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.

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.

A combined interpretation of oxygen-18 (delta O-18) and deuterium excess (d-excess) in various archives in the Indian monsoon-dominated region may add value to the isotopic climate significance. Yet, coupling water delta O-18 and d-excess together is rarely discussed. Here, we present measurements for both delta O-18 and delta H-2 in water vapor and precipitation samples collected in the Nujiang River valley, an important moisture corridor for the Indian monsoon in southwestern China, aiming for an improved understanding of the hydrological cycle on seasonal scales. The observation found a significant drop occurred in the earlier summer season for delta O-18 and d-excess in vapor and precipitation. However, an approximately one-month lag between vapor delta O-18 and vapor d-excess is observed in seasonal variations, revealing different drivers for the seasonal patterns of vapor d-excess and delta O-18. Spatial correlation analysis found that d-excess is mainly modulated by the relative humidity over the core moisture source over the Bay of Bengal (BOB), while the sharp decrease of vapor delta O-18 corresponds to the onset of the Indian summer monsoon associated with large-scale convective activities, which significantly depleted the vapor heavy isotopes. The finding of the phase difference in the seasonal isotope signals and the underlying mechanism will benefit the study in particularly using both delta O-18 and d-excess for an improved understanding of the hydrological processes in the Indian monsoon-dominated region, and will provide new insight into studies of paleoclimate rebuilding by using isotope-based proxy as well.

萨吾尔山是中国西部14座冰川分布的山系之一，横跨中国和哈萨克斯坦两国，尽管冰川规模不大，但因二元政治主体割裂了科学研究的完整性，同时萨吾尔山冰川水资源对于新疆阿勒泰地区吉木乃县可持续发展具有重要意义，为此结合航摄地形图、Landsat及Sentinel卫星遥感影像，并参考已有冰川编目和Google Earth高分辨率历史图像等数据资料，在野外台站现场观测验证基础上对萨吾尔山冰川当前现状和过去30多年间的变化进行了详细研究。结果表明：（1）截止2022年，萨吾尔山共分布冰川31条，总面积11.47 km2，新疆吉木乃县境内的木斯岛冰川为最大规模冰川，面积2.95 km2，其余90%的冰川其面积不足1 km2。（2）过去30多年来，萨吾尔山冰川变化的总体趋势是冰川分裂、面积减小和末端后退持续增加。冰川数量从12条分裂成31条，1989—2022年冰川面积减少8.11 km2，退缩率达41.42%，冰川末端退缩11.30 m。气温升高、冰川反照率降低和冰川破碎程度加大是引起萨吾尔山冰川退缩的主要原因。（3）相较于我国其他13座高大山系，萨吾尔山在过去半个多世纪中冰川面积相对退缩幅度最大。未来在全球气候变暖背景下萨吾尔山冰川极大可能会基本消融殆尽，这对本就干旱贫水的吉木乃县可持续发展将产生重要影响，需提早统筹谋划以应对未来的水资源危机。

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Study regionThe Urumqi River basin located in eastern Tien Shan in Central AisaStudy focusGlacier runoff plays a pivotal role in water resources and stabilizing streamflow in mountainous regions. To assess the characteristics of glacier ice melt runoff in sub-basins within a single basin, three sub-basins with glacier ratios varying from 4% to 46% in the Urumqi River basin are investigated. Through the simulation by HBV light model on the basis of the observed meteorological and hydrological data. The characteristics and behaviour of glacier ice melt runoff in the three sub-basins are analysed.New hydrological insights for the regionIt was found that both the contribution ratios of ice melt runoff and glacier runoff increase linearly with the increasing glacier ratio for the three catchments, rather than logarithmically or exponentially as observed in previous studies. This is due to the relatively high contributions of ice melt and glacier runoff to river flow in a catchment characterized by high elevation and extensive glacier coverage (Catchment 1), resulting from the coincidence of summer precipitation maxima with snow and ice melt in this region. The coefficient of variations (CV) of river flow tends to decrease with the decreasing glacier ratio in sub-basins in the Urumqi River basin, indicating that river flow becomes more stable as it flows farther from the headwater in the Urumqi River basin. The lowest glacierized Catchment 3 exhibited the minimum CV value, demonstrating a stable outflow.

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.

Ice core oxygen isotope (delta 18O) records from low-latitude regions preserve high-resolution climate records in the past, yet the interpretation of these ice core delta 18O records is still facing difficulty due to the uncertainty of ice core dating. Here we present a new established delta 18O time series from Qiangtang (QT) No. 1 ice core retrieved from the central Tibetan Plateau. Due to the vague seasonal signals in the QT ice core, we investigated the spectral properties of delta 18O record with depth and discussed the implications of significant spectral power peaks in the QT ice core. We employed a variational mode decomposition (VMD) analysis for the upper part of the QT ice core to decompose the delta 18O depth series in order to separate the El Ni & ntilde;o Southern Oscillation (ENSO) mode, a signal strongly preserved in the QT ice core delta 18O record. With this approach, we established a time series of 335 years (1677-2011 CE) for the upper 50 m of the QT ice core. Subsequently, we examined the frequency of the new established delta 18O time series and detected strong signals of the bidecadal and multidecadal modes of Pacific Decadal Oscillation (PDO). The PDO consists of two modes with periods of approximately 25-35 years and 50-70 years, and we found that the 50-70 years periodicity has persisted since 1700 CE, succeeded by dominance of the 25-75 years periodicity after 1900 CE. Additionally, we analyzed the delta 18O series of the QT ice core during the past century and determined that the increasing frequency of El Ni & ntilde;o events is an important factor contributing to the increase in recent ice core delta 18O.

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.

Recent decades have witnessed the accelerated retreat of alpine glaciers, which likely portends a decline in the glacial ice melt on which large downstream populations rely for freshwater. Thus, estimating water storage in alpine glaciers is critical for predicting the trend of glacier melting. This study compiled a rich set of ice thickness observations for glaciers of varying sizes in western China. We here presented a first-order assessment of the various errors involved in interpreting ice thickness from ground-penetrating radar (GPR) observations. An empirical Bayesian kriging (EBK) method was used for ice thickness interpolation and volume estimation. We then established a new volume-scaling law specific to western China glaciers based on these 36 volume-area pairs. And together with the Second Chinese Glacier Inventory (SCGI), we obtain a regional volume estimate of 4451 ± 298 km3. By comparison, we believed that this result is the most reliable estimate of the total ice storage in western China and more reliably predicts gross glacier melting. However, our results show that the method of glacier division can strongly affect the total volume estimation, which previous studies ignored. This emphasizes the need for more surveyed glaciers data and more accurate glacier inventory to improve the evaluation of the climate impact on glacier melting water resources and to help ensure the future survival of these alpine glaciers.

基于天山乌鲁木齐河源1号冰川东支海拔4025 m处自动气象站的观测数据和同期物质平衡花杆观测数据,采用COSIMA模型,对该冰川东支2018年消融期单点能量-物质平衡进行了模拟.结果显示:物质平衡模拟值为(-0.67±0.03)m w.e.,与实测值有非常好的一致性,相关系数达0.96.造成冰川消融的能量来源于净短波辐射(84％)、感热通量(16％);冰川能量支出为净长波辐射(55％)、冰川消融耗热(32％)、潜热交换(7％)及地热通量(6％).受能量收支影响,模拟物质平衡主要取决于表面消融和固态降水.与我国其他区域大陆型冰川研究结果比较发现,乌鲁木齐河源1号冰川物质损失较为显著,能量通量主要取决于海拔以及气候条件,再冻结和固态降水显著小于羌塘1号冰川和扎当冰川,推测与单条冰川所处的大气环流有关.

基于2018年4月额尔齐斯河源至富蕴段的河水样品,综合运用Gibbs图、Piper三线图、相关矩阵分析等方法对河水中主要的化学离子、pH值、电导率、TDS和氢、氧稳定同位素等物理化学指标进行了分析.结果表明:额尔齐斯河源春季河水呈弱碱性,TDS平均值为72.02 mg·L-1,整体属于低矿化度水.河水中主要离子浓度序列为HCO3->SO42->Ca2+>Na+>Cl->NO3->Mg2+>K+,其中HCO3-、SO42-和Ca2+是最主要的阴阳离子.水化学类型从库依尔特河的HCO3--Ca2+型转变为额尔齐斯河富蕴段的(HCO3-,SO42-)-Ca2+型.从源区至富蕴段各离子含量整体呈增大趋势,但其增加过程受到复杂因素的影响而出现差异.河水离子主要受水-岩风化作用控制,且以碳酸盐岩(石灰岩、白云岩)为主的风化水解是离子的主要来源,其次是长石类矿物的风化,还包括下游人类活动的离子输入等.δD和δ18O沿程逐渐增大,在下游出现了富集现象.

本研究基于2017年8月和2018年8月在天山榆树沟6号冰川采集的雪坑和表层雪实测资料,通过海盐示踪法、相关分析法、HYSPLIT后向轨迹等方法,对冰川积雪的主要阴阳离子的化学特征进行了分析,并探讨了离子的来源及环境指示意义.研究发现,冰川积雪中平均离子浓度顺序为Ca2+ ＞SO42-＞Cl-＞Na+ ＞NO3-＞NH4+ ＞Mg2+ ＞K+,其中SO42-和Ca2+分别为主要的阴阳离子.雪坑中各离子平均浓度,pH值、电导率整体高于表层雪,且雪坑中的不溶微粒粉尘和化学离子峰值与污化层具有很好的对应关系.表层雪的化学离子浓度随海拔变化呈先减小后增大的趋势.冰川积雪中的离子来源主要包括,陆源矿物粉尘(Ca2+、Mg2+、K+)、海洋源海盐(C1-、Na+)、人为源(SO42-、NO3-、NH4+).

冰川物质平衡作为表征气候变化的重要指标,通常被用来评估冰川对径流及海平面上升的贡献.本文采用世界冰川监测服务处(World Glacier Monitoring Service,WGMS)最新公布的物质平衡、平衡线高度及积累区面积比率资料,以北极地区具有长时间观测序列的23条冰川为研究对象,分析了北极山地冰川物质平衡状况及物质平衡与平衡线高度和积累区比率的关系.分析表明:(1)1960-2017年北极冰川厚度平均减薄14.8 m,俄罗斯北极减薄最小,为4.3 m,阿拉斯加地区减薄最严重,为27.7 m;(2)23条冰川中,仅Engabreen冰川平均物质平衡为正值,Kongsvegen冰川保持微弱的负平衡,其他21条冰川的物质平衡均处于较强的负平衡状态,北极冰川整体物质损失严重;(3)过去60 a,北极冰川物质平衡整体呈负平衡,20世纪90年代后期开始,冰川开始加速消融,损失速率从-128.2 mm·a-1上升至-594 mm·a-1;(4)物质平衡与平衡线高度呈负相关,与积累区比率呈正相关,相关性显著;(5)北极气温升高是冰川物质消融的主要原因,90年代之后气温大幅度升高造成同期冰川物质大量流失,降水量对物质平衡影响较小.

科学监测祁连山积雪面积及变化特征对该区域气候研究、雪水资源开发利用、环境灾害预报及生态环境保护等具有重要意义.基于2001-2017年MOD10A2积雪产品和气象数据,分析祁连山积雪面积动态变化特征及与气温降水关系.结果显示:(1)2001-2017年祁连山积雪面积年际波动趋势较大,呈减小趋势,多年平均积雪面积约为5×104 km2,占祁连山总面积的25.9％;年内变化成“M”型,即在一个积雪年中有两个波峰和波谷,波峰出现在11月和1月,波谷出现在7月;季节变化波动趋势较大,夏冬季积雪面积减小趋势大于春季,秋季呈现略微增加趋势.(2)祁连山区积雪面积主要分布在3 000 ～4 000m及4 000～5 000m,积雪覆盖率随着海拔上升呈现逐渐增大的趋势;祁连山区不同坡向积雪覆盖面积差异较大,积雪覆盖率差异较小;积雪频率高值区呈典型的条带状分布,与祁连山地形相一致,呈西北一东南分布,且分布西部大于东部.(3)初步分析认为祁连山积雪面积变化对气温要素更敏感.

为认识全球变暖背景下中国西部大陆性冰川与海洋性冰川物质平衡变化及其对气候响应，本研究以天山乌鲁木齐河源1号冰川和藏东南帕隆94号冰川为例，结合大西沟与察隅站气象资料，对1980 — 2015年两条冰川的物质平衡变化特征及差异进行了分析。结果表明：36 a来乌源1号冰川与帕隆94号冰川物质平衡总体上均呈下降趋势，累积物质平衡达-17102与-8159 mm w.e.，相当于冰川厚度减薄19与9.01 m，且分别于1996、2004年左右发生突变。同期两条冰川所处区域年均温呈显著上升趋势，而降水量却表现出不同的变化态势；二者年内气温分配相仿，但降水分配差异较大。初步分析认为气温上升是导致乌源1号冰川与帕隆94号冰川物质亏损的主要原因，冰川区气温和降水变化幅度的差异和地性因子（坡度、冰川面积）的不同使得乌源1号冰川对气候变化响应的敏感性高于帕隆94号冰川，由于目前海洋性冰川物质平衡监测时段相对较短，为深入研究中国西部冰川物质平衡变化及过程仍需加强对冰川的持续观测。

冰川是气候变化的指示器,气候变化对冰川及其径流的影响研究是目前国内外关注的热点和前沿领域之一,目前的研究以模拟为主,实测资料十分有限且不确定性很大.以新疆天山乌鲁木齐河源1号冰川(简称"1号冰川")流域为例,基于中国科学院天山冰川观测试验站1959-2017年观测数据,研究了中国西部典型小型冰川流域径流及其组分长期变化以及对气候变化的响应,为冰川径流长期变化过程的认识提供重要参考.结果表明,1号冰川流域径流主要由冰川径流和非冰川区降水径流组成,分别占70％和30％.其中冰川径流又可分为冰川区降水径流和冰川融水径流,分别占44％和26％.59年间,冰川径流整体呈上升趋势,在1992年之后出现了一个阶梯式的上升,与气温升高和降水的增加有关,1997-2007年达到高峰,2008年以后出现波动下降趋势,其原因除了与该时段的降水有所减少有关之外,冰川面积减小的影响也不可忽视.另外,还利用实测径流和冰川物质平衡值,通过水量平衡模型,检验了模型使用的冰川区和非冰川区径流系数.