Aerosol Composition Retrieval based on Remote Sensing Measurements an d the Impact of Different Aerosol Mixing Rules

摘要

The composition of ambient aerosol, together with mixing states of aerosol particles that relate to atmospheric processes and conditions, determine the aerosol optical and physical properties, and thus play important roles in climate and environmental effects. This study focus on retrieval of main components of ambient aerosol, including Black Carbon (BC), Brown Carbon (BrC), Mineral Dust (DU), Ammonium Sulfate (AS), Sea Salt (SS) and Aerosol Water (AW), which might have distinguishable optical and microphysical properties. For example, BC has strong and spectrally independent absorption through the whole visible region while BrC absorption is enhanced at short wavelengths, DU and BrC have the opposite spectral pattern of single scattering albedo between 675 and 870 nm. The non-absorbing components SS and AS have very similar optical properties, however, the significant difference in particulate size makes it possible to distinguish these two components. According to the sensitivity study of optical properties to aerosol components, we develop a residual minimization optimized scheme (between the observed and simulated properties) to obtain the six components’ volume fraction and mass concentration using the properties such as refractive indices, volume size distribution, optical depth and single scattering albedo, which are derived from the direct solar and diffused sky radiation measurements by ground-based instrument, the sun/sky radiometer CE318.