基于HYSPLIT模型的京津冀地区大气污染物输送的路径分析

Route analysis of air pollutant transport in Beijing-Tianjin-Hebei region based on HYSPLIT model

以京津冀地区为研究区域,通过HYSPLIT模型后向轨迹、地面气象监测数据和高空观测资料分析2014年11月17—23日重污染天气的形成和消散过程,并对气象因子进行分析。结果表明:京津冀重污染天气的形成过程中,主要为高压或均压状态,该状态下大气层较稳定,大气混合层高度降低形成静稳天气;同时,对流层下的高湿、高压、弱风、逆温层导致其垂直方向无法形成对流,水汽和污染物无明显扩散。利用HYSPLIT模型模拟北京市300 m高度下气流后向轨迹,通过聚类分析方法分析本月气团轨迹的代表性输送路径,与地面气象监测数据和高空观测资料进行对比分析。结果表明:在极端天气条件下,京津冀地区重污染天气形成过程80%受西南方向气流影响,大气污染物的输送轨迹主要是自南向北;京津冀地区重污染天气消散过程90%受北部气流影响,北部气流的快速入境使污染物迅速消散。

Taking Beijing-Tianjin-Hebei region as the research area, the formation and dissipation process of atmospheric heavy polluted weather from November 17, 2014 to November 23, 2014 were analyzed by HYSPLIT model, combined with the ground meteorological monitoring data and aerial observations data, and the meteorological factors were analyzed. The results show that during the formation of heavy polluted weather in Beijing-Tianjin-Hebei, it is mainly at high pressure or uniform pressure state, the atmosphere is stable, and the atmosphere mixing layer is lower and facilitate to form static and stable weather. At the same time, the high humidity, high pressure, weak wind and inversion in the troposphere will suppress the convection of the water vapor and pollutants and cause them unable to spread obviously. The HYSPLIT model was used to simulate the flow back trajectory of 300 m height in Beijing, and the representative route of air mass trajectory was analyzed by cluster analysis method, which was compared with the ground meteorological monitoring data and aerial observations. The analysis shows that in the extreme weather conditions, the air pollution in Beijing-Tianjin-Hebei region is 80%affected by the southwest air flow, and the transportation trajectory of air pollutant is mainly from south to north.The dissipation process of atmospheric heavy pollution weathers in Beijing-Tianjin-Hebei region is 90% affected by the northern air currents. The rapid entry of the northern airflow will quickly dissipate the pollutants.