Improved inversion of aerosol components in the atmospheric column from remote sensing data

Abstract. A method to calculate the complex refractive index of a multicomponent liquid system is introduced into the retrieval of atmospheric columnar aerosol components from optical remote sensing data. The aerosol components comprise five species, combining eight sub-components including black carbon (BC), water-soluble (WSOM) and water-insoluble organic matter (WIOM), ammonium nitrate (AN), sodium chloride (SC), dust-like (DU), and aerosol water in the fine and coarse modes (AWf and AWc). The uncertainty in the retrieval results is analyzed based on the simulation of typical models, showing that the complex refractive index obtained from instantaneous optical-physical inversion compares very well with that obtained from chemical estimation. The algorithm was used to retrieve the columnar aerosol components over China using the ground-based remote sensing measurements from the Sun-sky radiometer Observation NETwork (SONET) in the period from 2010 to 2016. The results were used to analyze the regional distribution and interannual variation. The analysis shows that the atmospheric columnar DU component is dominant in the northern region of China, whereas the AW is higher in the southern coastal region. The AN significantly decreased from 2011 to 2016, by 26.8 mg m−2, which is inseparable from China's environmental control policies.