华北中部夏季气溶胶垂直分布及其与云凝结核和云滴转化关系的飞机观测研究

气溶胶的时空分布及其核化成云的转化过程是云降水物理研究的重点，也是气候变化中气溶胶间接效应关注的热点问题。利用2013～2014年期间在华北中部山西地区开展的9架次夏季晴天和积云天气情况下的气溶胶、云凝结核（CCN）及云滴数浓度观测资料，分析研究了气溶胶的垂直分布、谱分布、来源特征及其与云凝结核、云滴数浓度的转化关系。研究结果表明，大气边界层逆温层结对气溶胶、CCN垂直分布有重要影响，不同天气条件下气溶胶谱型在低层差异较大而高层基本一致；垂直方向上CCN数浓度与气溶胶数浓度有较好的相关性，过饱和度0.3%条件下CCN比率（云凝结核/凝结核）与气溶胶有效直径呈线性关系；积云云下气溶胶与云滴的线性拟合方程为y=1.3x?616.3，拟合相关系数为0.96，气溶胶转化为云滴的比率可达到47%。在过饱和度0.3%条件下，云下CCN与云滴的线性拟合方程为y=1.6x?473.8，拟合相关系数也为0.96，CCN转化为云滴的比率可达到69%。

Aircraft Measurements of Summer Vertical Distributions of Aerosols and Transitions to Cloud Condensation Nuclei and Cloud Droplets in Central Northern China

Aerosols greatly influence the cloud’s microphysical properties and climate change by acting as cloud condensation nuclei (CCN). Properties of vertical distribution, size distribution, and source regions of aerosols, as well as their transition relationships with the CCN and cloud droplet number concentration, are investigated using nine flights of aircraft measurements under clear and cloudy conditions in Shanxi, central northern China. Results indicate that the atmospheric boundary inversion layer structure has an important impact on the vertical distributions of aerosols and CCN. Size distributions under different weather conditions are similar in the upper atmospheric layers but quite different in the lower layers. There is a high positive linear correlation between the aerosol number concentrations and CCN number concentrations at 0.3% supersaturation in the vertical. A linear regression of y=1.3x?616.3 is established between the cloud droplet number concentrations and aerosol number concentrations near cumulus cloud bases with a correlation coefficient of 0.96. Moreover, the conversion rate from aerosol number concentrations to cloud droplet number concentrations was about 47%. A good linear regression of y=1.6x?473.8 is also found between the CCN number concentrations and cloud droplet number concentrations near cumulus cloud bases with a correlation coefficient of 0.96 at 0.3% supersaturation. The conversion rate is found to be about 69%.