IN-SITU MEASUREMENTS OF CHANGES IN STRATOSPHERIC AEROSOL AND THE N2O-AEROSOL RELATIONSHIP INSIDE AND OUTSIDE OF THE POLAR VORTEX

Two optical particle counters on the ER-2, together covering a particl e size diameter range from 0.1 mum to 23 mum, were used to measure the aerosol bulk quantities integral number, aerosol surface and volume, as well as detailed size distributions inside and outside of the polar vortex in the lower stratosphere. While AASE I (Arctic Airborne Strat ospheric Expedition, (Dec. 88-Feb. 89) was conducted in a period of re lative volcanic quiescence, enhancements in aerosol number, surface an d volume of factors around 10, 25 and 100 were observed during AASE Il (Aug. 91-Mar. 92) due to the eruption of Mt. Pinatubo. The changes in these bulk quantities as well as in the size distributions measured b oth outside and inside the the polar vortex are presented and compared with those obtained in polar stratospheric cloud events (AASE I). Exc ept for a shift towards larger aerosol mixing ratios the general shape of correlograms between the measured N2O and particle mixing ratios r emain similar before and after the eruption. Similar correlograms are used to interpret data from vertical profiles inside and outside of th e polar vortex.