基于后向轨迹模式的区域大气污染及传输特征分析

选取南京市2017年PM2.5逐时观测数据，分析其颗粒物污染特征，并利用聚类分析、潜在源贡献因子法和GDAS气象数据，分析不同高度、季节下南京市主要气流输送路径及PM2.5污染的主要潜在源区。结果表明：南京市PM2.5污染冬季最严重，夏季最轻，逐时PM2.5浓度变化范围夏季小于冬季；夏季气流轨迹主要来自东南方向，秋冬春等季节以偏西和西北路径为主，且随着高度的增加，气流输送速度逐渐加快；冬季对南京市PM2.5污染的贡献最为显著，低层PM2.5污染贡献源区主要集中在近地区域，且贡献率较高，随着高度的增加，贡献源区由研究区域向四周辐散，贡献范围广，贡献率降低。

Analysis of Regional Air Pollution and Transmission Characteristics Based on Backward Trajectory Model

PM2.5 hourly observation data in Nanjing in 2017 were selected to analyze the pollution characteristics of particulate matter, the main airflow transport paths and major potential source areas of PM2.5 pollution in Nanjing under different altitudes and seasons were analyzed by using cluster analysis, potential source contribution factor method and GDAS meteorological data. The results showed that PM2.5 pollution in Nanjing was the most serious in winter and the lightest in summer. The variation range of PM2.5 hourly concentration in summer was less than that in winter. The airflow trajectory was mainly from the southeast in summer, and from the west or northwest in autumn, winter and spring. The air transport speed gradually accelerated with the increase of height. Winter had the most significant contribution to PM2.5 pollution in Nanjing. The contribution sources of low-level PM2.5 pollution were mainly concentrated in the near ground region, and the contribution rate was high. With the increase of height, the contribution source area diverged from the study area to the surrounding area, the contribution range was wide, and the contribution rate decreased.