成都市冬季大气消光系数及其组成的特征研究

Characteristics of atmospheric extinction coefficient and its components in winter in Chengdu

由于气溶胶吸湿增长的复杂性和不确定性,大气消光的演化机理至今尚不十分清晰.为此,利用成都市2017年12月浊度仪和黑碳仪的逐时观测资料,结合同时次的环境气象监测数据,系统研究了该区域冬季对应550 nm大气消光系数及其组成的特征.结果表明:①观测期间大气消光系数为(1173.42±641.21) Mm^(-1),其中"干"气溶胶散射系数、"干"气溶胶吸收系数、干洁大气散射系数、气态污染物吸收系数和气溶胶吸湿性消光系数对其平均贡献率分别是53.02%、6.54%、1.50%、1.65%和37.29%.②大气消光系数、"干"气溶胶散射系数和气溶胶吸湿性消光系数的日变化为"单峰单谷型",而"干"气溶胶吸收系数和气态污染物吸收系数的日变化则分别表现为"单谷型"和"双峰双谷型".③明确了单位质量大气消光系数及其组成随相对湿度的变化特征,并就其各自成因进行了分析.

Due to the complexity and uncertainty of aerosol hygroscopic growth, the evolution mechanism of atmospheric extinction is not completely understood so far. By using the observed hourly data from nephelometer and aethalometer, as well as the simultaneous monitored data of environmental meteorology in Chengdu during December 2017, the characteristics of atmospheric extinction coefficient and its components at 550 nm were investigated. The results showed that:①In observational period, atmospheric extinction coefficient was(1173.42±641.21) Mm^-1, and its average contribution rate of "dry" aerosol scattering coefficient,"dry" aerosol absorption coefficient, gas scattering coefficient, gas absorption coefficient and aerosol hygroscopicity extinction coefficient were 53.02%, 6.54%, 1.50%, 1.65% and 37.29% respectively.②Diurnal variation of atmospheric extinction coefficient,"dry" aerosol scattering coefficient, and aerosol hygroscopicity extinction coefficient showed a consistent pattern of "single peak and single valley","dry" aerosol absorption coefficient showed pattern of "single valley", and gas absorption coefficient showed pattern of "double peak and double valley".③The variation characteristics of unit mass atmospheric extinction coefficient and its components with relative humidity were expounded, and corresponding causes were also given.