Abstract: 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 particle 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 102-103cm-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 decreases significantly inside the cloud, while it is high outside the cloud. The size distributions of aerosol under different weather conditions and different heights of sunny day in Shijiazhuang are consistent and just have a single peak. The fine particles 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.

Key words: Aerosols, Different weather conditions, Airplane observation, Aerosol number concentration