Infrared aerosol extinction from visible and near-infrared light scattering

The capability to scale from short-wavelength scattered light measured by several hypothetical instruments to IR aerosol extinction coefficients is evaluated in this simulation. Instruments consisting of a forward-scatter meter, integrating nephelometer, and combinations thereof are exposed to a large number of maritime aerosols with size distributions weighted by their frequency of occurrence. Statistical analysis of the wavelength scaling shows that particular two-channel scattering instruments give estimates of IR extinction for wavelengths between 1.06 and 10.6 μm with an accuracy of ≤10%. A forward-scattering instrument gives an output proportional to particle volume and extinction at 10.6 μm.