Journal Article

FZJ-2023-00411

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Pathways of Influence Between Northern Hemisphere Blocking and Stratospheric Polar Vortex Variability

Yessimbet, K. (Corresponding author) ; Shepherd, T. G.FZJ* ; Ossó, A. C. ; Steiner, A. K.

2022
Wiley Hoboken, NJ

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Please use a persistent id in citations: http://hdl.handle.net/2128/33564  doi:10.1029/2022GL100895

Abstract: We apply a causal inference-based framework to test and quantify previously suggested causalrelationships between Northern Hemisphere blocking, upward wave-activity fluxes and stratospheric polarvortex (SPV) variability using reanalysis data. We show that the influence of blocking on the polar vortex isentirely mediated by upward wave-activity fluxes, as the classical view would suggest. However, the causalpathway is not completely straightforward. In contrast to the vortex-weakening effect of European blocking,the vortex-strengthening effect of west Pacific blocking on lower stratospheric wave-activity fluxes is onlypartially mediated by upper tropospheric wave-activity fluxes. In addition, only two-thirds of the effectof upper tropospheric wave-activity fluxes on polar vortex variability is mediated by lower stratosphericwave-activity fluxes. We also show that sudden stratospheric warmings are not entirely explainable in terms ofupward wave-activity fluxes. These findings help clarify the pathways of influence between blocking and SPVvariability.

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Contributing Institute(s):

1. Jülich Supercomputing Center (JSC)
2. Stratosphäre (IEK-7)

Research Program(s):

1. 5111 - Domain-Specific Simulation & Data Life Cycle Labs (SDLs) and Research Groups (POF4-511) (POF4-511)
2. 2112 - Climate Feedbacks (POF4-211) (POF4-211)

Appears in the scientific report 2022

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; SCOPUS ; Web of Science Core Collection

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