Atlantic Niño Types Differentially Impact Antarctic Sea Ice

Distinct Climate Links Revealed

A recent study has revealed that the Central Atlantic Niño (CAN) and East Atlantic Niño (EAN) impact sea ice variability in West Antarctica differently. The research emphasizes how these climate patterns, despite originating in the Atlantic, trigger distinct atmospheric responses. These responses affect Antarctic sea ice concentration (SIC) during the austral winter (June-August).

The study, using observational data, discovered that CAN induces significant increases in SIC in region A (100°W-150°W). EAN leads to weaker increases in region B (80°W-100°W) and decreases in region C (160°W-180°W). CAN's influence is stronger and more extensive, accounting for approximately 20% of the total SIC variance in region A, compared to EAN's less than 10% in regions B and C.

These distinct impacts are primarily due to differences in atmospheric circulation anomalies. CAN strengthens the Amundsen Sea Low (ASL), leading to southerly wind anomalies and cold air advection. This favors sea ice formation and offshore drift. EAN generates weaker wind anomalies, resulting in less pronounced temperature changes and sea ice drift. The findings enhance the understanding of climate dynamics and could improve seasonal sea ice predictions for West Antarctica.