scattering cross-section, σscat

The scattering coefficient per particle ( $cm 2 particle$ );

$b scat = n σ scat$

where $n$ is the number concentration of particles ( $particles cm −3$ ) and $σ scat$ is the scattering cross-section. $b scat$ , the scattering component of extinction due to gas and particles, is measured in the atmosphere using a nephelometer. For a homogeneous atmosphere it is related in theory to the meteorological range ( $L V$ ): $L V = 3.9 b scat$ ; $b scat$ and $b abs$ represent the scattering and absorption coefficients per unit length for a light beam (of path length $L$ ) which has a spectral radiance (intensity) $I 0$ incident on a sample of air and $I$ is the transmitted spectral radiance (intensity), $ln ( I 0 I ) = L ( b scat + b abs )$ .

Source:

PAC, 1990, 62, 2167 (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2212