| 合肥市夏季夜间臭氧浓度升高特征及成因研究 |
| Study on the Characteristics and Causes of Nocturnal Surface Ozone Enhancement in Hefei City During Summer |
| 投稿时间：2024-12-04 修订日期：2025-02-21 |
| DOI：10.19316/j.issn.1002-6002.2026.01.18 |
| 中文关键词: 夜间臭氧 低空急流 垂直混合 水平传输 |
| 英文关键词:nocturnal surface ozone low-level jet vertical mixing horizontal transport |
| 基金项目:安徽省重点研发计划(202304a05020010);安徽省科技重大专项(202203a07020004) |
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| 中文摘要: |
| 合肥市作为长三角地区重要省会城市之一,正面临着十分突出的臭氧(O3)污染问题。目前,大多数研究都集中在日间O3峰值浓度水平上,对夜间O3浓度上升的研究相对不足。本研究基于2021—2024年合肥市10个国控站点常规监测数据,研究夜间近地面O3增强(NSOE)事件的特征,并探讨其形成机制。研究期间,合肥市夏季平均NSOE事件发生频率为45%±7%。NSOE事件和非夜间近地面O3增强(NNSOE)事件前的日间O3峰值浓度分别123 μg/m3和116 μg/m3。低空急流(LLJ)和垂直混合是影响合肥市NSOE事件的主要因素。3个代表性站点在NSOE事件过程中的低空急流类型主要为LLJ-1,其在3个站点的出现频率均不低于87%。此外,NSOE事件前残留层中高浓度O3的存在和NSOE事件期间大气稳定性的降低有利于上层O3向下混合。NSOE事件对应的水平传输过程的气团来源主要为周边省市,其贡献占比约为76%。综上,本研究提供了对合肥市NSOE事件从特征到机制的重要概述,强调了未来开展夜间O3垂直观测和详细研究的必要性。 |
| 英文摘要: |
| Hefei is one of the important provincial capitals in the Yangtze River Delta region,which faces a prominent issue of O3 pollution.At present,most studies focus on daytime peak O3 concentrations,while research on the increase in nighttime O3 concentrations remains relatively insufficient.Based on routine monitoring data from 10 national control stations in Hefei City from 2021 to 2024,this study investigated the characteristics of nocturnal surface O3 enhancement (NSOE) events and explored their formation mechanisms.During the study period,the average frequency of NSOE events in Hefei during summer was 45%±7%.The daytime peak O3 concentrations preceding NSOE events and non-NSOE (NNSOE) events were 123 μg/m3 and 116 μg/m3,respectively.Low-level jets (LLJ) and vertical mixing were identified as the primary factors affecting NSOE events in Hefei.Among three representative sites,the predominant LLJ type during NSOE events was LLJ-1,with its occurrence frequency no lower than 87% across all three sites.In addition,the presence of high O3 concentration in the residual layer before the NSOE events and the reduction of atmospheric stability during the NSOE events facilitated the downward mixing of upper-level O3.Horizontal transport affecting NSOE events mainly originated from neighboring provinces and cities,accounting for 76%.In conclusion,this study provides a significant overview of the characteristics and mechanisms of NSOE events in Hefei,emphasizing the need for future nighttime vertical O3 observations and detailed studies. |
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