The role of mid-latitude zonal wind anomalies in extreme glacier mass loss on central Tibetan Plateau

Long-term in-situ glacier mass balance records on central Tibetan Plateau (TP) are pivotal for assessing climate change impacts, yet the drivers of extreme mass loss events remain poorly understood. Here, we examined Xiao Dongkemadi Glacier, which possesses the longest continuous mass balance record on central TP, to address this knowledge gap. We identified three extreme mass loss events (2005/2006: −917 mm w.e., 2009/2010: −1066 mm w.e., and 2021/2022: −881 mm w.e.), with magnitudes 3.3, 3.8, and 3.1 times the 1989−2022 average annual mass loss, respectively. Return period analysis indicated that these events were statistically rare, with the 2009/2010 mass loss representing an approximately 1-in-39.1-year event. These extreme events were closely associated with pronounced June−September heatwaves in 2006, 2010, and 2022, driven by anomalies in the surface energy balance characterized primarily by increased absorbed shortwave radiation. Interannual mass balance variability was significantly correlated with mid-latitude zonal winds ( r = 0.4, p < 0.05). Further analysis revealed that extreme mass loss events were closely associated with anomalously weak and northward-shifted zonal winds ( p < 0.05). This pattern was distinctly different from that in years of positive mass balance. Based on unique long-term measurements, this study provided detailed analysis of extreme mass loss events on central TP, advancing the mechanistic understanding of their drivers and offering critical insights into the future state and fate of glaciers and their implications for water resource management under climate change.