An overview of Sun–Sky Radiometer Observation Network (SONET) measurements in China is presented. Based on observations at 16 distributed SONET sites in China, atmospheric aerosol parameters are acquired via standardization processes of operational measurement, maintenance, calibration, inversion, and quality control implemented since 2010. A climatology study is performed focusing on total columnar atmospheric aerosol characteristics, including optical (aerosol optical depth, ÅngstrÖm exponent, fine-mode fraction, single-scattering albedo), physical (volume particle size distribution), chemical composition (black carbon; brown carbon; fine-mode scattering component, coarse-mode component; and aerosol water), and radiative properties (aerosol radiative forcing and efficiency). Data analyses show that aerosol optical depth is low in the west but high in the east of China. Aerosol composition also shows significant spatial and temporal variations, leading to noticeable diversities in optical and physical property patterns. In west and north China, aerosols are generally affected by dust particles, while monsoon climate and human activities impose remarkable influences on aerosols in east and south China. Aerosols in China exhibit strong light-scattering capability and result in significant radiative cooling effects.
Abstract. The detailed formation mechanism of an increased number of haze
events in China is still not very clear. Here, we found that reduced surface
visibility from 1980 to 2010 and an increase in satellite-derived columnar
concentrations of inorganic precursors from 2002 to 2012 are connected with each
other. Typically, higher inorganic mass fractions lead to increased aerosol
water uptake and light-scattering ability in elevated relative humidity.
Satellite observation of aerosol precursors of NO2 and
SO2 showed increased concentrations during the study period. Our
in situ measurement of aerosol chemical composition in Beijing also confirmed
increased contribution of inorganic aerosol fraction as a function of
the increased particle pollution level. Our investigations demonstrate that the
increased inorganic fraction in the aerosol particles is a key component in
the frequently occurring haze days during the study period, and particularly
the reduction of nitrate, sulfate and their precursor gases would contribute
towards better visibility in China.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.