Atmospheric winter response to a projected future Antarctic sea-ice reduction: a dynamical analysis
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Several studies have analysed the atmospheric response to sea-ice changes in the Arctic region, but only few have considered the Antarctic. Here, the atmospheric response to sea-ice variability in the Southern Hemisphere is investigated with the atmospheric general circulation model ECHAM5. The model is forced by the present and a projected future seasonal cycle of Antarctic sea ice. In September, the mean atmospheric response exhibits distinct similarities to the structure of the negative phase of the Southern Annular Mode, the leading mode of Southern Hemisphere variability. In the reduced Antarctic sea-ice integration, there is an equatorward shift of the Southern Hemisphere mid-latitude jet and the storm tracks. In contrast to a recent previous study, our findings indicate that a substantial impact of Southern Hemispheric future sea-ice reduction on the mid-latitude circulation cannot be ruled out.
KeywordsZonal Wind Storm Track Southern Annular Mode Equatorward Shift Eady Growth Rate
We are grateful to two anonymous reviewers and Davide Zanchettin who has done the internal review at MPI-M. The UK Meteorological Office and Hadley Centre is acknowledged for providing the HadISST 1.1—global SST—data-set. We also thank Dr. Kevin Hodges (University of Reading, UK) for providing the storm tracking algorithm TRACK. This work was supported by the Max Planck Society, the Federal Ministry of Education and Research in Germany (BMBF) through the research programme “MiKlip” (FKZ: 01LP1158A) and by the DecCen project funded by the research council of Norway.
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