[Optical properties of aerosol during haze-fog episodes in Beijing].
The purpose of this study is to investigate the optical properties of aerosol during haze-fog episodes in Beijing. The aerosol optical depth (AOD), Angstrom exponent (alpha), size distribution and single scattering albedo (omega) during haze-fog episodes were analyzed between 2002 and 2008 using AERONENT data. During haze-fog episodes, the aerosol optical depth showed a decreasing trend with wavelengths, and showed high values with an average 1.34 at 440 nm. The magnitude of Angstrom exponent was relatively high during haze-fog episodes and the mean values reached 1.11. The frequency distribution of alpha was up to 94% when alpha > 0.9, indicating the predominance of fine particles during haze-fog episodes in Beijing. The aerosol volume size distributions presented a bimodal structure (fine and coarse modes). The maxima (peaks) radius of fine mode showed an increasing trend with AOD, however, those of coarse mode showed a decreasing trend with AOD. The size distribution showed a distinct difference in dominant mode for the different AOD. The single scattering albedo showed an increasing trend with AOD during haze-fog episodes in Beijing. The mean value of omega was 0.89 at the four wavelengths and the omega exhibited a low sensitivity to wavelengths.
Key Laboratory of Meteorological Disaster of Ministry of Education, Nanjing University of Information Science & Technology, Nanjing 210044, China. xnyu@nuist.edu.cn
Xing-Na
XN
Yu
Xin-Mei
XM
Li
Zen-Grandeng
ZG
Deng
Qing-Yangzong
QY
De
Shuai
S
Yuan
D000336:Aerosols / Q000032:analysis*; D000393:Air Pollutants / Q000032:analysis*; D002681:China; D002947:Cities; D004784:Environmental Monitoring; D055620:Optical Phenomena; D052638:Particulate Matter / Q000032:analysis*; D014887:Weather
D000336:Aerosols; D000393:Air Pollutants; D052638:Particulate Matter