Spectral Atmospheric Aerosol Absorption Coefficients

In several field campaigns over the last six years (PRIDE, SAFARI 2000, ACE Asia, ICARTT), we have used data from the Solar Spectral Flux Radiometer (SSFR) and the Ames Airborne Tracking Sunphotometer (AATS-14) to determine the solar spectral absorption due to atmospheric aerosols. These absorption results show that the aerosol absorption coefficient in all cases decreases with wavelength. This absorption wavelength dependence can be most simply described by λ^-n where n varies from - 1 for highly absorbing carbonaceous material to approximately - 3 for some mineral dusts and smoldering combustion. This talk will discuss how these results in conjunction with other recent studies can be used to derive expressions that may be useful for parameterization of aerosol absorption in global models.