Abstract. We report repeated drainage from the Purepu supraglacial lake system in the central Himalaya using high-resolution satellite imagery. A satellite-inferred 2023 drainage event is constrained to 12–15 July, whereas a reported GLOF occurred early on 8 July 2025. Both followed lake expansion to ~0.70–0.72 km², but DEM-constrained lake-volume loss increased from 0.87 × 10⁶ m³ in 2023 to 3.55 × 10⁶ m³ in 2025. The 2025 event remained incomplete, and flood-volume reconstruction suggests additional englacial or subglacial contributions cannot be excluded. Residual water persisted into 2026, supporting high-frequency monitoring in early July 2026.

Basin-scale glacier surface mass balance (SMB) reconstruction is a bottleneck for glacier research. In this study, the performances of the enhanced temperature-index model (ETI) and simplified energy-balance model (SEB) for simulating glacial SMB in the Laohugou (LHG) Basin 1980–2020 were compared using the observed and reanalysis datasets. (1) The ETI exhibited more stable and better simulations at the basin scale, which was mainly attributed to the physical structural differences between the two models. (2) In the last 40 years, the annual and cumulative SMB have been −0.39±0.29, −16.020±3.97 m w.e., respectively. After 1990, the rate of glacier ablation approximately tripled that of the 1980s. From 2011 to 2020, a more rapid loss occurred, with a rate of −0.56 m w.e. yr−1. (3) The SMB showed the highest sensitivity to temperature. The sensitivity of the SEB to downward shortwave radiation (SW↓) was approximately triple that of the ETI. Additionally, a significant negative correlation was found between the westerlies-monsoon synergy index and the annual SMB (R=−0.44, p<0.05). These findings present a basic method of SMB simulation at basin scales, where glacier changes are more significantly influenced by temperature.

The rapid shrinkage of the climate-regulating cryosphere, driven by global warming and anthropogenic activities, underscores the urgency of understanding its impact on regional ecological vulnerability. This study develops a Sensitivity–Resilience–Pressure (SRP) model-based framework comprising 21 natural and socio-economic indicators, employs spatial autocorrelation and center of gravity migration to characterize spatiotemporal patterns in the Qilian Mountains region, and integrates Random Forests (RF) with Shapley Additive Explanations (SHAP) to identify key drivers. Results reveal a downward trend in the Ecological Vulnerability Index (EVI) from 2000 to 2020, with areas of very heavy vulnerability declining from 21.05% to 14.73%, indicating gradual ecological recovery. The study area exhibits moderate vulnerability, with the western region dominated by heavy and very heavy vulnerability, whereas the eastern region is characterized by potential and light vulnerability, indicating a high-west, low-east spatial pattern. A significant positive spatial autocorrelation is observed, revealing that areas with high vulnerability are highly clustered and primarily overlap with regions of high elevation and sparse vegetation. The RF–SHAP analysis demonstrates that natural factors dominate the EVI, with fractional vegetation cover, biological abundance, glacial meltwater volume, annual precipitation, and the landscape diversity index emerging as the main drivers, and the EVI changing sequentially as each indicator approaches its threshold: 0.16, 56.57, 2.23 mm, 400.73 mm, and 0.39. In conclusion, although ecological vulnerability in the Qilian Mountains has declined, future management strategies should leverage these threshold effects to implement precise, indicator-based monitoring and regulation.

Glacier foreland and permafrost microbiomes exhibit distinct taxonomic and functional specialization adapted to extreme cold. Metagenomic analysis reveals dominance of Thermoproteota and Methanobacteriota in archaea, Ascomycota and Basidiomycota in eukaryotes, and enriched Actinomycetota, Planctomycetota, and Gemmatimonadota in bacteria, compared to temperate sediments. Genus-level distributions further reflect niche partitioning, with cold-adapted taxa such as Pseudogymnoascus (fungi) and pigment-producing/cold-shock protein-encoding bacteria enriched in frozen habitats. Genetically, these communities are fortified with DNA repair, osmoregulation, and cold-shock genes, supporting resilience under UV, osmotic, and freezing stress. Functionally, they show enhanced polysaccharide degradation and Type II methanotrophy but constrained denitrification. Network analysis identified four microbial modules, each representing specialized strategies for nutrient cycling, methane metabolism, phototrophic symbiosis, and resource scavenging in cold environments through cross-domain collaboration and metabolic complementarity. Collectively, this study advances our understanding of extremophile life by demonstrating that microbial survival in cryospheric ecosystems is orchestrated through a sophisticated integration of community composition, genetic inventory, and interspecies cooperation. These insights are essential for predicting the ecological responses and climate feedbacks of cryospheric ecosystems under global warming.

Accurate precipitation data play a vital role in hydrological and climate studies, with their significance being especially pronounced in alpine cold regions where in-situ observational data are limited. However, existing gridded precipitation datasets often suffer from low resolution and significant biases, making them inadequate for addressing the strong spatiotemporal heterogeneity of alpine areas. To address these challenges, this study developed a novel Three-Layer Intelligent Downscaling and Calibration (TLIDC) framework, integrating Geographically Weighted Regression (GWR) and Convolutional Neural Network-Bidirectional Long Short-Term Memory (CNN-BiLSTM) model, to generate high-precision gridded precipitation data tailored for alpine regions. The TLIDC framework was quantitatively evaluated using data from 100 rain gauge stations in the Qilian Mountains and applied to reconstruct daily precipitation data at a 0.01 degrees x 0.01 degrees spatial resolution for the Qilian Mountains from 1950 to 2024. The results demonstrate that: (1) The TLIDC framework effectively downscales the coarse spatial resolution ERA5-Land precipitation data, producing high spatial resolution outputs that preserve the temporal periodicity and overall spatial distribution, while markedly enhancing spatial detail and visual clarity. (2) The calibration module of the TLIDC framework effectively corrected the bias in the raw precipitation data, significantly improving data performance, particularly in areas with scarce ground observation data. Compared to CHM_PRE, CN05.1, and TRMM, the generated data showed a 15.95 % similar to 25.20 % improvement in precipitation event identification accuracy. Furthermore, the Pearson correlation coefficient (CC) for precipitation simulation accuracy increased by 0.30-0.55, while the root mean square error (RMSE) and mean absolute error (MAE) decreased by 3.33-4.58 mm/day and 1.42-2.27 mm/day, respectively. (3) The high-precision precipitation dataset for the Qilian Mountains, reconstructed using the TLIDC framework, has a multiyear average of 296.84 mm/year for the period 1999-2019. This value is close to the multi-year averages of three other precipitation products, which range from 296.43 to 352.47 mm/year. Additionally, the spatial distribution pattern of this dataset aligns with those of the other products. (4) From 1950 to 2024, precipitation in the Qilian Mountains has increased at a linear rate of 2.49 mm per decade (p < 0.05), exhibiting a spatial pattern of decreasing precipitation from southeast to northwest. Our findings offer a viable solution for generating high-precision precipitation data in alpine cold regions with complex topography and sparse observational networks, addressing a critical gap in current climate and hydrological research.

This study represents the first investigation into the pollution characteristics and sources of atmospheric carbonaceous aerosols in the high-altitude region of Taibai Mountain in the Qinling Mountains during the winter season. Atmospheric particulate matter (PM2.5) samples were collected from December 2019 to February 2020. The OC/EC ratio, principal component analysis, and backward trajectory analysis were employed to characterize the composition and potential sources of carbonaceous components in PM2.5. The results showed that during the winter sampling period, the average mass concentrations of PM2.5, OC, and EC were 49.20 ± 27.73 μg/m3, 9.88 ± 3.68 μg/m3, and 2.01 ± 1.04 μg/m3, respectively. OC and EC accounted for 20.1

Trans-boundary black carbon aerosols from South Asia profoundly affects the climate and cryosphere of the Tibetan Plateau. However, the integration effects of black carbon on radiative forcing and precipitation, as well as on solid water storage remain to a large extent unknow. This study presents the systematic assessment of both direct melting and indirect precipitation mass supply effects on glaciers for the 2007-2016 period. Key findings reveal that South Asian black carbon deposition reduced glacial albedo, increasing melt by 7.5%, while black carbon-induced precipitation reduction caused an additional 6.1% mass loss. Combined, these effects drove 33.7% solid water storage decreases in the Himalayas. The excess ice-loss poses a critical threat to water resource for downstream population centers in Indus and Ganges-Brahmaputra exorheic basins, with reductions of approximately 18.9% and 25.7%, respectively. This evidence highlights the urgent need for regional black carbon mitigation strategies to safeguard water security and ecosystem stability.

Climate change is profoundly reshaping species distributions, especially for ecologically important taxa like Sphagnum, which represent a key functional group responsible for carbon sequestration function in peatland ecosystems. Understanding their potential distribution is crucial for developing effective conservation strategies and sustainable management practices. The MaxEnt model was applied in this study to predict the suitable habitats of Sphagnum across the Hengduan Mountains (HDM), with a particular attention to the differences between the western Hengduan Mountains (WHDM) and the entire HDM region. Our analysis identified precipitation during the coldest quarter is the most influential climatic variable determining Sphagnum distribution. Currently, suitable habitat within HDM spans 26,000 km2. Projections indicate this area may expand more than eightfold under future scenarios, accompanied by a noticeable northeastward and upslope shift. In contrast, WHDM's current suitable habitat (10,600 km2) is projected to contract by over 70% under most future scenarios, shifting southward and to lower elevations. These contrasting regional responses of Sphagnum to climate change provide new thinking for targeted protection.

Irreversible glacier mass loss has profound impacts on water resource regulation,climate change adaptation,ecosystem sustain-ability,and socioeconomic development,aligning closely with the 17 Sustainable Development Goals set by the UN for 2030.More-over,the question"What would happen if all the ice on the planet melted?"was listed as one of the top 125 frontier scientific ques-tions published by Science.The"International Year of Glaciers'Preservation,"declared as 2025,and the"Decade of Action for Cryospheric Sciences(2025-2034)"were launched to build resili-ence to the melting cryosphere.Therefore,achieving consensus regarding how best to enhance effective glacier research and preservation is an urgent priority.

Perfluoroalkyl acid analogs (PFAAs) are a class of chemically stable environmentally persistent organic pollutants (POPs) that are difficult to degrade and have a strong capacity to accumulate in the human body. PFAAs have been found to be biotoxic to humans and have been detected in various environmental media, especially in the cryosphere at trace concentrations. The cryosphere, sensitively responds to climate change, plays a crucial role in the global water, carbon and energy cycles. However, researches on cryosphere PFAAs especially in Tibetan Plateau (TP) is limited. Therefore, we summarize the physicochemical properties, physiological toxicity, spatiotemporal distribution, sources, diffusion and migration pathways, as well as analysis and removal methods of PFAAs in the cryosphere regions. The results show that PFAAs pollutants are mainly produced and distributed in the more economically developed countries in Europe and the United States, as well as in East Asia, and PFAAs can be transported by atmospheric circulation and water cycle to remote regions including cryosphere regions. The current detection methods for PFAAs in cryosphere need to be further refined for increased accuracy and convenience. There is also a need to develop more effective removal methods that will reduce the environmental and human threats posed by these PFAAs. Finally, we propose key scientific questions for future research in cryosphere including PFAAs redistribution influenced by cryosphere changes, human activities, and the interaction of other spheres.

Study region: Laohugou Glacier No. 12 in the Qilian Mountains, northeast Tibetan Plateau. Study focus: Alpine glacier meltwater from the Qilian Mountains (QMs), northeast Tibetan Plateau, is the main source of water for the surrounding arid zones. Accurately reconstructing long-term mountain glacier mass balance (MB) and projecting glacier changes under climate warming are pivotal in cryospheric scientific research. In this study, Laohugou Glacier No. 12 (LHG12), in the western QMs, was selected as a study area. Based on the Coupled Model Intercomparison Project (CMIP6) models, the degree-day and glacier retreat models were used to predict the glacier changes under three scenarios for 2020-2100. New hydrological insights for the region: From 2020-2100, the annual mass loss of LHG12 simulated using CanESM5 and EC-Earth3 which perform best increased compared to the measured data in the historical period (2010-2014) (i.e., annual MB of -0.26 m w.e) by a factor of 1.04 and 1.73 under SSP1-2.6, 4.62 and 4.88 under SSP3-7.0, and 6.23 and 7.15 times under SSP5-8.5. By 2100, the ice volume and area of LHG12 simulated using CanESM5 and EC-Earth3 reduced to 0.03x10(9) (1.6 %) and 0.01x10(9) (0.4 %) m(3), 1.87 and 0.75 km(2) under SSP5-8.5, respectively.

Global warming in tandem with surface albedo reduction caused by black carbon (BC) deposition on glaciers accelerated glacier melting; however, their respective contributions remain unclear. Glaciers in the Qilian Mountains are crucial for the development of oases in the Hexi Corridor; however, their area has decreased by more than 20% over the past half-century. Thus, this study developed a dynamic deposition model for light-absorbing particles (LAPs), coupled with a surface energy and mass balance model. We comprehensively assessed the effects of BC and warming on the melting of a typical glacier in the Qilian Mountains based on the coupled model. BC on the glacier surface caused 13.1% of annual glacier-wide melting, of which directly deposited atmospheric BC reduced the surface albedo by 0.02 and accounted for 9.1% of glacier melting. The air temperature during 2000–2010 has increased by 1.5 °C relative to that during the 1950s, accounting for 51.9% of current glacier melting. Meanwhile, BC emission have increased by 4.6 times compared to those of the early Industrial Revolution recorded in an ice core, accounting conservatively for 6.3% of current glacier melting. Mitigating BC emissions has a limited influence on current glacier melting; however, in the long-term, mitigation should exert a noteworthy impact on glacier melting through the self-purification of glaciers.

In the hydrological year 2022/2023, the glaciers in the Qilian Mountains experienced unprecedented mass loss. The glacier -wide mass balance was -1,188 mm w.e., in contrast to -350 mm of average mass balance since 1990 over the Bailanghe Glacier No. 12 in the middle of Qilian Mountains. The temperature during 2022-2023 reached the highest value ever recorded, second only to 2022, while at the same time the precipitation amount was less compared to other year since 2000, which together led to the strongest glacier mass loss during 2022-2023. The atmospheric circulation analysis shows that the high temperature in the Qilian Mountains in 2023 was jointly caused by the Arctic air mass and East Asian monsoon.

As global warming accelerates,leading to the retreat of glaciers,the effectiveness of artificial coverings,in particular geotextiles,in reducing glacier ablation has emerged as a topic of increasing concern.Nevertheless,a critical gap in knowledge persists regarding the specific physical processes involved in the mitigation provided by these coverings.This study explores the underlying mechanisms that govern the interaction through field observations and COSIPY model simulations at Bailanghe Glacier No.21 in the Qilian Mountains from 26 June to September 17,2023.It compares covered and uncovered areas to evaluate differences in mass and energy balance fluxes.It was discovered that geotextiles could decrease ice melt by up to 1000 mm w.e.in comparison to the surface of glaciers without cover,primarily because of a 23％increase in albedo compared to ice,leading to a decrease in net short-wave radiation and available melt energy.The effect of covering the entire glacier with a geotextile,which has varying albedo properties,was also simulated.It was found that,with every 5％increase in the albedo of the geotextile,ablation was reduced by 10％-25％,resulting in a decrease in ice volume loss of approximately 2.5 x 105 m3.While artificially covering glaciers can reduce ablation rates,it faces challenges such as high costs,environmental risks,and issues with replicability.Ultimately,this study aims to analyze the feasibility of glacier coverage from a mechanistic perspective for glacier management amidst ongoing climate change.

Continuously monitoring and mapping glacial lake variation is of great importance for determining changes in water resources and potential hazards in alpine cryospheric regions. The semi-automated glacial lake mapping methods used currently are hampered by inherent subjectivity and inefficiency. This study used improved YOLOv5 strategies to extract glacial lake boundaries from Sentinel-2 imagery. These strategies include using the space-to-depth technique to identify small glacial lakes, and adopting the coordinate attention and the convolution block attention modules to improve mapping performance and adaptability. In terms of glacial lake extraction, the improved YOLOv5-seg network achieved values of 0.95, 0.93, 0.96, and 0.94 for precision (P), recall (R), mAP_0.5, and the F1 score, respectively, indicating an overall improvement in performance of 12% compared to that of the newest YOLOv8 networks. In High Mountain Asia (HMA), 23,108 glacial lakes with a total area of 1847.5 km² were identified in imagery from 2022 using the proposed method. Compared with the use of manual interpretation for lake boundary extraction in test sites of HMA, the proposed method achieved values of 0.89, 0.87, and 0.86 for P, R, and the F1 score, respectively. Our proposed deep learning method has improved accuracy in glacial lake extraction because it can address the challenge represented by frozen or high-turbidity glacial lakes in HMA.

Light-absorbing particles, which are vital components of aerosols, can cause significant snow albedo darkening and accelerate melting. However, restricted by the poor quality of remote sensing-based aerosol products in High Mountain Asia (HMA), previous studies have seldom reported the long-term pattern of aerosols. In this study, we analyzed the spatial and temporal distribution characteristics of AOD in HMA and surrounding areas using Moderate Resolution Imaging Spectroradiometer and Ozone Monitoring Instrument data from 2004 to 2023. The Mann-Kendall test was applied to analyze the temporal trend and abrupt changes in AOD, while Rotated Empirical Orthogonal Function was used to identify subregions and investigate spatiotemporal variations. Moreover, random forest and XGBoost-Shap models were employed to quantify the contributions of the aerosols to changes in snow albedo and melting. The results indicate that the annual (monthly) average highest and lowest AOD occurred in 2021 (April) and 2022 (September) between 2004 and 2023, respectively. The AOD first increased and then decreased during our study period and an abrupt decline was detected in 2013. The REOF model revealed three regions in HMA (northern, southwestern, and southeastern parts) with strong variations in AOD load, which are strongly correlated with atmospheric circulation and monsoon driving. Specifically, REOF1, REOF2, and REOF3 are primarily associated with frequent dust events during springtime atmospheric circulation and anthropogenic emission transport during the monsoon season. Aerosol types were divided into four types, BC aerosol, DUST aerosol, MIX aerosol, and clean conditions, whose proportions were 16.7%, 16.1%, 6.6%, and 60.6%, respectively. The clean conditions constituted the main aerosol type in the region. The AOD notably decreased snow albedo (17.8%) and increased snowmelt (9.0%); we highlight the contribution of AOD to the intensification of snowmelt. These results could provide guidance for further studies on the relationship between snowmelt and AOD.

Due to potential powerful destruction, the compound extreme temperature and precipitation events have continuously captured the interest of scientists. However, the lack of in-situ datasets limits the knowledge of compound extreme events in the alpine mountains. We selected the Qilian Mountains and analyzed the change trends of four types of compound extreme weather events, and further evaluated the performances of five reanalysis datasets for compound extreme weather events based on the observed daily datasets from 33 meteorological stations from 1980 to 2020. The results showed that (1) The frequency of four compound extreme weather events from highest to lowest is cold-dry events, high temperature-dry events, cold-heavy precipitation events, and high temperature-heavy precipitation events. High temperature-heavy precipitation events and high temperature-dry events showed increasing trends, while cold-dry events and cold-heavy precipitation events showed decreasing trends. (2) All five reanalysis datasets underestimated temperature and overestimated precipitation. In terms of extreme temperature and extreme precipitation events, ERA5-Land performed best, followed by ERA5, Har v2 and Merra2, and JRA55 performed worst. (3) For the four types of compound weather events, the reanalysis datasets performed better for high-temperature or dry events than cold or heavy precipitation events in the Qilian Mountains. The reanalysis datasets performed best for compound high temperature-dry events and worst for compound extreme temperature-heavy precipitation events. According to the results, we recommend ERA5-Land and ERA5 for the research on the compound extreme events. The research results provide theoretical support for the study of compound extreme temperature-precipitation events in alpine regions with sparse in-situ datasets.

Climate change is one of the most serious challenges facing mankind. Sphagnum moss plays an important role in the carbon sink of peatland. Understanding the potential distribution of Sphagnum moss under climate change scenarios is critical for the conservation and rational exploitation of it. In this study, we divided the Hengduan Mountains (HDM) into east (EHDM) and west (WHDM) parts to see the difference between the whole and the parts, and understand the effects of integrity and connectivity of the landscape on species distribution. Since no enough occurrence data in EHDM, we applied the occurrence data in WHDM. Then, MaxEnt model was employed to predict the potential distribution of Sphagnum moss and computed the migratory paths of the distribution center points. We found precipitation in the coldest quarter, daily range of average temperature, isothermality and slope were the main factors affecting the suitable habitat for Sphagnum moss in HDM and WHDM. In HDM, the current potential suitable habitat is 2.6×104 km2, and will increase over 8 times and tend to shift northeastward and higher elevations in the future. In WHDM, the suitable area is 1.06×104 km2, but will decline exceeds 70% under most future climate scenarios, and tend to shift southward and lower elevations. Landscape integrity and connectivity have a great impact on the distribution of HDM Sphagnum moss species. Overall, our findings provide a reference for the conservation and management of Sphagnum moss.

Despite projections of extreme reduction in glacier volume in the Qilian Mountains by the end of the century, comprehensive studies of regional glacier-wide mass and energy balance characteristics remain lacking. This study undertook a comparative analysis of the surface energy and mass balance characteristics of Laohugou glacier No. 12 (LHG glacier) in the Shule River Basin (western Qilian Mountains) and Bailanghe glacier No. 21 (BLH glacier) in the Heihe River Basin (middle Qilian Mountains) based on in situ measurements from September 2020 to August 2021. During the cold season (September–April), precipitation was greater on the BLH glacier than on the LHG glacier. This resulted in a more positive mass balance on the BLH glacier during the cold season, and less melting in May–June owing to the higher incoming shortwave radiation. During the ablation season (May–August), snowfall was greater on the LHG glacier owing to its higher elevation, while melting was also greater owing to the anomalously low cloud fraction during summer 2021. The annual mass balance was notably more negative on the LHG glacier than on the BLH glacier at the same elevation below 5000 m, whereas the annual glacier-wide mass balance was just slightly more negative on the LHG glacier than on the BLH glacier because most of the area in the LHG glacier is at higher elevation. The equilibrium line altitude varied between 4900 and 5100 on the glaciers of Qilian Mountains during recent two decades, which signified that only 5.8–25.5