Aerosols, tiny suspended liquid and solid particles in air, are involved in several critical processes in the atmosphere. They directly affect the thermodynamic profile of the atmosphere through scattering and absorption of radiation, and indirectly by modulating cloud formation and life cycle. ARM has deployed aerosol observing systems (AOS) containing numerous instruments to measure aerosol optical properties and related parameters at multiple sites worldwide.
The ARM aerosol observing systems include measurements of aerosol extensive properties (AEP). Extensive properties are bulk properties that depend on size, mass, or amount. Also of interest are intensive properties that are inherent, normalized, and independent of amount or bulk quantity.
AEPs include scattering and absorption coefficients. Aerosol intensive properties (AIP) include single-scattering albedo, backscatter fraction, asymmetry parameter, and Angstrom exponents representing the wavelength dependence of optical properties.
The Aerosol Optical Properties (AOP) value-added product (VAP) applies final calibrations and corrections to measurements from the AOS to yield final AEP and related AIP. Since the instruments from these AOS operate and deliver data at different flow and operational conditions, extensive checks and processing via software are required so the resulting datastreams are comparable. This AOP VAP applies the aosaop1flynn VAP from either AOS suite of instruments to yield a uniform data product with consistent application of calibrations and corrections.