Trends in Extreme Precipitation Events Across Antarctica

This study investigates trends in extreme precipitation events (EPEs) across Antarctica from 1979 to 2023, analyzing changes in EPE frequency, intensity, and the proportion of extreme to total precipitation. Using Self-Organizing Map (SOM) techniques, the study distinguishes contributions from thermodynamic, dynamic, and interaction components in explaining these trends. Positive EPE occurrence trends are observed across the Bellingshausen and Weddell Seas, Dronning Maud Land, and parts of the Southern Ocean, with declines limited to Queen Mary Land. Thermodynamic factors, responsible for 96.0% of the overall trend, are driven by increased water vapor content in polar air masses. Dynamic contributions, representing 10.8%, are linked to a strengthened Amundsen Sea Low (ASL) associated with the Southern Annular Mode (SAM) and Pacific South American (PSA) trends. Interaction effects contribute slightly negatively (-6.8%) to overall trends. Variations in water vapor transport and vertical velocity tied to annual 500-hPa geopotential height anomalies further explain EPE trends. These findings offer insight into atmospheric processes influencing Antarctic EPEs, with implications for understanding climate impacts on the polar environment.