太原地区近地面风场和大气输送特征分析OA北大核心

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.