[M-IS15] Global Antarctic Science: connecting the chain of changing huge ice sheets and global environments

[MIS15-P08] Response of the Antarctic coastal ocean–cryosphere system to ±6°C temperature forcing

*Kazuya Kusahara¹ (1.Japan Agency for Marine-Earth Science and Technology)

The Antarctic cryosphere has been undergoing significant changes in the ongoing global warming. Two major Antarctic cryosphere processes of ice shelves and sea ice strongly interact with the Southern Ocean. In this study, we investigate how these cryosphere-ocean processes respond to atmospheric warming using a coupled sea ice-ocean model with an ice-shelf component. We performed a series of numerical experiments by applying air temperature anomalies ranging from −6°C to +6°C, envisioning conditions from glacial to interglacial periods. The model results show that winter sea-ice extent and coastal sea-ice production respond almost linearly to the warming, while summer sea-ice extent diminishes to reach a lower limit. Ice-shelf basal melting exhibits a super-linear response to the warming, driven by increased contributions from two warm water masses: Antarctic Surface Water and Circumpolar Deep Water. This suggests that under warmer conditions, the response of Antarctic ice shelves may be much larger than previously understood, highlighting the need for a more nuanced understanding of ice-shelf basal melting under future warming scenarios.