ENHANCEMENT OF STRATOSPHERIC AEROSOLS AFTER SOLAR PROTON EVENT

The lidar measurements at Verhnetulomski observatory (68.6 degrees N, 31.8 degrees E) at Kola peninsula detected a considerable increase of stratospheric aerosol concentration after the solar proton event of GL E (ground level event) type on the 16/02/84. This increase was located at precisely the same altitude range where the energetic solar proton s lost their energy in the atmosphere. The aerosol layer formed precip itated quickly (1-2 km per day) during 18, 19, and 20 February 1984, a nd the increase of R(H) (backscattering ratio) at 17 km altitude reach ed 40% on 20/02/84. We present the model calculation of CN (condensati on nuclei) altitude distribution on the basis of an ion-nucleation mec hanism, taking into account the experimental energy distribution of in cident solar protons. The meteorological situation during the event wa s also investigated.