Abstract:

[Objective] This study aimed to characterize ozone (O₃) variations under different weather regimes in Fujian Province and identify their major influencing factors, thereby providing a scientific basis for regional O₃ pollution prevention and control. [Methods] The structured self-organizing map (S-SOM) algorithm and the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model were used to classify atmospheric circulation patterns and analyze backward air-mass trajectories over Fujian Province from June 2022 to December 2023. [Results] Atmospheric circulation over Fujian Province was classified into four weather regimes in 2022. Among them, the high-low pressure transition regime (S-SOM-III in 2022) exhibited the highest O_3-8h mass concentration (110 µg·m⁻³). In 2023, five weather regimes were identified, with the marine low-pressure-dominated regime (S-SOM-I in 2023) exhibiting the highest O_3-8h mass concentration (98.7 µg·m⁻³). Overall, O₃ mass concentrations under the weather regimes in 2022 were approximately 4.85% higher than those in 2023. In both years, O₃ mass concentrations were higher in coastal cities than in inland cities, with an average difference of approximately 45.3%. Backward trajectory analysis identified five major air-mass transport pathways across the province, among which Pathway IV accounted for the largest proportion (39.8%). This pathway originated from the Taiwan Strait and transported air masses northwestward from Pinghai Bay to the Daiyun Mountains. [Conclusion] The spatial distribution and variation of O₃ concentrations under different weather regimes in Fujian Province were closely related to air-mass transport patterns and meteorological conditions. High temperatures, low relative humidity, limited precipitation, and external pollutant transport favored O₃ accumulation. Pollutant transport mainly originated from the coastal areas of Zhejiang Province and entered Fujian Province through northern Fujian and along the coast of the Taiwan Strait, whereas clean marine air masses and humid, rainy conditions were unfavorable for O₃ formation or accumulation.

Key words: weather classification, backward trajectory analysis, ozone, pollutant transport, Fujian Province

摘要：

【目的】揭示福建省不同天气类型下臭氧浓度变化特征及其成因，为区域臭氧污染防治提供依据。【方法】使用结构化自组织映射算法（S-SOM）和混合单粒子拉格朗日积分轨迹（HYSPLIT）模型，对福建省2022年6月－2023年12月的大气环流进行天气分型和后向轨迹分析。【结果】福建省的大气环流在2022年分为4种类型，其中高压-低压过渡带型（2022年S-SOM-Ⅲ）下O_3-8h质量浓度最高（110 µg·m⁻³），2023年分为5种类型，海上低压控制型（2023年S-SOM-Ⅰ）下O_3-8h质量浓度最高（98.7 µg·m⁻³），并且2022年各天气分型臭氧质量浓度整体高于2023年（约4.85%），但都表现为沿海城市臭氧质量浓度高，内陆城市臭氧质量浓度低，平均高约45.3%。后向轨迹表明全省主要有5条气团输送路径，其中Ⅳ型占比最多（39.8%），源于台湾海峡，自平海湾向西北方输送至戴云山山脉。【结论】福建省不同天气类型下的臭氧浓度空间分布及其变化与气团输送模式和气象条件密切相关，高温、低湿、较少降水以及外来污染物输送有利于臭氧的积累，污染物输送主要源自浙江省沿海区域，经福建北部和台湾海峡沿岸输入福建省；而海洋清洁气团和高湿多雨条件不利于臭氧的生成或积累。

关键词: 天气分型, 后向轨迹分析, 臭氧, 污染物输送, 福建省