Search

The Belvedere glacier is an intensively studied glacier in the Italian Alps on the east face of the Monte Rosa, which is currently undergoing a fast deglaciation connected to various slope failures and Glacial Lake Outburst Floods. Measurements of the terminus position have been carried out since the 1920s. Since 2000, more attention has been paid to this area due to the occurrence of large mass movements and a surge-type event. In this review, research articles and various reports dealing mainly with glacier dynamics, rock and ice avalanches, Glacial Lake Outburst Floods, and other hazardous processes were considered. Aerial photogrammetry, Unmanned Aerial Vehicles, satellite stereo-processing and several terrestrial approaches (laser scanning, geophysics, measurements of near-surface heat flow, ablation stakes and camera-lapse) provided a base for quantifying the ongoing processes. Despite efforts based on the comparison of Digital Elevation Models, this review shows that the evolution of the Belvedere glacier in terms of ice volume is still partially unknown due to the low temporal frequency of aerial surveys, technical limitations of the Unmanned Aerial Vehicles used, and the fact that most studies focus only on the lower part of the glacier. The hazardous supraglacial Effimero lake that appeared during the surge-type event has been well documented, and interventions to mitigate potential risks were put in place, but the trigger of the event and the evolution of the lake basin have not yet been clarified. Mass wasting and outburst floods are mainly documented in the grey literature. The degradation of permafrost was suggested to be the driver of rock and ice avalanches, including one of the largest ice avalanches in the Alps, which occurred in 2005. In summary, the Belvedere Glacier and the surrounding rock walls have experienced repeated slope failures, an incident of surge and several outburst floods. Despite regular monitoring, a clear picture of its behavior due to the changing climate is still unknown. This review is intended to pave the way for further integrative studies. [ABSTRACT FROM AUTHOR]

Over the recent years, there have been focused international efforts to coordinate the development and compilation of rock glacier inventories. Nevertheless, in some contexts, identifying and characterizing rock glaciers can be challenging as complex conditions and interactions, such as glacier–rock-glacier interactions, can yield landforms or landform assemblages that are beyond a straightforward interpretation and classification through ordinary visual means alone. To gain a better understanding of the spatial and temporal complexity of the ongoing processes where glacier–permafrost interactions have occurred, the characterization of the subsurface of the Gruben rock glacier and its adjacent complex contact zone with the then more extended Little Ice Age Gruben glacier is quantitatively assessed using a petrophysical joint inversion (PJI) scheme, based on electrical resistivity (ERT) and refraction seismic (RST) data. Surface dynamics are assessed using both in situ and close-range remote sensing techniques to monitor daily and seasonal displacements and to monitor landform-wide surface changes at high spatial resolution, respectively. Both the geophysical and geodetic surveys allowed two zones to be identified: the rock glacier zone and the complex contact zone where both permafrost and embedded surface ice are present. In the complex contact zone extremely high ice contents (estimated up to 85 %) were found. Widespread supersaturated permafrost conditions were found in the rock glacier zone. Surface displacement rates in this zone are typical of permafrost creep behaviour, with a gradual acceleration in late spring and a gradual deceleration in winter. Moreover, the coherent nature of the rock glacier zone surface deformation contrasts with the back-creeping and slightly chaotic surface deformation of the complex contact zone. Favouring a multi-method approach allowed a detailed representation of the spatial distribution of ground ice content and origin, which enabled us to discriminate glacial from periglacial processes as their spatio-temporal patterns of surface change and geophysical signatures are (mostly) different. [ABSTRACT FROM AUTHOR]

Runoff originating from ground ice contained in rock glaciers represents a significant water supply for lowlands. Pseudo-relict rock glaciers contain patchy permafrost but appear to be relict, and therefore they can be misinterpreted when using standard classification approaches. The permafrost content, spatial distribution and frequency of this type of rock glacier are poorly known. Therefore, identifying pseudo-relict rock glaciers that might still contain permafrost, and potentially ice, is crucial for understanding their hydrological role in a climate change context. This work analyses rock–glacier spring-water temperature in a 795 km2 catchment in the eastern Italian Alps to understand how many rock glaciers classified as relict could have spring-water temperatures comparable to active or transitional rock glaciers as possible evidence of their pseudo-relict nature. Spring-water temperature, often auxiliary to other approaches for specific sites, was used for a preliminary estimate of the permafrost presence in 50 rock glaciers classified as relict. In addition, we present electrical resistivity tomography (ERT) results on two relict rock glaciers with opposing spring-water temperature and surface characteristics to constrain spring-water temperature results at the local scale. The results show that about 50 % of the rock glaciers classified as relict might be pseudo-relict, thus potentially containing permafrost. Both supposedly relict rock glaciers investigated by geophysics contain frozen sediments. The majority of the cold springs are mainly associated with rock glaciers with blocky and scarcely vegetated surfaces, but geophysics suggest that permafrost may also exist in rock glaciers below 2000 m a.s.l., entirely covered by vegetation and with a spring-water temperature of up to 3.7 °C. We estimate that pseudo-relict rock glaciers might contain a significant portion (20 %) of all the ice stored in the rock glaciers in the study area. These results highlight the relevance of pseudo-relict rock glaciers in periglacial environments. Even if not a conclusive method, spring-water temperature analyses can be used to preliminarily distinguish between relict and pseudo-relict rock glaciers in wide regions. [ABSTRACT FROM AUTHOR]

Rock glaciers – periglacial landforms commonly found in high-mountain systems – are of significant scientific value for inferring the presence of permafrost, understanding mountain hydrology, and assessing climate impacts on high-mountain environments. However, inventories remain patchy in many alpine regions, and as a result they are poorly understood for some areas of High Mountain Asia such as the Tibetan Plateau. To address this gap, we compiled a comprehensive inventory of rock glaciers for the Tibetan Plateau, i.e., TPRoGI (v1.0), developed using an innovative deep learning method. This inventory consists of a total of 44 273 rock glaciers, covering approximately 6000 km2 , with a mean area of 0.14 km2. They are predominantly situated at elevations ranging from 4000 to 5500 m a.s.l., with a mean of 4729 m a.s.l. They tend to occur on slopes with gradients between 10 and 25°, with a mean of 17.7°. Across the plateau, rock glaciers are widespread in the northwestern and southeastern areas, with dense concentrations in the Western Pamir and Nyainqêntanglha, while they are sparsely distributed in the inner part. Our inventory serves as a benchmark dataset, which will be further maintained and updated in the future. This dataset constitutes a significant contribution towards understanding, future monitoring, and assessment of permafrost on the Tibetan Plateau in the context of climate change. The dataset is available at https://doi.org/10.5281/zenodo.10732042 (Sun et al., 2024a). [ABSTRACT FROM AUTHOR]

Intact rock glaciers (RG) are considered valuable water storage because containing permafrost ice volumes. The hydrological relevance of RG is forecasted to increase with respect to glaciers under climate change scenarios, as well as RG's role as water resources in alpine basins for multiple uses. Besides the assessment of water amount stored in intact rock glaciers, the evaluation of water quality is of primary importance. Here, we present the results of a chemical survey performed on five outflows from intact RG in 2020–2023 in the Piedmont region, Western Alps, Italy, along a latitudinal gradient and in different geological settings. The survey aimed to assess the water quality of RG outflows based on chemical indicators (major ions, nutrients, trace metals). Sampling and analyses were performed according to standard methods for freshwater samples, paying specific attention to the analytical quality and consistency of the data. We considered seasonal and interannual variability of the main chemical variables and the possible effects of RG outflows on the chemistry of lakes and ponds located in proximity to the RG. All the investigated sites were characterized by low to moderate ion content, low nutrients, and trace metals close to or below the detection limit, indicating a good water quality status. Results suggested lithology as the main factor affecting the chemical composition of RG outflows. The results of this study indicate it is advisable to develop shared protocols and joint monitoring programs for data collecting at RG outflow sites all over the Alps, possibly integrating chemical and biological indicators, with the final aim of monitoring the water quality of these valuable resources and its temporal evolution under climate change. [ABSTRACT FROM AUTHOR]

Oncostreams are self-organized structures formed by spindle-like, elongated, self-propelled cells recently described in glioblastomas and especially in gliosarcomas. Cells within these structures either move as large clusters in one main direction, flocks, or as linear, intermingling collections of cells advancing in opposite directions, streams. Round, passive cells are also observed, either inside or segregated from the oncostreams. Here we generalize a recently formulated particle-field approach to investigate the genesis and evolution of these structures, first showing that, in systems consisting only of identical self-propelled cells, both flocks and streams emerge as self-organized dynamic configurations. Flocks are the more stable configurations, while streams are transient and usually originate in collisions between flocks. Stream degradation is easier at low self-propulsion speeds. In systems consisting of both motile and passive cells, the latter block stream formation and accelerate their degradation and flock stabilization. Since the flock appears to be the most effective invasive structure, we thus argue that a phenotype mixture (motile and passive cells) may favor glioblastoma invasion. hlBy relating cellular properties to the observed outcome, our model shows that oncostreams are self-organized structures that result from the interplay between speed, shape, and steric repulsion. [ABSTRACT FROM AUTHOR]

Atmospheric blocking is characterized by persistent anticyclones that "block" the midlatitude jet stream, causing temperature and precipitation extremes. The traffic jam theory posits that blocking events occur when the Local Wave Activity flux, a measure of storm activity, exceeds the carrying capacity of the jet stream, leading to a pile up. The theory's efficacy for prediction is tested with atmospheric reanalysis by defining "exceedance events", the time and location where wave activity first exceeds flow capacity. The theory captures the Northern Hemisphere winter blocking climatology, with strong spatial correlation between exceedance and blocking events. Both events are favored not only by low carrying capacity (narrow roads), but also a downstream reduction in capacity (lane closures causing a bottleneck). The theory fails, however, to accurately predict blocking events in time. Exceedance events are not a useful predictor of an imminent block, suggesting that confounding factors explain their shared climatological structure. Plain Language Summary: An atmospheric block is a large, high pressure weather pattern that blocks the jet stream, affecting many regions in the midlatitudes including North America and Europe. Blocks are notable for their persistence, driving extreme weather conditions for up to a week or longer. Despite their significant societal impact, we don't fully understand the mechanism(s) that generate blocks. A traffic jam theory was proposed, which suggested that the onset of a block is caused by having too much "storm activity flux", which leads to a pile up of storm activity, just as a traffic jam is precipitated by conditions where the vehicular flux exceeding the road capacity, blocking traffic. This analogy is useful for understanding the preferred locations of atmospheric blocks in the time‐mean sense, but is not predictive in terms of individual blocking events. We further propose to incorporate additional regional constraints on flux capacity, analogous to "traffic bottlenecks", to improve our understanding of preferred blocking locations. Key Points: Flow capacity exceedance events, predictors of blocking onset in the traffic jam theory, are defined and evaluated in climate reanalysesA downstream reduction in flow capacity is ubiquitous for both exceedance and blocking events: lane closures favor traffic jamsBlocks are co‐located with exceedance events in space but not in time, limiting the utility of the traffic jam theory for prediction [ABSTRACT FROM AUTHOR]

Glaciers are a source of fine‐ground rock flour to proglacial and coastal marine environments. In these environments, suspended rock flour may affect light and (micro)nutrient availability to primary producers. Due to high loads of glacier rock flour, the particulate metal load of glacier runoff typically exceeds the dissolved metal load. As glacier rock flour is deposited in downstream environments, short‐term exchange between particulate and dissolved metal phases may have a moderating influence on dissolved metal concentrations. Here we compare the behavior of iron (Fe), manganese (Mn), cobalt (Co) and silica (Si) following the addition of different glacier‐derived sediments into seawater under conditions of varying sediment load (20–500 mg L−1), time (0.5 hr–21 days), temperature (4–11°C) and light exposure (dark/2,500 Lux). Despite a moderately high labile Fe content across all particle types (0.28–3.50 mg Fe g−1 of dry sediment), only 0.27–7.13 μg Fe g−1 was released into seawater, with less efficient release as sediment load increased. Conversely, Si, Mn, and Co exhibited a more constant rate of release, which was less sensitive to sediment load. Dissolved Si release was equivalent to 17% ± 22% of particulate amorphous Si after 1–2 weeks. Dissolved Mn concentrations in most incubations exceeded dissolved Fe concentrations within 1 hr despite labile Mn content being 12‐fold lower than labile Fe content. Our results show the potential for glacier‐derived particles to be a large source of Mn and Co to marine waters and add to the growing evidence that Mn may be the bio‐essential metal most affected by glacier‐associated sources. Plain Language Summary: Glacier runoff is associated with high sediment loads derived from glacier weathering. Particle surfaces can, depending on ambient conditions, act as a source or sink for dissolved metals in solution. With increasing glacier discharge and ongoing glacier retreat around the Arctic, shifts in the seasonal timing and magnitude of sediment delivery to the coastline are expected. However, the net effect of glacier‐derived particles on marine metal and nutrient availability is not clear, especially for elements other than Fe, which are less well studied. Here we used sediment‐seawater incubations with different glacier and iceberg sediment samples from Greenland and Svalbard to quantify the change in Fe, Mn, Co, and Si concentrations when particles were suspended in Atlantic seawater. Our results and a comparison with in situ concentrations reveal the significance of particle dissolution on elemental cycles, particularly for Mn. Key Points: Changing light and temperature had no effect on the net release of Fe, Mn, Co, or Si from glacier rock flour in seawaterA small fraction of labile particulate Fe was soluble in seawater, although this was partially reversible over short (<24 hr) timescalesMn and Co showed a consistent gradual dissolution behavior with Mn present at dissolved concentrations ∼8× higher than Fe within 24 hr [ABSTRACT FROM AUTHOR]

This research introduces an innovative approach by utilising rock glaciers (RGs) as a proxy for mapping debris‐covered glaciers (DCGs). This approach focuses on the interconnected nature of glaciers, DCGs and RGs in a continuum where DCGs can transform into RGs over time due to various processes. This study utilises six machine learning models—logistic regression (LR), support vector machine (SVM), K‐nearest neighbour (KNN), Naïve Bayes (NB), decision tree (DT) and random forest (RF)—combined with multispectral satellite data (Sentinel‐2 and Landsat 8) and topographical data derived from ALOS PALSAR DEM. Performance metrics such as accuracy, area under the curve (AUC) score, precision, recall and F1‐score were evaluated to assess model performance. This detailed mapping provides a precise estimation of the extent of DCGs in the Kinnaur district. The estimated DCG areas revealed intriguing variation across models, with RF (9.71%), KNN (9.67%) and NB (9.41%) yielding similar predictions. SVM (11.61%) projected a slightly larger DCG area, whereas DT (5.54%) and LR (25.55%) provided contrasting results. Validation against high‐resolution satellite images, Google Earth images and glacier inventories confirmed the accuracy and reliability of our approach. Based on our findings for our specific study, the most effective method for mapping DCGs is RF, followed by KNN, NB, DT and SVM. The combination of machine learning models and RG data presents a novel and promising approach to remote sensing‐based DCG mapping, with potential applications for other regions and broader environmental studies. [ABSTRACT FROM AUTHOR]

Rock avalanches onto glaciers are rare in Norway. Here, we examine a rock avalanche that spread onto the regenerated Brenndalsbreen, an outlet glacier from Jostedalsbreen ice cap. The rock avalanche is intriguing in that limited information exists with respect to the exact time of failure, location of detachment area, and preparatory and triggering processes. Based on an analysis of ice stratigraphy and photographic documentation, we assess that the event happened between mid-March and June 4, 2010. A potential triggering factor could have been heavy snow and rainfall combined with above freezing air temperatures on March 18–19, 2010. We use digital terrain models to determine that the detachment area is at an almost vertical rock slope in a narrow gorge above Lower Brenndalsbreen. The deposit volume is estimated to 0.130 ± 0.065 Mm3, and the H/L ratio and fahrböschung are 0.45 and 24°, respectively. We apply a Voellmy flow model to confirm the detachment location and volume estimate by producing realistic runout lengths. Although glacial debuttressing may have been a likely preparatory process, the detachment area was exposed for 45–70 years before the rock avalanche occurred. The supraglacial rock avalanche debris was separated into two branches with a distinct melt-out line across the glacier. The debris reached the glacier front in 2019 and 2020, where it started being deposited proglacially while Lower Brenndalsbreen kept receding. The 2010 Brenndalsbreen rock avalanche may not be a unique event, as deposits constituting evidence of an old rock avalanche are currently melting out at the glacier front. [ABSTRACT FROM AUTHOR]

Satellite imagery has become a major source for identifying and mapping terrestrial and planetary landforms. However, interpretating landforms and their significance, especially in changing environments, may still be questionable. Consequently, ground truth to check training models, especially in mountainous areas, can be problematic. This paper outlines a decimal format, [dLL], for latitude and longitude geolocation that can be used for model interpretation and validation and in data sets. As data have positions in space and time, [dLL] defined points, as for images, can be associated with metadata as nodes. Together with vertices, metadata nodes help build 'information surfaces' as part of the Digital Earth. This paper examines aspects of the Critical Zone and data integration via the FAIR data principles, data that are; findable, accessible, interoperable and re-usable. Mapping and making inventories of rock glacier landforms are examined in the context of their geomorphic and environmental significance and the need for geolocated ground truth. Terrestrial examination of rock glaciers shows them to be predominantly glacier-derived landforms and not indicators of permafrost. Remote-sensing technologies used to track developing rock glacier surface features show them to be climatically melting glaciers beneath rock debris covers. Distinguishing between glaciers, debris-covered glaciers and rock glaciers over time is a challenge for new remote sensing satellites and technologies and shows the necessity for a common geolocation format to report many Earth surface features. [ABSTRACT FROM AUTHOR]

Geomorphological mapping of glaciers and glacial landforms helps describe the current environment and investigate past glacial changes. Here we present the first detailed 1:80,000 glacial geomorphological map of the Vanch River basin (about 2100 km2), the western Pamirs, Tajikistan [38.6667°N, 72.0000°E]. Mapping was performed using DEM (30 m), Landsat 8 imagery (15 m), and Google Earth images (∼1 m). The resultant map provides the spatial distribution of glaciers and associated erosional and depositional landforms such as cirques, glacial valleys, rock glaciers, and moraines. Morphology of the lower section of the main valley outlines the limits of Vanch Glacier in the Middle Pleistocene. Comparison with former glacier inventories indicates that the glaciers have generally been stable, but the proportion of debris-covered areas has increased since 2007. The identified 184 intact rock glaciers represent hidden water storage, providing a new basis for estimating water resources in the basin.

Projections of sea‐level rise from ice‐sheet shrinkage in a warming world have large uncertainties, linked to limited knowledge of changes at the ocean‐ice sheet interface. This interface most typically is modeled as a grounding line, across which still‐connected ice flows into the ocean to float as an ice shelf, or where icebergs calve from a cliff before the ice begins to float. But, extensive and rapidly increasing evidence shows that this is really a grounding zone, and that processes in this grounding zone omitted from many models could exert major controls on sea‐level rise. Plain Language Summary: Marine‐terminating glaciers flow into the ocean across extensive grounding zones. These kilometers‐long and glacier‐wide zones represent the last broad region of glacier contact with the rock and sediments below before the ice enters the ocean as a floating ice shelf or calved icebergs. Loss of this basal drag along with enhanced basal melting caused by tidally driven seawater intrusion leads to faster outflow and rapid thinning of the overlying ice. As a result of the local thinning, grounding zones retreat inland and sea level rises with more loss of previously grounded ice. Most ice‐sheet models used in sea‐level projections do not include grounding‐zone processes, but rather stop their ice‐ocean interactions at a grounding line. They are thereby omitting important dynamic feedbacks and underestimating future sea‐level contributions from the marine‐based sectors of the Greenland and Antarctic ice sheets. Key Points: Tidally modulated seawater intrusion leads to loss of ice‐bed contact as well as significant (maximal) basal melting within grounding zonesThe future dynamics of marine outlet glaciers are ultimately controlled by coupled processes operating within and through grounding zonesDespite the importance of grounding zones to ice‐sheet dynamics, most ice‐sheet models used in sea‐level projections do not include them [ABSTRACT FROM AUTHOR]

Rock glaciers are crucial freshwater resources, yet detailed knowledge about their distribution, characteristics, and dynamics in the Himalayan region is scarce. This study presents a comprehensive rock glacier inventory of the Jhelum basin, Kashmir Himalaya, India, using high-resolution Google Earth data. We identified 240 rock glaciers covering an area of 41.24 ± 2.2 km2, with ~76% classified as active, ~20% inactive, and 3.7% relict. The average areas and lengths of these rock glacier types were 0.19 km2, 0.06 km2, and 0.29 km2, and 699 m, 426 m, and 952 m, respectively. Most rock glaciers (~90%) were oriented northwards (N, NE, NW), while only 5% faced southwards (S, SE, SW). The lower limit of permafrost in the Jhelum basin is about 3316 m asl. Furthermore, we estimated the ice storage of rock glaciers in the Jhelum basin at 0.80 ± 0.13 km3, equivalent to 0.72 ± 0.12 km3 of water volume. This study enhances our understanding of permafrost distribution and the characteristics and dynamics in the basin. Given their greater resilience to climate change compared to clean glaciers, the hydrological significance of rock glaciers is expected to increase under projected climate change scenarios. This study highlights their importance as a vital water resource amidst the accelerated recession of clean glaciers. [ABSTRACT FROM AUTHOR]

Rock glaciers are geomorphological features often used as a visible expression of mountain permafrost. These are creeping ice-debris with distinct ridge and furrow structures on the surface with a steep frontal slope. Rock glaciers, being the valuable past permafrost indicators, also have utmost hydrological significance in near future. Therefore, mapping of rock glaciers is an important step in order to understand permafrost regimes better. The Himalayas have large occurrences of these features and this study in Himachal Himalayas complied 789 rock glaciers, covering an area of about 336.2 km2. Different labels based on genesis, location, shape, form, surface relief and activity revealed rock glaciers were mainly derived from talus slopes (239) and exhibited tongue shape (377), primarily found in cirques (531). Most of them were classified as simple units (603) with well-developed surface relief (387), and they were found to be predominantly intact (760). The topographical parameters suggest majority of the rock glaciers are located between 4000 and 4800 m with mean elevation to be 4635 m. These rock glaciers are present at gentle to steep slope gradient (0 to 45°) with curvature ranging between −3.5 and 4.5, and majority showing convex curvature. The slope aspect conducive for formation of rock glaciers in Himachal is northerly (N, NW, NE). Principal geology for these rock glaciers belongs to slate, phyllite, quartzarenite, limestone and meta basics. The climatic parameters and indices also affect the rock glaciers occurrence significantly. The mean land surface temperature (LST) for majority rock glaciers lies between 0 and −15°C. While, the mean NDSI of all the rock glaciers varies from 0.04 to 0.68 and mean NDVI varies from −0.06 to 0.08. Overall, the inventory along with labels is a valuable database for understanding the distribution and characteristics of rock glaciers in the Himachal Himalayas. [ABSTRACT FROM AUTHOR]

The southeastern Qinghai-Xizang Plateau has significant topographical variations, active tectonic movements and developed glaciers and permafrost. A variety of geotechnical disasters occur frequently in this region. In order to study the distribution characteristics and movement patterns of geotechnical hazards in this region, the Degin section of the Lancang River was selected as the research area. Based on the data form ALOS-2 satellite of one track and Sentinel-1A satellite of three tracks, large-scale geotechnical hazards investigation in the study area were conducted using Stacking-InSAR technology, while time-series monitoring of typical debris flow source areas was carried out using DS-InSAR technology. Singular spectrum analysis (SSA) was employed to extract the periodic characteristics of deformation. The results show that there are a total of 670 deformation areas in the study area, most of which are rock glaciers located on the mountain tops of high elevations, and 27 landslides are distributed within a 5 km- distance from the Lancang River; the deformation time series of the selected typical debris flow source area from 2017 to 2022 shows a linear trend; both precipitation and temperature are correlated with the periodic deformation of the rock glacier from this source area. [ABSTRACT FROM AUTHOR]

The steep and unstable terrain found on debris-covered glaciers, rock glaciers, talus slopes, moraines and other proglacial features often make terrestrial ground-penetrating radar (GPR) surveys unsafe or cost-prohibitive. To address these challenges, this research introduces a novel approach for studying buried ice using multi-low-frequency drone-based GPR. Monostatic antennas of 50, 100, and 200 MHz were flown along a transect spanning a debris-covered glacier and an ice–debris complex at Shár Shaw Tagà (Grizzly Creek) in southwest Yukon, Canada. The drone-based results were compared to manual GPR at two locations along the transect. The two manual segments were conducted using the same radar system in a bi-static mode and included common mid-point (CMP) surveys. Overall, the drone-based radar successfully identified buried ice and enabled estimation of ice body thickness. Notably, CMP results confirmed layer characteristics and enabled depths to be measured across the entire drone-based transect. Discrimination of detail across a range of depths was made possible by comparing the three low frequencies, highlighting the possibility of using this method for future investigations of debris thickness in addition to quantifying buried ice. This study confirms the effectiveness of drone-based GPR combined with manual CMP for surveying ice beneath previously inaccessible terrain. [ABSTRACT FROM AUTHOR]

Seismic refraction tomography is a commonly used technique to characterise rock glaciers, as the boundary between unfrozen and ice-bearing layers represents a strong impedance contrast. In several rock glaciers, we observed a reversed polarity of the waves refracted by an extended ice-bearing layer compared to direct-wave arrivals. This phase change may be related to the presence of a thin low-velocity layer (LVL), such as fine- to coarse-grained sediments, above a thicker ice-rich layer. Our results are confirmed by the modelling and analysis of synthetic seismograms to demonstrate that the presence of a low-velocity layer can produce a polarity reversal on the seismic gather. [ABSTRACT FROM AUTHOR]

Estimating permafrost distribution in high‐mountain areas is challenging. In these situations, rock glaciers, provide valuable insights into permafrost distribution and are often used as proxies for identifying permafrost occurrence. Integrating various climatological and topographical conditioning factors with rock glaciers enables inferring the distribution of permafrost in these environments. This study utilized three machine learning models such as random forest (RF), support vector (SVM), and artificial neural network (ANN), and one statistical model, namely, the frequency ratio (FR), to assess the permafrost probability over the northern Kargil region of Indian Himalayas. Among 198 rock glaciers identified through high‐resolution images from Google Earth, 70% are used as training dataset, rest 30% as testing dataset. The study considered eight factors: slope, aspect, elevation, curvature, mean annual land surface temperature (MA‐LST), mean annual normalized difference snow index (MA‐NDSI), mean annual normalized difference water index (MA‐NDWI), and lithology for mapping. Furthermore, the SHapley Additive exPlanations (SHAP) test assessed the variable importance for model performance. The results revealed that the RF model performs best for permafrost probability mapping, followed by the SVM, FR, and ANN models. The study also found that 11% of the total geographic area has a high and very high probability of permafrost occurrence. [ABSTRACT FROM AUTHOR]

Glacier inventories are fundamental in understanding glacier dynamics and glacier-related environmental processes. High-resolution mapping of glacier outlines is lacking, although high-resolution satellite images have become available in recent decades. Challenges in development of glacier inventories have always included accurate delineation of boundaries of debris-covered glaciers, which is particularly true for high-resolution satellite images due to their limited spectral bands. To address this issue, we introduced an automated, high-precision method in this study for mapping debris-covered glaciers based on 1 m resolution Gaofen-2 (GF-2) imagery. By integrating GF-2 reflectance, topographic features, and land surface temperature (LST), we used an attention mechanism to improve the performance of several deep learning network models (the U-Net network, a fully convolutional neural network (FCNN), and DeepLabV3+). The trained models were then applied to map the outlines of debris-covered glaciers, at 1 m resolution, in the central Karakoram regions. The results indicated that the U-Net model enhanced with the Convolutional Block Attention Module (CBAM) outperforms other deep learning models (e.g., FCNN, DeepLabV3+, and U-Net model without CBAM) in terms of precision for supraglacial debris identification. On the testing dataset, the CBAM-enhanced U-Net model achieved notable performance metrics, with its accuracy, F1 score, mean intersection over union (MIoU), and kappa coefficient reaching 0.93, 0.74, 0.79, and 0.88. When applied at the regional scale, the model even exhibits heightened precision (accuracies = 0.94, F1 = 0.94, MIoU = 0.86, kappa = 0.91) in mapping debris-covered glaciers. The experimental glacier outlines were accurately extracted, enabling the distinction of supraglacial debris, clean ice, and other features on glaciers in central Karakoram using this trained model. The results for our method revealed differences of 0.14% for bare ice and 10.36% against the manually interpreted glacier boundary for supraglacial debris. Comparison with previous glacier inventories revealed raised precisions of 8.74% and 4.78% in extracting clean ice and with supraglacial debris, respectively. Additionally, our model demonstrates exceptionally high exclusion for bare rock outside glaciers and could reduce the influence of non-glacial snow on glacier delineation, showing substantial promise in mapping debris-covered glaciers. [ABSTRACT FROM AUTHOR]

Recent studies have demonstrated the rock glacier destabilisation and permafrost thawing induced by warming climate represent a continuous threat to life, infrastructure and socio‐economic development in the mountainous regions of the Hindu Kush Himalaya. This study presents the first systematic rock glacier inventory for the Shigar and Shayok basins, quantifying rock glacier geomorphology and kinematics based on morphological evidence using Google Earth images and interferometric synthetic aperture radar (InSAR). The certainty index of each inventoried rock glacier is recorded, along with its geomorphological properties and kinematic attributes. The rock glacier velocity is estimated through the InSAR time series analysis of Sentinel‐1 images from 2020 to 2021, with temporal baselines at 12‐day intervals. We developed a rock glacier inventory consisting of 84 rock glaciers covering an area of 29 km2 for the Shigar Basin and 2206 rock glaciers encompassing 369 km2 for the Shayok Basin. Among these rock glaciers, 69% and 52% are categorised as active rock glaciers, respectively. Rock glaciers in both catchments are confined to elevations between 3600 and 5875 m a.s.l., with a mean area of 0.22 km2. The maximum recorded velocity for active rock glaciers in the Shigar Basin is 101 ± 9 cm year−1, with a median of 27 ± 10 cm year−1, and in the Shayok Basin 114 ± 10 cm year−1 (median of 29 ± 9 cm year−1). Temporal variations in the surface velocities of the rock glaciers reveal that they increase with rising temperatures in both catchments, highlighting the seasonality in the rock glacier surface velocity. In total, we recorded the kinematic attributes of 98% of the inventoried rock glaciers in the study area. [ABSTRACT FROM AUTHOR]

A 1 millisecond (1‐ms) vision system that guarantees high efficiency and timely response for tomato defect detection is essential for factory automation. Because of various defect appearances, recently many existing researches focus on CNN based defect detection, but few of them attempt to reach high processing speed to adapt to the factorial assembly line. This paper proposes a global to multi‐scale local based parallel architecture with hardwired CNN for tomato defect detection. This architecture breaks down image‐wise detection into pixel‐wise localization and block‐wise classification. The pixel‐wise localization utilizes tomato‐aware information as constraints for localization performance. The block‐wise classification uses a fully pipelined network structure to obtain the classification result for each block as the pixel stream moves through the network. The classification network has a six‐layer lightweight network structure with quantization for hardwired type implementation on FPGA. The experiment results show that the proposed architecture processes 1000 FPS images with 0.9476 ms/frame delay. And for detection performance, this architecture keeps f1−score$f_{1}-score$ at 80.18%, only 1.31% lower than ResNet50 based detection system. [ABSTRACT FROM AUTHOR]

In the realm of smart communication systems, where the ubiquity of 5G/6G networks and IoT applications demands robust data confidentiality, the cryptographic integrity of block and stream cipher mechanisms plays a pivotal role. This paper focuses on the enhancement of cryptographic strength in these systems through an innovative approach to generating substitution boxes (S-boxes), which are integral in achieving confusion and diffusion properties in substitution–permutation networks. These properties are critical in thwarting statistical, differential, linear, and other forms of cryptanalysis, and are equally vital in pseudorandom number generation and cryptographic hashing algorithms. The paper addresses the challenge of rapidly producing random S-boxes with desired cryptographic attributes, a task notably arduous given the complexity of existing generation algorithms. We delve into the hill climbing algorithm, exploring various cost functions and their impact on computational complexity for generating S-boxes with a target nonlinearity of 104. Our contribution lies in proposing a new cost function that markedly reduces the generation complexity, bringing down the iteration count to under 50,000 for achieving the desired S-box. This advancement is particularly significant in the context of smart communication environments, where the balance between security and performance is paramount. [ABSTRACT FROM AUTHOR]

Rock fall accidents in mountainous cliff areas have significant consequences for human life and transportation. This study aimed to evaluate the rockfall hazard in the Cap Aokas cliff region located along the northeast coast of Algeria by identifying the key factors contributing to rockfall occurrence. We employed a combination of kinematic analysis, Matterocking method, and 3D trajectory simulations to determine zones that are susceptible to rockfall mobilization. By using a probabilistic and structural approach in conjunction with photogrammetry, we identified the controlling factors. The kinematic analysis revealed the presence of five discontinuity families, which indicated both plane and wedge failure modes. The 3D trajectory simulations demonstrated that the falling blocks followed the stream direction. We then validated the susceptibility maps generated from the analysis using aerial photos and historical rockfall events. The findings of this study enhance our understanding of rockfall phenomena and provide valuable insights for the development of effective strategies to mitigate rockfall hazards. [ABSTRACT FROM AUTHOR]

Mountain snowpack has been declining and more precipitation has fallen as rainfall than snowfall, particularly in the western US. Isotopic composition in stream water, springs, groundwater, and precipitation was examined to understand the impact of declining snowpack on hydrologic processes in the mid Merced River catchment (1873 km 2), Sierra Nevada, California. Mean isotopic values in small tributaries (catchment area < 122 km 2), rock glacier outflows, and groundwater from 2005 to 2008 were strongly correlated with mean catchment elevation (R2= 0.96 for δ2 H, n= 16, p < 0.001), with an average isotopic lapse rate of - 1.9 ‰ per 100 m for δ2 H and - 0.22 ‰ per 100 m for δ18 O in meteoric water. The lapse rate did not change much over the seasons and was not strongly affected by isotopic fractionation. A catchment-characteristic isotopic value, representing the catchment arithmetic mean isotopic signature in meteoric water, was thus established for each sub-catchment based on the lapse rate to elucidate hydrometeorologic and hydrologic processes such as the duration and the magnitude of snowmelt events and elevational water sources of streamflow and groundwater for ungauged catchments. Compared to Tenaya Creek without water falls, the flow and flow duration of Yosemite Creek appear to be much more sensitive to seasonal temperature increases during the baseflow period due to a strong evaporation effect caused by waterfalls, suggesting a possible prolonged dry-up period of Yosemite Falls in the future. Groundwater in Yosemite Valley (∼ 900–1200 m) was recharged primarily from the upper snow–rain transition zone (2000–2500 m), suggesting its strong vulnerability to shifts in the snow–rain ratio. The information gained from this study helps advance our understanding of hydrologic responses to climate change in snowmelt-fed river systems. [ABSTRACT FROM AUTHOR]

In dry southwestern South Tyrol, Italy, rock glaciers are dominant landforms of the high-mountain cryosphere. Their spatial distribution and degree of activity hold critical information on the current state of discontinuous permafrost and consequently on the response potential to climate warming. Traditional geomorphologic mapping, however, owing to the qualitative expert-based nature, typically displays a high degree of uncertainty and variability among operators with respect to the dynamic classification of intact (permafrost-bearing) and relict (permafrost-devoid) rock glaciers. This limits the reliability of geomorphologic rock glacier inventories for basic and applied purposes. To address this limitation, (i) we conduct a systematic evaluation of the improvements that synthetic aperture radar interferometry (InSAR) can afford to the detection and dynamic classification of rock glaciers and (ii) build an integrated inventory that combines the strengths of geomorphologic- and InSAR-based approaches. To exploit fully InSAR-based information towards a better understanding of the topo-climatic conditions that sustain creeping permafrost, we further explore how velocity and the spatial distribution of moving areas (MAs) within rock glaciers may vary as a function of simple topographic variables known to exert first-order controls on incoming solar radiation, such as elevation and aspect. Starting from a geomorphologic inventory (n=789), we characterize the kinematics of InSAR-based MAs and the relevant hosting rock glaciers on 36 Sentinel-1 interferograms in the 2018–2019 period. With respect to the original inventory, InSAR analysis allowed us to identify 14 previously undetected rock glaciers. Further, it confirmed that 246 (76 %) landforms, originally interpreted as intact, do exhibit detectable movement (i.e., ≥1 cm yr -1) and that 270 (60 %) of the relict labeled counterparts do not, whereas 144 (18 %) were kinematically undefined due to decorrelation. Most importantly, InSAR proved critical for reclassifying 121 (15 %) rock glaciers, clarifying that 41 (13 %) of those interpreted as being intact do not exhibit detectable movement and that 80 (17 %) of the original relict ones do move. Reclassification (i) allowed us to identify a cluster of intact rock glaciers below 2000 m a.s.l. associated with positive mean annual air temperature (MAAT), and (ii) by increasing the altitudinal overlap between intact and relict rock glaciers, it depicts a broad transition belt in the aspect–elevation space, which varies from 50 m on west-facing slopes to 500 m on easterly ones. This finding deteriorates the significance of elevation and aspect as topographic proxies for modeling permafrost occurrence and highlights the importance of using InSAR to inform such models. From a process-oriented standpoint, InSAR information proves fundamental for imaging how this altitudinal transition manifests through changing rates and styles of rock glacier surface deformation. Specifically, we find that, as rock glaciers move faster, an increasingly larger proportion of their surface becomes kinematically involved (i.e., percent MA cover) and that this proportion increases with elevation up to 2600–2800 m, beyond which an inflection occurs and consistent average values are attained. Considering that the inflection falls between the -1 and -2 °C MAAT – the lower boundary for discontinuous permafrost – and is independent of slope gradient, we conclude that this altitudinal pattern represents a geomorphic signature: the dynamic expression of increasing permafrost distribution, from sporadic to discontinuous. [ABSTRACT FROM AUTHOR]

Similarities and differences between the features related to the productivity of onshore and offshore wind energy are developed with the aid of information theory techniques complemented by normal statistics. The data comes from the 13‐year period between 2010 and 2022 for the registered turbines in Germany (practically all). The information content of the generated power is dynamically measured by the mutability of the files storing the information. Monthly statistics show that in spite of the Summer months being relatively unproductive, the corresponding mutability shows the possibility of making use of short periods of intermediate productivity in the case of offshore plants. Favorable conditions for wind energy generation in Wintertime are reached for both onshore and offshore production, although the latter is favored. More homogeneity and stability in the data are still necessary to generalize algorithms, protocols, and criteria. This general study shows the success of the information theory techniques in describing wind ramps. Applications to specific zones could improve the efficiency and capacity factor of particular wind turbines depending on their exposure to wind streams or the blocking of nearby mountains and forestry. The information theory techniques presented here allow for a different and novel viewpoint to detect favorable and unfavorable wind energy periods. [ABSTRACT FROM AUTHOR]

Vertical deformation associated with the displacement of rock glaciers in the upper Mapocho river basin, in the central Andes of Chile, was monitored using a series of PAZ radar satellite images and the DInSAR technique. Forty-one PAZ images of ascending and descending orbit were processed with the Small Baseline Subset (SBAS) technique. Regarding the obtained results, it was estimated that the vertical displacement velocity of rock glaciers between October 9, 2019 and April 22, 2021 reached up to -22 mm/year and the movement in the W-E direction ranged from -47 to 38 mm/year. This remote sensing technique is a useful tool to measure the surface displacement of rock glaciers, compared to conventional techniques such as GNSS point measurements, especially in the semi-arid Andes, which is one of the most important reservoirs of these geoforms worldwide. [ABSTRACT FROM AUTHOR]

In the Central Eastern Alps, an increasing number of high-altitude streams display high concentrations of toxic solutes such as Al, F-, Mn, and Ni that may strongly exceed drinking water limits. Previous studies have shown that these elements are mobilized from rock glaciers occurring at the origin of the streams. This is caused by the weathering of pyrite producing sulfuric acid and therefore promoting the leaching of these elements from the crystalline host rocks. After mobilization, the elements are temporally stored and enriched in the rock glacier ice. Today, the climate-change-induced accelerated melting of rock glaciers thus leads to a quick and focused export in summer when ice melt export rates are high. The temporal storage of mobilized elements in the rock glacier ice opens up the opportunity to use the strong chemical signal in the streams to track rock glacier melt dynamics and to identify the governing processes controlling the export of ice melt. To test this and to assess the consequences of accelerated rock glacier melt on streamwater quality, here we present a two-year dataset (2021, 2022) of monitoring a high-alpine stream originating from an intact rock glacier located in Eastern Switzerland. The monitoring includes monthly sampling and discharge measurements at the rock glacier outlet, as well as continuous tracking of the geogenic fluxes of toxic solutes using a pressure and conductivity probe. Our monitoring revealed high annual fluxes with strong seasonal variation, whereby the fluxes were highest during the warm summer months. In 2021, the annual fluxes were up to several tons each, which is remarkable given that the area of the rock glacier covers only about 40'000 m2. Interestingly, in 2022 the fluxes were about 30 % lower despite the record-high summer temperatures. A similar difference was observed for the annual discharge recorded for the two years. This suggests that the export of both ice melt and toxic solutes are strongly controlled by the amount of water from snowmelt and precipitation infiltrating into the rock glacier system. The dry weather and low discharge rates in 2022 thus likely lead to lower export rates compared to 2021, when snow height and precipitation rates were above average. Nevertheless, in both monitoring years the degradation of the rock glacier significantly contributed to the discharge of the downhill stream. Based on these aspects, we present conceptual models for accumulation of toxic solutes in rock glacier ice well as for their water driven mobilization during accelerated rock glacier degradation. Finally, we argue that monitoring solute fluxes exported from rock glaciers is a promising future research direction for obtaining more reliable estimates of the amount of ice melt exported from rock glaciers. [ABSTRACT FROM AUTHOR]

Although rock glaciers (RGs) are prevalent in the southwestern Pamirs, systematic studies on them are scarce. This article introduces the first inventory of RGs in the southwestern Pamirs, situated at the western edge of the High Mountain Asia region. The inventory, established through a combination of Google Earth optical imagery and Interferometric Synthetic Aperture Radar (InSAR) techniques, encompasses details on the locations, geomorphological parameters, and kinematic attributes of RGs. A total of 275 RGs were cataloged in an area of 55.52 km2 from 3620 to 5210 m in altitude. Our inventory shows that most RGs in this region are talus-connected (213 landforms), with the highest frequency facing northeast (23%). The distribution of RGs thins from west to east and is more abundant in higher altitudes. The Shakhdara range to the south hosts a denser and more active population of RGs than the Shughnon range to the north, highlighting the influence of topography and precipitation. Overall, RGs in the southwestern Pamirs exhibit high activity levels, with active RGs predominating (58%). A comparison between active and transitional RGs showed no significant differences in elevation, temperature, and slope. Glacier-connected and glacier forefield-connected RGs demonstrated higher line-of-sight (LOS) velocities than talus-connected and debris-mantled slope-connected RGs, underscoring the significant impact of precipitation and meltwater on their activity. [ABSTRACT FROM AUTHOR]

We estimate the surface energy balance (SEB) of the Murtèl rock glacier, a seasonally snow-covered permafrost landform with a ventilated coarse blocky active layer (AL) located in the eastern Swiss Alps. We focus on the parameterisation of the turbulent heat fluxes. Seasonally contrasting atmospheric conditions occur in the Murtèl cirque, with downslope katabatic jets in winter and a strongly unstable atmosphere over the heated blocky surface in summer. We use a novel comprehensive sensor array both above the ground surface and in the coarse blocky AL to track the rapid coupling by convective heat and moisture fluxes between the atmosphere, the snow cover, and the AL for the time period September 2020–September 2022. The in situ sensor array includes a sonic anemometer for eddy-covariance flux above-ground and sub-surface long-wave radiation measurements in a natural cavity between the AL blocks. During the thaw seasons, the measurements suggest an efficient (∼ 90 %) export of the available net radiation by sensible and latent turbulent fluxes, thereby strongly limiting the heat available for melting ground ice. Turbulent export of heat and moisture drawn from the permeable AL contributes to the well-known insulating effect of the coarse blocky AL and partly explains the climate resiliency of rock glaciers. This self-cooling capacity is counteracted by an early snow melt-out date, exposing the low-albedo blocky surface to the intense June–July insolation and causing reduced evaporative cooling due to exacerbated moisture scarcity in the near-surface AL during dry spells. With climate change, earlier snowmelt and increased frequency, duration, and intensity of heat waves and droughts are projected. Regarding the parameterisation of the turbulent fluxes, we estimated the year-round turbulent fluxes using a modified scheme. The monthly SEB is closed within 20 Wm-2 except during the snowmelt months and under katabatic drainage winds in winter. Detected sensible turbulent fluxes from nocturnal ventilation processes, although a potentially important ground cooling mechanism, are within our 20 Wm-2 uncertainty because nighttime wind speeds are low. Wintertime katabatic wind speeds needed to be scaled to close the SEB, which hints at the limits of parameterisations based on the Monin–Obukhov similarity theory in complex mountain terrain and katabatic drainage winds. The present work contributes to the process understanding of the SEB and climate sensitivity of coarse blocky landforms. [ABSTRACT FROM AUTHOR]

Viscous-flow features in perennially frozen talus/debris called rock glaciers are being systematically inventoried as part of the global climate-related monitoring of mountain permafrost. In order to avoid duplication and confusion, guidelines were developed by the International Permafrost Association to discriminate between the permafrost-related landform "rock glacier" and the glacier-related landform "debris-covered glacier". In two regions covered by detailed field measurements, the corresponding data- and physics-based concepts are tested and shown to be adequate. Key physical aspects which cause the striking morphological and dynamic differences between the two phenomena/landforms concern the following: tight mechanical coupling of the surface material to the frozen rock–ice mixture in the case of rock glaciers, contrasting with essential non-coupling of debris to the glaciers they cover; talus-type advancing fronts of rock glaciers exposing fresh debris material from inside the moving frozen bodies, as opposed to massive surface ice exposed by increasingly rare advancing fronts of debris-covered glaciers; and increasing creep rates and continued advance of rock glaciers as convex landforms with structured surfaces versus predominant slowing down and disintegration of debris-covered glaciers as often concave landforms with primarily chaotic surface structure. Where debris-covered surface ice is or has recently been in contact with thermally controlled subsurface ice in permafrost, complex conditions and interactions can develop morphologies beyond simple either–or-type landform classification. In such cases, the remains of buried surface ice mostly tend to be smaller than the lower size limit of "glaciers" as the term is applied in glacier inventories and to be far thinner than the permafrost in which they are embedded. [ABSTRACT FROM AUTHOR]

We extend a numerical modeling approach developed to explicitly model convective heat transfer in periglacial landforms to represent the ground thermal regime of low‐altitude talus slopes. Our model solves for heat conduction and accounts explicitly for air convection adopting a Darcy term with a Boussinesq approximation for air circulation in the porous ground. Numerical model experiments for the low‐altitude talus slope Dreveneuse, Switzerland, confirm that air convection is the key to forming and maintaining ground ice. In the model, the porous talus slope is underlain by a layer of water‐bearing morainic material. In years, where the gradient between air and talus temperature is sufficiently large to result in increased convection and therefore cooling, ground ice forms due to air convection within the porous material and lasts for more than a year. It is only by considering convection that the model is able to represent the occurrences of ground ice, in accordance with temperature observations on‐site. These findings are important, as they confirm that ground ice can be formed and maintained in landforms with a mean annual air temperature > 0°C if ground air convection is present combined with the presence of water. [ABSTRACT FROM AUTHOR]

This note suggests that decimal latitude/longitude [dLL] locations should be used to identify features of interest, landforms, sample and investigations sites, in an 'information landscape' provided by the geomorphological literature. All the information associated with a labelled, or tagged, geolocation should be available for examination as part of information landscapes that can be explored and represented in books, papers and other publications. This note also outlines the 'open' and FAIR data that are findable, accessible, interoperable and reusable and how the principles can be used to better explain landscapes, especially in the mountain landscape domain. Tors and rock glaciers illustrate [dLL] geolocation to identify sites and inform fieldwork and literature searching. Any [dLL]‐specified location is an identifying label, as are names given to landforms and toponyms. Two letters (digraph) are used as landform labels: TO for tors and RG for rock glaciers. Citations, (author–date–title–source) attributions, are also labels. The note shows how these attributions can be linked to [dLL] geolocations specifying locations in time and space and in the literature. The addition of [dLL] will facilitate future literature searches and modelling to explore 'unknowns' in the landscape, and this paper suggests ways in which this can be achieved, including geoheritage and geotourism. [ABSTRACT FROM AUTHOR]

Rock glaciers are common in alpine landscapes, but their evolution over time and their significance as agents of debris transport are not well-understood. Here, we assess the movement of an icecemented rock glacier over a range of timescales using GPS surveying, satellite-based radar, and cosmogenic 10Be surface-exposure dating. GPS and InSAR measurements indicate that the rock glacier moved at an average rate of ~10 cm yr 1 in recent years. Sampled boulders on the rock glacier have cosmogenic surface-exposure ages from 1.2 to 10 ka, indicating that they have been exposed since the beginning of the Holocene. Exposure ages increase linearly with distance downslope, suggesting a slower long-term mean surface velocity of 3 ± 0.3 cm yr 1. Our findings suggest that the behavior of this rock glacier may be dominated by episodes of dormancy punctuated by intervals of relatively rapid movement over both short and long timescales. Our findings also show that the volume of the rock glacier corresponds to ~10 m of material stripped from the headwall during the Holocene. These are the first cosmogenic surface-exposure ages to constrain movement of a North American rock glacier, and together with the GPS and satellite radar measurements, they reveal that rock glaciers are effective geomorphic agents with dynamic multi-millennial histories. Plain Language Summary Rock glaciers are slowly moving mixtures of ice and rock debris found in many cold mountain environments. Although they are common, questions remain about their rates of movement, age, and effectiveness in shaping mountain landscapes. We studied a typical rock glacier in the Uinta Mountains of Utah (USA), demonstrating that it formed about 10,000 years ago and is currently moving at a rate of about 10 cm per year. This is about 3 times faster than the long-term average calculated from the age and length of the rock glacier, meaning that it is now moving faster than usual. We were also able to estimate that this rock glacier is transporting a volume of debris equivalent to about 10 m of erosion from the cirque headwall above it, confirming that rock glaciers, although slow moving, are important agents of erosion. [ABSTRACT FROM AUTHOR]

Copyright of Advances in Earth Science (1001-8166) is the property of Advances in Earth Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We estimate the sub-surface energy budget and heat fluxes in the coarse-blocky active layer (AL) of the Murtεave;l rock glacier, a seasonally snow-covered permafrost landform located in the eastern Swiss Alps. In the highly permeable AL, conductive/diffusive heat transfer including thermal radiation, non-conductive heat transfer by air circulation (convection), and heat storage changes from seasonal accretion and melting of ground ice shape the ground thermal regime. We quantify individual heat fluxes based on a novel in-situ sensor array in the AL and direct observations of the ground ice melt in the years 2020–2022. Two thaw-season mechanisms render Murtεave;l rock glacier comparatively climate-resilient. First, the AL intercepts ~70 % (55–85 MJ m−2) of the thaw-season ground heat flux by melting ground ice that runs off as meltwater, ~20 % (10–20 MJ m−2) is spent on heating the blocks, and only ~10 % (7–13 MJ m−2) is transferred into the permafrost body beneath and causes slow permafrost degradation. Second, the effective thermal conductivity in the ventilated AL increases from 1.2 W m−1 K−1 under strongly stable temperature gradients to episodically over 10 W m−1 K−1 under unstable temperature gradients, favouring convective cooling by buoyancy-driven Rayleigh ventilation (thermal semiconductor effect). In winter, radiatively cooled air infiltrating through a discontinuous, semi-closed snowcover leads to strong AL cooling. The two characteristic parameters (effective thermal conductivity and intrinsic permeability) are sensitive to debris texture, hence these convective undercooling processes are specific to highly permeable coarse-blocky material. [ABSTRACT FROM AUTHOR]

In the Andes, mountains, rocks, and stones (all conceptually related) are powerful entities that engage with human beings in different ways. Among other qualities, they take human shape, accomplish great deeds, heal, protect fields, or increase fertility. One aspect that has not been explored much is how stones can also work to reestablish a positive relationship between humans and superior forces. This article examines this capacity in the context of the largest Peruvian pilgrimage (also the highest in the world), the pilgrimage to the sanctuary of the Taytacha Qoyllurit'i (dear father of the shiny snow) located in Cuzco, Peru. This analysis takes place in relation to the central concept underlying the pilgrimage, that of pampachay, which literally means "flattening the ground." While the whole pilgrimage is a way to maintain a reciprocal relationship with the Taytacha Qoyllur Rit'i (an image of Christ crucified on a rock at the bottom of a glacier), the traditional on-foot travel has specific key rituals that must take place along the way to reestablish this reciprocity. Pilgrims need to carry stones uphill and put them in designated places where they will leave them for good. By doing so pilgrims leave behind the part of themselves that might have disturbed the reciprocal relationship with the Taytacha. Resumen: En los Andes, montañas, rocas y piedras (todas conceptualmente relacionadas) son entidades poderosas que interactúan con los seres humanos de diversas maneras. Entre otras cualidades toman forma humana, logran grandes hazañas, curan, protegen los campos o aumentan la fertilidad. Un aspecto que no ha sido muy explorado es cómo las piedras son también un medio para restablecer una relación positiva entre los seres humanos y las fuerzas superiores. Este artículo examina dicha capacidad en el contexto de la peregrinación más grande del Perú (y la más alta del mundo), la peregrinación al santuario del Taytacha Qoyllurit'i (querido padre de la nieve resplandeciente) en Cuzco, Perú. Este análisis se realizará en relación con el concepto central que está detrás de esta peregrinación que es el de pampachay, que literalmente significa "aplanar o nivelar el terreno." Mientras que toda la peregrinación se puede ver como una forma de mantener una relación recíproca con el Taytacha Qoyllurit'i (una imagen de Cristo crucificado en una roca), en la caminata tradicional a pie hay rituales específicos que los peregrinos deben realizar a lo largo del camino para restablecer esa reciprocidad. Los peregrinos necesitan cargar piedras a la espalda en subidas empinadas y colocarlas en lugares designados para dejarlas allí permanentemente. Al hacer esto los peregrinos dejan la parte de ellos que puede haber dañado la relación recíproca con el Taytacha. [ABSTRACT FROM AUTHOR]

The disruption of a star by the tidal forces of a spinning black hole causes the stellar stream to precess, affecting the conditions for triggering the tidal disruption event (TDE). In this work, we study the effect that precession imprints on TDE light curves due to the interaction of the TDE wind and luminosity with the stream wrapped around the black hole. We perform two-dimensional radiation-hydrodynamic simulations using the moving-mesh hydrodynamic code jet with its radiation treatment module. We study the impact of black hole mass, accretion efficiency, and inclination between the orbital and spin planes. From our results, we identified two behaviours: (i) models with low-mass black holes (M h ∼ 106 M⊙), low inclination (i ∼ 0), and low accretion efficiency (η ∼ 0.01) show light curves with a short early peak caused by the interaction of the wind with the inner edge of the stream. The line of sight has little effect on the light curve, since the stream covers a small fraction of the solid angle due to the precession occurring in the orbital plane; and (ii) models with high-mass black holes (M h ≳ 107 M⊙), high inclination (i ∼ 90°), and high accretion efficiency (η ∼ 0.1) produce light curves with luminosity peaks that can be delayed by up to 50–100 d depending on the line of sight due to presence of the precessed stream blocking the radiation in the early phase of the event. Our results show that black hole spin and misalignment do not imprint recognizable features on the light curves but rather can add complications to their analysis. [ABSTRACT FROM AUTHOR]

While glacial remnants in the form of viscous flow features in the mid-latitudes of Mars are considered to be cold-based in the present-day, an increasing amount of geomorphic evidence suggests that at least some flow features were previously wet-based or had a mixed thermal state (polythermal) at during their evolution. Many of the viscous flow features known as glacier-like forms have been observed to emerge from alcoves that appear similar to cirques on Earth. Terrestrial cirques are typically characterized by a concave basin connected to a steep backwall. Cirques are expected to form from depressions in mountainsides that fill with snow/ice and over time support active glaciers that deepen the depressions by wet-based glacial erosion. To assess which alcoves on Mars are most "cirque-like", we mapped a population of ~2000 alcoves in Deuteronilus Mensae, a region in the mid-latitudes of Mars characterized by mesas encompassed by glacial remnants. Based on visual characteristics and morphometrics, we refined our dataset to 386 "cirque-like alcoves", which is five times the amount of glacier-like forms in the region, and used this to assess the past extent and style of glaciation on Mars. Using high resolution imagery, we find geomorphic evidence for glacial occupation associated with the cirque-like alcoves, including crevasse-like features, surface lineations, polygonal terrain, and moraine-like ridges. We propose that the cirque-like alcoves with icy remnants similar to rock glaciers on Earth represent a late stage of glacier-like form evolution. We also outline stages of cirque-like alcove evolution, linking a potential early stage of cirque-like alcoves to gully activity. On a population-wide scale, the cirque-like alcoves have a south to southeastward aspect bias, which may indicate a requirement for increased insolation for melting to occur and a connection to gullies on Mars. While the alcoves also have similarities to other features such as landslide scarps and amphitheater-headed valleys, the cirque-like alcoves have unique morphologies and morphometrics that differentiate their origin. Assuming warm-based erosion rates, the cirque-like alcoves have timescales consistent with both glacier-like forms and other viscous flow features like lobate debris aprons, whereas cold-based erosion rates would only allow the older timescales of lobate debris aprons. We propose that based on the geomorphic features and southward aspect, cirque-like alcove formation is more consistent with warm-based glaciation. [ABSTRACT FROM AUTHOR]

The prevalent climate warming across the mountain regions worldwide has exacerbated the snow melt, glacier recession and permafrost thawing that is impacting the hydrological cycle. The rock glaciers, a manifestation of ice-rich permafrost, could be regionally important for sustaining the streamflow, especially in the lean season in the Himalaya. Several rock glacier inventories have been developed for high-mountain areas worldwide. However, there are sporadic studies that have characterized rock glaciers in the Himalaya. In this study, a comprehensive rock glacier inventory has been generated for the western Himalayan regions of Jammu-Kashmir and trans-Himalayan Ladakh spread over six mountain ranges utilizing optical satellite images from Google Earth and Sentinel 2A. The inventory has characterized each rock glacier with 22 attributes following the guidelines of the International Permafrost Association (IPA). The inventory contains 5492 rock glaciers (4973 intact and 519 relict) with a total area of 573 km² and an average area of 0.1 km². The highest number of rock glaciers (n=1772) were found in the Zanskar range and the lowest (n=311) were found in the Pir Panjal range. The majority of rock glaciers (~83%) have a talus origin, and the remaining ~17% have a glacier origin. The inventory reports 4756 tongue-shaped and 736 lobate rock glaciers. The average Potential Incoming Solar Radiation (PISR) was observed to be 511 (kWH m-2). The rock glaciers are located between the elevation range of 3301 m asl and 5605 m asl with 63% of these having a north- or northeastor northwest-facing aspect. The Mean Annual Air Temperature (MAAT) and precipitation of the rock glaciers range from -8 °C to 8 °C (mean -4°C) and 71 mm to 1135 mm (mean 328 mm), respectively. The rock glacier inventory provides direct evidence of the presence of permafrost in this ecologically sensitive region and provides a lower bound on the elevation of the permafrost. This inventory shall serve as a baseline for the future hydrological impacts of permafrost and its response to regional climate change. The rock glacier inventory is publicly available at https://doi.org/10.5281/zenodo.10559297 (Bhat et al., 2024). [ABSTRACT FROM AUTHOR]