Role of the subtropical southern Indian Ocean in the interannual variability of Antarctic summer sea ice

Through data diagnosis and dynamic analysis, this study aims to reveal the potential influence of the Subtropical Dipole Pattern (SDP) in the southern Indian Ocean on the interannual variation of south polar sea ice. The results indicate that a robust teleconnection exists between the SDP and south polar sea ice. At least two months in advance, the SDP significantly affects the Antarctic summer sea-ice anomalies. Specifically, during the positive (negative) phase of the SDP, the Amundsen–Ross Sea and the western Indian Ocean sectors exhibit significant positive (negative) sea-ice anomalies, accompanied by negative (positive) sea-ice anomalies in the Bellingshausen Sea and the Weddell Sea. Planetary wave trains, stimulated over the SDP by anomalous rainfall and latent heat release, establish this teleconnection. These planetary wave trains, guided by westerly jets, then spread eastward and poleward, causing atmospheric circulation anomalies that affect Antarctic sea ice. The Antarctic sea-ice anomalies connected to the SDP are mostly consistent with abnormalities in the surface air temperature and wind fields.