Key Laboratory of Meteorological Disaster, Ministry of Education (KLME), Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science and Technology, Nanjing 210044, China.
Key Laboratory of Meteorological Disaster, Ministry of Education (KLME), Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science and Technology, Nanjing 210044, China.
Sci Total Environ. 2022 Sep 1;837:155762. doi: 10.1016/j.scitotenv.2022.155762. Epub 2022 May 6.
There are concerns that in the 21st century, global warming will lead to more frequent heat wave days (HWDs), which could amplify ozone pollution (OP). However, a recent study projected that future atmospheric circulation variations may benefit OP control in Beijing-Tianjin-Hebei (BTH). To investigate the possible reasons for this contradiction, this paper discussed the ozone amplification capacity between different HWD types and their future projections based on observations and Community Earth System Model Large Ensemble Simulations (CESM-LENS). Composite analysis shows that not all HWDs amplify the OP in BTH. The main factor determining whether HWDs aggravate OP is the accompanying circulation anomalies rather than the intensity of the HWDs. The HWDs that aggravate ozone pollution are usually accompanied by stable saddle-like circulation anomalies and atmospheric blocking (blocking HWDs), which weaken the meridional temperature gradient and strengthen atmospheric stability. In contrast, HWDs with wave-train circulation anomalies have a limited ability to exacerbate OP in BTH due to their weak atmospheric stability. We introduce the Ozone Weather Index (OWI) to discern the influence of meteorological conditions on OP and overcome the lack of ozone concentration data in CESM-LENS under RCP 8.5 scenario. The OWI shows a significant downward trend in the 21st century, which indicates that the summer mean atmospheric circulation variations are beneficial for OP control in BTH. However, the frequency of blocking HWDs, which could amplify OP, will increase significantly in the 21st century. By the end of the 21st century, the frequency of blocking HWDs will be three times more than that of the end of 20th century. These findings inform policymakers that it is imperative to consider the mean climate state and the risks associated with extreme events when formulating future ozone pollution control policies.
人们担心在 21 世纪，全球变暖将导致更频繁的热浪日（HWDs），从而加剧臭氧污染（OP）。然而，最近的一项研究预测，未来大气环流变化可能有利于京津冀（BTH）地区的 OP 控制。为了探讨这一矛盾的可能原因，本文基于观测和地球系统模式大集合模拟（CESM-LENS）讨论了不同 HWD 类型之间的臭氧放大能力及其未来预测。综合分析表明，并非所有 HWD 都会加剧 BTH 的 OP。决定 HWD 是否加剧 OP 的主要因素不是 HWD 的强度，而是伴随的环流异常。加剧臭氧污染的 HWD 通常伴有稳定的鞍状环流异常和大气阻塞（阻塞 HWDs），这会削弱南北温度梯度并增强大气稳定性。相比之下，由于大气稳定性较弱，具有波列环流异常的 HWD 对 BTH 中 OP 的加剧作用有限。我们引入臭氧天气指数（OWI）来辨别气象条件对 OP 的影响，并克服 CESM-LENS 在 RCP8.5 情景下缺乏臭氧浓度数据的问题。OWI 显示出 21 世纪显著的下降趋势，表明夏季平均大气环流变化有利于 BTH 的 OP 控制。然而，能够加剧 OP 的阻塞 HWD 的频率在 21 世纪将显著增加。到 21 世纪末，阻塞 HWD 的频率将是 20 世纪末的三倍。这些发现提醒决策者，在制定未来的臭氧污染控制政策时，必须考虑到平均气候状态和极端事件带来的风险。
