Subsurface warming of West Antarctic coastal waters linked to ENSO events

El Niño-Southern Oscillation (ENSO) is the dominant mode of variability in the Earth's climate system on interannual time scales. Through its atmospheric teleconnection to the Amundsen Sea, ENSO impacts water masses and grounded ice shelves on the Antarctic continental shelf. Recent studies have documented ENSO's impact on West Antarctica using satellite observations, yet sparse observations and incomplete models limit our knowledge of the oceanic response in this region. Here, we use a high-resolution global ocean-sea ice model to investigate how El Niño and La Niña might control temperature changes in subsurface waters on the West Antarctic shelf. We find that during El Niño events, water masses on the continental shelf in the Amundsen and Bellingshausen Seas warm on average by 1°C, while the opposite occurs during La Niña events. Our results indicate that these temperature anomalies arise from wind-driven changes in the circulation that brings Circumpolar Deep Water (CDW) onto the shelf. During El Niño, CDW is advected onto the shelf and eastward towards the peninsula, while during La Niña, this shelf transport is largely inhibited. This study highlights how ENSO variations can regulate mass loss of West Antarctic ice shelves via interior ocean temperature changes and basal melting.