The characteristics of near-surface wind field and atmospheric transport in Taiyuan region were revealed using data from 57 ground-based meteorological stations and NCEP/FNL analysis data in 2017. The hourly near-surface wind field and daily transport trajectories were calculated employing the CALMET wind field diagnostic model and the trajectory calculation method. Based on the wind field and trajectory characteristics, the wind field can be classified into two distinct types: weather background type and local circulation type. Among these, the frequency of weather background type reaches 66.3%, while the local circulation type occurs with a frequency of 33.7%. The wind field associated with the local circulation type is characterized by pronounced day-night alternation of valley winds, whereas the weather background type undergoes significant changes in speed and direction within a day. The atmospheric transport trajectories originating from the urban area of Taiyuan exhibit notable seasonal variations in weather background type. The primary transport pathways include an eastward direction toward Shouyang along the southern valley, a southwestward trend following the basin terrain, and a northwestward path through the mountainous regions. Conversely, trajectories associated with the local circulation type are mostly confined to the city of Taiyuan and nearby mountains, resulting in a confined impact zone. Therefore, this condition is unfavorable for the diffusion of local air pollutants, making it susceptible to triggering pollution events.

使用太原地区2017年57个地面常规气象站的观测数据和NCEP/FNL资料, 分析当地近地面风场和大气输送特征。使用CALMET风场诊断模式和轨迹计算方法, 获取当地逐时近地面风场和逐日大气输送轨迹, 并根据风场和轨迹分布特征, 将当地风场分为天气背景型和局地环流型两类。天气背景型全年出现频率达66.3%, 局地环流型全年出现频率为33.7%。局地环流型风场具有明显的山谷风日夜更替特征, 而天气背景型风场在一天之内风速和风向都有较大的变化。以太原城区为源点的大气输送轨迹显示, 天气背景型的轨迹分布季节变化较大, 主要有偏东的寿阳以南山谷方向、偏西南的沿盆地走势方向和偏西北的山地方向。局地环流型的轨迹集中在太原市区及附近山地, 影响范围小, 不利于当地大气污染物的扩散, 易引发污染事件。