Microphysical parameters of smoke aerosols based on the results of inversion of aerosol scattering and extinction coefficients in a big aerosol chamber of IAO SB RAS

Abstract

Measurements of polarization scattering phase functions and spectral extinction coefficients were carried out in smoke aerosols formed as a result of thermal decomposition of wood materials, in a big aerosol chamber (BAC) of the IAO SB RAS. The results are presented of reconstructing of the parameters of the microstructure and the complex refractive index of smoke aerosols based on the developed algorithm for inverting optical measurements. Temporal variability of the microphysical characteristics of smoke is studied.

Microphysical extrapolation method in studying optical characteristics of smoke

“…The growth of ) cos( is related with an increase in the average radius of smoke particles during the observation period (see Fig. 8 in 23 ).…”

“…Such "blackening" of smoke is related with altering in its dispersion composition during "aging" when there was the monotonous increase in the mean particle radius from 0.19 to 0.6 µm (see Fig. 8 in 23 ). The mean cosine of the scattering angle is a quantitative characteristic of the degree of elongation of the scattering phase function.…”

“…Smoke aerosol was formed as a result of thermal decomposition of wood samples (pine) in the low-temperature pyrolysis mode at a temperature of 400 ºС. The microstructure and complex refractive index i n m of pyrolysis smoke aerosol were reconstructed using the algorithm for inverting polarization scattering phase function 23 . The integral distribution function S(r) is used to describe the aerosol microstructure, which characterizes the geometric cross section of particles with a radius of at least r in a unit volume of the medium.…”

Reconstruction of the integral distribution function of the aerosol particle number concentration from the light scattering characteristics

“…Let us compare the time variations of the function ) (r N with the behavior of the volumetric concentration of smoke particles. Figure 4, a shows the time series of volume concentration of smoke particles 14 reconstructed from the same distributions ) (r S which are discussed in the previous section.…”

“…Optical measurements were carried out using a polarization spectral nephelometer and atmospheric path transparency meter. The integral distribution functions ) (r S of smoke aerosol were reconstructed using the algorithm for inverting polarization scattering phase function 14 . ) ( ~r N : aparticle radii less than r; bparticle radii greater than r.…”