Signature of the stratosphere-troposphere coupling on recent record-breaking Antarctic sea ice anomalies

Abstract

Abstract. By influencing the circumpolar westerly winds, the stratospheric polar vortex has played a major role in the Antarctic surface climate in recent decades. However, the footprint of the polar vortex variability in the year-to-year changes of the Antarctic sea ice cover remains obscured. Here, we combine satellite retrievals and reanalysis data to study the response of the sea ice extent around Antarctica to changes in the polar vortex strength. We focused on the last two decades that have seen sharp changes in the stratospheric zonal flow, the tropospheric westerly winds, and the sea ice cover (the latter climbed to record highs in 2013 and 2014 before dropping to record lows in 2017 and 2022). We found that this unprecedented interannual variability has been noticeably influenced by the polar vortex dynamics. The signature of the stratosphere-troposphere coupling is apparent on recent all-time records (highs and lows) in the sea ice around Antarctica.