AOD

The core purpose of ARM is to reduce uncertainties in earth system model predictions. The single largest source of uncertainty in these models is the radiative impact of aerosols, which is often divided into direct and indirect radiative effects.

The Aerosol Optical Depth (AOD) family of value-added products (VAPs) is focused on several aerosol optical properties responsible for the direct radiative impact of aerosols. The most important of these properties is AOD, which is a measure of the total aerosol burden in the atmosphere. The spectral dependence of AOD, typically described by the Angstrom exponent, is also an indicator of particle size, with large particles having Angstrom exponent values near zero and smaller particles exhibiting larger Angstrom exponent values. Improved knowledge of these properties will help reduce the uncertainties associated with aerosol effects in earth system models.

Within the AOD family of VAPs, AODs have been derived from the multifilter rotating shadowband radiometer (MFRSR), normal incidence multifilter radiometer (NIMFR), Cimel sunphotometer (CSPHOT), and shortwave array spectroradiometer–hemispheric (SASHe). For more information about these AOD products, please refer to the AOD technical report for the MFRSR and NIMFR products, the CSPHOT instrument handbook, and the AOD technical report for the SASHe product, or to the output product pages linked below.