中文摘要：

利用2015年1月气溶胶散射和吸收系数、PM_（2.5）质量浓度、大气能见度以及常规气象观测数据,分析了南京冬季大气气溶胶散射系数与吸收系数的变化特征,给出了散射系数与吸收系数对大气消光的贡献,以及能见度与PM_（2.5）质量浓度和相对湿度的关系.结果表明,观测期间南京大气气溶胶的散射系数和吸收系数分别为（423.4±265.3）Mm^（-1）和（24.5±14.3）Mm^（-1）,对大气消光的贡献分别为89.2%和5.2%,表明大气消光主要贡献来自于气溶胶的散射.散射系数与PM_（2.5）相关性较好（R2=0.91）,能见度随PM_（2.5）质量浓度呈指数下降,也与相对湿度保持一定负相关性.能见度均值为4.3km,且连续出现能见度不足2km的低能见度天气,霾天气下消光系数和PM_（2.5）质量浓度大幅超过非霾天气,最高值分别达到1471.2Mm^（-1）和358μg/m^3,霾天气下能见度的降低来自颗粒物与相对湿度的共同影响.

英文摘要：

The variation characteristics of aerosol scattering and absorption coefficients, their contributions to atmospheric extinction and the relationship between visibility, PM2.5 mass concentration and relative humidity were presented based on the aerosol absorption and scattering coefficients, PM2.5 mass concentration, visibility and meteorological data in January 2015 in Nanjing. The results indicated that aerosol scattering and absorption coefficients were （423.4＆#177;265.3） Mm-1 and （24.5＆#177;14.3）Mm-1, and their contribution to the atmospheric extinction were 89.2% and 5.2% respectively. The atmospheric extinction was mainly contributed to the aerosol scattering during observation period. The relationship between aerosol scattering coefficient and PM2.5 mass concentration showed a good agreement （R2=0.91）. The visibility decreased exponentially with PM2.5 mass concentration, and showed a negative correlation with relative humidity. The mean visibility during the observation period was 4.3km, and low visibility episodes （＆lt;2km） frequently happened. Light extinction coefficient and PM2.5 mass concentration during haze episodes were evidently higher than those of non-haze periods with the highest values during haze episodes reached 1471.2Mm-1 and 358μg/m3 respectively. The visibility degradation was contributed to the influences of particles and relative humidity.