摘要
利用2010年5月积分浊度仪、PCASP-X2和能见度仪的观测资料,分析了石家庄大气气溶胶的散射特征及其与气溶胶粒子浓度、能见度、气象条件的关系.结果表明,观测期间,450,550,700nm 3个波段的气溶胶散射系数平均值±标准差分别为（257±293）,（199±237）和（143±173）Mm-1,散射系数的变化很大,但气溶胶微物理特征相对比较稳定.散射系数日变化呈3峰分布,峰值出现在8：00、13：00和0：00.以550nm波长为例,气溶胶散射系数的变化范围为144~308Mm-1,夜间散射系数大于白天,非晴天散射系数平均值（524.9Mm-1）是晴天散射系数（112.3Mm-1）的4.7倍.气溶胶3个波段后向散射比均大于0.15,说明石家庄细粒子污染比较严重.散射系数和体积浓度成正比,但由于局地气象条件和污染源的影响,有气溶胶体积浓度变大,散射系数变化不大的情况出现.气溶胶散射系数和能见度呈负相关;根据Koschmieder公式计算得到的能见度,能较好反映实际观测情况.当大气相对湿度较高时,气溶胶散射系数随湿度增大呈现两种不同的变化趋势,即一部分气溶胶的散射系数有明显的增大,而另一部分则随着相对湿度的增加并未增大,反而比干气溶胶散射系数要小.局地风场也会影响气溶胶散射特性.
The data measured by a three-wavelength integrating nephelometer,a PCASP-X2 and a visibility meter over Shijiazhuang,Hebei Province,China,from May 7~23,2010,were used to investigate the scattering properties of aerosol particles and the relationship with particle size spectra,visibility and meteorological conditions.The results show that the scattering coefficients were（257±293）,（199±237）,and（143±173） Mm-1,respectively,for the three wavelengths,450,550 and 700 nm,and that the values varied significantly from day to day,while the microphysical property of aerosol is stable.It was also found that the daily variation of the aerosol scattering coefficient was a tri-peak shape,with the coefficient reaching peak values at about 8,13 and 0 o＇clock,respectively,and higher values were measured during nighttime.There was also a significant difference in the mean scattering coefficient under different weather conditions,with the mean value（524.9Mm-1） of overcast days was 4.7 times higher than that of fine days（112.3Mm-1）.The ratios of backscattering coefficient to the total scattering coefficient of three wavelengths were all larger than 0.15,indicating that a significant fraction of the particular matter in Shijiazhuang was attributed to fine mode particles.There existed a positive correlation between the scattering coefficient and the volume concentration of aerosol,but sometimes when the volume concentration was large,the scattering coefficient was small,maybe because of the local emission source or meteorological condition.There was a negative correlation between the scattering coefficient and visibility.Our results also find that the scattering coefficient would exhibit two different trends when the relative humidity increases,and the local wind direction and speed could also influence the scattering properties of aerosol.
出处
《中国环境科学》
EI
CAS
CSCD
北大核心
2012年第5期769-779,共11页
China Environmental Science
基金
科技部公益性行业(气象)科研专项经费(GYHY200706036)
江苏省“333人才工程”项目
江苏省高校优秀创新团队项目和江苏高校优势学科建设工程项目(PAPD)
关键词
气溶胶
散射系数
体积浓度
能见度
气象条件
aerosol
scattering coefficient
volume concentration
visibility
meteorological condition
