Evolution of the Arctic stratospheric aerosol mixing ratio measured with balloon-borne aerosol backscatter sondes for years 1988-2000

Balloon-borne aerosol backscatter measurements were made at 12 Arctic stations as part of a polar stratospheric cloud study. The record starts in 1988, which is well before the eruption of Mount Pinatubo in the beginning of June 1991. and continues to 2000. These measurements provide absolutely calibrated in situ detection of atmospheric aerosols with simultaneous measurements of pressure, temperature, relative humidity, and O-3 partial pressure. The instrument is also capable of operating during cloudy conditions. which may be considered as an advantage compared with lidar measurements. Even though backscatter soundings represent the state of the atmosphere at the sounding time and site, we demonstrate here that with a limited. homogeneous set of measurements it is possible to effectively study the time development of atmospheric aerosol loading. The initial aim of the study has been to define the general features of aerosol distribution in the Arctic winter troposphere and stratosphere and then to document the perturbation in the lower stratospheric aerosols caused by the eruption of Mount Pinatubo and, in addition, to infer the back-ground state of lower stratospheric aerosol loading during the pre- and post-Pinatubo conditions. Our measurements suggest that the e-folding time for the decaying volcanic aerosol intrusion was similar to0.7 year and the full recovery of the Arctic lower stratosphere from the Mount Pinatubo perturbation was roughly 5 years.