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 stati ons 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 J une 1991. and continues to 2000. These measurements provide absolutely cali brated in situ detection of atmospheric aerosols with simultaneous measurem ents of pressure, temperature, relative humidity, and O-3 partial pressure. The instrument is also capable of operating during cloudy conditions. whic h may be considered as an advantage compared with lidar measurements. Even though backscatter soundings represent the state of the atmosphere at the s ounding time and site, we demonstrate here that with a limited. homogeneous set of measurements it is possible to effectively study the time developme nt of atmospheric aerosol loading. The initial aim of the study has been to define the general features of aerosol distribution in the Arctic winter t roposphere and stratosphere and then to document the perturbation in the lo wer stratospheric aerosols caused by the eruption of Mount Pinatubo and, in addition, to infer the back-ground state of lower stratospheric aerosol lo ading during the pre- and post-Pinatubo conditions. Our measurements sugges t that the e-folding time for the decaying volcanic aerosol intrusion was s imilar to0.7 year and the full recovery of the Arctic lower stratosphere fr om the Mount Pinatubo perturbation was roughly 5 years.