Antarctic Sea ice is a critically important component of our Climate system. It is at once habitat for penguins, a moderator of the largescale atmospheric circulation and an influence on the global thermohaline circulation. While similar in many respects to Arctic sea ice, there are distinct differences. Antarctic sea ice variability is strongly regional - five distinct regions of variability have been defined. While exhibiting similar annual cycles, these regions vary in their times of advance and retreat as well as in overall sea ice extent. They also have different spectral signatures with interannual frequencies of varying strengths. Antarctic sea ice trends are also strongly regional with positive trends occurring, for example, in the Ross Sea and negative trends in the Bellingshausen-Amundsen Seas.
Some of the intrinsic spatial variability in the sea ice is probably due to the effect of the geography of Antarctica and the influence of the ocean. Some is due to the influence of the largescale atmospheric circulation – the Southern Hemisphere Annular Mode, Zonal Wave Three and the Amundsen Sea Low. In this presentation I discuss how these components of the atmospheric circulation exert their influence on different regions of sea ice and how the sea ice might be expected to change as the atmospheric circulation changes. I also discuss the recent extremes in Antarctic sea ice and the supporting role that these atmospheric circulation mechanisms played in initiating and supporting them.
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About the Speaker
Marilyn Raphael is a Professor of Geography at the University of California, Los Angeles, Director of UCLA’s Institute of Environment and Sustainability and Fellow of the American Academy of Arts and Sciences. Her research interests are in climate variability and change in the high latitude Southern Hemisphere. Her work explains the way in which sea ice and the atmosphere interact thereby creating potential for prediction of Antarctic climate change at the seasonal, interannual and decadal timescales. The results of her research have implications not only for Antarctic climate, but also for global climate change and for the global, societal response. She is currently President of the American Association of Geographers, Chair of the Scientific Committee on Antarctic Research’s expert group, Antarctic Sea ice Processes and Climate (ASPeCt) and Co-Chair of the World Climate Research Programme’s (WCRP) Polar Climate Predictability Initiative (PCPI). In these roles she promotes research on Antarctic sea ice observations and modeling and coordinates the efforts of the international science community bringing together expertise on the observational and modeling aspects of the climate.
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