淮河流域典型农田区气溶胶散射特性的日变化和季节变化研究

Diurnal and seasonal variations of aerosol scattering characteristics over typical farmland area of Huaihe River Basin

利用2019年寿县国家气候观象台气溶胶散射系数、气溶胶质量浓度及相关气象观测数据,统计分析了淮河流域农田区域的气溶胶散射特征及其成因,为该区域气溶胶污染辐射强迫及其对农业生产影响方面的研究提供了定量观测证据。研究表明:该地区气溶胶散射系数具有显著的季节变化规律,冬季最高,夏季最低;三个波长(450、525、635 nm)气溶胶日平均散射系数分别为329.8±180.0、270.2±153.7、214.4±128.4 Mm^(-1),并且散射系数日变化与天气要素和大气层结日变化规律具有很好的相关性,且冬季日振幅远小于其他三季;?ngstr?m指数年平均值为1.32,后向散射比年平均值为0.15,气溶胶质量散射系数年平均值为4.83 m^(2)/g,表明淮河流域农田区域的气溶胶以细颗粒为主;气溶胶散射系数大小主要受偏西风调控,散射系数与能见度具有高度的负相关幂函数关系;污染日的气溶胶散射系数远大于清洁日,污染物很大程度上影响了光辐射在大气中的传输能力,污染程度高,大气的散射作用就越强。

Based on the aerosol scattering coefficient,aerosol mass concentration and meteorological observation data of Shouxian National Climate Observatory Anhui,China,in 2019,the characteristics and causes of aerosol scattering over farmland area of the Huaihe River Basin is statistically analyzed,providing quantitative observation evidence for the study of aerosol radiative forcing and its impact on agricultural production over the Huaihe River Basin.It is shown that the aerosol scattering coefficient in the region has a significant seasonal variation,with the highest in winter and the lowest in summer.The daily average scattering coefficients of aerosols at three wavelengths(450,525,635 nm)are 329.8±180.0,270.2±153.7,214.4±128.4 mm^(-1),respectively.The diurnal variation of aerosol scattering coefficient has a good correlation with weather factors and atmospheric diurnal variation,and the diurnal amplitude in winter is much smaller than that in the other three seasons.The annual average values of Angstrom index,backscattering ratio and aerosol mass scattering coefficient are 1.32,0.15 and 4.83 m^(2)/g,respectively,indicating that the aerosols over farmland area of the Huaihe River Basin are dominated by fine particles.It is also foungd that the aerosol scattering coefficient is mainly controlled by the westerly winds,and there is a high negative correlation between the scattering coefficient and visibility.In addition,the aerosol scattering coefficient of pollution days is much greater than that of clean days,and pollutants greatly affect the transmission of light radiation in the atmosphere,so the higher the pollution degree,the stronger the scattering effect of the atmosphere is.