EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Stratospheric water vapor affecting atmospheric circulation

Edward Charlesworth1, Felix Plöger1, Thomas Birner2, Rasul Baikhadzhaev1, Marta Abalos4, Luke Abraham8, Hideharu Akiyoshi5, Slimane Bekki6, Fraser Dennison10, Patrick Jöckel7, James Keeble8, Doug Kinnison16, Olaf Morgenstern10, David Plummer11, Eugene Rozanov12, Sarah Strode13, Guang Zeng10, and Martin Riese1
Edward Charlesworth et al.
  • 1Institute for Energy and Climate Research: Stratosphere (IEK–7), Research Center Jülich, Jülich, Germany
  • 2Institute for Atmospheric and Environmental Research, University of Wuppertal, Wuppertal, Germany
  • 4Earth Physics and Astrophysics Department, Universidad Complutense de Madrid, Madrid, Spain
  • 5National Institute for Environmental Studies, Tsukuba, Japan
  • 6Laboratoire de Météorologie Dynamique (LMD/IPSL), Palaiseau, France
  • 7Institut für Physik der Atmosphäre, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Oberpfaffenhofen, Germany
  • 8National Centre for Atmospheric Science (NCAS), University of Cambridge, Cambridge, UK
  • 10National Institute of Water and Atmospheric Research, Wellington, New Zealand
  • 11Climate Research Branch, Environment and Climate Change Canada, Montreal, Canada
  • 12Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
  • 13Goddard Earth Sciences Technology and Research (GESTAR-II), Morgan State University, Baltimore, MD, USA
  • 16National Center for Atmospheric Research, Boulder, CO, USA

Water vapor plays an important role in many aspects of the climate system, by affecting radiation, cloud formation, atmospheric chemistry and dynamics. Even the low stratospheric water vapor content provides an important climate feedback, but current climate models show a substantial moist bias in the lowermost stratosphere. Here we report crucial sensitivity of the atmospheric circulation in the stratosphere and troposphere to the abundance of water vapor in the lowermost stratosphere. We show from a mechanistic climate model experiment and inter-model variability that lowermost stratospheric water vapor decreases local temperatures, and thereby causes an upward and poleward shift of subtropical jets, a strengthening of the stratospheric circulation, a poleward shift of the tropospheric eddy-driven jet and regional climate impacts. The mechanistic model experiment in combination with atmospheric observations further shows that the prevailing moist bias in current models is likely caused by the transport scheme, and can be alleviated by employing a less diffusive Lagrangian scheme. The related effects on atmospheric circulation are of similar magnitude as climate change effects. Hence, lowermost stratospheric water vapor exerts a first order effect on atmospheric circulation and improving its representation in models offers promising prospects for future research.

How to cite: Charlesworth, E., Plöger, F., Birner, T., Baikhadzhaev, R., Abalos, M., Abraham, L., Akiyoshi, H., Bekki, S., Dennison, F., Jöckel, P., Keeble, J., Kinnison, D., Morgenstern, O., Plummer, D., Rozanov, E., Strode, S., Zeng, G., and Riese, M.: Stratospheric water vapor affecting atmospheric circulation, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-14506,, 2023.