Climate response associated with the Southern Annular Mode in the surroundings of Antarctic Peninsula: A multimodel ensemble analysis

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Abstract

[1] This paper is an attempt to extract an average picture of the response of the Southern Annular Mode (SAM) to increasing greenhouse gases (GHG) forcing from a multimodel ensemble of simulations conducted in the framework of the IPCC 4th assessment experiments. Our analysis confirms that the climate change signal in the mid- to high southern latitudes projects strongly into the positive phase (PP) of the SAM. Over the present climate time slice (1970–1999), multimodel ensemble mean reproduce the regional warming around the Antarctic Peninsula (AP) associated with the SAM. When increasing GHG (future time slice, 2070–2099), warming in the neighborhoods of the AP and decreasing sea-ice volume in the sea-ice edge region in the Amundsen and Weddell Seas intensifies, suggesting that recent observed sea-ice trends around AP could be associated to anthropogenic forcings. Changes in surface temperature and sea-ice are consistent with anomalous atmospheric heat transport associated with circulation anomalies.

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