Sea Ice Dipole Around East Antarctica Induced by Remote Forcing From Indian Ocean

Abstract

While the variability of West Antarctic sea ice, represented by the Antarctic Dipole (ADP), has been extensively investigated, the sea ice variability around East Antarctica has received relatively less attention. In this study, we identify significant dipole-like sea ice variability over the Bellingshausen, Weddell, and King Hakon VII Seas during austral winter, which is comparable in magnitude to the ADP and is termed the East Antarctic sea ice Dipole (EAD). Our analysis shows that the EAD pattern is driven by local thermodynamic and dynamic processes associated with an anomalous low-pressure system over the Weddell Sea, which is linked to a Rossby wave train triggered by tropical sea surface temperature variabilities, particularly those over the Indian Ocean. This teleconnection between the Indian Ocean and East Antarctica is further confirmed by numerical model experiments, with Indian Ocean warming identified as the main forcing. Our findings highlight the importance of this teleconnection in improving sea ice prediction models, especially in light of the projected acceleration of Indian Ocean warming in climate models.