Long-term spatiotemporal variability and driving mechanisms of tropospheric total column water vapor over Antarctica based on radiosonde, GNSS, and reanalysis data

Total column water vapor (TCWV) is a crucial indicator of atmospheric processes in the troposphere and a key driver of climate change. However, the severe environmental conditions in Antarctica constrain research on spatiotemporal variability and its underlying driving mechanisms. Based on multi-source datasets including radiosonde, global navigation satellite system (GNSS), and reanalysis data, this study calculates and analyzes the spatiotemporal variations of water vapor over Antarctica and investigates the mechanisms behind these changes. Key findings indicate that Antarctic TCWV exhibits significant spatial heterogeneity, ranging from 0 to 6 mm annually, with the highest values occurring over the Antarctic Peninsula and coastal West Antarctica, decreasing sharply inland. Temporally, a weak overall drying trend (−9.91 × 10−4 mm/decade) was observed, with a notable shift around 2015. Analysis further reveals that atmospheric circulation anomalies during 2009–2016 drove corresponding TCWV and precipitation anomalies in West Antarctica and the Antarctic Peninsula. Importantly, positive TCWV anomalies enhanced the surface energy budget, leading to elevated surface temperatures – most markedly over the Antarctic Peninsula, where increases reached ~1.8 K, and contributed to intensified surface melt. These results advance our understanding of TCWV dynamics in Antarctic climate and highlight its critical role in surface warming and ice-sheet melting, providing a valuable basis for improved climate and ice-sheet modeling in polar regions.