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Higher-resolution tropopause folding accounts for more stratospheric ozone intrusions
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  • Samuel Bartusek,
  • Yutian Wu,
  • Mingfang Ting,
  • Cheng Zheng,
  • Arlene Fiore,
  • Michael Sprenger,
  • Johannes Flemming
Samuel Bartusek
Columbia University

Corresponding Author:sbartusek2@gmail.com

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Yutian Wu
Lamont-Doherty Earth Observatory of Columbia University
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Mingfang Ting
Columbia University
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Cheng Zheng
Lamont-Doherty Earth Observatory, Columbia University
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Arlene Fiore
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Michael Sprenger
Institute for Atmospheric and Climate Science
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Johannes Flemming
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Ozone in the troposphere is a pollutant and greenhouse gas, and it is crucial to better understand its transport from the ozone-rich stratosphere. Tropopause folding, wherein stratospheric air intrudes downward into the troposphere, enables stratosphere-to-troposphere ozone transport (STT). However, systematic analysis of the relationship between folding and tropospheric ozone, using data that can both capture folding’s spatial scales and accurately represent tropospheric chemistry, is lacking. Here, we compare folding in both high-resolution (0.25°) reanalysis ERA5 and low-resolution (0.75°) chemical reanalysis CAMSRA over one year. High-resolution folding is dramatically more frequent and significantly better-correlated with tropospheric ozone. In particular, folding of deep tropospheric extent is nearly 100% missing at low resolution, and folding–ozone correlations increase most with resolution along midlatitude storm tracks, where deep folding is most common. Our results imply that STT is more attributable to tropopause folding than implied by low-resolution analysis, likely associated with resolving filamentary, deep folding.