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

Abstract

This study focused on remote influences of El Niño–Southern Oscillation (ENSO) and Indian Ocean dipole (IOD) on the interannual variability of the West Antarctic sea ice. The sea ice of the West Antarctic has a large variability and is linked to tropical conditions such as ENSO and IOD. The sea ice of the Antarctic is important. According to previous studies, the sea ice extent of the Antarctic is 20% greater than in the Arctic, thus could result in dramatic changes to planetary albedo. Also, feedbacks sea ice change and ocean temperature and salinity play a role in determining the stability of Antarctica’s massive ice shelves and its melting directly associated with global sea-level-rise. ENSO and IOD are well known phenomena that impact on the Antarctic sea ice, but which one has a higher impact is not revealed due to strong correlation (=0.61). For this reason, this study figures out 1) How ENSO and IOD impact the Antarctic and 2) Both of them, which one has more powerful effects? To classify the effects of ENSO and IOD, linear and partial regression analysis and Geophysical Fluid Dynamics Laboratory (GFDL) model experiment is conducted. In the results of linear regression analysis, the teleconnection pattern between ENSO and IOD is not significantly different. On the other hand, using a partial regression analysis, remote influences induced by the ENSO and IOD is kind of different. For example, ENSO is dominant to develop the atmospheric circulation in the Amundsen-Bellingshausen Sea (ABS). Meanwhile, IOD is contributed to form a low-pressure nearby the date line and high-pressure on the interior of ABS. This finding implies that both ENSO and IOD impact the sea ice of the West Antarctic, especially, ENSO in the Pacific Ocean has the greatest effect.