GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel
Wischhofstr. 1-3
24148 Kiel
Tel.: 0431 600-0
Fax: 0431 600-2805
E-mail: info(at)geomar.de
11:00 h, Hörsaal, Düsternbrooker Weg 20
Abstract:
Recent climate models struggle to simulate the present Antarctic sea-ice increase over the past decades due to large internal variability. In this study we investigate processes in coupled models which cause large scale oceanic and sea-ice variability over the Southern Ocean. We find that spurious open ocean convection can trigger large anomalies in all Southern Ocean state variables. Changes in the meridional transports of heat and freshwater as well as the interaction between Antarctic-Circumpolar-Current and both Subpolar Gyres (Ross and Weddel) can initiate a self-sustaining (multi) decadal oscillation. In real world open ocean convection in the Southern Ocean is prevented by seasonal sea-ice cover, but could be become more likely if sea-ice decreases under a warming climate.