2009年石家庄地区不同天气条件下大气气溶胶分布特征

Distribution characteristics of atmospheric aerosols in 2009 in Shijiazhuang area under different weather conditions

利用2009年石家庄地区4次机载PMS探测资料,对不同天气条件下大气气溶胶的数浓度、平均直径垂直分布和谱分布及一次晴天条件下的水平分布进行分析。结果表明:PCASP探头探测的0.1—3.0μm气溶胶粒子最大数浓度量级为102—104cm-3之间,平均值量级为102—103cm-3之间,平均直径最大值介于0.225—0.717μm,平均值介于0.148—0.167μm。晴天条件下,气溶胶的数浓度随高度递减,直径随高度变化不大;逆温层底气溶胶明显积累,气溶胶浓度在大气边界层内明显高于其他层次;阴天轻雾情况下边界层内的气溶胶数浓度大于雨天和晴天,雨天气溶胶浓度最低;晴天气溶胶数浓度的水平分布不均匀;在云中气溶胶浓度明显下降,在云外气溶胶浓度较高。不同天气条件和晴天不同高度情况下,石家庄地区气溶胶谱型呈单峰分布,小于0.3μm的细粒子对气溶胶的数浓度贡献最大,且随高度的增加谱宽变窄。

Based on the aerosol data obtained using particle measuring system （PMS） from four flights in 2009 in Shijiazhuang area, the vertical distributions of number concentrations ,mean diameter of atmospheric aerosol parti- cle and its spectral distribution under different weather conditions,its horizontal distribution in a sunny day were analyzed. The results show that the maximum number concentration of aerosol particles with the diameter of 0. 1- 3.0 μm detected by PCASP probe changes from 102 cm-3 to 104 cm-3,and the average magnitude is from l02- 103 cm-3. The maximum of the average diameter ranges from 0. 225 μm to 0. 717 μm and the average is between 0. 148- 0. 167 μm. The number concentration of aerosol particles decreases with the increase of the height under the sunny weather condition, while the diameter changes seldom at the same condition. The aerosol accumulates distinctly on the bottom of inversion temperature layer, and its concentration in the atmospheric boundary layer is significantly higher than in the other levels. The aerosol number concentration of boundary layer is higher in cloudy and fog weather than in rain and sunny weather, and it is the lowest in rain weather. The horizontal distribution of aerosol number concentration is uneven in sunny weather. The aerosol number concentrations decrease significantly inside the cloud, while it is high outside the cloud. The size distributions of aerosol under different weather condi- tions and different heights of sunny day in Shijiazhuang are consistent and just have a single peak. The fine parti- cles that the diameter is less than 0. 3 μm are the main contributor to the number concentration of aerosol,and the spectral width is narrowed with the increase of the height.