Anthropogenic aerosols have significant impacts on the environment and human health in the Yangtze River Delta region,one of the most densely populated regions in the world.A biomass-burning plume swept across this area(Shanghai) in May 2009,leading to changes in the physical and optical properties of aerosols,which were investigated using ground-based remote sensing and in situ measurements via comparisons with dust pollution and background conditions.Experiments show that the biomass-burning plume led to an increase in the average aerosol optical depth(AOD) at 500 nm from 0.73 to 1.00(37%higher),an absorption Angstrom exponent(AAE) of 1.48,and an increase in the Angstrom exponent(α) up to 1.53.Furthermore,local dust aerosols derived from road dust and/or construction dust also led to higher values of AOD(2.68) and AAE(2.16),and a daily average value of α of 1.05.For the biomass-burning plume,the aerosol particles exhibited significant variations in short-wavelength spectra.The single scattering albedo at 670 nm decreased remarkably under the influence of the biomass-burning plume,indicating the significant absorptive ability of the biomass-burning pollution and higher ratio of absorption aerosols within the plume.Under the effects of the biomass-burning,the volume concentration of fine-mode aerosols increased significantly and the PM-fine/PM-coarse volume concentration ratio reached 12.33.This relatively large change in fine-mode particles indicates that biomass-burning has a greater impact on fine-mode aerosols than on coarse-mode aerosols.
利用完全耦合大气化学模式WRF—Dust（Weather Research and Forecasting—Dust）对2011年5月1-4日影响上海地区的一次典型沙尘天气过程进行了数值模拟研究，并与观测资料进行了对比分析．结果表明：WRF—Dust模式成功模拟了此次沙尘过程的形成、发展和演变的整体特征及其影响时间及范围；较好地模拟了沙尘到达上海的时间（模式和观测均在1日11：00前后）和直接影响的结束时间（2日02：00前后），而且模式沙尘浓度与观测资料较为一致；但局部地区和部分时段的气象条件和沙尘模拟还存在一定的偏差，未能准确模拟过程后期沙尘回流对长三角沿海地区的影响．分析了导致模拟偏差的原因，并探讨了提高模式沙尘模拟能力的可能途径．
