Studies of the stratosphere aerosol layer based on polarization measurements of the twilight sky

The paper is devoted to an analysis of observational manifestations of the aerosol layer in the Earth’s stratosphere and to a method of determining their optical properties. It is based on polarization measurements of the twilight sky background in the zenith vicinity and in a broad spectral band with an effective wavelength of 5250 Å. An increased abundance of the stratosphere aerosol was found in December 2006 for the first time in several years of observation. The suggested method allows one to determine the ratio of radiation scattering coefficients by the stratosphere aerosol and by air molecules, as well as the degree of polarization of aerosol scattering in the stratosphere. The appearance of the stratosphere aerosol is associated with explosive eruption of Rabaul volcano having occurred in the beginning of October 2006.