Monday, 11 January 2016
To investigate the climate and environmental effects of Sand and Dust Storm (SDS), the physical characteristics of natural dust and anthropogenic aerosols were analyzed, by comparing the sunphotometer measurements at selected sites in Lanzhou, Xilinhot and Beijing. Being frequently influenced by SDS in spring, Lanzhou and Xilinhot are located in the semi-arid area in China, close to dust sources, while Beijing is a megacity also suffering from air pollution. Spatial and temporal analysis of measurements at these selected sites is helpful to understand the differences between natural dust and anthropogenic aerosols. Aerosol optical properties of sunphotometer were investigated by four episodes, i.e. the heating and non-dusty period (November to January), heating and dusty period (February to March), dusty and non-heating period (April to May), and non-dusty and non-heating period (June to October). In addition, atmospheric temperature and humidity profiles of Xilinhot observed by air balloon sounding were also analyzed and compared to AIRS measurements for further analysis. It is found that aerosol volume size distributions of Lanzhou city present a bimodal pattern (fine and coarse modes). During dusty period, the dust events cause decrease of fine mode particles ranging from 0.15 to 0.4μm, and the radius range of coarse mode is wider. During non-dusty period, the peak value of size distribution in Beijing is much higher than that of Lanzhou city. During summer, the obvious peak of fine mode in Beijing shows linkage to atmospheric water vapor content. Further comparison also found that the single scattering albedo at the selected sites in spring is higher than other seasons because of the SDS events, and the monthly average aerosol optical depth shows a peak value in spring for Lanzhou and Xilinhot, and in summer for Beijing. More detailed comparison and analysis will be presented by combining air sounding measurements.
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