12.06.2023: Ocean Circulation and Climate Dynamics Colloquium

When?  Monday, 12 June  2023 at 11 am
Where?    Lecture Hall, Düsternbrooker Weg 20

Abstract:
The evolution of Antarctic sea ice has been remarkably different to the Arctic over the satellite era. Antarctic sea ice area increased slightly from 1979 to 2014, and has declined rapidly since. State of the art climate models have generally failed to reproduce this behaviour. One proposed reason for the discrepancy between models and observations is the lack of increasing meltwater from the Antarctic ice sheet and ice shelves in models. In this talk I will summarize efforts to simulate this increased meltwater in models and show that the response of Antarctic sea ice depends strongly on the model used. I will outline the Southern Ocean Freshwater release model Experiments InitiAtive (SOFIA), a model intercomparison with standardized meltwater forcing that aims to investigate the reasons for this model-dependent response.
I will also highlight some recent work examining the effect of Antarctic meltwater on climate sensitivity. We showed that adding Antarctic meltwater in historical and future scenarios in the Community Earth System Model resulted in cooling in the Southern Ocean and tropical Eastern Pacific. This cooling increased low cloud cover and in turn caused radiative feedbacks to become more stabilizing (corresponding to lower climate sensitivity. Thus, increasing Antarctic meltwater can have both local (Antarctic sea ice) and global (climate sensitivity) impacts.   

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