Higher‐Resolution Tropopause Folding Accounts for More Stratospheric Ozone Intrusions

Abstract Ozone in the troposphere is a pollutant and greenhouse gas, it crucial to better understand its transport from ozone‐rich stratosphere. Tropopause folding, wherein stratospheric air intrudes downward into troposphere, enables stratosphere‐to‐troposphere ozone (STT). However, systematic analysis of relationship between folding tropospheric ozone, using data that can both capture folding's spatial scales accurately represent chemistry, limited. Here, we compare high‐resolution reanalysis ERA5 (0.25° horizontal, <21 hPa vertical) low‐resolution chemical CAMSRA (0.75°, <40 hPa), against over 1 year. Folding becomes dramatically more frequent at high resolution, with vertical resolution overwhelmingly responsible. Deeper, filamentary almost entirely unrepresented low resolution. Higher‐resolution better‐correlated (especially along midlatitude storm tracks, where deep most common); STT therefore likely attributable tropopause than coarsely‐resolved capture.