基于PSCF与CWT方法的赣江新区大气污染物潜在源区个例分析

利用TrajStat软件和GDAS全球同化气象数据，对江西省赣江新区2011—2020年四季72 h气团后向轨迹进行聚类分析，并结合PM2.5和O3逐小时浓度数据，运用潜在源贡献因子分析法（PSCF）和浓度权重轨迹分析法（CWT）分析了2016年12月2—10日一次污染天气过程中大气污染物输送对赣江新区上空污染物浓度的贡献。结果表明，赣江新区2011—2020年四季气团后向轨迹中占比最大的均为短支气流，其中春季的短支气流来源于东侧，其他季节均来源于东北方向的安徽省，夏季和冬季的长支气流与季风的季节性变化一致。在2016年12月2—10日的污染天气过程中，赣江新区的PM2.5潜在源区主要分布于江西省北部、湖北省东南部，O3潜在源区主要分布于江西省北部、湖北省南部和湖南省东北小部分地区；同时天气形势显示，赣江新区处在槽后脊前，湖北省东南部存在偏强西北风，为大气污染物向赣江新区的输送创造了条件。

Case Study on Potential Sources of Air Pollutants over Ganjiang New District Based on PSCF and CWT Methods

Based on the TrajStat software and the global data assimilation system (GDAS), the 72 hours backward trajectories of the year and for seasons during 2011-2020 were assessed by cluster analysis over Ganjiang New District in Jiangxi Province. Combined with hourly PM2.5 and O3 concentration data, the contribution of air pollutants transport over Ganjiang New District during a polluted weather process of December 2-10, 2016 was analyzed by the potential source contribution function (PSCF) and concentration weighted trajectory (CWT). Results showed that short branch airflow trajectories accounted for the largest proportion in four seasons over Ganjiang New District during 2011-2020, among which the airflow mainly originated from the direction of Anhui, except in spring the airflow originated from the east. The long branch airflow in summer and winter were consistent with the seasonal variation of monsoon. During December 2-10, 2016, the potential source areas of PM2.5 in Ganjiang New District were mainly distributed in northern Jiangxi and southeastern Hubei, and the potential sources of O3 were mainly distributed in northern Jiangxi, southern Hubei and a small part of northeastern Hunan. The weather situation presented that the Ganjiang New District was just in front of the ridge, while the northwesterly wind in southeastern Hubei was much stronger, which created the conditions for transporting air pollutants to the Ganjiang New District.