TRACER-TRACER RELATIONSHIPS AND LOWER STRATOSPHERIC DYNAMICS - CO2 AND N2O CORRELATIONS DURING SPADE

Simultaneous measurements of CO2 and N2O from the NASA ER-2 aircraft d uring SPADE deployments in November 1992, April/May 1993, and October 1993 provide new information on transport rates in the lower stratosph ere. The tropospheric seasonal cycle in CO2, superimposed on the long- term trend, is observed to propagate into the stratosphere. The compac t correlations observed between CO2 and N2O indicate that meridional t ransport is sufficiently rapid to create a uniform set of relationship s over the northern hemisphere up to at least 21 km even though CO2 ch anges significantly on a time scale of 8 to 12 weeks. The observed sea sonal dependence of the correlations indicates that vertical transport above 20 km is slower in northern summer than in winter and slow thro ughout the year between 19 km and the tropopause. The inferred amplitu de of the seasonal CO2 oscillation in the stratosphere, viewed relativ e to N2O, places constraints on the mean latitude for air entering the stratosphere.