2012—2014年冬季北京上甸子气溶胶观测研究

Observations of Aerosols at Shangdianzi Station in Winters from 2012-2014 in Beijing

为了分析冬季上甸子本底站气溶胶的变化特征,利用2012—2014年每年1月上甸子本底站的能见度、ρ（PM2.5）、ρ（BC）、ρ（CO）等数据,结合气象资料对上甸子地区气溶胶特性进行分析.结果表明：2012—2014年每年1月地面月均风速分别为2.5、2.4和2.4 m/s,RH（相对湿度）分别为45.6%、59.5%和45.8%,ρ（PM2.5）分别为38.6、54.7和45.2μg/m^3,MSE（气溶胶质量散射系数）分别为5.3、5.9和4.9 m^2/g.虽然地面风速基本没有变化,但2013年1月的RH比2012年和2013年1月平均高出30%,并且同期ρ（PM2.5）和MSE也高于2012年和2013年1月.ρ（PM2.5）的增加导致太阳辐射减弱,但对SSA（气溶胶单次反照率）影响不大.对2013年1月数据分析可知,各种RH区段下,能见度与ρ（PM2.5）均呈负相关,其中在80.0%10 km时,bext和Bext（分别以能见度和大气组分计算的大气消光系数）基本相当,二者在这3年的拟合斜率平均值高达0.99;当能见度〈5 km时,2014年1月的bext和Bext之间不存在线性关系,2012年和2013年1月的bext和Bext的R2分别是0.88和0.92.

In order to analyze the characteristics of aerosol changes at Shangdianzi background station in winters from 2012 to 2014,air environmental chemical factors were observed including air visibility,PM2. 5,BC,radiation and CO in each January to study the aerosol characteristics combined with meteorological data. The results showed that the average speeds of the ground wind in the three years were2. 5,2. 4 and 2. 4 m/s,and the relative humidities were 45. 6%,59. 5% and 45. 8%,while the MSE（ mass scattering efficiency） were5. 3,5. 9 and 4. 9 m^2/g separately. Comparing the results,the ground wind speed did not change obviously,while the relative humidity increased by 30% in 2013. Both PM2. 5mass concentration and aerosol MSE were higher in 2013 than those in the other two years. The increase of PM2. 5concentration weakened the solar radiation,but it did not have an obvious effect on the aerosol single scattering albedo（ SSA）. According to the data in 2013,visibility and PM2. 5concentrations were negatively correlated in various RH segments. The RMSE（ root mean square error） reached a peak of 1. 43 when RH was less than or equal to 70. 0%,while it was 1. 98 when the RH was greater than 70. 0% and less than 80. 0%,and it was 1. 42 when the RH was greater than 80. 0% and less than 100%. When visibility was more than 10 km,the bext（ bext= 2. 996 /visibility） and Bext（ Bext= bag＋ bsg＋ bap＋ bsp） were roughly equal,and the three-year average slope fitting was up to 0. 99; when visibility was less than 5 km,there was no linear relationship between bextand Bextin 2014. The squares of linear correlation coefficient between bextand Bextwere 0. 88 and0. 92 in 2012 and 2013,respectively.