摘要:利用2017年151个地面气象站的逐时观测数据和相关高空资料分析关中盆地近地面风场与输送特征。首先分析盆地内代表性站点的风速和风向观测事实，然后用CALMET风场诊断模式和轨迹计算模式获取当地逐小时风场和每日逐小时传输轨迹，分析风场类型。结果表明：关中盆地内日平均风速约1～3 m s?1，夏季风速高、秋冬季低；盆地中央的主导风向以沿地形走向的东北风和西南风为主，盆地四周测站的主导风向表现出顺着地形向盆地中央汇流的趋势。各站主导风向的季节变化不大。盆地内风场分为系统控制型、弱天气背景型和局地环流型3类，全年出现日数比例分别占8%、17.3%和74.7%。以山谷风日夜循环为特征的局地环流型风场最多。以西安城区为源点的大气输送轨迹显示，系统控制型风场以偏东北方向的输送为主，弱天气背景型和局地环流型风场的轨迹输送都大致以偏东北和偏西（以及偏西南）沿盆地走向以及偏东南朝向秦岭山地这三个方向为主。局地环流型的轨迹影响范围小，集中于盆地中央和南侧山地之间，表明这是一种不利于污染扩散的风场类型。
关键词:关中盆地/
风场和输送/
诊断分析
Abstract:The characteristics of wind fields and transport pathways in the Guanzhong Basin were revealed based on data from 151 surface meteorological stations in 2017. Wind speed and wind direction data from five representative stations in the basin were analyzed by calculating windy days, daily average wind speed and wind direction frequency in four seasons, and hourly wind field and transport trajectories were calculated by CALMET and trajectory model. The results show that daily average wind speed in the Guanzhong Basin is about 1?3 m s-1, which is higher in summer but lower in autumn and winter. The dominant wind direction in the center of the basin mainly includes northeast and southwest winds along the terrain, while the dominant wind direction around the basin shows a converging trend along the terrain to the center of the basin. Seasonal changes in dominant wind direction at each station are not significant. The wind fields in the basin can be classified into three types, namely, systematic wind field, feeblish systematic wind field, and local atmospheric circulation. The local atmospheric circulation occurs most frequently in the year (74.7%), followed by feeblish systematic wind field (17.3%), and systematic wind field (8%). Airflows of systematic wind field are mainly transported northeasterly, while airflows of feeblish systematic wind field or local atmospheric circulation are transported northeasterly, westerly (including southwesterly), and southeasterly. Trajectories of the local atmospheric circulation are limited to a small area, concentrated between the central basin and southern mountains, which indicates that this wind field is not conducive to air pollution dispersion.
Key words:Guanzhong Basin/
Wind field and transport pathway/
Diagnostic analysis
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