In this paper, the characteristics of the atmospheric boundary layer (ABL) vertical structure over the North China Plain (NCP) during a comprehensive observation experiment conducted during 15–21 December 2018 were investigated. Observational data were obtained with a large tethered balloon, Doppler wind lidar, and ground-level instruments. The maximum concentration of PM_2.5 exceeded 200 µg m⁻³, and the ratio of PM_2.5/PM₁₀ was approximately 0.4 (its maxi-mum was approximately 0.8) during the whole observation period, indicating the explosive growth of dominant fine-mode aerosols in the winter heating season. Elevated concentrations of pollutants decreased the solar irradiance received by the ground, resulting in lower temperature at ground level. Our results illustrate three distinct types of vertical profiles: Type 1 (convective state)—the concentration of PM_2.5 decreased nearly linearly with increase of the height below approximately 600 m; Type 2 (stable state)—the PM_2.5 concentration sharply decreased from the ground to approximately 200 m; and Type 3 (multilayer structure)—some pollutants were suspended aloft in the upper air layer. Diurnal evolution of the vertical profiles of PM_2.5 and their relationship with the changes in meteorological factors were identified. From daytime to nighttime, the vertical profiles evolved from Type 1 to Type 2 or Type 3. All the 33 vertical PM_2.5 profiles that we obtained showed a strong relationship with elements of the ABL structure, such as the distributions of winds, the inversion layer, and turbulence activities. A light-wind layer and weak turbulence activity, especially within the inversion layer, contributed greatly to the accumulation of pollutants. Vertical PM_2.5 concentration patterns were also greatly affected by local ground-level emission sources and regional transport processes.

本文研究了2018年12月15日至21日在华北平原（NCP）上进行的大气边界层（ABL）垂直结构特征。观测数据是使用大型系留气球，多普勒测风激光雷达和地面仪器获得的。PM _2.5的最大浓度超过200 µg m ^-3，并且PM _2.5 / PM ₁₀的比率在整个观测期间，其大约为0.4（最大值约为0.8），这表明在冬季供暖季节，主要的精细模式气溶胶呈爆炸性增长。污染物浓度的升高降低了地面接收到的太阳辐射，从而导致地面温度降低。我们的结果说明了三种不同的垂直剖面类型：1型（对流状态）— PM _2.5的浓度随高度在大约600 m以下的增加而线性下降。类型2（稳定状态）— PM _2.5浓度从地面急剧下降至大约200 m；和3型（多层结构）-一些污染物被高空悬浮在高层空气层中。PM _2.5垂直剖面的日变化并确定了它们与气象因子变化的关系。从白天到夜间，垂直剖面从1型演变为2型或3型。我们获得的所有33个垂直PM _2.5剖面都与ABL结构的要素（如风的分布，反演层）之间显示出很强的关系。和湍流活动。轻风层和较弱的湍流活动，特别是在反演层内，是造成污染物积累的重要原因。垂直PM _2.5浓度模式还受到当地地面排放源和区域运输过程的极大影响。