Yongpeng Gao

The Western Kunlun Mountains are a region known for a high concentration of surge-type glaciers in High Mountain Asia and have long been of interest to glaciologists. This study examines the 2021–2023 surge of the eastern branch of ZhongFeng Glacier and reviews the 2003–2004 surge of its western branch, utilising multi-source digital elevation models (DEMs), Landsat MSS/ETM+/OLI, Sentinel-2, and meteorological data. Our findings reveal that surges in both the eastern and western branches of the ZhongFeng Glacier were initiated during the summer, with durations of 2 years and 1 year, respectively. Peak flow velocities exceeded 10 m/day, more than 50 times the velocities observed during quiescent periods. During surges, the glacier termini of the eastern and western branches thickened by 60.25 ± 3.07 m and 76.21 ± 8.05 m, respectively, corresponding to ice mass gains of 0.53 ± 0.03 km³ and 0.74 ± 0.08 km³. Based on the timing characteristics of these surges, we conclude that both branches of the ZhongFeng Glacier are influenced by hydrological mechanisms. Furthermore, differences in surface and subglacial topography are determined to be the primary factors contributing to the asynchrony of surges between the two branches.

Moraine-dammed glacial lakes (MDLs) are not only vital sources of freshwater but also a hazard to mountain communities if they drain in sudden glacial lake outburst floods (GLOFs). Accurately measuring the water storage of these lakes is crucial to ensure sustainable use and safeguard mountain communities downstream. However, thousands of glacial lakes still lack a robust estimate of their water storages because bathymetric surveys in remote regions are difficult and expensive. Here we geometrically approximate the shape and depths of moraine-dammed lakes and provide a cost-effective model to improve lake water storage estimation. Our model uses the outline and the terrain surrounding a glacier lake as input data, assuming a parabolic lake bottom and constant hillslope angles. We initially validate our model using data from four newly surveyed glacial lakes on the Qinghai–Tibet Plateau. Subsequently, we incorporate data from 40 additional measured lakes as a sample set to compare and evaluate the model's performance against other existing models. Our model overcomes the autocorrelation issue inherent in earlier area/depth–water storage relationships and incorporates an automated calculation process based on the topography and geometrical parameters specific to moraine-dammed lakes. Compared to other models, our model achieved the lowest average relative error of approximately 14 % when analyzing a dataset of 44 observed lakes, surpassing the > 44 % average relative error from alternative models. Finally, the model is used to calculate the water storage change in moraine-dammed lakes in the past 30 years in High-mountain Asia. The model has been proven to be robust and can be utilized to update the water storage of lake water for conducting further management of glacial lakes with the potential for outburst floods in the world.

Moraine-dammed glacial lakes are vital sources of freshwater but also pose a hazard to mountain communities if they drain in sudden glacial lake outburst floods. Accurately measuring the water storage of these lakes is crucial to ensure sustainable use and safeguard mountain communities downstream. However, thousands of glacial lakes still lack a robust estimate of their water storages because bathymetric surveys in remote regions are difficult and expensive. Here we geometrically approximate the shape and depths of moraine-dammed lakes and provide a cost-effective model to improve lake water storage estimation. Our model uses the outline and the terrain surrounding a glacier lake as input data, assuming a parabolic lake bottom and constant hillslope angles. We validate our model using ten new bathymetrically surveyed glacial lakes on the Qinghai-Tibet Plateau, and compiled data from 34 recently measured lakes. Our model overcomes the autocorrelation issue inherent in earlier area/depth-water storage relationships and incorporates an automated calculation process based on the topography and geometrical parameters specific to moraine-dammed lakes. Compared to other models, our model achieved the lowest average relative error of approximately 14 % when analyzing 44 observed data, surpassing the >44 % average relative error from alternative models. Finally, the model is used to calculate the water storage change of moraine-dammed lakes in the past 30 years in High Mountain Asia. The model has been proven to be robust and can be utilized to update the water storage of lake water for conducting further management of glacial lakes with the potential for outburst floods in the world.

Glacier surges (GSs) are a manifestation of glacier instability and one of the most striking phenomena in the mountain cryosphere. Here, we utilize optical images acquired between 1973 and 2021 to map changes in glacier surface velocity and morphology and characterize differences in surface elevation using multi-source DEMs in the Tuanjie Peak (TJP), located in the Qilian Mountains (QLMs). These data provide valuable insights into the recent dynamic evolution of glaciers and hint at how they might evolve in the next few years. We identified a confirmed surge-type glacier (STG), three likely STGs, and three possible STGs. Our observations show that TJP GSs are generally long-term, although they are shorter in some cases. During the active phase, all glaciers exhibit thickened reservoir areas and thinned receiving areas, or vice-versa. The ice volume transfer was between 0.11 ± 0.13 × 10⁷ m³ to 5.71 ± 0.69 × 10⁷ m³. Although it was impossible to obtain integrated velocity profiles throughout the glacier surge process due to the limitations of available satellite imagery, our recent observations show that winter velocities were much higher than summer velocities, suggesting an obvious correlation between surge dynamics and glacial hydrology. However, the initiation and termination phase of GSs in this region was slow, which is similar to Svalbard-type STGs. We hypothesize that both thermal and hydrological controls are crucial. Moreover, we suggest that the regional warming trend may potentially increase glacier instability and the possibility of surge occurrence in this region.

The China–Pakistan international Karakoram Highway passes through the core area of the “Karakoram Anomaly,” whose glaciers have maintained or increased their mass during a period when most glaciers worldwide have receded. We synthesized the literature and used remote-sensing techniques to review the types, distribution, characteristics, causes and frequency of major glacial hazards along the Karakoram Highway. We found that the glacier-related hazards could be divided into direct and indirect hazards, including glacier surges, glacial lake outburst floods, and glacial floods, which are concentrated in East Pamir and the Hunza River Basin. In the past 100 years, hazards from glaciers surges and glacial floods only occurred once and twice, respectively, which appear suddenly, with the hazard-causing process being short-lived and occurring mainly in the summer. Glacial lake outburst floods mainly occur in the spring and summer in the Hunza River Basin. Among these, ice-dammed lakes have the highest frequency of flooding, their formation and outbursts being closely related to the sudden advancement of surge-type glaciers. Under the background of global climate warming, we speculate that the glacier surge cycle may shorten and the frequency of the formation and outbursts in the glacial lakes may increase. In the future, we should combine models and new field observations to simulate, and deepen our understanding of the physical mechanisms of different glacier-related hazards. In particular, on-site monitoring should be carried out, to include the evolution of glaciers subglacial hydrological systems, the thermal state at the base of the glaciers, and the opening and closing of drainage channels at the base of the ice dams.