龙凤山大气气溶胶散射特性观测分析

Characteristics of aerosol scattering coefficient at Longfengshan regional background station

利用2018年龙凤山区域大气本底站(简称龙凤山站)气溶胶散射系数、PM_(10)质量浓度及常规气象观测资料,研究了东北本底地区气溶胶散射系数的变化特征.结果表明,2018年龙凤山站3个波长下气溶胶散射系数的均值为(194.1±202.4)Mm^(-1)(450 nm)、(133.4±139.2)Mm^(-1)(550 nm)、(81.8±85.3)Mm^(-1)(700 nm).龙凤山地区散射系数具有明显的日变化特征,且不同季节的日变化特征具有较大区别.龙凤山地区地处相对洁净的背景地区,气溶胶散射系数水平相对较低,春季受局地及长距离风沙的影响散射系数均值较高,冬季东北地区采暖燃烧排放量比较大,大气层相对稳定,不利于气溶胶污染物的扩散,冬季气溶胶散射系数最高.夏秋季受湿沉降与植被条件的影响气溶胶散射系数最低.散射系数与PM_(10)质量浓度相关性较好,相关系数r为0.82.龙凤山PM_(10)的质量散射效率为3.6 m^(2)·g^(-1)(550 nm).2018年龙凤山PM_(10)气溶胶的散射Angstrom指数(SAE)平均值为1.96±0.25,表明在观测期间气溶胶主要是以较小的粒子主导,夏季的SAE最大,秋季的SAE最低,春季和冬季居中.

Based on the aerosol scattering coefficient,PM_(10) mass concentration and meteorological data at Longfengshan Regional Atmospheric Background Station from Jan 2018 to Feb.2019,the characteristics of aerosol scattering coefficient in Northeast China background area were investigated.The results showed that the mean values of aerosol scattering coefficients at Longfengshan station were(194.1±202.4)Mm^(-1)(450 nm),(133.4±139.2)Mm^(-1)(550 nm),(81.8±85.3)Mm^(-1)(700 nm).The diurnal variation of scattering coefficient was obvious with great difference in different seasons.The Longfengshan area is located in a relatively clean background area,and the aerosol scattering coefficient was relatively low.The average value of the scattering coefficient in spring was relatively high due to the influence of local and long-distance dust.In winter,the aerosol scattering coefficient was the highest due to the relatively high emissions from heating and relatively stable atmosphere,which was not conducive to the diffusion of pollutants.The lowest aerosol scattering coefficient in summer and autumn was due to wet deposition and vegetation conditions.The scattering coefficient was significantly correlated with the mass concentration of PM_(10),with a correlation coefficient of 0.82.The PM_(10) mass scattering efficiency at the wavelength of 550 nm was 3.6 m^(2)·g^(-1)at Longfengshan station.The average aerosol Scattering Angstrom Exponent(SAE)of the PM_(10) was 1.96±0.25,which indicated that the aerosol was mainly dominated by smaller particles during the observation period.The maximum value of SAE occurred in summer,the minimum value appeared in autumn,and the value in spring and winter was in between.