Environmental Science and Engineering Seminar

Changes in Antarctic sea ice have wide-ranging implications for climate, ocean circulation and marine ecosystems. In this talk, I will give a brief overview of Antarctic sea ice and its representation in state-of-the-art climate models. Results from recent coupled model experiments demonstrate the key role that winds have played in the recent trends and large interannual variability of Antarctic sea ice extent. Despite this large interannual variability, the seasonal cycle of Antarctic sea ice extent is remarkably consistent in shape. The mean seasonal cycle is asymmetric, with the period of ice retreat being nearly two months shorter than the period of ice advance. Using a range of climate models of varying complexity, I show that the asymmetry has a simple physical explanation that is markedly different from those proposed in previous studies. I will end by discussing some implications for the seasonality of Arctic sea ice.