Aerosol extinction contribution to atmospheric attenuation in infrared wavelengths.

Atmospheric attenuation in several good transmission windows is estimated for long sea-level paths using relatively unsophisticated techniques. The estimates consist of separate estimates of gas and water vapor absorption, aerosol extinction, and aerosol liquid absorption. The contribution of aerosol extinction and aerosol liquid absorption to total atmospheric attenuation is explored. Estimated spectral aerosol extinction and absorption coefficients between the wavelengths of 2 microm and 14 micron are plotted for a wide variety of relative humidities and aerosol nucleation particle distributions. Total attenuation estimates are compared to accepted field measurement data. The agreement is sufficiently good to provide a base for estimating infrared instrument performance under similar conditions.