STRATOSPHERIC CONSTITUENT TRENDS FROM ER-2 PROFILE DATA

Trend analysis of the AASE ER‐2 profile data reveals an average decrease in N2O on potential temperature isentropes which can be attributed to diabatic cooling of inner vortex air. This conclusion is independently supported by radiative transfer computations. Trends in ozone and water vapor over the same period are not consistent with the magnitude of the diabatic descent. After accounting for the diabatic motion (estimated from N2O) an additional 0.44±.3%/day average anomalous O3 decrease above 440K (∼20 km) is needed to balance the continuity equation. This ozone decrease suggests additional photochemical destruction of ozone in the presence of the high amounts of ClO observed during the mission. A 0.4±0.3%/day average anomalous increase in H2O is also observed near 420K (∼18 km) which may be due to the evaporation of ice crystals falling from higher, colder stratospheric layers. Copyright 1990 by the American Geophysical Union.