Suchergebnisse

Aerosol pollution in eastern China is an unfortunate consequence of the region's rapid economic and industrial growth. Here, sun photometer measurements from seven sites in the Yangtze River Delta (YRD) from 2011 to 2015 were used to characterize the climatology of aerosol microphysical and optical properties, calculate direct aerosol radiative forcing (DARF) and classify the aerosols based on size and absorption. Bimodal size distributions were found throughout the year, but larger volumes and effective radii of fine-mode particles occurred in June and September due to hygroscopic growth and/or cloud processing. Increases in the fine-mode particles in June and September caused AOD440 nm > 1.00 at most sites, and annual mean AOD440 nm values of 0.71–0.76 were found at the urban sites and 0.68 at the rural site. Unlike northern China, the AOD440 nm was lower in July and August (∼ 0.40–0.60) than in January and February (0.71–0.89) due to particle dispersion associated with subtropical anticyclones in summer. Low volumes and large bandwidths of both fine-mode and coarse-mode aerosol size distributions occurred in July and August because of biomass burning. Single-scattering albedos at 440 nm (SSA440 nm) from 0.91 to 0.94 indicated particles with relatively strong to moderate absorption. ; This work was supported by a grant from the National Key R & D Program Pilot Projects of China (2016YFA0601901), the National Natural Science Foundation of China (41590874, 41475138 & 41375153), the Natural Science Foundation of Zhejiang Province (LY16010006), the CAMS Basis Research Project (2016Z001 & 2014R17), the Climate Change Special Fund of CMA (CCSF201504), the Special Project of Doctoral Research supported by Liaoning Provincial Meteorological Bureau (D201501), the Hangzhou Science and Technology Innovative project (20150533B17) and the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement no. 262254.