西安泾河夏季黑碳气溶胶及其吸收特性的观测研究

为研究西安泾河夏季黑碳气溶胶及其吸收特性,利用2011年夏季西安远郊泾河大气成分站观测的黑碳气溶胶浓度、颗粒物质量浓度、探空资料、地面气象资料,计算边界层顶高度、气溶胶吸收系数、大气消光系数,导出单次散射反照率,并对其进行分析讨论.结果表明:西安夏季黑碳气溶胶浓度为6.07μg/m3;黑碳气溶胶占颗粒物质量浓度PM1.0比值为21.9%,黑碳气溶胶与颗粒物质量浓度PM1.0、PM2.5、PM10相关系数分别为0.69、0.85、0.91;黑碳气溶胶浓度受城市边界层顶高度影响,风向、风速对泾河黑碳气溶胶的堆积输送有不同作用;气溶胶吸收系数和大气消光系数日变化显著,气溶胶吸收系数占大气消光系数比值范围在12%~30%;季单次散射反照率平均值为0.76,变化范围在0.70~0.84.

Observed summer variation and absorption characteristics of black carbon at Xi'an suburban

The data of black carbon, particle size concentration, visibility, and various meteorological variables observed during summer of 2011 at Xi￠an Jinghe were used to calculate planetary boundary layer top height, aerosol absorption coefficient, and atmospheric extinction coefficient, and then derived single scattered albedo. Variation and absorption characteristics of black carbon were analyzed in this study. Results showed that the mean value of black carbon concentration was 6.07μg/m3 with a range of 2.0~13.4μg/m3 which are very different from Xi’an downtown. The ratio of black carbon concentration in PM1.0 was 21.9%, and the correlation coefficients between black carbon and particles mass concentration PM1.0, PM2.5, and PM10 were 0.69, 0.85, and 0.91, respectively. Black carbon concentration was affected by planetary boundary layer top, and the accumulation and transportation were affected by wind direction and speed. The ratio of aerosol absorption coefficient in atmospheric extinction coefficient was 21.9% with a range of 12% ~ 30%. Both coefficients show distinct diurnal cycle. The mean summer single scattering albedo was 0.76 ranging from 0.70 to 0.84.