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GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L17814, doi:10.1029/2006GL026509, 2006

A physical mechanism of the atmospheric response over Antarctica to decadal trends in tropical SST

Barbara Grassi

CETEMPS/Department of Physics, University of L'Aquila, Coppito-L'Aquila, Italy


Gianluca Redaelli

CETEMPS/Department of Physics, University of L'Aquila, Coppito-L'Aquila, Italy


Guido Visconti

CETEMPS/Department of Physics, University of L'Aquila, Coppito-L'Aquila, Italy


Abstract

The atmospheric response to the tendency of oceanic equatorial temperature observed during recent decades has been simulated, leading to the identification of a possible link between tropical Sea Surface Temperature (SST) and Antarctic climate change. The dynamical mechanism, by which changes in tropical SSTs exert an influence on the upper latitude atmospheric dynamics, is investigated. The analysis of the simulations suggests that the perturbations of the atmospheric circulation are induced by changes in the annual cycle of the tropical convective activity, which influences the intensity of the wave forcing. In particular, the introduction of the SST perturbation generates a strong vertical wind shear at middle latitude during the Antarctic winter affecting the propagation of convectively generated waves during the following spring.

Received 5 April 2006; accepted 9 August 2006; published 13 September 2006.

Index Terms: 3305 Atmospheric Processes: Climate change and variability (1616, 1635, 3309, 4215, 4513); 3337 Atmospheric Processes: Global climate models (1626, 4928); 3339 Atmospheric Processes: Ocean/atmosphere interactions (0312, 4504).

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Citation: Grassi, B., G. Redaelli, and G. Visconti (2006), A physical mechanism of the atmospheric response over Antarctica to decadal trends in tropical SST, Geophys. Res. Lett., 33, L17814, doi:10.1029/2006GL026509.