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gfdl on-line bibliography > forthcoming citations
Phase speed spectra and the recent poleward shift of Southern Hemisphere surface westerlies
| Chen, G., and I. Held, 2007: Phase speed spectra and the recent poleward shift of Southern Hemisphere surface westerlies. Geophysical Research Letters. 2/07. |
| 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. Based on the space-time spectra of the eddy momentum fluxes, it is argued that a key to this displacement of the circulation is an increase in the eastward phase speed of the tropospheric eddies, which, in turn, results in a poleward displacement of the region of wave breaking in the subtropics. This enhancement in the eddy phase speeds is thought to be due to the direct influence on tropospheric eddy propagation of the positive zonal wind anomalies in the lower stratosphere. |