Southern Hemisphere Atmospheric Circulation Response to Global Warming

PDF: http://ams.allenpress.com/amsonline/?request=get-abstract&doi=10.1175%2F1520-0442(2001)014%3C0001:SHACRT%3E2.0.CO%3B2

doi: 10.1175/1520-0442(2001)014<0001:SHACRT>2.0.CO;2
Journal of Climate: Vol. 14, No. 10, pp. 2238–2249.

Southern Hemisphere Atmospheric Circulation Response to Global Warming
Paul J. Kushner, Isaac M. Held, and Thomas L. Delworth

NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey


(Manuscript received February 24, 2000, in final form August 1, 2000)


ABSTRACT

The response of the Southern Hemisphere (SH), extratropical, atmospheric general circulation to transient, anthropogenic, greenhouse warming is investigated in a coupled climate model. The extratropical circulation response consists of a SH summer half-year poleward shift of the westerly jet and a year-round positive wind anomaly in the stratosphere and the tropical upper troposphere. Along with the poleward shift of the jet, there is a poleward shift of several related fields, including the belt of eddy momentum-flux convergence and the mean meridional overturning in the atmosphere and in the ocean. The tropospheric wind response projects strongly onto the model’s “Southern Annular Mode” (also known as the “Antarctic oscillation”), which is the leading pattern of variability of the extratropical zonal winds.