Optical Depth and Vertical Profile of Stratospheric Aerosol based on Multi-Year Polarization Measurements of the Twilight Sky

The method of detection of light scattering on stratospheric aerosol particles on the twilight sky background is considered. It is based on the data on sky intensity and polarization in the solar vertical at zenith distances of up to 50 deg from the sunset till the moment of the Sun depression to 8 deg below the horizon. The measurements conducted in central Russia since 2011 had shown the negative trend of stratospheric aerosol content, this can be related with the relaxation of the stratosphere after the number of volcanic eruptions during the first decade of XXI century.