Variability in Parameters of the Near-Surface Aerosol Microstructure in Summer According to Results of Inversion of Measurements of Spectral Extinction of Light on a Horizontal Path in Tomsk: Part I-Geometrical Cross Section of Fine and Coarse Particles

Results on retrieving parameters of the near-surface aerosol microstructure from spectral measurements of the coefficient of aerosol extinction of light in summer are presented. The experimental data have been obtained using an atmospheric transmittance meter at 11 wavelengths in the range 0.45-3.91 m on a horizontal path near Tomsk. The inverse problem was solved using a numerical algorithm based on the integral distribution method. In the first part of the work, the variability of the geometrical cross section of particles from the fine fraction, coarse fraction, and total ensemble is analyzed. The effect of the smoke pollution of the atmosphere on variations in microstructure parameters has been considered. It has been shown that the main contribution (73-77%) to the total cross section of near-surface aerosol is made by particles of the fine fraction. Coefficients of variation in the cross sections of particles on monthly intervals without regard to the influence of smokes are high within 53-61% for the fine fraction and 53-69% for the coarse fraction of aerosol. The correlations between the aerosol extinction coefficients at different wavelengths and retrieved parameters of the aerosol microstructure have been studied.