Orals: Mon, 28 Apr | Room 1.31/32
Permafrost is classified as an essential climatic variable (ECV) by the Global Climate Observing System (GCOS) because of its sensitivity to changes in climatic conditions. The Swiss Permafrost Monitoring Network PERMOS documents the state and changes of permafrost conditions in the Swiss Alps since 2000 based on long-term field measurements. To account for the heterogeneous distribution and characteristics of mountain permafrost, PERMOS developed and implemented a comprehensive monitoring strategy, which relies on three complementary observation elements: (1) direct observation of ground temperatures, (2) permafrost electrical resistivity to determine changes in ground ice content, and (3) rock glacier velocities, which are considered a proxy to assess the permafrost thermal regime.
In this contribution, we discuss permafrost conditions in the Swiss Alps during the hydrological year 2024 with respect to the observations of the past 25 years. Striking changes in permafrost conditions were recorded for all three observation elements. Most recently, the hydrological year 2024 was characterized by the warmest winter on record since 1864 and by an early onset of the snow cover in autumn 2023 following a hot summer. These atmospheric conditions led to the warmest permafrost conditions since the start of the measurements revealed by all observation elements.
How to cite: Pellet, C. and Noetzli, J. and the PERMOS Scientific Commitee: 25 years permafrost monitoring in the Swiss Alps, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17443, https://doi.org/10.5194/egusphere-egu25-17443, 2025.
In high mountain environments, permafrost in steep slopes has been increasingly studied since the 2000s, driven by the increase of rock slope failure caused by permafrost degradation. In the European Alps, estimating permafrost distribution is a first step in understanding its current state and evolution, evaluating associated hazards, and investigating its impact on infrastructure. The only existing model to map permafrost in steep rock slope has been published in 2012 and is based on a limited number of data mostly collected in the Northern European Alps. However, over the past decade, numerous temperature loggers have been installed in the French Alps, over a latitudinal range for 46° to 44° and the collected data allow to fit a new statistical model to map permafrost in the steep rock wall of the French Alps. This study presents an updated statistical model of permafrost distribution in the steep rock slopes of the French Alps.
To achieve this, we first measured ground surface temperature from 80 temperature sensors installed on steep slope or rockwalls over 22 study sites in the French Alps that provide 176 multi-year temperature points are used to fit a multiple linear regression model explaining the mean annual rock surface temperature (MARST) with the potential incoming solar radiation (PISR) and mean annual air temperature (MAAT). PISR is calculated with GIS tools with a 10 m resolution DEM while the MAAT is interpolated from the reanalysis climate data from the S2M-SAFRAN model of Météo France. The model is then implemented with the MAAT of the 1991-2020 period to map the MARST that is then used to calculated permafrost probability (i.e., the probability of the MARST to be < 0°C). We then analyse the spatial distribution of permafrost over the French Alps and compare it to the previous permafrost map.
This map is an important baseline for any permafrost investigation and hazard assessment from alpine rockwalls in the French Alps.
How to cite: Cathala, M., Magnin, F., Monzie, N., Ravanel, L., and Malet, E.: Statistical modelling of permafrost distribution in steep rock slope, application to the French Alps, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16337, https://doi.org/10.5194/egusphere-egu25-16337, 2025.
Tracking the movement of saline tracers by time-lapse electrical resistivity tomography (ERT) has been established as a suitable method in hydrogeological investigations. In our study, we test the potential of the method to illuminate discontinuities (i.e., joints, fractures and clefts) in bedrock permafrost. Identification of such features is key as they represent preferential flow paths for water and advective heat exchange between the atmosphere and the subsurface (i.e., the permafrost body). Recent studies have suggested that clefts and fractures might lead to the large heterogeneity in subsurface temperature and ice content observed at the Cime Bianche plateau (Aosta valley, Italy), a mountain permafrost monitoring area at 3100 m a.s.l. undergoing permafrost degradation. In this study, we injected saltwater into eight locations at the Cime Bianche site and monitored changes in the subsurface electrical conductivity by time-lapse ERT to investigate the presence and geometry of water flow paths of the saline solution. ERT data were collected with the Syscal Terra (from Iris Instruments) within a 3D electrode grid array with a temporal resolution of 3–7 minutes. To resolve temporal changes in the electrical conductivity in the subsurface we inverted the data with a time-lapse difference approach using the R3t code in the ResIPy wrapper. In three of the eight injection points the water infiltrated quickly into the subsurface (within a few seconds) and, based on the time-lapse ERT results, moved into depths of up to 10 m, suggesting the presence of fractures. In the other five positions, the water infiltrated slowly into the subsurface (within a couple of hours) leading to only small changes in the electrical conductivity close to the injection point. While our study demonstrates the potential of time-lapse ERT to localize clefts and fractures in bedrock permafrost, the results demonstrate the need for stochastic inversion strategies to resolve thin and sharp objects more accurately. Knowing the geometry and location of such features is essential in thermal modeling and further understanding of the permafrost degradation processes at the site.
How to cite: Moser, C., Roser, N., Gluzinski, T., Morra di Cella, U., Hauck, C., and Flores Orozco, A.: Illuminating discontinuities in alpine bedrock permafrost by saline tracer tests coupled with 3D time-lapse electrical resistivity tomography, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13436, https://doi.org/10.5194/egusphere-egu25-13436, 2025.
Alpine permafrost is warming globally and has been extensively studied through electrical resistivity monitoring and borehole temperature measurements. However, permafrost degradation is often primarily attributed to rising air temperatures and related conductive heat fluxes in the ground, while the crucial role of water flow on the thermal and mechanical regime of rockwalls is frequently oversimplified or overlooked. To address this research gap and improve the knowledgeof how bedrock permafrost will respond to climate change, year-round observations of hydrothermal processes are essential, despite the challenges posed by such extreme environments.
Here, we present results from daily repeated electrical resistivity tomography (ERT) and piezometric pressure measurements conducted in 2024 in the permafrost-affected north flank of the Kitzsteinhorn (Hohe Tauern range, Austria). Ground temperature time series from four deep boreholes indicate a maximum permafrost active layer thickness of 4.3 m, with evidence of non-conductive heat fluxes reflected in abrupt temperature anomalies and long-term regime changes between 2016-2019 and 2020-2024. A distinct reduction in electrical resistivity values at the end of May coincides with the onset of snowmelt recorded at a nearby weather station. Persistently low electrical resistivity values (<4 kΩm) throughout the summer suggest water-saturated conditions in the active layer. This hypothesis is additionally supported by piezometric measurements, which show water heads of up to 11.8 m, suggesting pressurised water injection into a widespread fracture network. In mid-September, rising electrical resistivity values in the upper layers coincide with the onset of the freezing season, with partial freezing of cleft water. Furthermore, we compared temperature-resistivity relations derived from laboratory experiments on rock samples from the study site with field observations.
Our study shows that high-frequency electrical resistivity monitoring can effectively detect seasonal periods of enhanced water flow, playing a critical role in the warming process of bedrock permafrost and increasing hydrostatic pressure on rock faces – both key factors contributing to slope instability and failure.
How to cite: Offer, M., Weber, S., Hartmeyer, I., Keuschnig, M., Rau, M., and Krautblatter, M.: From ice-filled fractures to pressurised water flow in permafrost bedrock: seasonal changes in rockwall hydrology, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15585, https://doi.org/10.5194/egusphere-egu25-15585, 2025.
In recent decades, widespread impacts of permafrost degradation and glacier recession on rock instability have been well-documented in the Alps and other mountain regions worldwide. While these changes have largely been attributed to shifts in resisting forces – such as the stability of rock, ice, and rock-ice interfaces – changes in stress regimes have received less attention, primarily due to the significant challenges in measuring and recording them.
In this contribution we study seasonal and multiannual changes in the stress regime of a warming permafrost rock slope based on a unique five-year dataset (2016-2020) of loads measured at the heads of three grouted anchors at the Kitzsteinhorn, Central Alps, Austria. The studied steel anchors (total length 25 m) are located in a recently deglaciated rock-face below a high-alpine cable car station and are interpreted as extensometers which register stress changes in the surrounding rock mass. Variations in recorded load are interpreted as proxies for deformation along the 18-meter free anchor length, offering valuable insights into the deep subsurface. In this zone, the effects of climate warming are often more discernible due to the reduced influence of strongly fluctuating atmospheric conditions.
In the five-year observation period loads ranged from 350-600 kN at the three studied anchors. A strong seasonal variation of 40-125 kN was observed (high winter loads, low summer loads), which translates to strains of 1.3 to 4.1 mm. Seasonal load increases were found to correlate strongly with negative thermal gradients in the subsurface, which drive cryosuction and ice segregation. Autumn and winter load increases are thus likely associated with the seasonal formation of segregated ice in the active layer, while the summertime load decreases are attributed to the seasonal melt of ground ice.
Small variations of the maximum thickness of the permafrost active layer – measured in a 20 m deep borehole situated just a few meters from the rock anchors – seem to have a critical effect on the observed loads, pointing to ice melt at the base of the active layer as a critical driving force for load (stress) variation. Recorded anchor loads decreased by up to 24 % in warm summers and recovered only partially in the following winters resulting in a gradual, long-term load decline in the observation period.
How to cite: Pläsken, R., Hartmeyer, I., Keuschnig, M., and Krautblatter, M.: Seasonal ground temperature variation controls stress regime and rock anchor tension in warming permafrost rock slopes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19318, https://doi.org/10.5194/egusphere-egu25-19318, 2025.
Permafrost collapse features (PCFs) have been increasingly prevalent in permafrost regions due to the warming climate, yet their drivers remain less understood. This study leverages high-quality datasets of PCFs and water systems, along with a physically-based permafrost model, to investigate the relationships between water system dynamics and PCF development. We found a large amount of the PCF is directly linked to water systems (rivers and lakes). These water-linked PCFs are primarily driven by a warming-wetting climate and are accelerated near waterbodies due to the heating impact of water on adjacent permafrost. Simulations at a representative permafrost river section indicate a ~2 °C higher mean annual ground temperature and a significantly thicker active layer in river-controlled permafrost compared to air-controlled permafrost, facilitating the formation of PCFs. In response to climate changes, the rivers on the Tibetan Plateau are generally warming and widening, substantially accelerating the surrounding permafrost thaw and increasing the frequency of PCFs along rivers, thereby increasing river sediment flux, threatening infrastructure safety, and accelerating the land-to-river carbon transport.
How to cite: Zhao, Y. and Li, D.: Warming rivers accelerate the permafrost thaw and thermokarst landslide development in the Tibetan Plateau, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11258, https://doi.org/10.5194/egusphere-egu25-11258, 2025.
Monitoring permafrost is of paramount importance due to its critical role as the foundation of soil mechanical and biological stability. Periglacial environments serve as valuable indicators of past and present climate conditions, offering unique insights into geomorphological processes and landscape evolution. However, degrading permafrost, driven by the warming climate, poses significant challenges. It affects soil hydrology and stability, alters carbon storage and release dynamics, and threatens ecosystems reliant on frozen ground. Furthermore, these changes have cascading effects on human infrastructure and contribute to feedback mechanisms that exacerbate global climate change.
There is no direct evidence for the presence of permafrost in southern Patagonia, apart from geomorphological processes. However, Tierra del Fuego (54°S), an archipelago shared by Argentina and Chile, is an extensive region where dozens of mountains exceed 1,500 m in elevation, and probabilistic maps of permafrost speculate that it may exist in elevated areas.
At the end of the austral summer 2024, a pioneering geophysical campaign was carried out in a remote area of the N-E Darwin Cordillera (54°S), without any assistance from vehicles or helicopters. We applied two of the most used and complementary geophysical techniques, i.e. Electrical Resistivity Tomography (ERT) and Seismic Refraction Tomography (SRT) with enough sensitivity to discretize either partially frozen ground or very shallow lenses of degrading permafrost profiles. The investigations were motivated by the expansion of the infrastructure network toward the southern national border and the encounter with the Darwin Range along the Beagle Channel, as the recent degradation of frozen soils could alter the compaction and settlement of the soil surface, leading to subsidence and frost heave. In particular, the road under construction involves reaching passes over the Cordillera, at whose elevations frozen ground is likely to be found.
In this work, we present a preliminary characterization of the periglacial environment in Yendegaia park, Tierra del Fuego. The use of electro-seismic geophysics, coupled with field observations and analysis, enabled to obtain more accurate subsoil models through a non-invasive approach. Validation by direct invasive techniques (i.e., soil coring) was unfortunately not possible at that moment, due to logistic complications and costs. The geophysical results obtained, coupled with the geomorphological slope processes observed, suggest the presence of frozen ground, active-state mountain periglacial processes and potentially permafrost around its probability limits in Tierra del Fuego, above 650 m a.s.l., becoming essential information at both geotechnical and climatic levels.
How to cite: Carrera, A., Pavoni, M., Ruiz-Pereira, S., Balázs, N., and Boaga, J.: First geophysical exploration of periglacial landforms in southern Tierra del Fuego, Chile, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8138, https://doi.org/10.5194/egusphere-egu25-8138, 2025.
The northern part of James Ross Island, Ulu Peninsula, is one of the largest ice-free areas in Antarctica. Its diverse local conditions, including variations in altitude, lithology, topography, and vegetation cover, create unique opportunities for active layer research. Monitoring of active layer temperature and thickness on the Ulu Peninsula began in 2006, with the installation of soil temperature measurement profiles at two initial sites. Over time, the network expanded to 12 locations, comprising more than 20 profiles that measure soil temperatures from the surface layer (5 cm depth) down to the upper permafrost boundary (75–200 cm). These sites were strategically selected to represent different lithological and altitudinal conditions. In 2014, the first Circumpolar Active Layer Monitoring South (CALM-S) site was established near the Johann Gregor Mendel Station, with two additional CALM-S sites added in 2017.
Long-term data from Abernethy Flats (45 m a.s.l.) showed mean annual ground temperatures (MAGT) ranging from –5.7 °C at 5 cm depth to –6.0 °C at 50 cm depth during 2006–2023. Ground temperatures at other sites varied by approximately +0.5 °C to –2.0 °C compared to Abernethy Flats. Over the study period, significant cooling (approximately –1.0 °C per decade) was observed until 2013–2015, followed by a warming trend, culminating in 2023 as the warmest year recorded on James Ross Island. Active layer thickness showed high variability, largely influenced by lithology, with typical values ranging from 50 to 90 cm. Maximum thicknesses exceeding 130 cm were recorded at the CALM-S JGM site. Similar to temperature trends, the active layer thinned until 2013 (approximately 10–15 cm per decade) and then thickened at a comparable rate thereafter.
How to cite: Hrbáček, F., Kňažková, M., Láska, K., Kaplan Pastíriková, L., and Uxa, T.: Active Layer Monitoring on James Ross Island, Antarctica: Results from 2006–2023, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18375, https://doi.org/10.5194/egusphere-egu25-18375, 2025.
Permafrost regions occupy almost one quarter of the Northern Hemisphere land area and store a globally relevant carbon pool in permafrost soils. As a consequence of global warming, permafrost is also warming at a global scale, leading to destabilization of landscapes and infrastructure as well as mobilizing previously freeze-locked soil carbon and releasing the greenhouse gases methane and carbon dioxide to the atmosphere. Long-term observation data are needed in order to understand how permafrost responds to a warming climate and how much greenhouse gas contributions from thawing permafrost we can expect in the future.
The Global Terrestrial Network for Permafrost (GTN-P) is the primary international programme concerned with sustained long-term monitoring of the state of permafrost. Members of the GTN-P community from more than 30 countries collect permafrost borehole temperature and active layer data across diverse permafrost regions and contribute them to the GTN-P data platform. The previous management system and web portal was developed in 2015 and is now technically outdated, requiring the establishment of a new system. Based on community input and under guidance of the GTN-P Steering Committee of the IPA, the new GTN-P database is being developed in the Permafrost Research Section of the Alfred Wegener Institute. Designed as the primary community platform for sharing data collected by a large and diverse network of researchers and institutions, it provides access to global information on permafrost data acquisition sites and data availability, while data ownership is retained with the original providers.
The new GTN-P database provides data for the two Permafrost ECV products Permafrost Temperature (PT) and Active Layer Thickness (ALT) with the potential to add additional products such as Rock Glacier Velocity (RGV). When designing the new system, special attention was paid to ensure a clear and self-explanatory user interface. As a central access point, it provides a platform for the scientific community to explore data availability and standardized metadata, as well as visualize temperature and depth time series. Data downloads are offered in different formats and for different levels of aggregation, e.g. for individual time series, PT boreholes, ALT sites and research sites. A new feature of the data platform will be an annual global compilation product of all available data, which includes co-authorship by all contributors. Special data products synthesizing the monitoring data will also be made available. Existing collaborations with the WMO will be used to establish a consolidated permafrost data profile, which will be aligned with internationally recognized data standards. These conventions will form the basis for better meeting the ‘interoperability’ and ‘reusability’ aspects of the FAIR Data Principles. For data providers, the upload capabilities have been streamlined and are coupled with an automated quality check that provides intermediate feedback during the upload. Building on the existing, well-established IT infrastructure at AWI, the new GTN-P data system is guaranteed long-term availability.
How to cite: Irrgang, A., Lübker, T., Laboor, S., Lantuit, H., Grosse, G., and Streletskiy, D.: Introducing the New Global Terrestrial Network for Permafrost (GTN-P) Database – the Primary Data Repository for the Permafrost Essential Climate Variable (ECV), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7435, https://doi.org/10.5194/egusphere-egu25-7435, 2025.
The magnitude and frequency of slope failures in permafrost zones have increased in recent decades. Permafrost warming and thawing represent major contributing factors to large slope failures, which have the potential to damage infrastructure and pose a risk to human life and surrounding ecosystems. Understanding the link between permafrost thaw and slope movement is thus crucial for identifying and adapting to related geohazards and increasing public safety in mountain communities.
We aim to provide quantitative and time-dependent context for interpreting past events and establish correlations between slope failures and potential driving factors, such as changes in air temperatures, ground temperatures, thaw depth, and water availability. We demonstrate our system by investigating the change in these driving factors and their connection with recent slope movements in northern British Columbia and the Yukon.
We developed a simulation workflow to generate 1D ensemble simulations of the ground thermal regime at any point globally, whose parameterization is helped by in-situ observations where available. Furthermore, we model temperature inversions in sub-arctic valleys where cold-air pooling is particularly intense in cold months and use it to correct 75 years of atmospheric reanalysis data forcing, increasing the accuracy and reliability of our results. We then produce summary statistics of drivers at permafrost landslide sites. This full-scale analysis is carried out for sites with varying degrees of remoteness, topographic parameters, and atmospheric conditions, producing an ‘ensemble’ of simulations. This framework allows for consistent and efficient production and analysis of mountain permafrost simulations in relation to slope failures. However, its main strength and appeal lie in its ability to be used globally and for a large number of sites, efficiently. Most workflows are contained in the Python packages SuPerSim and GlobSim, new packages for model testing and for producing climate change scenarios are added.
We observe a general increase in extreme events in the variables we analyze compared to earlier decades, and we correlate their timings with those of landslides. Such research may help establish proxies for permafrost landslide preconditioning and triggers, providing a tool to support research and prediction concerning hazards in mountain terrain.
How to cite: Pozsgay, V., Gruber, S., and Brown, N.: Global, consistent, and efficient production of transient permafrost ensemble simulations for investigating climatic influences on slope failures, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11426, https://doi.org/10.5194/egusphere-egu25-11426, 2025.
Posters on site: Mon, 28 Apr, 10:45–12:30 | Hall X5
There is much debate about the presence and role of fluid water in the permafrost active layer in steep bedrock environments. This holds for water both at the macro and micro scale (pores). While initial long-term experiments e.g. by Hasler started investigations based on the hypothesis that large ice bodies progressively formed inside deep cleft structures found in rockwalls and ridges this could not be backed up by observations. As far as observations at depth in solid rockwalls are possible, compact ice lenses have only been documented at significant scale in deeper sections of rupture planes of (large) rock falls.
The boundary conditions of an active layer on an inclined plane (steep rock walls or steep sections of rock glaciers) are significantly different from low to neglectable slope angles predominantly found in arctic permafrost environments. In arctic soil or rock columns fluid water mobilized on or in the active layer sits for long periods of time on an impermeable permafrost body with runoff only happening slowly in dominantly horizontal directions. Contrary to this we argue that in steep (30 degree plus) environments fluid water runs off or escapes quickly through the active layer effectively draining the latter when observed over significant timescales. Especially with climate-induced permafrost warming at a global scale, the refreezing of fluid water on the permafrost table is minimal. This effectively leads to a “drying” of the steep mountain peaks. Our assumptions are backed up by observations that (i) fluid water availability through snowmelt dominates in periods of active layer deepening and not during refreezing, (ii) iceshields and firn flanks are reduced leaving only bare rock/soil as well as (iii) the boundary conditions found in first order physical principles, e.g. energy balance, gravity as well as fluid flow. In this presentations we approach these questions from a conceptual perspective, highlight principle boundary conditions and invite further collaborators to further the discussion.
How to cite: Beutel, J., Amschwand, D., and Weber, S.: Active Layer Boundary Conditions in Steep Rockwall Permafrost, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17074, https://doi.org/10.5194/egusphere-egu25-17074, 2025.
Climate change poses a significant challenge to humanity, with its global repercussions threatening economies and livelihoods for future generations. Developing effective strategies to enhance climate resilience through adaptation requires reliable baseline data, including climate observations and the Essential Climate Variables (ECVs) identified by the Global Climate Observing System (GCOS). However, substantial gaps persist in the global climate observing system, especially in high-altitude mountain regions. This issue is particularly pronounced in developing countries, where baseline data is either lacking or at risk to be continued, therefore also increasing uncertainty about the impacts of climate change. Such information is crucial for predicting future changes and devising appropriate adaptation strategies.
Climate change in the mountainous regions of Central Asia significantly affects water resources and increases the frequency and intensity of natural hazards. To address these challenges, the Cryospheric Observation and Modelling for Improved Adaptation in Central Asia (CROMO-ADAPT) project has focused on closing data gaps and strengthening cryospheric monitoring systems, including snow, glaciers, and permafrost. As part of this initiative, new permafrost boreholes have been installed across Central Asia.
Three boreholes, each approximately 30 meters deep, were drilled at sites in Kazakhstan (Zholsalykezen Pass), Kyrgyzstan (Akshiirak), and Tajikistan (Uy Bulak Pass). All boreholes confirmed permafrost conditions and are continuously monitored. Recorded temperatures at 20 m depth are approximately -0.17°C in Kazakhstan, -1.6°C in Kyrgyzstan, and -1.1°C in Tajikistan. Additionally, geophysical surveys have been conducted at these locations and are compared with the borehole data to provide a more comprehensive understanding of permafrost conditions.
How to cite: Hoelzle, M. and the CROMO-Adapt Project: Permafrost boreholes and geophysical observations in Central Asia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7199, https://doi.org/10.5194/egusphere-egu25-7199, 2025.
The elevation dependence (ED) of atmospheric warming in mountain regions is debated, with studies showing varying trends due to data, spatial, and temporal differences. Permafrost, a critical component of alpine environment, also exhibits elevation dependent changes in response to climate change. This study investigated the ED of permafrost changes on the Qinghai-Tibet Plateau, the world’s largest alpine permafrost region, using multi-forcing ensemble simulations with a numerical model. We analyzed the ED of ground temperature (GT) at various depths and active layer thickness (ALT) changes over recent decades.
Three gridded meteorological datasets from reanalysis and remote sensing consistently show a negative ED of air warming (i.e., its trend decreases with increasing elevation) in permafrost regions (primarily above 3800m). Our ensemble simulations reveal that the ED of ALT and surface GT (GT0m) is consistently negative. However, interestingly, below 5000m elevation, the ED of GT at deeper depths (e.g., GT3m) becomes positive. This apparent discrepancy can be explained by the sensitivity of GT3m to air warming: in warmer permafrost (lower elevations), the increase in GT3m per unit of air warming is smaller compared to colder permafrost (higher elevations). This sensitivity is fundamentally linked to the soil freezing characteristic curve, which governs how heat is partitioned between temperature increases and ice melting. Similarly, the sensitivity of ALT to air warming is larger in warmer permafrost regions. Consequently, the consistently negative ED of ALT is a result of the combined influence of air warming ED and ALT sensitivity.
Under Coupled Model Intercomparison Project 6 (CMIP6) scenarios, we projected future permafrost changes by using the sensitivities of GT3m and ALT derived from historical simulations. Despite variations in air warming ED across scenarios and periods, the ED of GT3m and ALT changes remained consistent with historical period, demonstrating that air warming ED alone does not solely determine the ED of permafrost changes. Our findings were further corroborated by analysis of additional gridded dataset and in-situ observations. This study highlights the consistent ED of permafrost changes despite the variability in atmospheric warming trends across elevations, advancing our understanding of the diverse responses of ground temperature and ice to climate change in permafrost regions.
How to cite: Ji, H. and Nan, Z.: Consistent Elevation-Dependent Permafrost Changes Despite Variable Elevation Dependence of Atmospheric Warming, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15326, https://doi.org/10.5194/egusphere-egu25-15326, 2025.
This study investigates the relationship between electrical resistivity, ground temperature, and soil moisture across two contrasting lithologies within the permafrost environment on James Ross Island, located in the north-eastern Antarctic Peninsula. The region is characterized by continuous permafrost and a semi-arid polar continental climate with a mean annual air temperature of approximately -7 °C. The monitoring transect crosses a lithological boundary between a Holocene marine terrace and finer-grained Cretaceous sediments. An automated electrical resistivity tomography (A-ERT) system, utilizing a 4POINTLIGHT_10W (Lippmann) device, was installed near the Czech Antarctic station Johann Gregor Mendel in February 2023. The system performs daily resistivity measurements along a 23-metre transect with 47 electrodes spaced 0.5 m apart, probing depths up to 4.5 meters. Complementary temperature sensors (placed at depths from 5 to 200 cm) and soil moisture sensors (at 5, 35, 55, and 75 cm) provide additional context on thermal and moisture regimes within each of the distinctive lithologies.
Approximately two years of data reveal significant lithology-dependent variations in resistivity. Resistivity values are consistently higher in the coarser-grained Holocene marine terrace than in the finer-grained Cretaceous sediments. Overall, resistivity increases rapidly during winter (approximately 1–2 kΩm) and decreases during the thawing phase (approximately 10–100 Ωm), closely following the changes in ground temperature and soil moisture. The thaw front progression is readily observable in resistivity data, highlighting contrasting thermal and hydrological responses between lithologies. These relationships also form the basis for modelling ground temperature across the whole transect using resistivity data, offering a predictive approach to understanding permafrost dynamics.
This study demonstrates that A-ERT provides robust, high-resolution insights into the interplay between lithology, thermal regime and soil moisture in permafrost environments, surpassing the spatial limitations of traditional borehole methods and enabling effective long-term monitoring in extreme Antarctic conditions.
How to cite: Kňažková, M., Farzamian, M., Hrbáček, F., Herring, T., and Hauck, C.: A-ERT Insights: Linking resistivity, temperature, and moisture dynamics in two distinctive Antarctic permafrost lithologies, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18453, https://doi.org/10.5194/egusphere-egu25-18453, 2025.
Deep-seated landslides rockslides and related displacement waves threaten coastal settlements, infrastructure, and shipping routes in the Arctic. However, the occurrence, dynamics, and impact of such rockslides under a warming climate are poorly understood owing to scarce observational data. We have investigated two rockslides on the permafrost coastline of Forkastningsfjellet, Svalbard. Along this coastline, which was dormant for at least the last 80 years, a 175,000 m³ rockslide occurred in August 2016, followed by a second rockslide of 750,000 m³ in November 2022. Based on extensive field data collection starting in 2017, which includes the acquisition and differencing of drone-based DEMs, point-based displacement measurements (dGNSS), ground surface temperature logging, and field mapping, we documented accelerating surface deformation and the redirection of the drainage pathways from the surface into the ground that drove the dynamics of the 2022 rockslide. Our findings indicate that this rockslide was governed by rapid fluvial incision and accelerated thermo-erosion along colluvium-covered, pre-existing zones of weakness.
We attribute this localized permafrost degradation to climate warming, which increases the active layer thickness and water availability. Cliff instability is linked to cohesion loss and rising pore water/ice pressures from the refreezing cleft ice within the joint system of the bedrock.
Given continued Arctic warming with increasing permafrost temperatures, active layer depths, and changing precipitation patterns, thermal erosion might play a key role in permafrost degradation and future destabilization of rock slopes along the Arctic coastlines. In this context, the morpho-structural development of Forkastningsfjellet could serve as a model for the future development of other polar coastal landscapes.
How to cite: Kuhn, D., Hermanns, R. L., Fuchs, M., Schüßler, N., Torizin, J., Aga, J., Bendle, J., and Eiken, T.: Warming‐induced destabilization of the polar coastal rock cliff of Forkastningsfjellet, Svalbard, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4734, https://doi.org/10.5194/egusphere-egu25-4734, 2025.
This paper discusses mechanical modelling strategies for instable permafrost bedrock. Modelling instable permafrost bedrock is a key requirement to anticipate magnitudes and frequency of rock slope failures in a changing climate but also to forecast the stability of high-alpine infrastructure throughout its lifetime.
The last 5-10 years have brought upon significant advances in the (i) knowledge of relevant hydrostatic pressures in permafrost rock, (ii) the brittle-ductile transitions of ice relevant for larger permafrost rock slope failures, (iii) techniques that can help to decipher the preparation phase of large rockslides and also (iv) many new examples have delivered additional insight into multi-phase failure.
High-alpine rock faces witness the past and present mechanical limit equilibrium. Rock segments where driving forces exceed resisting forces fall of the cliff often leaving a rock face behind which is just above the limit equilibrium. All significant changes in rock mechanical properties or significant changes in state of stress will evoke rock instability which often occurs with response times of years to 1000 years. Degrading permafrost will act to alter (i) rock mechanical properties such as compressive and tensile strength, fracture toughness and most likely rock friction, (ii) warming subcero conditions will weaken ice and rock-ice interfaces and (iii) increased cryo- and (iv) hydrostatic pressures are expected. Laboratory experiments provide estimations of the serious impact of thawing and warming rock and ice-mechanical properties (ad i and ii), which often lose 25-75% of their strength between -5°C and -0.5°C. Approaches to calculate cryostatic pressure (ad iii) have been published and are experimentally confirmed. However, the importance and dimension of extreme hydrostatic forces (ad iv) due to perched water above permafrost-affected rocks has been assumed but has not yet been quantitatively recorded.
This paper presents data and strategies how to obtain relevant (i) rock mechanical parameters (compressive and tensile strength and fracture toughness, lab), (ii) ice- and rock-ice interface mechanical parameters (lab), (iii) cryostatic forces in low-porosity alpine bedrock (lab and field) and (iv) hydrostatic forces in perched water-filled fractures above permafrost (field).
We demonstrate mechanical models that base on the conceptual assumption of the rock ice mechanical (Krautblatter et al. 2013) and rely on frozen/unfrozen parameter testing in the lab and field. Continuum mechanical models (no discontinuities) can be used to demonstrate permafrost rock wall destabilization on a valley scale over longer time scales, as exemplified by progressive fjord rock slope failure in the Lateglacial and Holocene. Discontinuum mechanical models including rock fracture patterns can display rock instability induced by permafrost degradation on a singular slope scale. Discontinuum mechanical models also have capabilities to link permafrost slope stability to structural loading induced by high-alpine infrastructure such as cable cars and mountains huts.
Over longer time scales the polycyclicity of hydro- and cryostatic forcing as well as material fatigue play an important role. We also introduce a mechanical approach to quantify cryo-forcing related rock-fatigue. This paper shows benchmark approaches to develop mechanical models based on a rock-ice mechanical model for degrading permafrost rock slopes.
How to cite: Krautblatter, M., Pfluger, F., Scandroglio, R., Offer, M., Hartmeyer, I., and Mühlbauer, S.: Novel concepts for the mechanical modelling of warming permafrost rock slopes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17476, https://doi.org/10.5194/egusphere-egu25-17476, 2025.
The warming of mountain permafrost due to climate change poses significant challenges for slope stability and ecosystem dynamics in alpine regions. Accurate permafrost maps are essential for hazard assessment, as they depict local permafrost conditions and account for meso-scale thermal variability caused by complex alpine topography. Over recent decades, several permafrost maps have been developed using field data (e.g., rock surface temperatures, rock glacier inventories) and statistical models that link permafrost evidence to air temperature, solar radiation, and, in some cases, precipitation.
These models effectively map permafrost in steep alpine rock slopes with limited snow accumulation and estimate permafrost probability in debris-covered slopes based on the distribution of active rock glaciers. However, they are unable to capture the complex thermal regimes associated with variable snow accumulations typical of high mountain environments. In particular, permafrost in intermediately steep slopes (40°–60° inclination) is strongly influenced by snow accumulation patterns, including timing, thickness, and interactions with solar radiation. These slopes, which form a significant portion of alpine landscapes, often exhibit fractured rock, surface debris, and variable snow cover, creating unique conditions for permafrost formation and evolution. Unlike steep rock faces, intermediately steep slopes may retain larger ice volumes due to the refreezing of meltwater from seasonal snow, resulting in distinct thermal regimes and geomorphological behaviors. Their complex micro-topography further amplifies variability in solar radiation and snow distribution, complicating their thermal and mechanical stability.
To address these knowledge gaps, this research applies the CryoGrid community energy and hydrological balance model to simulate temperature dynamics at monitored sites in the French Alps, spanning elevations of 2500 to 3800 m. The initial phase involves calibrating the model using data collected from 2019 to 2024 across diverse snow cover conditions. Calibration focuses on parameters such as maximum snow height, deposited snow fraction, near-surface convection, initial temperature profiles, and albedo, identified as critical for energy balance simulations in prior CryoGrid3 applications in alpine settings.
Once calibrated, the model will be generalized to account for variable slope angles, sun exposures, surface roughness, ground characteristics, and precipitation regimes. These calibration steps will enable spatial application of the model on digital elevation models (DEMs) to generate improved permafrost maps for alpine settings, encompassing steep rock walls, creeping debris slopes, and intermediately steep slopes. Additionally, the model outputs will provide insights into permafrost evolution in diverse mountain slopes and support stakeholders in developing effective risk mitigation strategies.
How to cite: Lehmann, B., Magnin, F., Cathala, M., and Westermann, S.: Towards improved alpine permafrost maps using the energy balance model of the CryoGrid community, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9185, https://doi.org/10.5194/egusphere-egu25-9185, 2025.
In recent years, frequent rock slope failures in permafrost regions exceeding 1 Mio m³ have been documented on a regional (European alps) and global (Andes, Caucasus) scale. Yet, the fracture behaviour of ice-filled joints under high loads remains insufficiently understood, precluding a definitive assessment of modelling approaches. Strictly speaking, the brittle-ductile transition is not yet defined for these loads in the ice mechanical literature.
This study presents novel data to extend the Mohr-Coulomb failure criterion for rock-ice interfaces (Krautblatter et al. 2013, Mamot et al. 2018) for rock overburden exceeding 16 m. Consequently, we propose a governing law for the transition between ductile ice creep and brittle fracture, explicitly incorporating the effects of temperature, stress, and deformation rate in permafrost rock environments.
More than 100 shear experiments were conducted at high normal stresses, simulating rock overburden of up to 65 m (1600 kPa). The tests were performed at temperatures ranging from -0.5 °C to -4 °C, with strain rates consistently maintained in the range of 10⁻³ s⁻¹.
Extending the Mohr-Coulomb criterion to higher overburden pressures revealed, for the first time, consistent increases in friction angle and cohesion as temperatures decreased within the examined range. We define 3 novel sectors of mechanical behaviour:
(i) Ductile deformation
(ii) Single-brittle failure
(iii) Stick-slip failure
Ductile ice deformation occurs within the temperature range of -1 °C to -0.5 °C and exhibits marginal dependence on normal stress. Below -1 °C and at normal stresses below 800 kPa, the rock-ice interface undergoes single brittle fracture. At higher stress levels, ice healing mechanisms are activated, leading to periodic stick-slip fracture behaviour.
We integrated this temperature- and stress-dependent characterization of material behaviour into a three-phase failure model to enhance the rheological representation with respect to numerical modelling of high-magnitude failures.
This study refines the Mohr-Coulomb failure criterion for ice-filled rock fractures by incorporating high-load mechanisms and defining the brittle-ductile transition as a function of stress and temperature, providing valuable insights to improve mechanical models of large-scale permafrost rock slope instabilities.
Krautblatter, M.; Funk, D.; Günzel, F. K. (2013): Why permafrost rocks become unstable: a rock-ice-mechanical model in time and space. In: Earth Surf Processes Landf 38 (8), S. 876–887. DOI: 10.1002/esp.3374.
Mamot, P.; Weber, S.; Schröder, T.; Krautblatter, M. (2018): A temperature- and stress-controlled failure criterion for ice-filled permafrost rock joints. In: The Cryosphere 12 (10), S. 3333–3353. DOI: 10.5194/tc-12-3333-2018.
How to cite: Mühlbauer, S. and Krautblatter, M.: Three modes of mechanical rock-ice failure in permafrost rock slopes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11363, https://doi.org/10.5194/egusphere-egu25-11363, 2025.
The Flüela rock glacier is located in the Eastern Swiss Alps, at the top of the Flüelapass (Grisons). Previous geophysical studies indicated the presence of an ice-rich frozen layer (Boaga et al. 2024, Bast et al. 2024) towards the central area of the rock glacier at ~ 5 m depth and absent close to the front. In August 2023, we collected electrical resistivity tomography (ERT) and seismic data along a longitudinal line (48 electrodes/geophones; spacing 3 m) in the central part of the lower rock glacier. The ERT results confirm the presence of the ice-rich frozen layer, but the P-wave velocities (Vp) obtained from the seismic refraction tomography (SRT) are surprisingly lower than the typical velocities of an ice-bearing sediment. The SRT results indicate, in fact, the typical Vp values of liquid water (~1500 m/s). Consequently, we hypothesised the presence of a shallow water-saturated sediment layer (supra-permafrost flow) that prevents P-wave penetration. Since the seismic survey was carried out with low-frequency geophones (4.5 Hz), we additionally ran a multichannel analysis of surface waves (MASW; Park et al., 1999) to retrieve the S-wave velocities (Vs), which are insensitive to the liquid phase in the medium. Another advantage of the MASW analysis, compared to the common SRT applied in permafrost environments, is that it allows detecting velocity inversions in the subsurface (i.e., a lower velocity layer between two higher velocity layers). The obtained Vs profiles agree with the ERT results and confirm the presence of a shallow high-velocity layer (Vs = 2000 m/s) in the upper part of the rock glacier, between 5-10 m depth and absent towards the front.
To confirm our results, we conducted full-wave seismic modelling, using a subsurface structure akin to that proposed for the Flüela rock glacier. This model consists of no permafrost in the first half and features a 5 m thick ice-rich layer and supra-permafrost water in the second half. The synthetic shot gathers were compared to the real ones, both in terms of surface wave dispersion and Vp first-arrival times. In both cases, we found a high correlation between synthetic and real data, confirming the reliability of the proposed rock glacier structure. Therefore, we encourage data acquisition using low-frequency geophones (e.g., 4.5 Hz) for future seismic surveys within mountain permafrost environments. This ensures that both the traditional SRT analysis and the MASW approach can be applied.
References
Bast, A., Pavoni, M., Lichtenegger, M., Buckel, J., & Boaga, J.: The Use of Textile Electrodes for Electrical Resistivity Tomography in Periglacial, Coarse Blocky Terrain: A Comparison With Conventional Steel Electrodes. Permafrost and Periglacial Processes, https://doi.org/10.1002/ppp.2257, 2024.
Boaga, J., Pavoni, M., Bast, A., and Weber, S.: Brief communication: On the potential of seismic polarity reversal to identify a thin low-velocity layer above a high-velocity layer in ice-rich rock glaciers, The Cryosphere, 18, 3231–3236, https://doi.org/10.5194/tc-18-3231-2024, 2024.
Park, C. B., Miller, R. D., & Xia, J.: Multichannel analysis of surface waves. Geophysics, 64(3), 800808, https://doi.org/10.1190/1.1444590, 1999.
How to cite: Pavoni, M., Barone, I., Boaga, J., Gaona Torres, S. J., and Bast, A.: Application of Multichannel Analysis of Surface Waves (MASW) to improve the characterization of an ice-rich rock glacier, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3029, https://doi.org/10.5194/egusphere-egu25-3029, 2025.
Across the Qinghai-Tibet Plateau, arid and cold conditions provide permafrost and seasonally frozen ground. In recent decades changing climate led to substantial hydrological changes and strongly variable lake levels in the region which again strongly impacts the local population and settlements. This study focuses on two endorheic lake catchments, lake Paiku and lake Hala, to advance the representation and understanding of the connection between increased evaporation, runoff, and changing thermal states of the ground using a 1D numerical permafrost model. Additionally, to ameliorate the scarcity of data and measurement points for ground ice content and to compare the model output to field data, a novel remote sensing approach is utilized. Here, the seasonal amplitude of frost heave and thaw subsidence measured through satellite-based Interferometric synthetic aperture radar (InSAR) is used to estimate the potential for ground ice content in the active and the seasonally frozen layers of permafrost ground and translated to predict ground ice content within the permafrost table together with landform information from geomorphological mapping.
This provides a tool to estimate how large the impact of changing permafrost hydrology and the loss of ground ice content might be on local lake levels and, ultimately, on settlements and societies in arid high mountain regions which are highly vulnerable to small changes in the hydrological system.
How to cite: Peter, M., Martin, L., and Westermann, S.: Numerical modeling of ground thermo-hydrological changes in two Tibetan catchments and implications for lake level changes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19777, https://doi.org/10.5194/egusphere-egu25-19777, 2025.
Under the background of climate warming, the degradation of frozen ground over the Tibetan Plateau (TP) will lead to a series of hydrological and ecological environmental issues. Therefore, it is important to study how seasonally frozen ground (SFG) will change in the future, especially on a finer scale. This study focuses on the maximum freeze depth (MFD) and freeze-thaw period (FTD) of SFG over TP from 2021 to 2100, based on air temperature and precipitation data with a 1 km×1 km spatial resolution from 13 CMIP6 models, using a well-tested fitting method. The study also evaluates how vegetation will change responds to changes on SFG. The results show that under the shared socioeconomic pathway SSP245, the average MFD and FTD over TP will be 118.4 cm and 198 days in the near future (2021-2040). In the far future (2081-2100), MFD and FTD will decrease to 92.1 cm and 177 days, considering the increased extent of SFG. Under the more extreme SSP585 scenario, the MFD and FTD will drop even further, reaching only 53.7 cm and 143 days, respectively. As radiative forcing increases, the rates of these decreases will also speed up. The impact of different socioeconomic pathways on MFD will be more significant at high altitudes, the MFD and FTD will show a faster decline as altitude increases. Vegetation indices, such as LAI, NPP, and GPP, will rise more sharply with the stronger degradation of SFG. This highlights the strong link between SFG changes and vegetation growth.
How to cite: Wang, J.: Variations in seasonally frozen ground over the Tibetan Plateau from 2021 to 2100, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10594, https://doi.org/10.5194/egusphere-egu25-10594, 2025.
