The 2023 record low Antarctic sea ice traced to synergistic influences of preconditioning, wind-induced transport and the ice albedo feedback

Antarctic sea ice extent (SIE) reached a new record low of 1.79 million km² on 21 February 2023, 38% lower than the climatological average. In this study, we trace this record back to its possible origins by providing a detailed view on the evolution of the coupled ocean-atmosphere-sea ice system during the 12 months that preceded the event (March 2022 to February 2023). The impact of preceding winter and spring conditions on the summer minimum is assessed with the help of observations, reanalyses, and output from a regional ocean-sea ice coupled model NEMO3.6-LIM3. We find that the 2022-2023 annual cycle was characterized by consistently low SIE values throughout the year preceding the record, by anomalously high SIE melting rates in December 2022, and by circumpolar negative SIE anomalies in almost all basins of the Southern Ocean in February 2023. Through autumn and winter (March to August 2022), advection-induced positive air temperature anomalies inhibited the development of sea ice in the Weddell and Bellingshausen Seas, which preconditioned an ice-free state in the Bellingshausen Sea as early as October 2022. Concurrently, strong southerly winds in the Eastern Ross Sea caused by an anomalously deep Amundsen Sea Low in spring (September to November) transported significant volumes of sea ice northward, contributing to severe melting offshore in December and, through increased divergence near the coast, triggered the ice-albedo feedback onshore. As a consequence, a coastal polynya appeared in the western part of the Amundsen Sea due to stronger surface sea ice melting. This ice-albedo feedback was unusually active in late 2022 and favored accelerated melt towards the minimum in February 2023. This study highlights the impacts of multifactorial processes during the preceding seasons to explain the recent summer sea ice minima.