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 article examines the 2021-2023 surge of the eastern branch of ZhongFeng Glacier (ZFG) and reviews the 2003-2004 surge of its western branch, utilising multisource digital elevation models, Landsat MSS/ETM+/OLI, Sentinel-2, and meteorological data. Our findings reveal that surges in both the eastern and western branches of the ZFG 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 km(3) and 0.74 +/- 0.08 km(3). Based on the timing characteristics of these surges, we conclude that both branches of the ZFG 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.

Study region: Purog Kangri ice field, inner Tibetan Plateau. Study focus: Due to limited field observations on extreme-glaciers, detailed insights into the ice thickness distribution, spatio-temporal patterns of glacier variation and its climatic drivers of such glaciers remain insufficiently scrutinized. This investigation mapped the ice thickness distribution of the Purog Kangri ice field by an improved distributed glacier thickness model and noted recent dynamism concerning its surface elevation and glacier surge episodes. This dynamism was subsequently connected to proximate climatic shifts and broad-scale atmospheric circulation configurations. New hydrologic Insights: The ice field retreated from 427.65 f 5.27 km2 in 1974 to 389.64 f 5.58 km2 in 2021 (0.19 % a-1). Digital elevation model differencing quantified a marginal mass deficit of-0.13 f 0.01 m a-1 or-0.11 f 0.02 m w.e.a-1 since 1974. The mass loss rates varied across different periods, showing an accelerating trend since 2012. We also identified four surge-type glaciers and reported observations of their surge behavior. Employing a perfect-plasticity framework, the aggregate volume estimation for the ice field in 2021 was established at 43.11 f 17.82 km3, signifying a mean ice thickness of 108.73 f 17.1 m. The findings indicated that the spatial-temporal patterns of Purog Kangri ice field variation can be explained by the regional climate change. From the perspective of large-scale circulation, the change in geopotential height and the cyclonic/anti-cyclonic circulation exhibited opposite spatial patterns during 1974-2000 and 2001-2021, which are associated with variations of the ice field. Our results deepen understanding of the response mechanisms of extreme-glaciers to climate change and provide a quantitative basis for predicting regional hydrological processes and ecosystem evolution in the inner Tibetan Plateau.

Understanding the differential responses of various tributaries of the same glacier to climate change under similar climatic conditions in the Karakoram is crucial for unraveling the complexity of glacier dynamics in this region.This study systematically examines the surface elevation,flow velocity,morphological changes,and climate responses for different tributary glaciers of the Musta Glacier,using multi-source remote sensing imagery and meteorological reanalysis data from 1976 to 2023.The findings reveal that the tributaries of Musta Glacier experienced a total of nine surges,with an average duration exceeding ten years.These surges typically began in spring and summer and concluded in summer and autumn.During these events,the glaciers transferred an estimated 1.32 km3 of material downstream,resulting in an average thickening of over 30 m in the receiving area.The analysis of velocities reveals that the acceleration phase of Musta Glacier tributary surges ranges from 1 to 12 years,with an average duration exceeding 6 years,while the deceleration phase consistently lasts less than 4 years.Among the tributaries,the South Chongtar Glacier exhibits the most rapid surge dynamics,with a total surge duration of just 5 years.Additionally,all surging tributaries of Musta Glacier induce notable geomorphic changes during their surge events,including the formation of ring-shaped moraines and terminal advances.Comparative analysis with previous studies reveals that the surge characteristics of most Musta Glacier tributaries resemble those of thermally controlled Svalbard-type surging glaciers.Furthermore,we observed that the surging patterns of Musta Glacier are closely linked to regional climatic variations,characterized by increased precipitation and noticeably cooling prior to surge initiation.On the other hand,we proposed that the asynchronous surging behavior among the tributaries of Musta Glacier is primarily driven by variations in the internal dynamic processes of each glacier in response to climatic changes.In conclusion,our findings provide a quantitative and detailed characterization of the surging processes of Musta Glacier,offering deeper insights into the complexity of glacier surging under changing climatic conditions.

Glacier surges are a primary trigger for various glacial hazards, including ice avalanches, glacier collapses, and glacial lake outburst floods. This study systematically examines the characteristics and subglacial processes of an unnamed glacier in the central Himalayas, leveraging high temporal resolution remote sensing data and glacier modelling. We identify a surge event that began in 2019 and persisted for less than eight month, marked by rapid acceleration and deceleration phases. During the surge, >0.23 km(3) of ice was transferred from higher to lower elevations, resulting in a thickness increase exceeding 70 m at the glacier terminus and an advance of over 800 m. This was accompanied by extensive crevasse formation across a larger surface area compared to pre-surge conditions. Our analysis quantitatively characterizes changes in basal stresses, strain rates, and sliding velocities, revealing that the surge was predominantly driven by subglacial sliding facilitated by surface meltwater infiltration. Regional climate fluctuations acted as external drivers, disrupting the glacier's dynamic equilibrium and triggering the surge, which was governed by a hydrological switch mechanism.

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.

Study region: Yunfeng Peak region, High Mountain Asia Study focus: High Mountain Asia is the most glacier-rich region outside the polar areas and plays a critical role in alleviating water resource pressures across Asia. Understanding the complexities of glacier responses to climate change in this region is essential for elucidating glacier-climate interactions and projecting future glacier dynamics. New hydrologic Insights: Our work highlights the contrasting responses of surge-type and normal glaciers to identical climatic conditions, identifies the underlying mechanisms of glacier surging, and examines the factors driving differential glacier dynamics. Influenced by atmospheric circulation patterns, the YFP region experienced increased precipitation and decreased temperatures between 1980 and 2010. This climatic shift caused pronounced fluctuations in glacier surface flow velocities between 1996 and 2010. Among the glaciers studied, the largest glacier initiated its surge in 2011, reached its peak velocity in 2014, and terminated the surge in 2020, with the terminus advancing over 1.5 km. In contrast, normal glaciers in the region showed slower flow velocities and pronounced terminus retreats during the same period. Notably, the mass balance trends between surge-type and normal glaciers were not markedly different, although the surgetype glacier redistributed over 0.2 km3 of ice from higher to lower elevations during its surge. Our comparative analysis revealed that the disparities in glacier responses to climate change in the YFP region primarily arise from differences in glacier size, which govern the rate of dynamic adjustments to external climatic drivers. The surging behavior of the glacier was primarily attributed to enhanced accumulation from climate-induced mass gain, which caused the basal temperatures to reach the pressure melting point. Surface meltwater infiltration through crevasses further elevated the basal water pressure. The formation of an efficient basal drainage network subsequently reduced the sliding velocity, bringing the surge to an end.

The Karakoram glaciers have exhibited anomalous stability amidst global glacier retreat, a phenomenon known as the "Karakoram anomaly". However, recent observations suggest a potential weakening of this anomaly. Here, we analyze four decades (1982-2020) of AVHRR and MODIS satellite data to quantify glacier surface albedo changes and their linkages to glacier dynamics. Results reveal a significant decline in annual mean albedo across 65 % of the glaciated area, with pronounced reductions in the central Karakoram (-0.004 yr(-1)) and northern slopes. Seasonal trends show accelerated summer-autumn darkening post-2000, driven by rising temperatures, reduced snowfall, and snow depth variability. Albedo decline correlates strongly with glacier mass loss, particularly at high elevations (>5000 m a.s.l.), where accumulation zones now exhibit accelerated darkening. Surge-type and avalanche-fed glaciers demonstrate slower albedo declines, linked to ice-mass transportation or fresh snow deposition, highlighting their relationship with the glacier anomaly. The primary drivers of albedo changes, including snowfall, air temperature, and radiation flux, with snow depth and temperature contributing most significantly to interannual albedo variability. Black carbon and dust have a minimal effect on albedo changes, only influencing it during the drier months. Since 2000, the ablation season has been extended to similar to 127 days, with earlier onset and delayed termination, leading to accelerated thinning and retreat. Mass balance reconstructions indicate a shift from slight positivity (0.06 +/- 0.03 m w.e.a(-1), 1982-2019) to accelerated loss post-2005, signaling a transition toward regional glacier retreat. These findings underscore the critical role of albedo feedbacks in modulating the Karakoram Anomaly and highlight urgent needs to integrate albedo dynamics into glacio-hydrological models for sustainable water resource management in High Mountain Asia.

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Glacier surges, a primary factor contributing to various glacial hazards, has long captivated the attention of the global glaciological community. This study delves into the dynamics of Kyagar Glacier surging and the associated drainage features of its Ice -dammed lake, employing high temporal resolution optical imagery. Our findings indicate that the surge on Kyagar Glacier began in late spring and early summer of 2014 and concluded during the summer of 2016. This surge resulted in the transfer of 0.321 +/- 0.012 km 3 of glacier mass from the reservoir zone to the receiving zone, leading to the formation of an ice -dammed lake at the glacier ' s terminus. The lake experienced five outbursts between 2015 and 2019, with the largest discharge occurring in 2017. And the maximum water depth during this period was 112 +/- 11 m, resulting in a water storage volume of (158.37 +/- 28.32) x 10 6 m 3 . On the other hand, our analysis of the relationship between glacier surface velocity and albedo, coupled with an examination of subglacial dynamics, revealed that increased precipitation during the active phase of the Kyagar Glacier results in accumulation of mass in the upper glacier. This accumulation induces changes in basal shear stress, triggering the glacier ' s transition into an unstable state. Consequently, glacier deformation rates escalate, surface crevasses proliferate, potentially providing conduits for surface meltwater to infiltrate the glacier bed. This, in turn, leaded to elevated basal water pressure, initiating glacier sliding. Furthermore, we postulated that the repetitive drainage of Kyagar Ice -dammed lake was primarily influenced by the opening and closing of subglacial drainage pathways and variations in inflow volumes. Future endeavors necessitate rigorous field observations to enhance glacier surge simulations, deepening our comprehension of glacier surge mechanisms and mitigating the impact of associated glacial hazards.

Study region: The northern region of the Karakoram Range. Study focus: Karakoram is a region in High Mountain Asia with many surge-type glaciers. This study employed over 200 high-temporal-resolution remote sensing images and investigated the variations in elevation and velocity of the Ghujerab River Head Glacier (GRHG) from 2019 to 2023. Furthermore, we elucidated the potential controlling mechanisms. New hydrological insights for the region: Our findings revealed that the GRHG, akin to typical surgetype glaciers in Karakoram, started to surge in the spring and finished surging in the summer, with a duration of less than two years. Throughout the surging process, the glacier transferred a mass of 0.11 +/- 0.003 km3 from the reservoir area to the receiving area, resulting in a thickening of 91.59 +/- 1.04 m at the glacier terminus and thinning of 11.78 +/- 1.04 m in the upper glacier. By analysing the mass balance and glacier surface albedo during surging, we proposed that climatic disturbances in the glacier region provided essential material inputs for the surge. Additionally, based on the seasonal evolution pattern of glacier flow velocity, we inferred a close correlation between surging and variations in subglacial hydrology. The duration of acceleration and deceleration during glacier surging, as well as a comparison with existing studies, further support our conclusion. Future research integrating multi-source remote sensing and onsite observations can support numerical simulations to quantitatively reveal the key processes occurring beneath and within glaciers during surge events.

The western Kunlun main peak region is among the areas in High Mountain Asia where surge-type glaciers are highly concentrated. Here, we analyse the surging characteristics of the eastern and western branches of the Western Kunlun Glacier and the factors controlling the asynchronous behaviour of their surges. The eastern branch entered an unstable state in 1999 and remained so until the culmination of its surge in the summer of 2019, spanning 21 years. Conversely, the surge of the western branch commenced in the summer of 2020. The surge duration for this glacier was four years, characterized by a rapid acceleration and deceleration process. Based on the glacier surge characteristics, we posit that western branch of Western Kunlun Glacier was influenced by hydrological mechanisms, while eastern branch was affected by subglacial thermal processes. These process intensifies crevasse formation on the glacial surface, providing conduits for surface meltwater to reach the glacier bed, thus elevating subglacial water pressure. The difference of subglacial hydrology and thermal processes caused by different subglacial topography and mass accumulation rates was the main factor of the asynchronous behaviour of the west and east branches of the West Kunlun glacier.

藏东南尼都藏布流域冰雪崩、滑坡和泥石流等山地灾害频发,研究团队于2021年10月对流域内的塔弄错进行了水深测量和周边地貌环境调查.同时,利用短基线合成孔径雷达干涉测量(SBAS-InSAR)技术监测了尼都藏布流域的地表形变速率,以识别冰湖周边的潜在滑坡体、崩塌体等诱灾因素.最后,基于数值模型RAMMS和波浪传播模型,评估了不同情景下崩塌体入湖和水量变化对冰湖溃决风险的影响.结果表明,塔弄错的最大水深为29.45 m,平均水深为15.21 m,水量为1820842 m3.塔弄错周边5个不稳定区域的平均形变速率远高于其他区域,将来可能会成为触发塔弄错溃坝的外界诱因.模型模拟显示,塔弄错在入湖崩塌体质量增加或水量增加情况下,产生的洪峰流量、溃口深度和坝顶承受的压力均显著增加.因此,建议在冰湖溃决风险评估工作中重点关注周边有崩塌隐患点且水量持续增长的冰湖,并实时观测崩塌区的动态变化,为下游及时做好冰湖溃决洪水的避险提供预警信息.

The Parlung Zangbo Basin, located in the southeastern Tibetan Plateau, where the marine glaciers are most concentrated. However, due to global climate warming over recent years, these glaciers have experienced substantial losses. By applying the Open Global Glacier Model (OGGM), we simulated the mass balance of 1,554 glaciers within the basin from 1980 to 2019. The results show that the mass balance of the entire Parlung Zangbo Basin was in a continuous state of loss from 1980 to 2019, with a rate of -0.41m w.e. a-1. The loss was even more severe in 2000-2019, reaching -0.56m w.e. a-1. Spatially, the southeast and northwest parts of the basin suffer from the most severe glacier losses, while the central and western parts have relatively less. The main causes of glacier mass loss are the increase in temperature and a slight decrease in precipitation. Through sensitivity analysis of temperature and precipitation, it was found that when the temperature rises by 1°C, the mass balance of 71.75% of the glaciers in the basin changes at a rate of -1000 to -500 mm w.e. a-1. When precipitation decreases by 20%, the mass balance of 62.81% of the glaciers changes at a rate of -450 to -300 mm w.e. a-1. Compared to precipitation, glaciers are more sensitive to changes in temperature. Meteorological data analysis from the National Meteorological Station and reanalysis data showed that the temperature increased by more than 1.5°C from 1980 to 2019. Total precipitation at the Bomi Station from 2000 to 2019 was 10% lower than in the previous 20 years, and the overall precipitation in the basin showed a decreasing trend. The ongoing rise in temperature, coupled with a marginal decline in precipitation, has resulted in sustained glacier mass reduction in the Parlung Zangbo Basin.

延时摄影因可靠、高效和低成本的优势,在冰川监测中应用广泛,特别是对于获取冰川表面连续变化信息而言.本文基于2020年3月—2021年9月物候相机拍摄的梅里雪山明永冰川末端照片及多期无人机影像,利用地面摄影测量技术和互相关算法,提取了日尺度冰川表面运动速度.结果表明:通过物候图像获取的冰川表面运动速度分辨率高,从海拔2880～3150 m a.s.l.,冰川总位移介于(129.38±7.76)～(669.95±247.88)m,年均表面运动速度达(79.14±4.74)～(412.86±152.75)m·a-1,呈从中间向两侧减缓的空间分布特征.冰川表面运动速度随季节变化,夏季流速[(0.13±0.06)～(1.99±0.37)m·d-1]快于冬季流速[(0.07±0.06)～(1.35±0.37)m·d-1].与冬季流速相比,夏季流速受降水和气温升高的影响不稳定.根据流速分离结果,明永冰川末端底部全年处于融化或压融状态,底部滑动对冰川表面运动速度的贡献介于76%～93%.冬季底部滑动占表面流速高达82%,夏季底部滑动对冰川运动起绝对主导作用.本文采用的技术为进一步研究季风海洋型冰川的运动机制提供了参考方案.

Multi-temporal glacier inventories provide key information about the glaciers, their characteristics, and changes and are inevitable for glacier modelling and investigating geodetic mass changes. However, to date, no consistent multi-temporal glacier inventory for the whole of the Karakoram exists, negatively affecting the monitoring of spatio-temporal variations in glaciers' geometric parameters and their related applications. We used a semi-automatic method combining automatic segmentation and manual correction and produced a multi-temporal Karakoram glacier inventory (KGI) compiled from Landsat TM/ETM+/OLI (Thematic Mapper, Enhanced Thematic Mapper Plus, and Operational Land Imager) images for the 1990s, 2000s, 2010s, and 2020s. Our assessments using independent multiple digitisation of 37 glaciers show that the KGI is sufficiently accurate, with an overall uncertainty of ±3.68 %. We also performed uncertainty evaluation for the contiguous glacier polygons using a buffer of half a pixel, which resulted in an average mapping uncertainty of ±5.21 %. We calculated more than 20 attributes for each glacier, including coordinates, area, supraglacial debris area, date information, and topographic parameters derived from the ASTER GDEM (Advanced Spaceborne Thermal Emission and Reflection Radiometer global digital elevation model). According to KGI-2020s, approximately 10 500 alpine glaciers (>0.01 km2 each) cover an area of 22 510±828 km2 of which 10.18±0.38 % (2290±84 km2) is covered by supraglacial debris. Over the past 3 decades, the glaciers experienced a loss of clean ice and/or snow area but a gain in supraglacial debris. Supraglacial debris cover has increased by 17.63±1.44 % (343.30±27.95 km2), while non-debris-covered glaciers decreased by 1.56±0.24 % (319.85±49.92 km2). The total glacier area was relatively stable and showed only a slight insignificant increase of 23.45±28.85 km2 (0.10±0.13 %). The glacier area has declined by 3.27±0.24 % in the eastern Karakoram, while the glacier area slightly increased in central (0.65±0.10 %) and western Karakoram (1.26±0.11 %). Supraglacial debris has increased over the whole of Karakoram, especially in areas above 4200 m a.s.l. (above sea level), showing an upward shift. The glacier area changes were characterised by strong spatial heterogeneity, influenced by surging and advancing glaciers. However, due to global warming, the glaciers are on average retreating. This is in particular true for small and debris-free glaciers. The multi-temporal KGI data are available at the National Cryosphere Desert Data Center of China: https://doi.org/10.12072/ncdc.glacier.db2386.2022 (F. Xie et al., 2022).

The Poiqu Basin is located in the Central Himalayas,with extensive glacial landforms and a complex and changing environment.It is one of the areas with the most glacial lakes and the most frequent glacial lake outburst floods worldwide.In September 2020,the authors conducted an in-situ bathymetric survey for five moraine-dammed lakes in this region.Additionally,glacial lake boundaries were extracted using 33 Landsat images from 1988,2000,2010 and 2020,as well as maps from 1974.On this basis,the optimal glacial lake volume estimation equation was then used to determine the lakes’ volume.The resulting dataset comprises（1） glacial lake bathymetry,（2） a glacial lake inventory from 1974 to 2020 and the boundary data of five glacial lakes in September 2020 and（3） glacial lake volume data.The dataset is archived in 102 data files in three group files in.tif,.shp,and.xls data formats with a total file size of 4.92 MB（compressed into a single 766 KB file）.

Due to the deep valleys, steep mountains and the influence of the Indian monsoon on the Mainri Mountains (Yunnan Province, China), it is difficult to estimate glacier change from microwave and optical remote sensing. To bridge the gap between low-quality space-borne remote sensing and scarce in situ measurements, airborne remote sensing, such as unmanned aerial vehicles (UAVs), may provide a remarkable opportunity to monitor glacier change with high-quality tools. To determine monsoon temperate glacier change, three UAV surveys were conducted on the Melang Glacier in the Mainri Mountains in November 2019, April 2020 and November 2020. Then, glacier surface elevation changes were estimated from UAV orthophotos and DSMs. High accumulation and high ablation (+10.5 m and −13.5 m) were observed in the accumulation period and ablation period, with a mean surface elevation change of −3.0 m in the surveyed glacier area from November 2019 to November 2020. The avalanche, debris cover, ice cliffs and proglacial lake resulted in a heterogeneous pattern of glacier surface elevation changes. Given that the glacier is more sensitive to temperature, the Melang Glacier may have experienced a substantial recession and mass loss in the past few decades. This study provides a more appropriate approach for monitoring the changes in a temperate glacier in the Mainri Mountains.