利用地基太阳光度计分类识别气溶胶类型

Identification and Classification of Different Aerosol Types Based on Ground-Based Sunphotometer Observation

该文利用AERONET北京站201309-201408的气溶胶产品,分析了北京地区气溶胶光学特性和气溶胶类型变化特征。研究发现该地气溶胶光学特性的变化主要由人为排放的污染物和从远处输送来的沙尘气溶胶引起。该文利用550 nm时的气溶胶光学厚度和Angstrom波长指数,采用阈值法,识别了北京地区主要来源、不同组分、不同光学特性的4种主要气溶胶类型:城市污染气溶胶、煤烟型气溶胶、沙尘气溶胶、混合型气溶胶。通过反演光谱曲率进一步分析了气溶胶粒子尺度与类型的分布特征。进而统计分析了各种类型气溶胶的季节变化特征。结果发现:北京地区春季沙尘和城市污染气溶胶共存,光学厚度最高,且粗粒子占主导地位;夏季以城市污染气溶胶为主,光学厚度较高,且具细粒子特征;秋冬季平均气溶胶光学厚度相对较低,秋季4种类型气溶胶所占比例相当,冬季以煤烟型气溶胶为主。

This paper reported the observational results of aerosol optical characteristics and discrimination of key aerosol types utilizing Sunphotometer Aerosol Products over Beijing Site of AERONET,from September 2013 to Augest 2014.The results showed that a pronounced spectral and temporal variability in the optical properties of aerosols was mainly due to anthropogenic emissions and dessert dust transported from remote distance.The paper took advantage of the daily mean values of aerosol optical depth at 550 nm and Angstrom exponent by applying the threshold values method to identify four different aerosol types over Beijing(coal burning aerosols(BC),desert dust aerosols(DD)and urban industry aerosols(UI),mixed type aerosols(MT))of differing origin,composition and optical characteristics.The paper also derived the spectral curvature to analyze the distribution characteristics on aerosol-particle size and type.Furthermore,the paper statistically analyzed the seasonal changes in aerosol characteristics of each of type of aerosol and the results revealed that during spring dessert dust and urban pollution aerosols were largely measured accompanied by the highest AOD and there was an extremely large fraction of coarse-mode aerosols.Summer was characterized by high AOD and an abundance of fine-mode aerosols caused by urban pollution aerosols.Autumn and winter had relatively low AOD.However,the percentage contribution of four type of aerosols expressed approximately equality in autumn and winter was dominated by coal burning aerosols.