Summer ozone pollution in northern China has long been linked to photochemical reactions, biomass burning (BB), and stratospheric intrusions (SI). A recent study led by Academician Chen Jingming’s team at Fujian Normal University provides new insights into the vertical dynamics of tropospheric ozone, challenging conventional understanding.
The team carried out detailed observations of strong convection and atmospheric composition at the Shandong Artificial Triggered Lightning Experiment (SHATLE) site, operated by the Institute of Atmospheric Physics, Chinese Academy of Sciences. Their investigation uncovered an unusual “bottom-heavy” ozone structure during the Northeast China Cold Vortex event.
The research demonstrated that, under the influence of the cold vortex, stratospheric air masses intruded into the mid-to-lower troposphere above SHATLE, leading to ozone concentrations significantly higher than the climatological average—at times exceeding the 90th percentile. Conversely, ozone levels in the upper troposphere–lower stratosphere (UTLS) region dropped sharply, falling by 33%–48% below typical values.
Using backward trajectory simulations and meteorological analysis, the team traced these low-ozone air masses back to the boundary layer over the Tibetan Plateau. They were transported eastward by convective systems into the UTLS region of North China. By incorporating multi-year satellite data, the researchers further quantified the effect of stratospheric intrusions, showing that SI events can cause short-term ozone spikes of up to 35% in the mid-troposphere. These findings highlight the significant role of natural processes in tropospheric ozone variability.
The study, entitled “Anomalous Vertical Structure of Tropospheric Ozone Due to Stratospheric Intrusions and Convective Transport,” has been published in Geophysical Research Letters. Fujian Normal University is listed as the first-affiliated institution. Associate Professor Chen Zhixiong is the first author, with Professor Liu Jingxian of FJNU and Researcher Qie Xiushu from the Institute of Atmospheric Physics, CAS, serving as corresponding authors. The research was supported by the National Natural Science Foundation of China and the CAS Strategic Priority Research Program.
Figure: Data from four ozone soundings (July 15–17, 2024) at SHATLE showing ozone concentration (red), relative humidity (green), and static stability (blue).
Full article link:
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025GL117160