Record-high Antarctic Peninsula temperatures and surface melt in February 2022: A compound event with an intense atmospheric river

Abstract

The Antarctic Peninsula (AP) experienced a new extreme warm event and record-high surface melt in February 2022, rivaling therecent temperature records from 2015 and 2020, and contributing to the alarming series of extreme warm events over this regionshowing stronger warming compared to the rest of Antarctica. Here, the drivers and impacts of the event are analyzed in detailusing a range of observational and modeling data. The northern/northwestern AP was directly impacted by an intense atmosphericriver (AR) attaining category 3 on the AR scale, which brought anomalous heat and rainfall, while the AR-enhanced foehn effectfurther warmed its northeastern side. The event was triggered by multiple large-scale atmospheric circulation patterns linking theAR formation to tropical convection anomalies and stationary Rossby waves, with an anomalous Amundsen Sea Low and a record-breaking high-pressure system east of the AP. This multivariate and spatial compound event culminated in widespread and intensesurface melt across the AP. Circulation analog analysis shows that global warming played a role in the amplification and increasedprobability of the event. Increasing frequency of such events can undermine the stability of the AP ice shelves, with multiple local toglobal impacts, including acceleration of the AP ice mass loss and changes in sensitive ecosystems.