Abstract

Next week we have a seminar from visiting PhD student Helen Shea (Monash University) who will be talking about Contrasting regional ocean processes sustaining low Antarctic sea ice coverage. So come along to Seminar Room 1 at 2pm!

Abstract: Antarctic sea ice increased for decades, peaked in 2014, then sharply declined in 2016 and has remained generally low since. This decline matters because Antarctic sea ice regulates global climate, influences ocean circulation, and supports ecosystems. Ocean-sea ice interactions are likely contributing to this low sea ice state, with upper ocean stratification central in sea ice formation and melt. Analysis of ocean properties from ORAS5 reanalysis finds the low sea ice period coincides with subsurface warming and stronger stratification in most Antarctic regions. Changes occurring in the Ross Sea are distinct from other regions, with a cooler and fresher subsurface and weakened stratification occurring during the low sea ice period. We suggest that the Ross Sea differences are linked to the presence of the Ross Gyre and an ocean-sea ice feedback. These findings highlight the importance of region-specific ocean processes in influencing Antarctic sea ice variability and its future under climate change.