AASE-II IN-SITU TRACER CORRELATIONS OF METHANE, NITROUS-OXIDE, AND OZONE AS OBSERVED ABOARD THE DC-8

We report in situ stratospheric measurements of CH4, N2O, and O3 obtai ned aboard the NASA DC-8 during the January-March 1992 Airborne Arctic Stratospheric Expedition Il field campaign. These data demonstrate a strong linear correlation between N2O and CH4 in the lower stratospher e thus indicating that both species are effective tracers of stratosph eric air motion. Measurements of both species on constant geometric he ight surfaces indicate that significant subsidence of the arctic strat ospheric air mass occurred at DC-8 altitudes over the course of the AA SE-II expedition. In addition, a widespread reduction in O3 mixing rat ios (up to 20%) relative to these conserved tracers was also observed in the lower stratosphere in March as compared to January and February results.