Impacts of increasing anthropogenic aerosols on the atmospheric circulation trends of the Southern Hemisphere: An air-sea positive feedback
Article first published online: 13 DEC 2007
Copyright 2007 by the American Geophysical Union.
Geophysical Research Letters
Volume 34, Issue 23, December 2007
How to Cite
2007), Impacts of increasing anthropogenic aerosols on the atmospheric circulation trends of the Southern Hemisphere: An air-sea positive feedback, Geophys. Res. Lett., 34, L23709, doi:10.1029/2007GL031706., and (
- Issue published online: 13 DEC 2007
- Article first published online: 13 DEC 2007
- Manuscript Accepted: 9 NOV 2007
- Manuscript Revised: 11 OCT 2007
- Manuscript Received: 21 AUG 2007
- anthropogenic aerosols;
- atmospheric circulation;
- poleward shift
 A recent model study shows that in response to an increasing aerosol forcing, the Southern Hemisphere (SH) ocean circulation, including the Agulhas outflow, its retroflection, and the entire subtropical gyre circulation intensify and shift polewards. Are these oceanic responses manifested in the SH atmospheric circulation? We demonstrate that as a result of the poleward shift, maximum sea surface temperature (SST) gradients, midlatitude storms and the westerly jet shift southward, intensifying the trend of the southern annular mode (SAM). Because the response of the atmospheric circulation to the underlying oceanic anomalies is equivalent barotropic, a poleward shift and intensification in zonal wind and vertical velocities are generated from the atmosphere-ocean interface to the middle troposphere. These atmospheric circulation responses, in turn, reinforce the ocean circulation changes. This constitutes an air-sea positive feedback. Our results illustrate an impact of Northern Hemisphere (NH) aerosols on the SH atmospheric circulation trends through a SH ocean circulation response.