Project C03:
Improving process understanding and model representation of stratospheric water vapour and related climate feedbacks

Brief Summary

Water vapor is one of the most important greenhouse gases in the upper troposphere and lower stratosphere (UTLS) and is subject to numerous influences (e.g. overshooting convection, isentropic mixing). Water vapor increases in the UTLS impact on the Earth’s radiation budget and cause a positive climate feedback as well as circulation feedbacks, involving upward and poleward shifts of strong wind pattern called jet streams, an intensified stratospheric air circulation, and displaced regional air circulation systems. However, current global climate models simulate a too moist UTLS region when compared to observations. These moist biases may cause significant biases in simulated feedbacks and climate predictions. In this project, the various influences on the UTLS water vapor budget will be examined and quantified using different aircraft observational data and model simulations. Observational data, which were collected and homogenized in Phase 1 of TPChange and additional satellite data, are analysed in order to improve the process understanding and their contributions to the UTLS moistening during spring and summer. Future changes in the processes and the UTLS moisture budget, related climate and circulation feedbacks, as well as potential ways to improve the process representation in models will be investigated using sophisticated climate models and idealized models.

Circulation impact of stratospheric water vapour increase during summer months (June, Juli, August). (a) Water vapour bias of EMAC climate model simulation as difference to SWOOSH satellite observations, (b) temperature effect induced by that bias, and (c) the related circulation impact as change of zonal wind.

Project Poster

Evaluation Poster Phase I in 2025

Members

Publications

Baikhadzhaev, R., F. Ploeger, P. Preusse, M. Ern, and T. Birner (2025): A dynamics-based separation of deep and shallow stratospheric circulation branches. Atmospheric Chemistry and Physics 25 (19), 12753–12777. doi: 10.5194/acp-25-12753-2025

Konopka, P., F. Ploeger, F. D’Amato, T. Campos, M. von Hobe, S. B. Honomichl, P. Hoor, L. L. Pan, M. L. Santee, S. Viciani, K. A. Walker, and M. I. Hegglin (2025): Isentropic Mixing vs. Convection in CLaMS-3.0/MESSy: Evaluation Using Satellite Climatologies and In Situ Carbon Monoxide Observations. EGUsphere 2025, [Preprint], 1–32. doi: 10.5194/egusphere-2025-1155.

Saunders, L. N., K. A. Walker, G. P. Stiller, T. von Clarmann, F. Haenel, H. Garny, H. Bönisch, C. D. Boone, A. E. Castillo, A. Engel, J. C. Laube, M. Linz, F. Ploeger, D. A. Plummer, E. A. Ray, and P. E. Sheese (2025): Age of air from ACE-FTS measurements of sulfur hexafluoride. Atmospheric Chemistry and Physics 25 (7), 4185–4209. doi: 10.5194/acp-25-4185-2025.

Wang, H., M. Park, M. Tao, C. Peña-Ortiz, N. Pilar Plaza, F. Ploeger, and P. Konopka (2025): Understanding boreal summer UTLS water vapor variations in monsoon regions: a Lagrangian perspective. Atmospheric Chemistry and Physics 25 (21), 14703–14718. doi: 10.5194/acp-25-14703-2025.

Weyland, F., P. Hoor, D. Kunkel, T. Birner, F. Plöger, and K. Turhal (2025): Long-term changes in the thermodynamic structure of the lowermost stratosphere inferred from reanalysis data. Atmospheric Chemistry and Physics 25 (2), 1227–1252. doi: 10.5194/acp-25-1227-2025.

Xu, J., M. Tao, J. Bian, D. Li, P. Konopka, and F. Ploeger (2025): Recent Changes in Hemispheric Asymmetry of Stratospheric Water Vapor. Journal of Geophysical Research: Atmospheres 130 (8), e2024JD043022 2024JD043022, e2024JD043022. doi: https://doi.org/10.1029/2024JD043022.

Yan, X., P. Konopka, F. Ploeger, and A. Podglajen (2025): Transport into the polar stratosphere from the Asian monsoon region. Atmospheric Chemistry and Physics 25 (2), 1289–1305. doi: 10.5194/acp-25-1289-2025.

Ebert, M., R. Weigel, S. Weinbruch, L. Schneider, K. Kandler, S. Lauterbach, F. Köllner, F. Plöger, G. Günther, B. Vogel, and S. Borrmann (2024): Characterization of refractory aerosol particles collected in the tropical upper troposphere-lower stratosphere (UTLS) within the Asian Tropopause Aerosol Layer (ATAL). Atmospheric Chemistry and Physics 24 (8), 4771-4788. doi: 10.5194/acp-24-4771-2024.

Garny, H., F. Ploeger, M. Abalos, H. Bönisch, A. E. Castillo, T. von Clarmann, M. Diallo, A. Engel, J. C. Laube, M. Linz, J. L. Neu, A. Podglajen, E. Ray, L. Rivoire, L. N. Saunders, G. Stiller, F. Voet, T. Wagenhäuser, and K. A. Walker (2024): Age of Stratospheric Air: Progress on Processes, Observations, and Long-Term Trends. Reviews of Geophysics 62 (4), e2023RG000832. doi: https://doi.org/10.1029/2023RG000832.

Ploeger, F., T. Birner, E. Charlesworth, P. Konopka, and R. Müller (2024): Moist bias in the Pacific upper troposphere and lower stratosphere (UTLS) in climate models affects regional circulation patterns. Atmospheric Chemistry and Physics 24 (3), 2033–2043. doi: https://doi.org/10.5194/acp-24-2033-2024.

Ploeger, F. and D. Kunkel (2024): Local Processes. Reference Module in Earth Systems and Environmental Sciences. Elsevier. doi: https://doi.org/10.1016/B978-0-323-96026-7.00109-0.

Turhal, K., F. Plöger, J. Clemens, T. Birner, F. Weyland, P. Konopka, and P. Hoor (2024): Variability and trends in the potential vorticity (PV)-gradient dynamical tropopause. Atmospheric Chemistry and Physics 24 (23), 13653–13679. doi: 10.5194/acp-24-13653-2024.

Charlesworth, E., F. Ploeger, T. Birner, R. Baikhadzhaev, M. Abalos, L. Abraham, H. Akiyoshi, S. Bekki, F. Dennison, P. Jöckel, J. Keeble, D. Kinnison, O. Morgenstern, D. Plummer, E. Rozanov, S. Strode, G. Zeng, and M. Riese (2023): Stratospheric water vapor affecting atmospheric circulation. 14, doi: https://doi.org/10.1038/s41467-023-39559-2.

Harzer, F., H. Garny, F. Ploeger, H. Bönisch, P. Hoor, and T. Birner (2023): On the pattern of interannual polar vortex–ozone co-variability during northern hemispheric winter. Atmospheric Chemistry and Physics 23 (18), 10661–10675. doi: 10.5194/acp-23-10661-2023.

Konopka, P., C. Rolf, M. von Hobe, S. M. Khaykin, B. Clouser, E. Moyer, F. Ravegnani, F. D’Amato, S. Viciani, N. Spelten, A. Afchine, M. Krämer, F. Stroh, and F. Ploeger (2023): The dehydration carousel of stratospheric water vapor in the Asian summer monsoon anticyclone. Atmospheric Chemistry and Physics 23 (20), 12935–12947. doi: https://doi.org/10.5194/acp-23-12935-2023.

Ploeger, F. and H. Garny (2022): Hemispheric asymmetries in recent changes in the stratospheric circulation. Atmospheric Chemistry and Physics 22 (8), 5559–5576. doi: https://doi.org/10.5194/acp-22-5559-2022.