Cyclone‐Like Features Within the Stratospheric Polar‐Night Vortex

Abstract Distinctive synoptic‐scale (∼1,500 km) flow features are identified within the core of the stratospheric polar‐night vortex at stratopause altitudes (∼50 km). Typically they comprise a train or a complex pattern of transient vortices, each characterized by enhanced values of potential vorti...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Huw C. Davies, Michael Sprenger
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2024
Subjects:
stratosphere
polar night vortex
cyclones
stirring
sudden stratospheric warming
barotropic instability
Geophysics. Cosmic physics
QC801-809
polar night
Online Access:https://doi.org/10.1029/2024GL109529
https://doaj.org/article/bab43847717141539a249d25a4440c84
Description
Summary:Abstract Distinctive synoptic‐scale (∼1,500 km) flow features are identified within the core of the stratospheric polar‐night vortex at stratopause altitudes (∼50 km). Typically they comprise a train or a complex pattern of transient vortices, each characterized by enhanced values of potential vorticity (PV) and relative vorticity but with a weaker thermal signal. In the MERRA‐2 (and two other) reanalysis fields these cyclone‐like features persist for several days, occur episodically, and form essentially within the core of the polar‐night vortex itself. Their origin is plausibly linked to a form of barotropic instability associated with a radiatively‐induced annular ring of enhanced PV. Moreover, their ubiquity and dynamics carries possible implications for: ‐ the structure of the larger‐scale polar vortex and its preconditioning ahead of a Sudden Stratospheric Warming event; the distribution of trace‐constituents within the core; and the features representation in extended range/seasonal prediction and climate models.

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