Models of the atmospheric aerosols and their optical properties

Aerosol models have been developed for the boundary layer, the upper troposphere, the stratosphere, and mesosphere. In the boundary layer they describe three different environments: rural, urban and maritime. In the upper troposphere and stratosphere two different models represent spring-summer and fall-winter conditions. In the stratosphere they describe several levels of volcanic dust concentrations and the background conditions. For each model the coefficients for extinction, scattering and absorption, the angular scattering distribution and other optical parameters have been computed for wavelengths between 0.2 and 40 micrometer. The aerosol models are being presented along with a discussion of their experimental basis. The optical properties of these models are being discussed and some examples of their effects on the overall atmospheric transmission properties and atmospheric contrast reduction are presented.