利用 WRF-Chem（V4. 4）模式模拟了 2016 年秋季（9-11 月）海南省海口市区域的臭氧（O3）浓度，结合 FLEXPART-WRF 模式进行后向轨迹分析，解析了 O3浓度变化的理化过程贡献、区域输送特征及潜在源区。通过过程分析方法定量评估了海口市秋季 O3浓度变化过程中各理化过程的贡献，发现化学过程与垂直混合和干沉降过程对 O3浓度的贡献存在显著日变化特征。白天化学过程平均贡献值为11. 5 μg·m⁻³，最大达到 17. 8 μg·m⁻³，夜间为负贡献；而垂直混合与干沉降过程则在白天起明显清除作用，夜间影响减弱。平流输送过程对浓度变化的影响相对较小，但在不同气团来源条件下输送贡献表现出较大差异。FLEXPART-WRF模式模拟的后向轨迹聚类分析发现，不同方向的气团输送时海口O3浓度差异显著，北部和东北方向的气团影响时 O3浓度较高，而东南和南部方向的气团则带来相对清洁的空气，海口O3浓度较低。整体上，化学过程是海口市秋季O3浓度升高的主要驱动力，而垂直混合与干沉降过程则为主要的清除过程，平流输送的贡献相对较小。此外，基于潜在源贡献因子算法（PSCF）和权重轨迹分析法（CWT）分析海口O3的潜在源区，发现海口市O3影响的主要潜在源区位于东北沿海及广东东南区域，月均贡献高达60~70 μg·m-3。研究结果对于理解热带沿海城市大气环境演变规律、科学制定区域空气质量管理策略具有重要意义。

The WRF-Chem model（v4. 4）was employed to simulate ozone（O3）concentrations in the Haikou re‐ gion of Hainan Province during the autumn of 2016（September to November），complemented by the FLEX‐ PART-WRF model for backward trajectory analysis. The research aimed to quantify the contributions of physical and chemical processes to O3 variations，examine the characteristics of regional transport，and identify potential source areas. Process analysis was applied to evaluate the influence of various mechanisms on O3 concentration changes. Results indicated significant diurnal variation in the roles of chemical processes，vertical mixing and dry deposition. During the day，chemical reactions contributed an average of 11. 5 μg·m-3 to O3 levels，with a peak of 17. 8 μg·m-3，while a net negative contribution was observed at night. Vertical mixing and dry deposition processes were major removal mechanisms during daylight hours but weakened considerably at night. Although advection transport had a relatively minor impact，its influence varied under different air mass origins. Cluster analysis of FLEXPART-WRF-simulated backward trajectories demonstrated that O3 concentrations in Haikou were strongly affected by the direction of incoming air masses. Higher concentrations were associated with north‐ ern and northeastern air masses，while lower levels were linked to cleaner air masses from the southeast and south. Overall，chemical processes dominated the increase in O3 concentrations，whereas vertical mixing and dry deposition processes served as the principal removal mechanisms. The contribution of advection transport to changes in O3 concentration is relatively small. Potential source regions were further identified using the Potential Source Contribution Function（PSCF）and Concentration Weighted Trajectory（CWT）methods. Key source ar‐ eas were located in the northeastern coastal regions and the southeastern part of Guangdong Province，contribut‐ ing an average of 60~70 μg·m-3 per month. These findings provide critical insight into the evolution of atmo‐ spheric composition in tropical coastal cities and offer a scientific basis for the development of regional air quali‐ ty management strategies.