphere. conclude there will be small impact on larger Finally, we our overall results fairly sensitive lower heating rates.