吐鲁番和若羌冬季气溶胶垂直分布的飞机观测分析

利用2019年冬季吐鲁番和2020年冬季若羌共14次完整机载探测气溶胶资料,结合宏观天气资料及大气污染数据,研究飞机爬升或降落阶段两地上空气溶胶粒子数浓度、粒子平均粒径的垂直变化规律,分析不同高度的粒子谱分布特征。结果表明：（1） 两地冬季气溶胶粒子数浓度及粒子直径存在明显差异。在无明显天气过程下,若羌气溶胶粒子数浓度均值（5354·cm^-3）明显高于吐鲁番（3948·cm^-3）;粒子平均粒径来看,均值差异不大,但吐鲁番出现大直径粒子（0.16 \mathrm{\mu } \mathrm{m}）数量高于若羌（0.13 \mathrm{\mu } \mathrm{m}）。2019年12月15日大风后最为明显,粒子直径最大值达到0.21 \mathrm{\mu } \mathrm{m},这与沙尘气溶胶多有关联。从垂直变化情况来看,两地气溶胶粒子数浓度均随高度增加而升高,若羌各层普遍高于吐鲁番,但吐鲁番近地面粒子直径随高度增加有明显下降,若羌整层变化很小。（2） 吐鲁番、若羌气溶胶粒子数浓度和粒子平均粒径受大风、降水等天气过程以及逆温层的影响十分明显。两地高层均主要为输入型气溶胶,低层差异主要是由于吐鲁番地区人为源气溶胶粒子的排放导致的大气环境污染。（3） 吐鲁番、若羌两地粒子谱分布在0.10~3.00 \mathrm{\mu } \mathrm{m}范围内变化趋势大体一致,主要以小粒径为主,谱分布受天气过程影响变化较为明显。（4） 从三模态粒径相似度对比可以得出,无论是吐鲁番还是若羌,在第一模态中数谱分布差异不大,若羌平均相似度为50.330%,略高于吐鲁番46.770%。有明显天气过程时,吐鲁番气溶胶数谱在二、三模态相似度（小于0.020%）急剧下降,而若羌第二模态相似度仍满足置信度95%,但第三模态中变化凸显,相似度不足0.020%。

Aircraft observation and analysis of vertical distribution of aerosols in winter in Turpan and Ruoqiang

The vertical changes to aerosol particle number concentration and average diameter in two areas during aircraft climb or landing were studied using a total of 14 airborne aerosol detection data in Turpan City, Xinjiang, China in the winter of 2019 and Ruoqiang County, Xinjiang, China in the winter of 2020, combined with macro weather and air pollution data. The characteristics of particle spectrum distribution at different heights were analyzed. The result shows: (1) There are obvious differences in the aerosol particle number concentration and particle diameter of aerosol particles in the two places in winter. In the absence of obvious weather change, the average aerosol particle number concentration data for Ruoqiang is significantly higher than that for Turpan; there is little difference in terms of average particle diameter between the two places, but the number of large-diameter particles in Turpan was higher than that for Ruoqiang, which was closely related to the presence of more dust aerosols in Turpan. (2) The aerosol particle number concentration and average particle diameter in the two places were significantly affected by weather processes such as strong wind and precipitation, as well as the temperature inversion layer. High wind process causes an increase in particle number concentration, and there is a slow updraft before the snowfall process, resulting in the aerosol particle number concentration that is 3-4 times higher than the average value. (3) In general, the upper layers of Ruoqiang and Turpan mainly contain imported aerosols, and the lower layers are mainly localized. The issue of environmental damage and air pollution is especially serious. Under clear sky or cloudy weather conditions, the aerosol particle number concentration is generally higher in Ruoqiang than in Turpan, indicating that the number of larger diameter particles in Ruoqiang is relatively less than that in Turpan, and its geographical location determines this. There are fewer industrial activities and fewer anthropogenic activities, so there are fewer particles emitted by humans. From the analysis of the aerosol particle number concentration and average diameter, it is believed that this area primarily has a large number of small dust aerosols. (4) The particle spectrum distribution in Turpan and Ruoqiang (0.10-3.00 μm diameter) is a single-peak and double-valley distribution; the peak is mainly concentrated at 0.4 μm, and the valley is mainly concentrated between 0.15 μm to 1.60 μm. The comparison of particle size similarity between the three modes shows that there is little difference in the number spectrum distribution in the first mode in Turpan or Ruoqiang, and the similarity is high. When there is an obvious weather process, the similarity of the Turpan aerosol number spectrum in the second and third modes drops sharply, and if only the third mode changes significantly, it indicates that the temperature inversion layer inhibits particle diffusion and hinders convective movement.