AN ANALYSIS OF AIRCRAFT EXHAUST PLUMES FROM ACCIDENTAL ENCOUNTERS

An analysis of data obtained during the second Airbone Arctic Stratosp heric Expedition (AASE-II) was made with emphasis on aircraft exhaust plumes accidentally encountered during the mission. Twenty spikes were found with peak NO(y) increments greater-than-or-equal-to ppbv. The e xamination of CO and CO2 indicates that there was only one NO(y) spike having clearly corresponding spikes of both CO and CO2, and another f our with unambigous CO2 spikes. No significant increases were found fo r CH4 and N2O for these 5 spikes. The ratio of the excess CO2 and NO(y ) compares well with the ratio of published subsonic aircraft emission indices. The study of the selected spikes from the DC-8 and another t wo spikes observed during other missions shows that the odd nitrogen o ther than NO(x) accounts for a very small percentage of the NO(y) incr ease associated with the observed spikes.