Saanvi Deobhankar: Understanding the mechanisms linking Antarctic sea ice decline to Australian climate
Antarctic sea ice extent has remained in an anomalously low state since 2016, which is expected to drive extensive Southern Ocean changes with widespread implications for both atmospheric and oceanic processes. These impacts can propagate across latitudes, extending into the tropics, yet their influence on Australian climate remains poorly understood.
This project aims to investigate the mechanisms through which changes in Antarctic sea ice influence extratropical and tropical climate variability and, in turn, Australia’s regional and seasonal climate. First, we will run targeted perturbation experiments with ACCESS-ESM1.5, reducing sea ice extent by modifying albedo parameters within the UM7.3 atmosphere component. Outputs from these experiments are evaluated with two additional CMIP6 models (CESM-WACCM and HadGEM3-GC3.1-LL) to assess the robustness and consistency of the multi-model response and quantify how SIE loss affects large-scale teleconnections such as SAM and ENSO.
Building on this, we will conduct further ACCESS-ESM1.5 experiments forced with anomalously low and high SIE states to determine whether teleconnection responses are linear or exhibit state-dependent behaviour under contrasting Antarctic conditions. Preliminary sensitivity tests reveal that ‘melting snow’, ‘cold dry snow’, and ‘bare ice’ albedo affect Antarctic SIE asymmetrically, with anomalously low values producing a greater decline than anomalously high values.
Lastly, we will analyse how teleconnection patterns emerging from both experiments impact Australian climate by assessing shifts in mean and extreme temperature and precipitation patterns. This project will contribute to understanding sea-ice-climate interactions in ACCESS-ESM1.5 and supports the ongoing experimentation and understanding across the ACCESS research community.
Keywords = Antarctic sea ice, climate teleconnections, ACCESS-ESM1.5, Australian climate extremes.