Influence of the New Antarctic Sea Ice State on Stratosphere-Troposphere Coupling and Southern Hemisphere Extreme Events (INSIST)

• Applicant: Dr. Raphael Köhler
• Subject Area: Atmospheric Science
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 562061899

The project "Influence of the New Antarctic Sea Ice State on Stratosphere-Troposphere Coupling and Southern Hemisphere Extreme Events (INSIST)" investigates how the recently observed Antarctic sea ice loss impacts large-scale atmospheric circulation and extreme weather events across the Southern Hemisphere, with a particular focus on Antarctica and Patagonia. By using high-resolution simulations and advanced methodologies, this project aims to provide critical insights into the role of the Antarctic cryosphere in global climate dynamics while isolating the specific impact of sea ice loss. A primary objective of the project is to understand the complex interactions between Antarctic sea ice variability and stratosphere-troposphere coupling. Using the ICON atmospheric model and state-of-the-art causal effect networks, we will identify and analyse cause-effect relationships within this system. These approaches will enable us to precisely quantify how the recent Antarctic sea ice decline influences the strength and stability of the stratospheric polar vortex and contributes to extreme events in the troposphere. The project will reveal how changes in the Antarctic cryosphere impact processes that connect Antarctic variability to mid-latitude circulation, thereby contributing to extreme events in both Antarctica and Patagonia. Another key objective of the project is to assess future scenarios of potential sea ice loss in Antarctica and its impacts on atmospheric circulation and extreme events. By simulating a plausible high-resolution sea ice loss scenario, the project will investigate whether continued ice loss might further weaken the polar vortex or potentially induce nonlinear effects, leading to new climatic states in the Southern Hemisphere. The results of this research will not only advance our understanding of the interactions between sea ice and atmospheric dynamics but also improve our ability to predict extreme events in Antarctica and Patagonia under future climate change conditions.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1158: Infrastructure area - Antarctic Research with Comparative Investigations in Arctic Sea Ice Areas
• International Connection: Finland, United Kingdom
• Cooperation Partners: Dr. Ella Gilbert; Professor Dr. Alexey Karpechko