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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, D10119, doi:10.1029/2006JD008087, 2007

Tropopause height and zonal wind response to global warming in the IPCC scenario integrations

David J. Lorenz

Center for Climatic Research, University of Wisconsin, Madison, Wisconsin, USA


Eric T. DeWeaver

Center for Climatic Research, University of Wisconsin, Madison, Wisconsin, USA


Abstract

The change in the extratropical circulation under global warming is studied using the climate models participating in the Intergovernmental Panel on Climate Change (IPCC) fourth assessment report. The IPCC models predict a strengthening and a poleward shift of the tropospheric zonal jets in response to global warming. The change in zonal jets is also accompanied by a strengthening and a poleward and upward shift of transient kinetic energy and momentum flux. Similar changes in circulation are simulated by a simple dry general circulation model (GCM) when the height of the tropopause is raised. The similarity between the simple GCM and the IPCC models suggests that the changes in midlatitude circulation are predominantly driven by a rise in the height of the tropopause, and that other factors such as increased moisture content and the change in the low-level pole-to-equator temperature gradient, play a secondary role. In addition, the variability about the ensemble-mean of the zonal wind response is significantly correlated with the variability of the tropopause height response over the polar cap, especially in the Southern Hemisphere.

Received 29 September 2006; accepted 12 April 2007; published 26 May 2007.

Keywords: global warming; tropopause; jets.

Index Terms: 1620 Global Change: Climate dynamics (0429, 3309); 3305 Atmospheric Processes: Climate change and variability (1616, 1635, 3309, 4215, 4513); 3319 Atmospheric Processes: General circulation (1223); 1626 Global Change: Global climate models (3337, 4928).

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 869313 bytes)

Citation: Lorenz, D. J., and E. T. DeWeaver (2007), Tropopause height and zonal wind response to global warming in the IPCC scenario integrations, J. Geophys. Res., 112, D10119, doi:10.1029/2006JD008087.