EGU21-9055, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-9055
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Extreme vertical drafts in the polar summer mesosphere: A super mesospheric bore?

Jorge Luis Chau1, Raffaele Marino2, Fabio Feraco2,3, Juan M. Urco1,4, Gerd Baumgarten1, Franz-Josef Luebken1, Wayne K. Hocking5, Carsten Schult1, Toralf Renkwitz1, and Ralph Latteck1
Jorge Luis Chau et al.
  • 1Leibniz Institute of Atmospheric Physics at University of Rostock, Kuehlungsborn, Germany
  • 2Laboratoire de Mécanique des Fluìdes et d’Acoustique, CNRS, École Centrale de Lyon, Université Claude Bernard, Lyon 1, INSA de Lyon, Écully, France
  • 3Dipartimento di Fisica, Universitá della Calabria - Arcavacata di Rende (CS), Italy.
  • 4Department of Electrical and Computer Engineering and Coordinated Science Laboratory, University of Illinois, Urbana-Champaign, Urbana, IL, USA
  • 5Department of Physics and Astronomy, University of Western Ontario, London, Ontario, Canada.

The polar summer mesosphere is the Earth’s coldest region, allowing the formation of mesospheric ice clouds, potentially linked to climate change. These clouds produce strong radar echoes that are used as tracers of mesospheric dynamics. Here we report the first observations of extreme vertical drafts in the mesosphere, characterized by velocities larger than 40 m/s, i.e., more than five standard deviations larger than the observed wind variability. The morphology seems to resemble mesospheric bores, however the scales observed are much larger. Powerful vertical drafts, intermittent in space and time, emerge also in direct numerical simulations of stratified flows, predicting non-Gaussian statistics of vertical velocities. This evidence suggests that mesospheric bores might result from the interplay of gravity waves and turbulent motions. Our extreme event is interpreted as a mesospheric "super-bore", impacting mesospheric mixing and ice-formation, and would potentially impact planning of sub-orbital flights, and the investigation of biological material in the near space.

How to cite: Chau, J. L., Marino, R., Feraco, F., Urco, J. M., Baumgarten, G., Luebken, F.-J., Hocking, W. K., Schult, C., Renkwitz, T., and Latteck, R.: Extreme vertical drafts in the polar summer mesosphere: A super mesospheric bore?, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9055, https://doi.org/10.5194/egusphere-egu21-9055, 2021.

Corresponding presentation materials formerly uploaded have been withdrawn.