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Barotropic decelerations of the southern stratospheric polar vortex
Author(s) -
Marques C. A. F.,
Castanheira J. M.
Publication year - 2017
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.2961
Subject(s) - barotropic fluid , baroclinity , polar vortex , vortex , middle latitudes , sudden stratospheric warming , climatology , atmospheric sciences , polar , physics , kinetic energy , geology , geophysics , environmental science , meteorology , classical mechanics , astronomy
The northern and southern polar vortices are subject to quite different dynamical forcings, with the variability of the northern polar vortex much more dominated by baroclinic wave processes. Some recent works describe a barotropic structure in vortex‐splitting sudden stratospheric warming events (SSWs). Performing an analysis of the anomalies of the energy cycle, we show that strong decelerations of the southern polar vortex are, in fact, dominated by the transfer of kinetic energy between barotropic components. A major role is played by the barotropic zonal wave number n = 3 in the energy transfer of kinetic energy. This result, conjugated with the fact that stationary tropospheric waves in the southern midlatitudes have an amplitude peak at zonal wave number n = 3, suggests that the barotropic mechanism of ‘nonlinear resonance tuning’ may be the cause of strong decelerations of the southern stratospheric polar vortex.