ANNUAL VARIATIONS OF SUBMICRON AEROSOL FRACTION AS ASSESSED FROM THE DATA OF AIRBORNE NEPHELOMETRIC MEASUREMENTS

This paper presents the results of the analysis of nephelometric data obtained during long-term airborne and ground based observations in th e lower troposphere over Western Siberia. It order to study variabilit y of submicron aerosol characteristics in more detail, separate analys is has been carried out of the coefficients of scattering of dry aeros ol substance sigma(d)(H) and of the condensation activity parameter ga mma. Some thermo-optical characteristics of the aerosol obtained at a controlled heating up to 250 degrees C are also considered. Annual beh avior of the total aerosol content at the heights up to 5 km is descri bed as well as seasonal peculiarities in the aerosol stratification, s igma(d)(H). Seasonal differences in the values of the condensation act ivity parameter and thermo-optical characteristics are discussed.