【摘要】 气溶胶散射特性对了解气溶胶的辐射效应具有重要意义。为进一步了解南京北郊秋冬季气溶胶散射特性,利用积分浊度仪观测了2015年和2016年秋冬季大气气溶胶散射系数,对比分析了秋冬季气溶胶散射系数的变化特征,并对散射特性相关参数Angstrom波长指数、后向散射比和不对称因子进行了讨论。结果表明,2015年1月平均气溶胶散射系数达到（359.52±254.24） Mm^-1,是2016年秋冬季平均散射系数（98.95±36.13） Mm^-1的3.6倍,最高日平均散射系数可达877.6 Mm^-1。2015年冬季气溶胶散射系数频率分布范围较广(52-1 363 Mm^-1),而2016年秋冬季气溶胶散射系数主要集中在160 Mm^-1以下的低值区。气溶胶散射系数日变化在2015年冬季呈"三峰型"分布;而在2016年秋冬季呈"双峰型"分布。南京北郊2015年1月、2016年秋季和冬季气溶胶Angstrom波长指数平均值分别为1.08、1.3和1.2,由此可知2016年秋冬季的气溶胶粒子以细粒子为主控粒子,而2015年冬季颗粒物粒径相对较大。2015年1月气溶胶粒子的后向散射比（0.097±0.006）低于2016年秋冬季的值（0.123±0.009）,表明2015年冬季气溶胶中含有一定比例粒径较粗的粗颗粒物（粒径>1.5μm）,而2016年秋冬季气溶胶粒子以粒径小于1.5μm的细粒子为主。其中2015年1月不对称因子高于0.67的样本约占总样本量的70%;而2016年秋冬季不对称因子主要集中在0.55-0.65之间,说明2015年冬季气溶胶粒子的粒径相对较大,且气溶胶粒子的散射以前向散射为主。更多还原

【Abstract】 The scattering properties of aerosols are important for understanding the radiation effects of aerosols. In order to further understand the scattering properties of aerosols during autumn and winter in the northern suburb of Nanjing, the scattering coefficients of aerosols in autumn and winter of 2015 and 2016 were observed by using an integrating nephelometer. The variation characteristics of aerosol scattering coefficient, Angstrom exponent, back scattering ratio and asymmetry factor were analyzed and discussed. The average aerosol scattering coefficient in January 2015 reached（359.52±254.24） Mm^-1, which was 3.6 times of autumn and winter of 2016 [（98.95±36.13） Mm^-1]. The maximum daily average scattering coefficient during the observation period was calculated to be 877.6 Mm^-1. The aerosol scattering coefficients in winter of 2015 showed a wide frequency distribution, ranging from 52 to 1 363 Mm^-1, while the values were mainly concentrated below 160 Mm^-1 in the autumn and winter of 2016. The diurnal variation of aerosol scattering coefficient showed tri-modal and bimodal distributions in 2015 and 2016, respectively. The average Angstrom exponents were 1.08 in January 2015, 1.3 in fall of 2016 and 1.2 in winter of 2016, respectively. This result indicated that fine particles dominated the aerosol size distribution in the autumn and winter of 2016, while there were particles with coarser size in winter of 2015. The back scattering ratio of aerosol particles in January 2015（0.097±0.006） was lower than that in the autumn and winter of 2016（0.123±0.009）, indicating that the coarser particles occurred in January 2015 and fine particles with d<1.5 μm in the autumn and winter of 2016. The asymmetric factor above 0.67 accounted for about 70% of the total samples in January 2015.However, this value varied mainly between 0.55 and 0.65 in the autumn and winter 2016. This result indicated that the size of the aerosol particles was relatively larger in winter of 2015, and the aerosol scattering was dominated by forward scattering.更多还原