Hourly wind fields were obtained in the period of 2016 to 2017, using the diagnostic model CALMET over the Baoding-Xiong’an area, Hebei province. Data from 22 meteorological observatories and the NCEP-fnl dataset were used in the procedure, and daily trajectories were derived. According to characteristics of the wind fields and trajectories, local air flows were classified into three types: systematic flow, local circulation, and weak synoptic winds. The analysis results depict that the proportion of the three type of flows are approximately 10%, 50% and 40%. The frequency of systematic flow is quite low, with a little more occurrence in spring and summer than that in autumn and winter. The local circulation appears more in autumn and winter than that in spring and summer. The frequency of weak synoptic winds changes little over the whole year, but slightly lower in autumn and winter. The air flow is characterized by the mountains in the northwest of the region, mountain and plain breeze circulations influence the range of about 100 km in front of the mountain, covering Baoding city and a major part of Xiong’an area. The transfer of mountain and plain breeze causes light winds in this area timely. The major transport pathways in this region are southwesterly and northeasterly, corresponding to large-scale background flows. Lateral transports caused by mountain and plain breeze circulations are relatively short in northwest and southeast directions. Occasionally, under conditions of systematic flow and weak synoptic winds in winter and spring, transport trajectories can also extend to southeast.

基于2016—2017年22个地面气象站点的观测资料和NECP-fnl数据, 使用CALMET风场诊断模式, 计算保定?雄安地区两个年份的逐时风场和每日输送轨迹。根据风场与流动轨迹特性, 从大气扩散输送的角度, 将当地大气流动划分为系统大风型、局地环流型与弱系统影响型 3 类。统计分析结果表明: 大气流动3个类型的大致比例为10%, 50%和40%; 系统大风型流动的占比较低, 且春夏季较多, 秋冬季较少; 局地环流型流动以秋冬季较多, 春夏季较少; 弱系统影响型的出现频率在全年变化不大, 但在秋冬季出现频率稍低; 大气流动受西北部山地影响, 山地-平原风可控制山前约100 km的范围, 覆盖保定市和雄安新区大部; 山地-平原风的转换可在山前区域形成部分时段的小风状况; 该地区大气输送的主要路径是西南-东北方向, 对应大尺度背景流动情况; 西北-东南方向的横向输送距离较短, 对应山地-平原风地形环流的影响; 在系统大风和弱系统影响下, 冬春季会出现部分直接向东南方向的输送轨迹。