Remote Influences of ENSO and IOD on the Interannual Variability of the West Antarctic Sea Ice

Abstract

West Antarctica exhibits a pronounced sea ice variability in interannual timescale, and 20%-30% of the total variance can be explained by the El Nino-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) during austral spring. The sea ice variation is primarily linked with anomalous atmospheric circulation in the Amundsen-Bellingshausen Sea (ABS) that modulates poleward atmospheric temperature advection and radiative forcing. With a co-varying relationship between ENSO and IOD, isolating their remote impacts on Antarctica has been limited in observations. An idealized experiment using the atmospheric model with a dry dynamical core suggests that the anticyclonic circulation anomaly in the ABS is primarily contributed by the ENSO in the Pacific Ocean, while the contribution of the IOD in the Indian Ocean is only one-third large. This study implies that atmospheric teleconnection through the southern Pacific Ocean is crucial for understanding the West Antarctic sea ice concentration variability.