Volume 16, No. 11, November 2016, Pages 2884-2896 PDF(1.19 MB)
Seasonal Variation of Aerosol Optical Properties in an Urban Site of the Yangtze Delta Region of China
Bing Qi1, Deyun Hu1, Huizheng Che2,3, Rongguang Du1, Yunfei Wu4, Xiangao Xia5, Ben Zha1, Jie Liu6, Yuwen Niu6, Hong Wang2, Xiaoye Zhang2, Guangyu Shi7
1 Hangzhou Meteorological Bureau, Hangzhou 310051, China
2 Key Laboratory for Atmospheric Chemistry (LAC), Institute of Atmospheric Composition, Chinese Academy of Meteorological Sciences (CAMS), CMA, Beijing 100081, China
3 Jiangsu Collaborative Innovation Center for Climate Change, Nanjing 210093, China
4 Key Laboratory of Regional Climate-Environment for Temperate East Asia(RCE-TEA), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
5 Laboratory for Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
6 Zhejiang Meteorological Science Institute, Hangzhou 310008, China
7 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
- Aerosol optical property (AOP) over urban area of YDR of China was investigated.
- High relative humidity could contribute to AOP variation in summer over YRD.
- Transportation of biomass burning emission could affect YRD urban region obviously.
The characteristics of aerosol optical properties during 2012 at Hangzhou (30°14′N, 120°10′E), an urban site in the Yangtze Delta Region of China, were analyzed, including aerosol scattering and absorption coefficients, aerosol optical depth (AOD), Ångström exponent (α), single scattering albedo (SSA), and aerosol size distribution. Both aerosol absorption and scattering coefficients were lowest in summer; the highest absorption coefficient was observed in autumn; while the scattering was highest in winter. There were no significant differences in the seasonal average of AOD, with values of approximately 1.0 in spring, autumn and winter, and 0.72 in summer. The averaged Ångström exponent was found to be relatively high throughout the year, with a minimum value of 1.14 in spring and a maximum of 1.35 in autumn. The fine modes of the aerosol volume size distributions showed the highest peak around radius 0.15 µm in spring, autumn and winter, and radius 0.25 µm in summer, while the coarse modes showed maximum peaks at radius 2.9 µm in all seasons. The volume concentrations of coarse mode aerosols over Hangzhou were highest in spring compared with other seasons. The mean total SSA values were 0.89, 0.93, 0.89 and 0.88 at 440 nm for spring, summer, autumn and winter, respectively, indicating that the aerosols were mainly composed of scattering particles in Hangzhou. Furthermore, it was found continuous pollution events appeared in East China as a result of biomass burning during June 10–13 in 2012. The main causes of extremely severe air pollution and poor visibility in Hangzhou were related to the long-distance transport of pollutants, local pollution emission and stagnant weather conditions. Aerosol optical properties exhibited high value in absorption AOD and high aerosol volumes, low SSA in coarse mode after biomass burning.
Aerosol optical properties; Pollution processes; Hangzhou.