Variations of optical characteristics of stratospheric aerosol

Solar radiation attenuation spectra obtained using an airborne spectrometer in the 0.4-2.2 micron range over the European portion of the USSR and in Central Asia are examined. It is observed that the optical characteristics of the stratosphere can vary within this broad spectral range. The effective size and concentration of small and medium-size particles for transparent and turbid stratospheric conditions are calculated. For both stratospheric states, very high concentrations of small particles (0.02-0.06 micron) of Aitken nuclei type are detected. The effects of medium-size particles (0.2-0.3 microns) on transparent and turbid states are analyzed. The data reveal that the influence of the particles on visible radiation attenuation in the transparent stratosphere is small; however, in the turbid state the role of the particles is dominant.