Climate change: A friend or foe for the future Antarctic sea ice mass budget? (fAntasie)

• Applicant: Dr. Stefanie Arndt
• Subject Area: Oceanography ; Atmospheric Science
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 502019812

Sea ice cover is an important component of the global climate system as it is a highly insulating layer between the ocean and the atmosphere, reflecting most of the incoming solar radiation. In the context of global warming, sea ice in both polar regions has experienced remarkably different changes over recent decades. While the extent and volume of Arctic sea ice decreased significantly, it has been increasing slightly as a whole in the Southern Ocean, however, with opposing regional trends. Therefore, the major questions remain: Why does the Antarctic sea ice volume not shrink compared to the Arctic? And: When and what might potentially change that evolution? However, describing the current state of Antarctic sea ice is a major challenge due to the lack of observational data and resulting substantial uncertainties in satellite-derived data products and respective sea ice models. fAnatasie aims therefore to better understand the temporal and spatial variability of the different components of the Antarctic sea ice mass budget and its interaction with the atmosphere and ocean. As such, it will serve to reduce the current significant uncertainties in satellite-derived data products and sea ice models for the ice-covered Southern Ocean, which is required also for assessing the future evolution of the Antarctic sea ice mass budget. I therefore propose in fAntasie to (1) quantify more accurately processes contributing to sea ice growth in different ice regimes in the Southern Ocean based on data from recent field observations and retrieved from satellite remote sensing. To understand the temporal and spatial evolution of the Antarctic sea ice mass balance, the prevailing atmospheric circulation patterns and their influence on the surface energy balance will be examined. These results will be related to the opposite evolution of Arctic sea ice by (2) investigating the impact of contrasting atmospheric conditions in the Arctic and Antarctic on their sea ice energy budgets. Finally, to (3) examine how climate change will affect the future evolution of the Antarctic sea ice mass and energy budgets, I will conduct sensitivity studies with suggested changing atmospheric and oceanic conditions as given in the recent IPCC report. Through this highly investigative and linked working program of observations, remote sensing, and model evaluation and sensitivity studies, fAntasie will significantly contribute to better understand the temporal and spatial variability of Antarctic’s sea ice mass budget. This will enable us to better describe interactions in the climate and ecosystem of the Southern Ocean – both for today’s climate and under conditions of future global warming.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1158: Infrastructure area - Antarctic Research with Comparative Investigations in Arctic Sea Ice Areas
• International Connection: Australia, United Kingdom
• Cooperation Partners: Dr. Petra Heil; Professor Dr. John King