Preprints
https://doi.org/10.5194/egusphere-2025-3452
https://doi.org/10.5194/egusphere-2025-3452
02 Sep 2025
 | 02 Sep 2025
Status: this preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).

Intercomparison of tropopause height climatologies: High-Resolution radiosonde measurements versus ERA5 reanalysis

Yu Gou, Jian Zhang, Wuke Wang, Kaiming Huang, and Shaodong Zhang

Abstract. The tropopause plays a critical role in stratosphere-troposphere exchange and climate change. Its height is widely defined based on the World Meteorological Organization (WMO) threshold temperature gradient. High-resolution (5–10 m) soundings, therefore, are expected to substantially minimize uncertainties of tropopause height (TH) arising from limited vertical resolution and imprecise temperature measurements. The near-global coverage of high-resolution radiosonde data, accumulated from 2000 to 2023, offers valuable insights into climatological tropopause variability. While radiosonde observations are limited by spatiotemporal coverage, European Centre for Medium–Range Weather Forecasts Reanalysis v5 (ERA5) reanalysis datasets offer globally complete tropopause representations. To leverage both the high resolution of radiosonde measurements and the global coverage of ERA5, this study compares their tropopause height estimates and analyzes long-term trends across different latitude zones and seasons. The results indicate that the mean and absolute differences (radiosonde minus ERA5) in TH were 32 m and 336 m, respectively, with larger discrepancies observed during the spring season in the tropics (±20°). Overall, point-to-point comparisons (with strict spatio-temporal matching) indicate that ERA5 effectively captures climatological tropopause height variations in both time and space. Long-term trend analyses revealed increases of +5 m/year (radiosonde) and +3 m/year (ERA5) based on point-to-point comparisons. However, these site-specific trends may differ substantially from the long-term trends observed in ERA5 with complete spatiotemporal resolution, even showing opposite trends. Therefore, continued accumulation of high-resolution radiosonde profile data is crucial to further characterize tropopause changes in a warming climate.

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Yu Gou, Jian Zhang, Wuke Wang, Kaiming Huang, and Shaodong Zhang

Status: open (until 14 Oct 2025)

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Yu Gou, Jian Zhang, Wuke Wang, Kaiming Huang, and Shaodong Zhang
Yu Gou, Jian Zhang, Wuke Wang, Kaiming Huang, and Shaodong Zhang
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Short summary
Tropopause height is a key climate change indicator, with accurate long-term trends vital for climate research. Radiosonde data, while reliable, has limited coverage. ERA5 is a reanalysis dataset that provides global data, enabling comparisons of tropopause height estimates and then analyzed for long-term trends. Results show a 32 m mean difference (radiosonde – ERA5) with trends of +5 m/year (radiosonde) and +3 m/year (ERA5), crucial for characterizing tropopause changes under climate change.
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