华北地区典型污染天大气气溶胶飞机探测个例分析

An Observational Study of Aerosol Property under Typical Polluted Weather Condition

利用2005年10月17日华北地区一次典型污染天气条件下的飞机探测资料,对石家庄和邯郸气溶胶的微物理特征进行了对比分析,初步讨论了该天气条件下大气气溶胶污染的微观特征和可能原因。结果表明,观测当天石家庄和邯郸地区的气溶胶粒子浓度很高,边界层内气溶胶平均数浓度为103cm-3量级,最高值出现在近地面附近,达到104cm-3量级;边界层以上的数浓度基本都在103cm-3量级,属于空气污染比较严重的一次过程。造成污染的原因是该日晴天风小,大气湍流较弱,不利于污染物扩散和稀释。基于美国国家海洋和大气局(NOAA)后向轨迹模式(HYSPLIT4)对颗粒物进行溯源和追踪分析,发现造成气溶胶浓度较高的气块传输路径主要为西北和偏西路径,境外源主要来自蒙古国,境内源主要来自我国西部,途经甘肃、宁夏、陕西及山西后进入河北。

The microphysical properties of aerosol particles in Shijiazhuang and Handan,Hebei Province,China are analyzed based on aircraft measurements conducted under a typical polluted weather condition on October 17,2005.The reasons for the heavy aerosol pollution are discussed.The results show that the particle number concentration over both areas are quite high,with the mean concentration in the boundary layer keeping at 103cm-3,and the maximum,which appeared close to the surface,reached 104cm-3.The aerosol particle concentration keeps greater than 103cm-3 above boundary layer.It is found that the relative weak wind and weaker turbulent mixing which lead to less efficient diffusion and dilution of aerosol particles are responsible for the pollutants accumulation.It is further found that the air pathways,which caused the high aerosol pollution,are mainly from northwest and west,with the sources of Mongolia or West China,passing through Gansu,Ningxia,Shanxi,then entering Hebei.