EGU24-20995, updated on 11 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Gravity Wave Lateral Propagation Prominence in the Extratropical Stratosphere

Aman Gupta1, Aditi Sheshadri1, and M. Joan Alexander2
Aman Gupta et al.
  • 1Doerr School of Sustainability, Stanford University, Stanford, California, USA
  • 2NorthWest Research Associates, Boulder, Colorado, USA

Internal gravity waves (GWs) exhibit both vertical and horizontal (lateral) propagation in the atmosphere, influenced by the background shear of the flow that supports them. GW model parameterizations, however, represent them in climate models assuming strict vertical propagation. This modeling assumption can have implications for modeled large-scale stratospheric circulation and variability. We use ERA5 reanalysis to produce the climatological distribution of resolved GW momentum fluxes and forcing in the stratosphere, and their composite evolution around prominent modes of extratropical stratospheric variability like sudden stratospheric warmings (SSWs) and springtime final warmings (FWs). The climatology reveals that lateral propagation leads to the formation of a belt of rich GW activity in the upper winter stratosphere, which is otherwise localized over orographic hotspots in the lower stratosphere. The resolved forcing due to lateral GW propagation is found to be roughly the same order of magnitude as resolved forcing due to vertical fluxes, underlining the importance of lateral propagation for future GW parameterizations. Strikingly different GW forcing profiles before vs. after SSWs and FWs, highlighting the strong two-way connection between GWs and the stratospheric mean flow.

How to cite: Gupta, A., Sheshadri, A., and Alexander, M. J.: Gravity Wave Lateral Propagation Prominence in the Extratropical Stratosphere, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20995,, 2024.