On the speed of the eddy-driven jet and the width of the Hadley cell in the Southern Hemisphere

Ceppi, P. and Hartmann, D. L. (2013) On the speed of the eddy-driven jet and the width of the Hadley cell in the Southern Hemisphere. Journal of Climate, 26 (10). pp. 3450-3465. ISSN 1520-0442 doi: 10.1175/JCLI-D-12-00414.1

Abstract/Summary

A strong correlation between the speed of the eddy-driven jet and the width of the Hadley cell is found to exist in the Southern Hemisphere, both in reanalysis data and in twenty-first-century integrations from the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report multimodel archive. Analysis of the space–time spectra of eddy momentum flux reveals that variations in eddy-driven jet speed are related to changes in the mean phase speed of midlatitude eddies. An increase in eddy phase speeds induces a poleward shift of the critical latitudes and a poleward expansion of the region of subtropical wave breaking. The associated changes in eddy momentum flux convergence are balanced by anomalous meridional winds consistent with a wider Hadley cell. At the same time, faster eddies are also associated with a strengthened poleward eddy momentum flux, sustaining a stronger westerly jet in midlatitudes. The proposed mechanism is consistent with the seasonal dependence of the interannual variability of the Hadley cell width and appears to explain at least part of the projected twenty-first-century trends.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/46106
Item Type	Article
Refereed	Yes
Divisions	No Reading authors. Back catalogue items Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Meteorological Society
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