An Investigation of Aerosol Scattering and Absorption Properties in Wuhan, Central China

摘要

Aerosol scattering and absorption properties were continuously measured and analyzed at the urban Laboratory for Information Engineering in Surveying, Mapping and Remote Sensing (LIESMARS) site in Wuhan, central China, from 1 December 2009 to 31 March 2014. The mean aerosol scattering coefficient σ s , absorption coefficient σ ab , and single scattering albedo (SSA) were 377.54 Mm−1, 119.06 Mm−1, and 0.73, respectively. Both σ s and σ ab showed obvious annual variability with large values in winter and small values in summer, principally caused by the annual characteristics of meteorological conditions, especially planetary boundary layer height (PBLH) and local emissions. The SSA showed a slight annual variation. High values of SSA were related to formation of secondary aerosols in winter hazes and aerosol hygroscopic growth in humid summer. The large SSA in June can be attributed to the biomass combustion in Hubei and surrounding provinces. Both σ s and σ ab showed double peak phenomena in diurnal variation resulting from the shallow stable PBLH at night and automobile exhaust emission during morning rush hours. The SSA also exhibited a double peak phenomenon related to the proportional variation of black carbon (BC) and light scattering particulates in the day and night. The long-term exploration on quantified aerosol optical properties can help offer scientific basis of introducing timely environmental policies for local government.