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The increasing global warming trend has resulted in the mass loss of most glaciers. The Urumqi Vally, located in the dry and cold zone of China, and its widely dispersed glaciers are significant to the regional ecological environment, oasis economic development, and industrial and agricultural production. This is representative of glaciers in Middle Asia and represents one of the world's longest observed time series of glaciers, beginning in 1959. The Urumqi Headwater Glacier No. 1 (UHG-1) has a dominant presence in the World Glacier Monitoring Service (WGMS). This paper supplies a comprehensive analysis of past studies and future modeling of glacier changes in the Urumqi Valley. It has received insufficient attention in the past, and the mass balance of UHG-1 was used to verify that the geodetic results and the OGGM model simulation results are convincing. The main conclusions are: The area of 48.68 ± 4.59 km2 delineated by 150 glaciers in 1958 decreased to 21.61 ± 0.27 km2 delineated by 108 glaciers in 2022, with a reduction of 0.47 ± 0.04 km2·a−1 (0.96% a−1 in 1958–2022). The glacier mass balance by geodesy is −0.69 ± 0.11 m w.e.a−1 in 2000–2022, which is just deviating from the measured result (−0.66 m w.e.a−1), but the geodetic result in this paper can be enough to reflect the glacier changes (−0.65 ± 0.11 m w.e.a−1) of the URB in 2000–2022. The future loss rate of area and volume will undergo a rapid and then decelerating process, with the fastest and slowest inflection points occurring around 2035 and 2070, respectively. High temperatures and large precipitation in summer accelerate glacier loss, and the corresponding lag period of glacier change to climate is about 2–3 years. [ABSTRACT FROM AUTHOR]

The ice phenomena are an inherent component of rivers in temperate, continental, and polar climate zones. Evident progress in global warming leads to a decrease in snow cover on land and ice phenomena in water bodies, disrupting the stability of the hydrological cycle and aquatic ecosystems. Although common observations indicate the disappearance of ice phenomena in rivers over recent decades, detailed quantitative research is lacking in many regions, especially in the temperate zone. In this paper, ice phenomena were analyzed on the rivers of southern Poland, located in the upland and mountain areas of the country, as no such studies have been conducted so far. The temporal changes in the annual number of days with ice (NDI) phenomena were studied in locations where ice phenomena were observed every year for at least 30 years between 1951 and 2021. Using straightforward but commonly accepted procedures, such as the Mann-Kendall test, statistically significant decreasing trends in the annual NDI were revealed for the majority of gauging stations. The Theil-Sen (TS) slope mean values were -1.66 (ranging from -3.72 to -0.56), -1.41 (from -3.22 to -0.29), and -1.33 (from -2.85 to -0.29) for the datasets representing the periods 1992–2020, 1987–2020, and 1982–2020, respectively. The results for the annual NDI were additionally presented within the context of meteorological characteristics such as annual and winter (Nov-Apr) air temperature, precipitation, and water temperature. Correlation and regression analyses revealed that the main factor triggering the decrease in NDI is the increase in the average winter air temperature. An increase in temperature by 1°C results in a decrease in NDI by up to twenty days. If these negative trends continue, ice phenomena may disappear completely from southern Polish rivers within few decades. [ABSTRACT FROM AUTHOR]

Glacial lake outburst floods (GLOFs) are among the most concerning consequences of retreating glaciers in mountain ranges worldwide. GLOFs have attracted significant attention amongst scientists and practitioners in the past 2 decades, with particular interest in the physical drivers and mechanisms of GLOF hazard and in socioeconomic and other human-related developments that affect vulnerabilities to GLOF events. This increased research focus on GLOFs is reflected in the gradually increasing number of papers published annually. This study offers an overview of recent GLOF research by analysing 594 peer-reviewed GLOF studies published between 2017 and 2021 (Web of Science and Scopus databases), reviewing the content and geographical focus as well as other characteristics of GLOF studies. This review is complemented with perspectives from the first GLOF conference (7–9 July 2021, online) where a global GLOF research community of major mountain regions gathered to discuss the current state of the art of integrated GLOF research. Therefore, representatives from 17 countries identified and elaborated trends and challenges and proposed possible ways forward to navigate future GLOF research, in four thematic areas: (i) understanding GLOFs – timing and processes; (ii) modelling GLOFs and GLOF process chains; (iii) GLOF risk management, prevention and warning; and (iv) human dimensions of GLOFs and GLOF attribution to climate change. [ABSTRACT FROM AUTHOR]

This document is a summary of a collection of research papers that focus on the impact of climate change and human activities on hydrological processes. It highlights the changes in precipitation patterns, glacier retreat, snowmelt regimes, and river flows as evidence of climate change. The document also discusses the influence of human activities such as deforestation, urbanization, and agricultural expansion on hydrological processes. It emphasizes the need for interdisciplinary collaborations and advanced technologies in studying these processes. The research papers included in the document cover topics such as climate change in specific regions, water resource management, and human interventions in environmental systems. The findings provide valuable insights for sustainable water management and conservation efforts. [Extracted from the article]

This Special Issue aims to highlight research articles focusing on the geographical scale of glacier and lake ice variations, as well as the engineering scale of ice properties and their practical applications via laboratory tests and numerical modeling. Additionally, it includes research on ecosystems under lake ice. The main goal is successfully achieved through the joint efforts of authors, anonymous reviewers, and editorial managers. In total, 1 review article and 15 research articles are included in this Special Issue. These articles cover a wide range of topics, including water resources from Chinese mountain glacier variation; lake ice phenology at different latitudes and altitudes around the world; ice properties from laboratory experiments and numerical modeling; ice engineering with different purposes in China and the Arctic; and ecosystem under lake ice at different temporal and spatial scales. This Special Issue received contributions from researchers from different parts of China and from Chinese international cooperation partners because of its focus on "higher temperature ice" under global warming. All papers presented are innovative and of high quality. This Special Issue can promote research on ice properties and their applications in practices ranging from mountains to sea, especially in popular water ecosystem environments under ice during seasonal ice period. [ABSTRACT FROM AUTHOR]

The glacial lakes in the Southeastern Qinghai–Tibet Plateau (SEQTP) have undergone dramatic expansion in the context of global warming, leading to several glacial lake outburst floods (GLOFs) disasters. However, there is a gap and incompleteness in glacial lake inventories across this area due to the heavy cloud cover. In this study, an updated and comprehensive glacial lake inventory was produced by object-based image analysis (OBIA) and manual vectorization based on the Sentinel-1 SAR and Sentinel-2 MSI images acquired in 2022. Detailed steps regarding the OBIA were provided, and the feature set of Sentinel-1 SAR images suitable for extracting glacial lakes was also determined in this paper. We found that the mean combination of ascending-orbit and descending-orbit images is appropriate for mapping glacial lakes. VV-polarized backscattering coefficients from ascending-orbit achieved a better performance for delineating glacial lakes within the study area. Moreover, the distribution of glacial lakes was characterized in terms of four aspects: size, type, elevation, and space. There were 3731 glacial lakes with a total area of 1664.22 ± 0.06 km2 in the study area; most of them were less than 0.07 km2. Ice-contacted lakes were primarily located in the Palongzangbo basin (13.24 ± 0.08 km2). Nyang Qu basin had the most abundant glacial lake resources (2456 and 93.32 ± 0.18 km2). A comparison with previously published glacial lake datasets demonstrated that our dataset is more complete. This inventory is useful for evaluating water resources, studying glacier–glacial lake interactions, and assessing GLOFs' susceptibility in the SEQTP. [ABSTRACT FROM AUTHOR]

Small intermountain river basins are most suitable for developing new methods to estimate water balance due to their well-defined catchment boundaries, relatively rapid runoff processes, and accessible landscapes for study. In general terms, dissecting the hydrograph of a small mountain river requires calibration of the flow model against multi-year data sets, including (a) glacier mass balance and snow water content, (b) radiation balance calculation, (c) estimation of the groundwater contribution, and (d) water discharge measurements. The minimum primary data set is limited to the precipitation and temperature distributions at the catchment. This approach postulates that the conditions for the formation of all components of river flow are known in advance. It is reduced to calculating the dynamic balance between precipitation (input part) and runoff, ablation, and evaporation (output part). In practice, accurately accounting for the inflow and outflow components of the balance, as well as the impact of regulating reservoirs, can be a challenging task that requires significant effort and expense, even for the extensively researched catchments. Our studies indicate the potential benefits of an approach based on one-time, but detailed, observations of stable isotope composition, temperature, and water chemistry, in addition to standard datasets. This paper presents the results of the 2022–2023 work conducted in the basin of the small mountain river Ala-Archa, located on the northern slope of the Kyrgyz Range in Tien-Shan, which was chosen as an example due to its well-studied nature. Our approach could identify previously unknown factors of flow formation and assess the time and effectiveness of work in similar conditions. [ABSTRACT FROM AUTHOR]

Herein, fast fracture initiation in glacier ice is modeled using a Material Point Method and a simplified constitutive law describing tensile strain softening. Relying on a simple configuration where ice flows over a vertical step, crevasse patterns emerge and are consistent with previous observations reported in the literature. The model's few parameters allows identification of a single dimensionless number controlling fracture spacing and depth. This scaling law delineates two regimes. In the first one, ice thickness does not play a role and only ice tensile strength controls the spacing, giving rise to numerous surface crevasses, as observed in crevasse fields. In this regime, scaling can recover classical values for ice tensile strength from macroscopic field observations. The second regime, governed by ice bending, produces large‐scale, deep fractures resembling serac falls or calving events. Plain Language Summary: In ice sheets and alpine glaciers, fast‐flowing sections are often characterized by crevasse fields that play a significant role in the cryo‐hydrologic system by facilitating meltwater flow, enhancing basal sliding, weakening the ice, and impacting glacier thermodynamics. Modeling these fractures at the glacier scale remains challenging and often necessitates integrating diverse models which hinders the straightforward consideration of physical issues associated with crevasse fields on a large scale. Here, a new numerical framework allows us to conduct field‐scale experiments and paves the way for a scaling law to elucidate the macroscopic factors influencing fracture fields and to easily incorporate crevasse depth and spacing into large‐scale models. A newly discovered scaling law highlights the transition between a mechanical behavior where the regular crevasse spacing is unaffected by geometry to a regime where geometry plays a significant role, particularly in large‐scale fracture processes like glacier calving. While the numerical experiments in this paper focus on glaciers, the model and conceptual framework is versatile and can address the mechanical behavior of fractures in broader geophysical contexts such as snow, rock or ice avalanches, tectonics and landslides. Key Points: Fractures in glacier flow are modeled using material point method with elastoplasticity and tensile strain softeningA dimensional analysis reveals a key dimensionless number characterizing two different regimes of fast fractureOne regime predicts acknowledged ice tensile strength from field observations and characterizes the regular crevasse spacing [ABSTRACT FROM AUTHOR]

The retreat of mountain glaciers inevitably leads to an increase in the number of outburst moraine lakes. One of the possible mechanisms of moraine dam outburst along with overflow over the crest is the formation of a filtration channel in the body of the moraine dam (piping). An algorithm for calculating the outburst flood hydrograph, describing the development of a filtration channel in the body of a moraine dam and the subsequent formation of water overflow when the soil above the channel collapses, is proposed in this paper. Verification of proposed methodology was carried out on the basis of experimental data and published data of real outbursts. Satisfactory results verifying this methodology made it possible to use the proposed methodology for the calculation of the hydrograph of the outburst of Lake Bashkara in the Elbrus region, which occurred on 1 September 2017. It is shown that the simulation results are quantitatively comparable with the estimates obtained from field data: the time of water discharge through the channel was 16 min, the period of the outburst wave passage was 40 min, and the maximum discharge was 636 m3/s. Thus, the possibility of applying the proposed methodology for calculating the destruction of natural moraine dams has been demonstrated. [ABSTRACT FROM AUTHOR]

The application of Structure-from-Motion (SfM) and Multi-View-Stereo matching with aerial images can be successfully used for deriving dense point clouds to analyse changes in the mountain environment, which is characterized by changes due to the action of natural process. The comparison of multiple datasets requires to setup a stable reference system, task that is generally implemented by means of ground control points (GCPs). On the other hand, their positioning may be sometimes difficult in mountains. To cope with this drawback an approach termed as Multitemporal SfM (MSfM) is presented: multiple blocks are oriented together within a unique SfM project, where GCPs are used in only one epoch for establishing the absolute datum. Accurate coregistration between different epochs depends on the automatic extraction of tie points in stable areas. To verify the application of MSfM in real cases, this paper presents three case studies where different types of photogrammetric data are adopted, including images from drones and manned aircrafts. Applications to glacier and mountain river erosion are entailed. [ABSTRACT FROM AUTHOR]

Since climate change has a significant impact on glaciers, it is essential to track their morphological change by identifying variations in ice mass. In combination with modern photogrammetric approaches, such as Structure-from-Motion (SfM) and Multi-View-Stereo (MVS) dense matching, historical aerial photographs may offer useful information for this objective. Point clouds of the 3D surface of the glaciers may be used to track changes in thickness and height during years. By using appropriate methods for calculating the distances between pairs of point clouds, this operation may be completed. Here, an Alpine glacier massif on Mount Blanc in the Italian Alps was chosen as the case study. National Geographic and the Forestry Institute of France (IGNF) provided seven data sets of digitized analog aerial photos. These were chosen, downloaded, and utilized for photogrammetric analysis. These data sets span almost 40 years, from 1967 to 2006, in total. While the change in ice thickness of these glaciers was relatively small until the mid-1990s, this study revealed an increasing reduction rate at the beginning of 21st century. This paper describes the adopted methodological approach for photogrammetric reconstruction, quality assessment and point cloud comparison. One of the two major glaciers in the considered group (Brenva Glacier) has been focused in this paper as case study. [ABSTRACT FROM AUTHOR]

This Special Issue intended to collect articles focusing on the assessment of the possible effects of climate changes on aquatic species inhabiting inland waters all over the world, including the possible synergistic effects in combination with other anthropogenic stressors. A total of six original articles were published that report on investigations of different freshwater ecosystems across the world, including the mountain streams of the Western United States and Northwest Italy, river basins of Northwest China and Central Italy, a larger lowland river in north Italy, and a high-elevation temporary pond in Central Italy. In most of these papers, special attention was devoted to the repercussions of the climate change and its effects on three important components of the biotic community: the fish, benthic macroinvertebrates, and zooplankton. According to the aims of this Special Issue, three of the articles offer new insight into the synergistic effects of global warming together with other anthropogenic stressors, including water exploitation and alien species invasions. In light of the studies' aim to highlight the effects of climate change, three papers provided analyses of environmental data collected through long-term monitoring. The scientific findings provided by these studies could help to create sound management strategies for freshwater biodiversity conservation. [ABSTRACT FROM AUTHOR]

Quantifying the effects of alpine GMB (Glacier Mass Balance) on river runoff is an important content of climate change. Uncertainty exists in GMB monitoring when applying remote-sensing technology. There are several reasons for these uncertainties, such as terrain deviation co-registration among different topographic data, the mismatch between GSE (Glacier Surface Elevation) from satellite monitoring and the GMB that comprises the physical glacier properties, the driving factors of GMB, and the response patterns of the runoff within the basin. This paper proposed a method based on the ridge line co-registration of DEMs (Digital Elevation Models), and the Tailan River basin, which is a typical glacier melt runoff recharge basin located in the southern Tianshan Mountains, was selected. Abnormal values in GSE changes were removed using ice thickness data, and the GSE results were optimized based on the regularity of the GSE change with altitude to estimate the GMB. The driving factors of the GMB and the response characteristics of the runoff in the basin were also explored. The results showed that the accuracy of the optimized GSE results across different periods has improved by more than 25%. The mean annual thinning value of GSE in the basin from 2000 to 2022 was −0.25 ± 0.02 m·a−1, corresponding to a GMB value of −0.30 ± 0.02 m w.e.a−1, indicating a consistent GMB loss state. Combined with climate data, the glaciers in the basin were impacted by rising temperatures, and the smallest increase in annual precipitation in the basin was insufficient to compensate for the GMB loss. Moreover, in the past 22 years, glacier meltwater accounts for 46.15% of the total runoff in the Tailan River basin. [ABSTRACT FROM AUTHOR]

Glacial debris flow is a common natural disaster, and its frequency has been increasing in recent years due to the continuous retreat of glaciers caused by global warming. To reduce the damage caused by glacial debris flows to human and physical properties, glacier susceptibility assessment analysis is needed. Most research efforts consider the effect of existing glacier area and ignore the effect of glacier ablation volume change. In this paper, we consider the impact of glacier ablation volume change to investigate the susceptibility of glacial debris flow. The susceptibility to mudslide was evaluated by taking the glacial mudslide-prone ditch of G318 Linzhi section of Sichuan-Tibet Highway as the research object. First, by using a simple band ratio method with manual correction, we produced a glacial mudslide remote sensing image dataset, and second, we proposed a deep-learning-based approach using a weight-optimized glacial mudslide semantic segmentation model for accurately and automatically mapping the boundaries of complex glacial mudslide-covered remote sensing images. Then, we calculated the ablation volume by the change in glacier elevation and ablation area from 2015 to 2020. Finally, glacial debris flow susceptibility was evaluated based on the entropy weight method and Topsis method with glacial melt volume in different watersheds as the main factor. The research results of this paper show that most of the evaluation indices of the model are above 90%, indicating that the model is reasonable for glacier boundary extraction, and remote sensing images and deep learning techniques can effectively assess the glacial debris flow susceptibility and provide support for future glacial debris flow disaster prevention. [ABSTRACT FROM AUTHOR]

Supraglacial, moraine-dammed and ice-dammed lakes represent a potential glacial lake outburst flood (GLOF) threat to downstream communities in many mountain regions. This has motivated the development of empirical relationships to predict lake volume given a measurement of lake surface area obtained from satellite imagery. Such relationships are based on the notion that lake depth, area and volume scale predictably. We critically evaluate the performance of these existing empirical relationships by examining a global database of measured glacial lake depths, areas and volumes. Results show that lake area and depth are not always well correlated (r² = 0.38), and that although lake volume and area are well correlated (r² = 0.91), there are distinct outliers in the dataset. These outliers represent situations where it may not be appropriate to apply existing empirical relationships to predict lake volume, and include growing supraglacial lakes, glaciers that recede into basins with complex overdeepened morphologies or that have been deepened by intense erosion, and lakes formed where glaciers advance across and block a main trunk valley. We use the compiled dataset to develop a conceptual model of how the volumes of supraglacial ponds and lakes, moraine-dammed lakes and ice-dammed lakes should be expected to evolve with increasing area. Although a large amount of bathymetric data exist for morainedammed and ice-dammed lakes, we suggest that further measurements of growing supraglacial ponds and lakes are needed to better understand their development. [ABSTRACT FROM AUTHOR]

In this study we present a series of sensitivity experiments conducted for the Last Glacial Maximum (LGM, ∼21 ka) over Europe using the regional climate Weather Research and Forecasting model (WRF). Using a four-step two-way nesting approach, we are able to reach a convection-permitting horizontal resolution over the inner part of the study area, covering central Europe and the Alpine region. The main objective of the paper is to evaluate a model version including a series of new developments better suitable for the simulation of paleo-glacial time slices with respect to the ones employed in former studies. The evaluation of the model is conducted against newly available pollen-based reconstructions of the LGM European climate and takes into account the effect of two main sources of model uncertainty: a different height of continental glaciers at higher latitudes of the Northern Hemisphere and different land cover. Model results are in good agreement with evidence from the proxies, in particular for temperatures. Importantly, the consideration of different ensemble members for characterizing model uncertainty allows for increasing the agreement of the model against the proxy reconstructions that would be obtained when considering a single model realization. The spread of the produced ensemble is relatively small for temperature, besides areas surrounding glaciers in summer. On the other hand, differences between the different ensemble members are very pronounced for precipitation, in particular in winter over areas highly affected by moisture advection from the Atlantic. This highlights the importance of the considered sources of uncertainty for the study of European LGM climate and allows for determining where the results of a regional climate model (RCM) are more likely to be uncertain for the considered case study. Finally, the results are also used to assess the effect of convection-permitting resolutions, at both local and regional scales, under glacial conditions. [ABSTRACT FROM AUTHOR]

The study of aerosols in high mountain regions is essential because particulate matter can play a role in altering the energy balance of high mountain regions, and aerosols can accelerate glacier melting in high mountain areas by darkening the ice surface, reducing its reflectivity (albedo). Studying aerosols in high mountain areas provides insights into long-range transport of pollutants, atmospheric dynamics, and climate change impacts. These regions can serve as valuable observatories for studying atmospheric processes. The main aim of this paper is to define the main sources of aerosols over an entire year of sampling at the Col Margherita Atmospheric Observatory (MRG; 46°22 ′ 0.059 ′′ N, 11°47 ′ 30.911 ′′ E; 2543 m a.s.l.), a high-altitude background site in the eastern Italian Alps. Here, we discuss the potential origins of more than 100 chemical markers (major ions, water-soluble organic compounds, trace elements, and rare earth elements) using different approaches. Some diagnostic ratios were applied, but source apportionment using positive matrix factorization (PMF) was used to define the main inputs of PM 10 collected at this high-altitude site, resulting in the identification of four factors: (1) Saharan dust events, (2) long-range marine/anthropogenic influence, (3) biogenic sources, and (4) biomass-burning and anthropogenic emissions. It can be inferred that, despite the distant location of the Col Margherita site, both regional pollution and long-range anthropogenic pollution have discernible effects on this area. [ABSTRACT FROM AUTHOR]

In this paper we present a reconstruction of climate conditions during the Last Glacial Maximum on a karst plateau in Dinaric Mountains (southern Slovenia) that bares evidence of glaciation. The reconstruction merges geomorphological ice limits, classified as either clear or unclear, and computer modelling approach based on Parallel Ice Sheet Model, which is an established numerical model for simulating glacier dynamics ranging from ice sheets to alpine glaciers. Based on extensive numerical experiments, where we studied the agreements between simulated and geomorphological ice extent, we propose to use a combination of high resolution precipitation model that accounts for orographic precipitation combined with simple elevation based temperature model. The geomorphological ice extent can be simulated with climate around 6 °C colder than modern and with a lower than modern amount of precipitation, which matches other state-of-the art climate reconstructions for the era. The results indicate that orographic precipitation model is essential for accurate simulation of the Snežnik with moist southern winds from the nearby Adriatic Sea having predominant effect on the precipitation patterns. Finally, this study shows that transforming climate conditions towards wetter and warmer or drier and colder does not significantly change conditions for glacier formation. [ABSTRACT FROM AUTHOR]

Rock glaciers are important hydrological reserves in arid and semi-arid regions. Their activity states can indicate the existence of permafrost. To help further explore the development mechanisms of rock glaciers in semi-arid and humid transition regions, this paper provides a detailed rock glacier inventory of the Guokalariju (also known as Goikarla Rigyu) area of the Tibetan Plateau (TP) using a manual visual interpretation of Google Earth Pro remote sensing imagery. We also estimated the water volume equivalent (WVEQ) in the study area for the first time. Approximately 5057 rock glaciers were identified, covering a total area of ∼404.69 km 2. Rock glaciers are unevenly distributed within the three sub-regions from west to east, with 80 % of them concentrated in the central region, where climatic and topographic conditions are most favorable. Under the same ground temperature conditions, increases in precipitation are conducive to rock glaciers forming at lower altitudes. Indeed, the lower limit of rock glaciers' mean altitude decreased eastward with increasing precipitation. Estimates of the water storage capacity of rock glaciers obtained by applying different methods varied considerably, but all showed the potential hydrological value of rock glaciers. The possible water storage in the subsurface ice of rock glacier permafrost was 1.32–3.60 km 3. The ratio between the amount of subsurface ice stored in rock glaciers and surface ice stored in local glaciers falls within the range of 1:2.32 to 1:1.26 , with an average ratio of 1:1.69. In the west region, where the climate is the driest, the water storage capacity of rock glaciers was estimated to be up to twice as large as that of the sub-region's glaciers. Changes in water resources and permafrost stability in the area where rock glaciers occur will have implications for regional water resource management, disaster prevention, and sustainable development strategies. [ABSTRACT FROM AUTHOR]

Remote sensing estimations of glacier flow velocity could provide effective methods for the long-term monitoring of glacier flow velocity. This paper calculated the velocity in the line-of-sight (LOS) direction by combining DInSAR and offset-tracking technology with ascending and descending Sentinel-1 images of the Urumqi Glacier No.1 from 2016 to 2017. Meanwhile, the velocity in the azimuthal direction was obtained by combining MAI and offset-tracking technology. Then, the eastward, northward, and upward flow velocities were retrieved using the Helmert variance component estimation method. Finally, the standard error of the mean and mean errors of surface velocity in non-glaciated areas of the Urumqi Glacier No.1 were calculated to evaluate the accuracy of the results generated by the proposed method. The results showed: (1) The ascending LOS velocity and the descending LOS velocity were 1.812 m/a and −1.558 m/a from 2016 to 2017. The ascending azimuthal and descending azimuthal velocities were 0.978 m/a and −2.542 m/a, respectively. (2) The glacier flow velocities were 2.571 m/a and 1.801 m/a, respectively, for the eastward and northward directions. In the vertical direction, the velocity was −0.554 m/a. (3) The accuracy of the results generated by the proposed method were 0.028 m/a, 0.085 m/a, and 0.063 m/a in the east, north, and vertical directions. Therefore, it is suitable to use ascending and descending Sentinel-1 images and the study method proposed in this paper to estimate the surface flow velocity of mountain glaciers. [ABSTRACT FROM AUTHOR]

People settle near water. Almost all life forms need water. Water is very important for life on earth. Consensus theory explains the circle of water through evaporation, precipitation and accumulation. Meteorologists don't know much about volcanoes. Volcanologists don't know much about weather. This is how modern science works, specialists for every small diversification of whatever science branch. How could anyone within that paradigm ever get a holistic picture of the whole? It is full of contradictions, misinterpreted results and it also seems to keep certain mysteries alive. Most of them could be more easily understood just by not being ignorant towards knowledge from laboratory experiments and peer-reviewed papers made decades ago. This paper is a thought-provoking new approach to the formation and activities of the Alps, and many of its features as a part of the greater environment. It also is meant as a serious warning for millions of people living in the Alps region, which spans from the North Sea down to the Mediterranean Sea and from the Black Sea to the Atlantic. Massive changes in the environment (Fig. 1) have been taking place in the past and it is crucial to understand that we are dealing with cyclical events, they are recurrent and will happen again in the future. [ABSTRACT FROM AUTHOR]

The anomalous movements of glaciers cause disasters, such as debris flows and landslides. It is very important to assess the glacier movements and their future trends. Glacier velocity refers to movement process. The current research aims to analyse past and current spatiotemporal changes in glacier velocity. No study has used neural network model to conduct a spatiotemporal prediction for glacier velocity. Therefore, this paper selected typical mountain glaciers G2 and G5 along the Sichuan-Tibet Railway as research objects and constructed the Convolutional Gate Recurrent Unit (ConvGRU) spatiotemporal prediction model based on 1988–2018 Landsat data to predict velocities in 2019–2028, and analysed the future trends of G2 and G5. The evaluation indexes met the model requirements to a large extent, quantitatively showing that the model has high accuracy and can successfully capture the fluctuation changes in time series data of glacier velocity. The mean deviations of G2 and G5 were 0.09 and −0.47 m/yr, respectively, reflecting the high reliability of the model applied to extraction of glacier velocity. The velocities of G2 and G5 showed a slow downtrend with fluctuations; that is, they will not cause damage to the construction and operation of the Sichuan-Tibet Railway in the short term. [ABSTRACT FROM AUTHOR]

In the summer of 1838, Arnold Guyot was asked by Louis Agassiz to gather information on Alpine glaciers, with the aim of reporting their findings in September, at the annual gathering of the French Geological Society. Guyot's observations of the internal structure of the ice and interpretations on glacier movements, reported orally at the conference, were new to science. Unfortunately, because of purported illness, Guyot did not send his manuscript to be published and missed his first opportunity to be recognized as a pioneer in glacier studies. During the years 1841 to 1847, Guyot published a series of notes, detailing results of his field work in tracing erratic blocks in the central Alpine region, in the Alpine foreland and in the Jura Mountains. The level of detail in his work was unprecedented and has not been replicated since. Recognizing that erratic blocks of similar lithology could be followed along organized paths of deposition, Guyot could invalidate those theories that sought to explain their deposition by chaotic means, such as floods, debacles or drifting icebergs loaded with rock debris. Only moraines, composed of material transported by glaciers, could explain the mapped arrangements of erratic blocks. Geological proofs for extensive glaciations in central Europe had just been found, and Guyot could demonstrate them on his hand-drawn map. But, in 1848, a revolution broke out in Neuchâtel. The local academy where Guyot was engaged as a professor shut down and all staff were left without pay. Answering a call from Agassiz who had emigrated to the USA in 1846, Guyot departed Switzerland and joined his friend there in the fall of 1848. In his luggage were all the papers on his unfinished project, including his map, and a full collection of erratic rock specimens. After arrival in the USA, Guyot had to begin a new professional life and could not devote significant attention to the subject of erratic blocks. In 1849, he showed his map of the erratic basins of Switzerland and discussed his results with various members of the American Association for the Advancement of Science (AAAS); he also shared his novel ideas about the climatic conditions required for the formation of large glaciers; however, he did not formally publish the results of his work in the Alps, and he thus lost his second opportunity for wider peer recognition and for driving the acceptance of the glacial theory. Only in 1874, 26 years after his arrival in the USA and a year after Agassiz's death, did Guyot open his boxes of alpine rock specimens and display his unpublished map in the Museum of the College of New Jersey (later Princeton University), where he was engaged as a professor. In 1883, at age 77, his memory of the unpublished 1838 report on glaciers was still in his conscience which finally pushed him to submit it for printing at Neuchâtel. It passed largely unnoticed, however, and Guyot died one year later without recognition attached to his name for his original, innovative work. This paper reviews Guyot's work and analyses his relationship with Agassiz while both were working in Neuchâtel. It seeks to evaluate his pioneering work on glaciers and on erratic blocks. It includes a copy of Guyot's map of the erratic basins of Switzerland, kept to this day in the archives of Princeton University. [ABSTRACT FROM AUTHOR]

The study of aerosol in high mountain regions is essential because particulate matter can play a role in altering the energy balance of high mountain regions, and aerosols can accelerate glacier melting in high mountain areas by darkening the ice surface, reducing its reflectivity (albedo). Studying aerosols in high mountain areas provides insights into long-range transport of pollutants, atmospheric dynamics, and climate change impacts. These regions can serve as valuable observatories for studying atmospheric processes. The main aim of this paper is to define the main sources of aerosol over an entire year of sampling at the Col Margherita Atmospheric Observatory (MRG 46° 22' 0.059" N, 11° 47' 30.911" E, 2543 m a.s.l.), a high-altitude background site in the Eastern Italian Alps. Here, we discuss the potential origins of more than one hundred chemical markers (major ions, water soluble organic compounds, trace elements, rare earth elements) using different approaches. Some diagnostic ratios were applied, but source apportionment using Positive Matrix Factorization was used to define the main inputs of PM10 collected at this high-altitude site. Moreover, a characterization of the air masses helped us to confirm the aerosol sources. [ABSTRACT FROM AUTHOR]

The climatic response of mountain permafrost and glaciers located in high-elevation mountain areas has major implications for the stability of mountain slopes and related geomorphological hazards, water storage and supply, and preservation of palaeoclimatic archives. Despite a good knowledge of physical processes that govern the climatic response of mountain permafrost and glaciers, there is a lack of observational datasets from summit areas. This represents a crucial gap in knowledge and a serious limit for model-based projections of future behaviour of permafrost and glaciers. A new observational dataset is available for the summit area of Mt Ortles, which is the highest summit of South Tyrol, Italy. This paper presents a series of air, englacial, soil surface and rock wall temperatures collected between 2010 and 2016. Details are provided regarding instrument types and characteristics, field methods, and data quality control and assessment. The obtained data series are available through an open data repository (10.5281/zenodo.8330289, Carturan et al., 2023). In the observed period, the mean annual air temperature at 3830 m a.s.l. was between -7.8 and -8.6 ∘ C. The most shallow layers of snow and firn (down to a depth of about 10 m) froze during winter. However, melt water percolation restored isothermal conditions during the ablation season, and the entire firn layer was found at the melting pressure point. Glacier ice is cold, but only from about 30 m depth. Englacial temperature decreases with depth, reaching a minimum of almost -3 ∘ C close to the bedrock, at 75 m depth. A small glacier located at 3470 m a.s.l., close to the summit of Mt Ortles, was also found in cold conditions down to a depth of 9.5 m. The mean annual ground surface temperature was negative for all but one monitored sites, indicating cold ground conditions and the existence of permafrost in nearly all debris-mantled slopes of the summit. Similarly, the mean annual rock wall temperature was negative at most monitored sites, except the lowest one at 3030 m a.s.l. This suggests that the rock faces of the summit are affected by permafrost at all exposures. [ABSTRACT FROM AUTHOR]

This paper reviews the achievements and failures in pursuing evidence‐driven and knowledge‐based transboundary water cooperation in Central Asia, with a focus on scientific cooperation under the umbrella of the Interstate Commission for Water Coordination in Central Asia. Despite its limitations, this scientific cooperation has contributed to facilitating evidence‐based dialog between the countries, to collaborative regional exchange of knowledge and expertise and to improved access to available data and information. This paper serves to show that more promising results can be achieved if joint research, fact‐finding, and planning are more widely promoted; water research is invested on a sustainable basis; knowledge between scientists, practitioners, water users, and local populations is co‐produced and shared; local capacity in science is supported and strengthened; traditional and innovative inter‐, trans‐, and multidisciplinary research is better used and developed. [ABSTRACT FROM AUTHOR]

This paper introduces the Instructed Glacier Model (IGM) – a model that simulates ice dynamics, mass balance and its coupling to predict the evolution of glaciers, icefields or ice sheets. The novelty of IGM is that it models the ice flow by a Convolutional Neural Network, which is trained from data generated with hybrid SIA + SSA or Stokes ice flow models. By doing so, the most computationally demanding model component is substituted by a cheap emulator. Once trained with representative data, we demonstrate that IGM permits to model mountain glaciers up to 1000 × faster than Stokes ones on Central Processing Units (CPU) with fidelity levels above 90% in terms of ice flow solutions leading to nearly identical transient thickness evolution. Switching to the GPU often permits additional significant speed-ups, especially when emulating Stokes dynamics or/and modelling at high spatial resolution. IGM is an open-source Python code which deals with two-dimensional (2-D) gridded input and output data. Together with a companion library of trained ice flow emulators, IGM permits user-friendly, highly efficient and mechanically state-of-the-art glacier and icefields simulations. [ABSTRACT FROM AUTHOR]

Most glaciers on the Tibetan Plateau have experienced continuous mass losses in response to global warming. However, the seasonal dynamics of glaciers on the southeastern Tibetan Plateau have rarely been reported in terms of glacier surface elevation and velocity. This paper presents a first attempt to explore the seasonal dynamics of the debris-covered Dagongba Glacier within the southeastern Tibetan Plateau. We use the multitemporal unoccupied aerial vehicle images collected over the lower ablation zone on 8 June and 17 October 2018, and 13 May 2019, and then perform an analysis concerning climatic fluctuations. The results reveal that the mean surface elevation decrease of the Dagongba Glacier during the warm season ($2.81\pm 0.44$ m) was remarkably higher than the cold season ($0.72\pm 0.45$ m). Particularly notable glacier surface elevation changes were found around supraglacial lakes and ice cliffs where ice ablation rates were $\sim$ 3 times higher than the average. In addition, a larger longitudinal decline of glacier surface velocity was observed in the warm season than that in the cold season. In terms of further comparative analysis, the Dagongba Glacier experienced a decrease in surface velocity between 1982–83 and 2018–19, with a decrease in the warm season possibly twice as large as that in the cold season. [ABSTRACT FROM AUTHOR]

Microbial biofilms have received great attention in the last few decades from both aquatic ecologists and biogeomorphologists. Most recently, this has focused on mapping biofilms to understand their spatial distributions and ecosystem services. Such studies often involve the use of satellite imagery, which typically provides large temporal and spatial scales and wide-range spectral information. Although satellites have the advantage of multi- and hyper-spectral sensors, images often have low spatial resolution that limits their use in river studies, where both rivers are narrower and stream processes occur at resolutions smaller than the footprint of satellite sensors. Spatial resolution is sensor quality dependent but also controlled by sensor elevation above the ground. Hence, high resolutions can be achieved either by using a very expensive sensor or by decreasing the distance between the target area and the sensor itself. To date, sensor technology has advanced to a point where multi- or even hyper-spectral cameras can be easily carried out by an Uncrewed Aerial Vehicle (UAV) at unprecedented spatial resolutions. Where such sensors have high spectral resolution, they are often prohibitively expensive, especially as their use in extreme environments such as glacial forefields risks UAV damage. In this paper, we test the performance of visible band ratios in mapping biofilms in an Alpine glacier forefield characterized by a well-developed and heterogeneous stream ecosystem but using a low-cost UAV. The paper shows that low-cost and consumer grade UAVs can be easily deployed in such extreme environments, delivering both quality RGB images for photogrammetric (SfM-MVS) processing and sufficient spectral information for benthic biofilm mapping at high temporal and spatial resolution. RGB cameras are an alternative to expensive multi- or hyper-spectral cameras. Phototrophic biofilms can be detected and mapped through visible band ratios. High-temporal and high-resolution imagery can be collected by consumer-grade UAVs. Biofilm presence is restricted to stable and water-fed terraces in summer. [ABSTRACT FROM AUTHOR]

From the Hindu Kush mountains to the Registan Desert, Afghanistan is a diverse landscape where droughts, floods, conflict, and economic market accessibility pose challenges for agricultural livelihoods and food security. The ability to remotely monitor environmental conditions is critical to support decision making for humanitarian assistance. The Famine Early Warning Systems Network (FEWS NET) Land Data Assimilation System (FLDAS) global and Central Asia data streams provide information on hydrologic states for routine integrated food security analysis. While developed for a specific project, these data are publicly available and useful for other applications that require hydrologic estimates of the water and energy balance. These two data streams are unique because of their suitability for routine monitoring, as well as for being a historical record for computing relative indicators of water availability. The global stream is available at ∼ 1-month latency, and monthly average outputs are on a 10 km grid from 1982–present. The second data stream, Central Asia (21–56 ∘ N, 30–100 ∘ E), at ∼ 1 d latency, provides daily average outputs on a 1 km grid from 2000–present. This paper describes the configuration of the two FLDAS data streams, background on the software modeling framework, selected meteorological inputs and parameters, and results from previous evaluation studies. We also provide additional analysis of precipitation and snow cover over Afghanistan. We conclude with an example of how these data are used in integrated food security analysis. For use in new and innovative studies that will improve understanding of this region, these data are hosted by U.S. Geological Survey data portals and the National Aeronautics and Space Administration (NASA). The Central Asia data described in this paper can be accessed via the NASA repository at 10.5067/VQ4CD3Y9YC0R (Jacob and Slinski, 2021), and the global data described in this paper can be accessed via the NASA repository at 10.5067/5NHC22T9375G (McNally, 2018). [ABSTRACT FROM AUTHOR]

Citizen science and related engagement programmes have proliferated in recent years throughout the sciences but have been reasonably limited in the cryospheric sciences. In the semiarid Andes we at the Centro de Estudios Avanzados en Zonas Áridas have developed a range of initiatives together with the wider community and stakeholder institutions to improve our understanding of the role snow and ice play in headwater catchments. In this paper we reflect on ongoing engagement with communities living and working in and near study sites of cryospheric science in northern Chile as a strategy that can both strengthen the research being done and empower local communities. [ABSTRACT FROM AUTHOR]

Mountain glaciers are crucial sources of fresh water, contributing directly and indirectly to water, energy and food supplies for hundreds of millions of people. Assessing the impact of diminishing glacial meltwater contributions to the security of this resource is critical as we seek to manage and adapt to changing freshwater dynamics in a warming world. Both water quantity and quality influence water (in)security, so understanding the fluxes of water, sediment and contaminants through glacial and proglacial systems is required for holistic assessment of meltwater contribution to downstream resource security. In this paper we consider the socio-environmental role of and pressures on glacier-fed waters, discuss key research priorities for the assessment of both the quantity and quality of meltwater and reflect on the importance of situating our understanding within a transdisciplinary and inclusive research landscape. [ABSTRACT FROM AUTHOR]

Gangotri glacier located in the Uttarkashi District of the Garhwal Himalaya, is one of the longest valley glacier. It exhibits Lateral Moraines (LM), Recessional Moraines (RM), Kame Terraces (KT) and Outwash Plains (OWP) as important landforms. The sediments coded in these landforms, provide the information about sedimentary characteristics, and the evolutionary history of the Gangotri Glacier Region (GGR). The Gangotri is a well studied glacier, however the sedimentological characteristics and evolution of many landforms are yet to be understood. Therefore, present paper aimed to explain the sedimentological characteristics and the evolutionary history of the outwash plain deposits. The OWP deposits were studied by making a trench near Bhujbas and collecting the samples from it. The granulometric analysis explain that the mean grain size of the OWP sediments varies from 0.258 φ to 2.006 φ indicate coarse to medium sand. The skewness, varies from 0.138 φ to 0.427 φ indicate dominance of fine grained sediments. The kurtosis varying from 0.839 φ to 1.067 φ explain the dominance of finer sediments. The standard deviation varies from 1.210 φ to 1.633 φ thus indicating poor sorting of the OWP deposits and fluctuation in the energy of the depositional environment. Five sedimentary facies identified are gravel sandy facies, ripple laminated silty sand facies, sandy facies, poorly sorted sandy facies and silty sand facies. The study describes that the OWP deposits are stratified, consolidated to semi-consolidated, coarse to fine grained silt, sand and gravels with primary sedimentary structures, which are evolved by glacio-fluvial environment under fluctuating energy conditions during the late Holocene period. [ABSTRACT FROM AUTHOR]

Analyzing the future changes in runoff is crucial for efficient water resources management and planning in arid regions with large river systems. This paper investigates the future runoffs of the headwaters of the Tarim River Basin under different emission scenarios by forcing the hydrological model SWAT-Glacier using six regional climate models from the Coordinated Regional Downscaling Experiment (CORDEX) project. Results indicate that compared to the period of 1976~2005, temperatures are projected to increase by 1.22 ± 0.72 °C during 2036~2065 under RCP8.5 scenarios, with a larger increment in the south Tianshan mountains and a lower increment in the north Kunlun Mountains. Precipitation is expected to increase by 3.81 ± 14.72 mm and 20.53 ± 27.65 mm during 2036–2065 and 2066–2095, respectively, under the RCP8.5 scenario. The mountainous runoffs of the four headwaters that directly recharge the mainstream of the Tarim River demonstrate an overall increasing trend in the 21st century. Under the RCP4.5 and RCP8.5 scenarios, the runoff is projected to increase by 3.2% and 3.9% (amounting to 7.84 × 108 m3 and 9.56 × 108 m3) in 2006–2035. Among them, the runoff of the Kaidu River, which is dominated by rainfall and snowmelt, is projected to present slightly decreasing trends of 3~8% under RCP4.5 and RCP8.5 scenarios. For catchments located in the north Kunlun Mountains (e.g., the Yarkant and Hotan Rivers which are mix-recharged by glacier melt, snowmelt, and rainfall), the runoff will increase significantly, especially in summer due to increased glacier melt and precipitation. Seasonally, the Kaidu River shows a forward shift in peak flow. The summer streamflow in the Yarkant and Hotan rivers is expected to increase significantly, which poses challenges in flood risk management. [ABSTRACT FROM AUTHOR]

This paper concerns a numerical stabilization method for free-surface ice flow called the free-surface stabilization algorithm (FSSA). In the current study, the FSSA is implemented into the numerical ice-flow software Elmer/Ice and tested on synthetic two-dimensional (2D) glaciers, as well as on the real-world glacier of Midtre Lovénbreen, Svalbard. For the synthetic 2D cases it is found that the FSSA method increases the largest stable time-step size at least by a factor of ten for the case of a gently sloping ice surface (3°), and by at least a factor of five for cases of moderately to steeply inclined surfaces (6° to 12°). Furthermore, the FSSA method increases the overall accuracy for all surface slopes. The largest stable time-step size is found to be smallest for the case of a low sloping surface, despite having overall smaller velocities. For Midtre Lovénbreen the FSSA method doubles the largest stable time-step size, however, the accuracy is in this case slightly lowered in the deeper parts of the glacier, while it increases near edges. The implication is that the non-FSSA method might be more accurate at predicting glacier thinning, while the FSSA method is more suitable for predicting future glacier extent. A possible application of the larger time-step sizes allowed for by the FSSA is for spin-up simulations, where relatively fast changing climate data can be incorporated on short time scales, while the slowly changing velocity field is updated over larger time scales. [ABSTRACT FROM AUTHOR]

In this paper future changes of surface water availability in Austria are investigated. We use an ensemble of downscaled and bias-corrected regional climate model simulations of the EURO-CORDEX initiative under moderate mitigation (RCP4.5) and Paris Agreement (RCP2.6) emission scenarios. The climatic water balance and its components (rainfall, snow melt, glacier melt and atmospheric evaporative demand) are used as indicators of surface water availability, and we focus on different altitudinal classes (lowland, mountainous and high alpine) to depict a variety of processes in complex terrain. Apart from analysing the mean changes of these components, we also pursue a hazard risk approach by estimating future changes in return periods of meteorological drought events of a given magnitude as observed in the reference period. The results show, in general, wetter conditions over the course of the 21st century over Austria on an annual basis compared to the reference period 1981–2010 (e.g. RCP4.5 + 107 mm, RCP2.6 + 63 mm for the period 2071–2100). Considering seasonal differences, winter and spring are getting wetter due to an increase in precipitation and a higher fraction of rainfall as a consequence of rising temperatures. In summer only little changes in the mean of the climatic water balance conditions are visible across the model ensemble (e.g. RCP4.5 ±0 mm, RCP2.6 -2 mm for the period 2071–2100). On the contrary, by analysing changes in return periods of drought events, an increasing risk of moderate and extreme drought events during summer is apparent, a signal emerging within the climate system along with increasing warming. [ABSTRACT FROM AUTHOR]

Cryospheric change occurs in unequal spaces. Societies living near ice are divided by race, class, gender, geography, politics and other factors. Consequently, impacts of ice loss are not shared equally, and everyone experiences cryospheric changes differently. Responsibility for recent ice loss is also driven by a relatively small portion of humanity: those who emit the most greenhouse gases. Additionally, people who study the cryosphere come from institutions and societies where inequality is often systemic, making research on ice and snow a symptom of and contributor to social inequality. To better understand unequal effects of cryospheric change within and across diverse communities, including research communities, this paper focuses on three areas, drawing primarily from glacier-related work: (1) the social context of cryospheric changes; (2) attribution and responsibility for cryospheric changes and (3) imbalances in knowledge about the cryosphere. Addressing these dimensions of ice loss requires transdisciplinary approaches that connect research to societies and link glaciology and other cryospheric sciences with social sciences and humanities. These concepts, cases and suggestions to help address inequalities also reveal that no singular conceptualization of sustainability exists. Different societies, residents and researchers possess distinct understandings of and goals for 'ice in a sustainable society'. [ABSTRACT FROM AUTHOR]

Climate warming has become indisputable, and it is now crucial to increase our understanding of both the mechanisms and consequences of climate change. The Antarctic region is subjected to substantial changes, the trends of which have been recognized for several decades. In the South Shetland Islands, the most visible effect of climate change is progressive deglaciation. The following review focuses on past glaciological studies conducted on King George Island (KGI). The results of collected cryosphere element observations are discussed herein in a comprehensive manner. Our analysis showed that there is a lack of temporal as well as spatial continuity for studies on the basic mass balance parameters on the entire KGI ice dome and only Bellingshausen Dome has a relatively long history of data collection. The methodologies of past work, which have improved over time, are also discussed. When studying the glacier front fluctuations, the authors most frequently use a 1956 aerial photography as reference ice coverage. This was the case for seven papers, while other sources are seldomly mentioned. In other papers as many as 41 other sources were used, and therefore comparison to photos taken up to 60 years later can give misleading trends, as small glaciers may have both advanced and retreated in that time. In the case of glacial velocities there is also an apparent lack of consistency, as different glaciers were indicated as the fastest on KGI. Only Lange, Anna, Crystal, Eldred, and eastern part of Usher glaciers were determined by more than one author as the fastest. Additionally, there are gaps in the KGI Ground Penetrating Radar (GPR) survey area, which includes three ice domes: the Warszawa Icefield, the Krakow Icefield, and eastern part of King George Island. Ideas for further work on the topic are also suggested, allowing for easier access to data and thus contributing to a better understanding of glacier development mechanisms. [ABSTRACT FROM AUTHOR]

West Antarctica is the main contributor to global sea level rise at present and in the coming decades, since it occupies 80% of mass loss in Antarctica. In this paper, a combination of Differential Interferometric Synthetic Aperture Radar (DInSAR) and offset tracking technology is used to extract the ice flow velocity of the Pine Island Glacier (PIG), a typical glacier in West Antarctica. Due to the large deformation gradients in PIG, DInSAR technology is used to extract ice flow velocity in bare rock and mountains, then offset tracking technology is used to extract ice flow velocity in areas where glaciers collapse frequently. Finally, the above two results are mosaiced into a new image of the interannual ice flow velocity of PIG in 2017. Through qualitative and quantitative evaluation, it is found that the ice flow velocity extracted by the combination has high accuracy in both high and low velocity areas. In summary, we concluded that the combination of DInSAR and Offset tracking can obtain reliable ice velocity products in glaciers that change rapidly. This combination is of scientific significance for monitoring the movement and evolution of glaciers in the West Antarctica. [ABSTRACT FROM AUTHOR]

Basal conditions directly control the glacier sliding rate and the dynamic discharge of ice. Recent glacier destabilization events indicate that some marine-terminating glaciers quickly respond to lubricated beds with increased flow speed, but the underlying physics, especially how this vulnerability relates to glacier geometry and flow characteristics, remains unclear. This paper presents a 1D physical framework for glacier dynamic vulnerability assuming sudden basal lubrication as an initial perturbation. In this new model, two quantities determine the scale and the areal extent of the subsequent thinning and acceleration after the bed is lubricated: Péclet number (Pe) and the product of glacier speed and thickness gradient (dubbed J0 in this study). To validate the model, this paper calculates Pe and J0 using multi-sourced data from 1996 to 1998 for outlet glaciers in the Greenland ice sheet and Austfonna ice cap, Svalbard, and compares the results with the glacier speed change during 1996/1998–2018. Glaciers with lower Pe and J0 are more likely to accelerate during this 20-year span than those with higher Pe and J0 , which matches the model prediction. A combined factor of ice thickness, surface slope, and initial flow speed physically determines how much and how fast glaciers respond to lubricated beds in terms of speed, elevation, and terminus change. [ABSTRACT FROM AUTHOR]

This paper reanalyses and reinterprets the GPR data set collected in 2018 on the Von Postbreen polythermal glacier, in the Tempelfjorden region of the Svalbard Islands. Different Ground Penetrating Radar (GPR) attributes were exploited as tools for the detection of peculiar patterns and inapparent glaciological facies in typical reflection amplitude data. Spectral attributes such as dominant frequency, instantaneous phase and sweetness were specifically calculated. In addition, some texture attributes like chaos and entropy were integrated with the previous ones, so as to enable the detection of a peculiar anomalous zone (AZ). This zone is non-ubiquitous, concentrated in specific areas of the glacier, where the ice is thicker and close to the main bedrock topographic highs. By means of thermal models available in the international literature, this AZ was related to local temperature variations, which are the consequence of increased heat transfer mechanisms due to peculiar stress conditions. The proposed approach can be applied to other glaciological GPR surveys on polythermal glaciers in order to obtain improved and more constrained data interpretation and thermal facies imaging. [ABSTRACT FROM AUTHOR]

The Quaternary strata on the Qinghai-Tibet Plateau contain rich information about the paleoclimate and environmental evolution, record the evolution process of the Quaternary regional tectonics, paleogeography, and geomorphology of the plateau, and are extremely important areas for studying the Quaternary geological events and regional environmental evolution. According to a comprehensive analysis of the regional stratigraphic data and the development and evolution characteristics of the biota, based on the differences in the lithostratigraphic units, sedimentary characteristics, landforms, and drainage systems, the Quaternary strata on the Qinghai-Tibet Plateau and its surrounding areas are divided into five stratigraphic regions: the Tarim region, Loess Plateau region, Qinghai-Tibet Plateau region, Yunnan-Guizhou Plateau region, and India-Ganges region. The Qinghai-Tibet Plateau stratigraphic region is divided into seven stratigraphic sub-regions: the West Kunlun-Karakorum, Altun-Qilian Mountains, Qaidam-Hehuang, East Kunlun-Bayan Har, Qiangtang, East Xizang-West Yunnan-West Sichuan, and Gangdise-Himalayan sub-regions. This paper briefly describes the lithostratigraphic units of the seven stratigraphic sub-regions of the Qinghai-Tibet Plateau. According to the lithostratigraphic sequence and its sedimentary characteristics, stratigraphic contact relationship, formation age, and evolution of the biota in each stratigraphic sub-region, the Quaternary tectonic paleogeographic evolution of the Qinghai-Tibet Plateau is divided into four stages. (1) The inherited differential uplift stage since the Pliocene (2.6−1.8/1.5 Ma): the regional sedimentary differences were significant, and the stratigraphic distribution was limited, the alluvial-proluvial sandy conglomerate was widely developed along the piedmont, and fluvial and lacustrine deposits were developed in the low-lying areas between the mountains. (2) The mountain range flattening stage (1.8/1.5−1.2/0.8 Ma): the erosion unconformity surfaces around the plateau were widely distributed, large rivers were formed, and lake sediments developed in the intermountain basins and the hinterland of the plateau. (3) 1.2/0.8−0.128 Ma: the plateau continued to rise in a large range, with significant topographic differences and intensified mountain erosion. At about 0.8 Ma, the plateau uplifted above the snow line and entered the cryosphere, mountain glaciers developed, and the alpine arid environment gradually formed. (4) 0.128 Ma-: the mountains rose and erosion intensified, and intermountain basins and lakes were widely distributed. There were significant differences in the regional sedimentary characteristics, and the sedimentary types developed toward diversification. The modern plateau landform pattern was basically formed. [ABSTRACT FROM AUTHOR]