Drivers of the 2018 Winter Temperature Anomaly Over East Antarctica: Dominant Role of Air‐Sea‐Ice Dynamical‐Thermodynamic Coupling

Abstract During the 2018 Southern Hemisphere winter, a pronounced surface air temperature positive anomaly occurred over East Antarctica, with Zhongshan Station recording its highest winter‐mean air temperature since 2007. Combining in situ observations, satellite remote sensing, and reanalysis data sets, this study diagnoses the temperature anomalies across representative isobaric surfaces (975, 500, and 300 hPa). Results indicate that this phenomenon originates from the disturbances of zonal wave, which in turn triggers anomalous regional sea‐ice‐atmosphere coupling processes. Specifically, this disturbance excited a persistent high‐pressure ridge or blocking high over the South Indian Ocean, and then directed poleward heat and moisture transport, dominating lower‐tropospheric temperature anomalies. Moreover, anomalous offshore winds induced by the pressure anomaly, combined with warm‐moist air mass intrusion, accelerated thermodynamic‐dynamic sea ice retreat, thereby enhancing upward sensible and latent heat fluxes from the ocean. In the mid‐to‐upper troposphere, anomalous subsidence driven by pressure perturbations caused warming primarily through vertical warm advection and adiabatic heating, with secondary contributions from horizontal advection. This study reveals a cross‐sphere coupled dynamic‐thermodynamic mechanism linking upper‐level zonal wave anomalies to Antarctic surface temperature extremes.