Surface mass balance, ice velocity and ice temperature on Baishui River Glacier No.1, Southeastern Tibetan Plateau from 2018 to 2022

Temperate glaciers in the southeastern Tibetan Plateau have experienced significant mass loss and retreat in recent decades, yet detailed on-site observations remain limited. Here we present the measured records of surface mass balance, ice velocity and surface ice temperature of Baishui River Glacier No. 1 in Yulong Snow Mountain from 2018 to 2022. Our observations reveal an annual mean mass balance of -1.29±0.16 m w.e., demonstrating a significant seasonal imbalance between reduced accumulation (multi-year average of 0.51±0.07 m w.e.) and enhanced ablation (multi-year average of 1.80±0.26 m w.e.), which provides crucial evidence for explaining the long-term mass loss. The average annual ice velocity, predominantly controlled by monsoon season dynamics which contribute 69%–74% of the total movement, was measured at 26.91±2.76 m yr^-1 and exhibited a decreasing trend of 1.73 m yr^-1. The ice temperature fluctuated between -13.41℃ to -0.04℃, with an average of -6.04℃. The ice temperature and air temperature synchronized well in the non-monsoon period, while the temperature rise was not synchronized and slightly delayed in the monsoon period.