Chen Zhixiong, Liu Jane, Qie Xiushu, Cheng Xugeng, Yang Mengmiao, Shu Lei, Zang Zhou
Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, School of Geographical Sciences, Fujian Normal University, Fuzhou, China.
Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
Nat Commun. 2024 May 14;15(1):4064. doi: 10.1038/s41467-024-48406-x.
Events of stratospheric intrusions to the surface (SITS) can lead to severe ozone (O) pollution. Still, to what extent SITS events impact surface O on a national scale over years remains a long-lasting question, mainly due to difficulty of resolving three key SITS metrics: frequency, duration and intensity. Here, we identify 27,616 SITS events over China during 2015-2022 based on spatiotemporally dense surface measurements of O and carbon monoxide, two effective indicators of SITS. An overview of the three metrics is presented, illustrating large influences of SITS on surface O in China. We find that SITS events occur preferentially in high-elevation regions, while those in plain regions are more intense. SITS enhances surface O by 20 ppbv on average, contributing to 30-45% of O during SITS periods. Nationally, SITS-induced O peaks in spring and autumn, while over 70% of SITS events during the warm months exacerbate O pollution. Over 2015-2022, SITS-induced O shows a declining trend. Our observation-based results can have implications for O mitigation policies in short and long terms.
平流层侵入地表事件（SITS）会导致严重的臭氧（O）污染。然而，多年来SITS事件在全国范围内对地表臭氧的影响程度仍是一个长期存在的问题，主要是因为难以确定SITS的三个关键指标：频率、持续时间和强度。在此，我们基于对臭氧和一氧化碳的时空密集地表测量，确定了2015年至2022年期间中国发生的27616次SITS事件，臭氧和一氧化碳是SITS的两个有效指标。本文概述了这三个指标，说明了SITS对中国地表臭氧的重大影响。我们发现，SITS事件优先发生在高海拔地区，而发生在平原地区的事件则更为强烈。SITS使地表臭氧平均增加20 ppbv，在SITS期间占臭氧总量的30%-45%。在全国范围内，SITS导致的臭氧峰值出现在春季和秋季，而温暖月份超过70%的SITS事件会加剧臭氧污染。在2015年至2022年期间，SITS导致的臭氧呈下降趋势。我们基于观测的结果可能对短期和长期的臭氧减排政策具有启示意义。
