Beyond Teleconnections - Uncovering Stable Drivers of Antarctic Sea Ice Anomalies

Antarctic Sea Ice (ASI) has experienced a sudden and drastic decline since 2016, following decades of gradual growth since the start of satellite observations. This sharp reversal caused suggestions that a regime shift has happened. However, the underlying drivers remain uncertain due to complex atmosphere-ocean interactions and pronounced regional variability. While atmospheric circulation patterns and large-scale teleconnections influence ASI variability, their spatial aggregation limits their ability to explain regional changes. Recent studies point to an increasing role of ocean heat content, yet its contribution relative to atmospheric influences has not been quantified. In this study, we address this gap by developing a framework to identify stable, spatially coherent climate drivers of regional ASI. We first introduce a workflow combining correlation analysis with HDBSCAN clustering to detect global clusters that have persistent correlations with regional ASI and can serve as robust predictors. We then use these clusters as input features in a linear regression model combining atmospheric variables and ocean heat content to assess how well ASI variability can be reconstructed. Finally, we evaluate how the relative importance of atmospheric and oceanic drivers has changed before and after the extreme low-ice events beginning in 2016.

Our results demonstrate that (1) the proposed clustering framework reliably identifies physically meaningful driver regions, (2) a linear model using these drivers can successfully reproduce regional ASI variability, and (3) the contribution of ocean heat relative to atmospheric forcing varies markedly across regions.