EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

The Footprint of Growing Stratospheric Transport Contribution in Tropospheric Ozone

Xiaodan Ma1,2, Jianping Huang3, Michael Sprenger4, Michaela Imelda Hegglin1, Patrick Jöckel5, and Tianliang Zhao2
Xiaodan Ma et al.
  • 1Institute for Energy and Climate Stratosphere (IEK-7), Research Center Juelich, Juelich, Germany (;
  • 2Nanjing University of Information Science and Technology, Nanjing, China (;
  • 3I.M. System Group, Environmental Modeling Center, NOAA National Centers for Environmental Prediction, College Park, MD, USA ( )
  • 4Institute for Atmospheric and Climate Science, ETH Zürich, Zurich, Switzerland (
  • 5Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, German (

The long-term ozone changes in the middle to upper troposphere, of importance to climate radiative forcing and setting the baseline for tropospheric ozone pollution, are not well quantified from observations in East Asia. In this study, three decades of observations from ozone soundings are examined with meteorological reanalysis data and climate model simulations to characterize regional features in tropospheric ozone and investigate their driving factors along the northwestern Pacific coastal region. A rapid increase in ozone is observed in the middle to upper troposphere over Naha (26 oN), Tsukuba (36 oN), and Sapporo (43 oN) in the warm season during 1990‒2020. Coincidentally, tongue-shaped hotspots with high tropospheric ozone extending from the stratosphere occur during the warm season. The timing for these ozone hotspots shows a time lag from late spring to summer with the increasing latitude of the observation sites. Intensified stratospheric intrusion (i.e., tropopause folding) events and enhanced buildup of ozone abundance in the lowermost stratosphere (likely driven by climate change) are the key factors causing the large increase over this region. With the aid of the chemistry climate model EMAC, the enhanced downward transport of stratospheric ozone into the troposphere is revealed by a surge in the stratospheric ozone tracer in the troposphere.

How to cite: Ma, X., Huang, J., Sprenger, M., Hegglin, M. I., Jöckel, P., and Zhao, T.: The Footprint of Growing Stratospheric Transport Contribution in Tropospheric Ozone, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1594,, 2023.

Supplementary materials

Supplementary material file