Preprints
https://doi.org/10.5194/egusphere-2025-82
https://doi.org/10.5194/egusphere-2025-82
11 Feb 2025
 | 11 Feb 2025

Shift in cold-point tropopause trends derived from radiosonde, satellite, and reanalysis data

Mona Zolghadrshojaee, Susann Tegtmeier, Sean M. Davis, Robin Pilch Kedzierski, and Leopold Haimberger

Abstract. The tropical tropopause layer (TTL) is the transition region between the well-mixed convective troposphere and the radiatively controlled stratosphere and plays a crucial role for air mass transport between these layers. In this paper, we present updated trends of TTL and lower stratospheric temperature from radiosonde and Global Navigation Satellite System – Radio Occultation (GNSS-RO) data and evaluate temperature trends in the reanalysis data sets ERA5, JRA-3Q, and MERRA-2. Given its importance in determining the concentration of water vapor entering the stratosphere, we focused in particular on temperature trends at the cold point tropopause, which we determined from radiosonde observations by removing time-varying bias effects from trends based on unadjusted data.

From 1980 to 2023, cold point tropopause cooling is shown in radiosondes, overestimated by JRA-3Q and underestimated by MERRA-2 and ERA5. Splitting into two periods reveals a shift in TTL temperature trends: cooling (1980–2001) to warming (2002–2023) across all datasets, highlighting post-2002 changes in tropical tropopause dynamics. Tropical upwelling estimates from the three reanalyses show opposite trends for 1980–2001 compared to 2002–2023 consistent with the cold point and lower stratosphere temperature trends. While the vertical residual circulation increased before 2000 consistent with cold point cooling, the circulation trends turned to zero (MERRA-2, JRA-3Q) or became positive (ERA5) after 2000 consistent with cold point warming. Between 2002–2023, GNSS-RO and reanalysis show significant warming at the cold point and lower stratosphere, aligning with observed patterns and seasonality. Warming trends anticorrelate with tropospheric cooling, strongest where upper troposphere cooling appears.

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Journal article(s) based on this preprint

07 Oct 2025
Shift in cold-point tropopause trends derived from radiosonde, satellite and reanalysis data
Mona Zolghadrshojaee, Susann Tegtmeier, Sean M. Davis, Robin Pilch Kedzierski, and Leopold Haimberger
Atmos. Chem. Phys., 25, 12213–12232, https://doi.org/10.5194/acp-25-12213-2025,https://doi.org/10.5194/acp-25-12213-2025, 2025
Short summary
Mona Zolghadrshojaee, Susann Tegtmeier, Sean M. Davis, Robin Pilch Kedzierski, and Leopold Haimberger

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2025-82', Anonymous Referee #1, 31 Mar 2025
    • AC1: 'Reply on RC1', Mona Zolghadrshojaee, 15 Jul 2025
  • RC2: 'Comment on egusphere-2025-82', Anonymous Referee #2, 02 Apr 2025
    • AC2: 'Reply on RC2', Mona Zolghadrshojaee, 15 Jul 2025

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2025-82', Anonymous Referee #1, 31 Mar 2025
    • AC1: 'Reply on RC1', Mona Zolghadrshojaee, 15 Jul 2025
  • RC2: 'Comment on egusphere-2025-82', Anonymous Referee #2, 02 Apr 2025
    • AC2: 'Reply on RC2', Mona Zolghadrshojaee, 15 Jul 2025

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
AR by Mona Zolghadrshojaee on behalf of the Authors (15 Jul 2025)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (16 Jul 2025) by Farahnaz Khosrawi
ED: Publish subject to minor revisions (review by editor) (23 Jul 2025) by Farahnaz Khosrawi
AR by Mona Zolghadrshojaee on behalf of the Authors (24 Jul 2025)  Author's response   Author's tracked changes   Manuscript 
ED: Publish as is (25 Jul 2025) by Farahnaz Khosrawi
AR by Mona Zolghadrshojaee on behalf of the Authors (31 Jul 2025)  Author's response   Manuscript 

Journal article(s) based on this preprint

07 Oct 2025
Shift in cold-point tropopause trends derived from radiosonde, satellite and reanalysis data
Mona Zolghadrshojaee, Susann Tegtmeier, Sean M. Davis, Robin Pilch Kedzierski, and Leopold Haimberger
Atmos. Chem. Phys., 25, 12213–12232, https://doi.org/10.5194/acp-25-12213-2025,https://doi.org/10.5194/acp-25-12213-2025, 2025
Short summary
Mona Zolghadrshojaee, Susann Tegtmeier, Sean M. Davis, Robin Pilch Kedzierski, and Leopold Haimberger
Mona Zolghadrshojaee, Susann Tegtmeier, Sean M. Davis, Robin Pilch Kedzierski, and Leopold Haimberger

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Short summary
The tropical tropopause layer (TTL) is a crucial region where the troposphere transitions into the stratosphere, influencing air mass transport. This study examines temperature trends in the TTL and lower stratosphere using data from weather balloons, satellites, and reanalysis datasets. We found cooling trends in the TTL from 1980–2001, followed by warming from 2002–2023. These shifts are linked to changes in atmospheric circulation and impact water vapor transport into the stratosphere.
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