Phase speed spectra and the recent poleward shift of Southern Hemisphere surface westerlies

Gang Chen, Isaac M. Held

Research output: Contribution to journalArticle

143 Scopus citations

Abstract

The poleward shift of the Southern Hemisphere surface westerlies in recent decades is examined in reanalysis data and in the output of coupled atmosphere-ocean and uncoupled atmospheric models. The space-time spectra of the eddy momentum fluxes in the upper troposphere reveal a trend that marks an increase in the eastward phase speed of the tropospheric eddies accompanied by a poleward displacement of the region of wave breaking in the subtropics. A dynamical mechanism is suggested that may help explain the connections among the lower stratospheric wind anomalies, the increased eastward propagation of tropospheric eddies and the poleward shift of the tropospheric circulation.

Original languageEnglish (US)
Article numberL21805
JournalGeophysical Research Letters
Volume34
Issue number21
DOIs
StatePublished - Nov 16 2007

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

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