EGU22-3420
https://doi.org/10.5194/egusphere-egu22-3420
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Recurrent Rossby wave packets in the Northern Hemisphere

Syed Mubashshir Ali1, Lukas Meyer1, Matthias Röthlisberger2, John Methven3, Jakob Zscheischler4, and Olivia Martius1
Syed Mubashshir Ali et al.
  • 1University of Bern, Institute of Geography and Oeschger Centre for Climate Change Research, Switzerland (mubashshir.ali@giub.unibe.ch)
  • 2Institute for Atmospheric and Climate Science, ETH Zürich, Zürich, Switzerland
  • 3Department of Meteorology, University of Reading, Reading, UK
  • 4Department of Computational Hydrosystems, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany

Recurrence of Rossby wave packets in a short time, termed as RRWPs, can lead to persistent and extreme weather events. Here, we study top RRWP events in the two basins: the North Atlantic and the East Pacific basins during 1979–2018 using ERA-5 reanalysis data. With the help of composite maps, we answer questions such as what are the characteristics of these events? Do they have a preferred phase? Is a particular flow configuration conducive to such events? What is the role of atmospheric blocks? And, whether these events are initiated by a common pathway such as tropical forcings or have several different pathways? We find that these events have a preferred phase configuration which varies with season. Both North Atlantic and East Pacific events are dominated by specific wavenumbers. In winter, dominant wavenumbers are 3, 4, and 5. In contrast, wavenumbers 5, 6, and 7 dominate in JJA. Furthermore, we address the role of low frequency zonal flow, blocks, and tropical convection during RRWP events using a causal network framework.

How to cite: Ali, S. M., Meyer, L., Röthlisberger, M., Methven, J., Zscheischler, J., and Martius, O.: Recurrent Rossby wave packets in the Northern Hemisphere, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3420, https://doi.org/10.5194/egusphere-egu22-3420, 2022.

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