基于WHCWT模型的宁夏地区季节性PM2.5传输路径及来源分析OA

To identify the key areas and primary contributing sources for the collaborative control of PM2.5 in Ningxia,based on hourly PM2.5 mass concentration monitoring data from five cities in Ningxia(Yinchuan City,Shizuishan City,Wuzhong City,Zhongwei City,and Guyuan City)from March 2023 to February 2024,Global Data Assimilation System(GDAS)meteorological data,and high-resolution land cover data,the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model and the Weighted Height-Weighted Concentration-Weighted Trajectory(WHCWT)model were used to systematically analyze the seasonal transport pathways and source characteristics of PM2.5 in Ningxia.The results indicate that PM2.5 mass concentration in Ningxia exhibits distinct seasonal patterns,with higher levels in winter and spring,and lower levels in summer and autumn.Spatially,concentrations were higher in the west during spring and summer and in the north during autumn and winter.Temporally,an overall bimodal and heterogeneous daily variation pattern was observed.The seasonal transport pathways are influenced by four types of airflow patterns,namely long-distance transport from the northwest(Xinjiang-Inner Mongolia/Gansu-Ningxia),short-distance transport from the northwest(Inner Mongolia/Gansu-Ningxia),short-distance transport from the northwest with an eastern detour(Inner Mongolia/Inner Mongolia-Mongolia border-Ningxia),and short-distance transport from the southeast(Shaanxi-Ningxia).Among these,the proportion of airflow from the northwest transport pathway peaked in winter(83.69%)and fell to a low in summer(56.42%).The potential source contributions showed seasonal differentiation,with significant contributions from the northwest in spring and dominance of the southeast in winter.The pollution source contributions also exhibited notable seasonal differentiation,with Inner Mongolia being the largest contributor in spring,summer,and autumn,while wind-blown dust sources,natural vegetation sources,and agricultural production sources contributed in decreasing order.In winter,Shaanxi Province became the largest contributor,with natural vegetation sources,agricultural production sources,and urban industrial sources as the main contributors.