The Critical Role of Moisture in the Record‐Breaking Warm Event Over East Antarctica in March 2022

Abstract

The warming of Antarctica has a significant impact on global weather and climate. An extreme warming event took place in East Antarctica in mid‐to‐late March 2022, peaking at 39°C above the climatological average. This was the largest temperature anomaly ever recorded and attracted global attention. In this work, we investigate and quantify the role of moisture through observational analysis and a series of numerical simulations using the Polar Weather Research and Forecasting (Polar WRF, version 4.1.1) model. Results show that water vapor plays a critical role in this warming event. The Polar WRF reproduces the temporal evolution reasonably well in the Control experiment (Exp‐CTRL). To validate the importance of water vapor, a sensitivity experiment (Exp‐0.0001) was conducted in which relative humidity was reduced to 0.01%. The near‐surface temperature was significantly underestimated by nearly 20°C and 10°C at Dome C and Vostok, respectively. Further analysis shows that reducing water vapor leads to a substantial reduction in downward longwave radiation near the surface (LWD), which decreases by 60%. Building on these results, we also find that enhanced boundary‐layer mixing modulates the near‐surface warming response. The boundary layer height exhibits considerable variation, with that in Exp‐CTRL being nearly six times higher than in Exp‐0.0001. These findings suggest that moisture is the critical amplifying factor of this extreme warming event. In contrast, the anomalously low extent of Antarctic Sea ice in February 2022 had a minimal impact.