TY  - JOUR
AU  - Yessimbet, Kamilya
AU  - Shepherd, Theodore G.
AU  - Ossó, Albert C.
AU  - Steiner, Andrea K.
TI  - Pathways of Influence Between Northern Hemisphere Blocking and Stratospheric Polar Vortex Variability
JO  - Geophysical research letters
VL  - 49
IS  - 23
SN  - 0094-8276
CY  - Hoboken, NJ
PB  - Wiley
M1  - FZJ-2023-00411
SP  - e2022GL100895
PY  - 2022
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000928052000028
DO  - DOI:10.1029/2022GL100895
UR  - https://juser.fz-juelich.de/record/917179
ER  -