Estimate of Atmospheric Columnar Aerosol Composition Based on Remote Sensing Measurements

The composition and mixing states of atmospheric aerosols are the essential properties as they decide aerosol optical and physical properties. This study uses microphysical parameters obtained by sun-sky radiometer measurements to estimate main tropospheric aerosol components, including black carbon, brown carbon, mineral dust, particulate organic matter, ammonia sulfate-like, sea salt and water uptake. Different internal mixing models are compared, and Maxwell-Garnett effective medium approximation is selected for forward modeling of refractive index. The composition-to-microphysical parameters look-up table is established and then an optimization procedure is employed to find the best fit between models and observations. Aerosol components under clean conditions during a campaign held in Beijing are quantitatively estimated, and aerosol optical, microphysical and compositional properties are comprehensively analysed.