This session is intended as a forum for scientists involved in state-of-the-art research on permafrost disturbance dynamics, associated processes, and impacts. We welcome contributions concerning studies on different scales, from local studies including, but not limited, to field observations, near-surface geophysics, and drone measurements, to regional and circumpolar analyses supported by modelling approaches and remote sensing techniques. We encourage submissions targeted at dynamic permafrost disturbance processes and their feedback to climate across Arctic-boreal, high-mountain, and coastal regions, including, e.g., thermokarst, coastal erosion, anthropogenic impacts, hydrology, mass movements, sediment fluxes, and biogeochemical cycling and associated fluxes.
This session seeks abstracts on (1) novel observations of permafrost disturbance-related phenomena; (2) the impact of permafrost changes on the natural and human environment; and (3) advances and new developments in the measurement, modelling, parametrization, and understanding of permafrost-related processes.
We particularly encourage contributions that (a) identify novel processes related to permafrost disturbances and environmental changes in permafrost regions; (b) present novel measurement and monitoring approaches; (c) outline new strategies to improve process understanding; (d) come from or interface with neighbouring fields of science or apply innovative technologies and methods; (e) investigate model validation, model uncertainty, and scaling issues; and (f) land surface models of diverse processes or scales.
Arctic-boreal fire regimes are intensifying, leading to a growing number of boreal forest fires and Arctic tundra fires occuring on permafrost terrain. After fires, the seasonally thawed active layer of permafrost soils usually thickens, and this can lead to long-term gradual or abrupt permafrost degradation. Permafrost soils store large amounts of carbon, and hence fire-induced thaw may lead to additional carbon emissions from permafrost soils for many years after the fire.
This presentation explores several spaceborne measurements for mapping fire-induced permafrost thaw and its associated carbon emissions and will cover two case studies and one continental application. First, we investigated a boreal forest fire in Eastern Siberia using several measurements from sensors on Landsat 8. We found that especially land surface temperature (LST) related strongly to field-measured thaw depth, and we developed a statistical model to map fire-induced thaw depth over the entire fire scar. Second, we mapped post-fire permafrost soil subsidence after several tundra fires in Northeastern Siberia using Sentinel-1 interferometric synthetic aperture radar (InSAR) data. We found that burned areas experienced about three times higher soil subsidence than adjacent unburned areas in the growing season after the fire (4.88 cm/year vs. 1.54 cm/year), and this difference was primarily driven by fire-induced surface albedo darkening. Lastly, we used the ESA Climate Change Initiative permafrost product to estimate post-fire active layer thickening and associated carbon emissions for all fires in boreal North America between 2001 and 2019. We estimate that post-fire carbon emissions from permafrost thaw amount up to 30 % of the direct carbon emissions during fires, demonstrating the importance of including permafrost thaw when estimating climate feedbacks from boreal forest fires.
Taken together, this presentation highlights the use of multi-source remote sensing products for estimating post-fire surface deformation and active layer thickening of fires in permafrost ecosystems, and provides a first continental assessment of the climate warming feedback from carbon emissions from fire-induced permafrost thaw.
How to cite: Veraverbeke, S., Diaz, L., van Gerrevink, M., and Wangchuk, S.: Estimating fire-induced permafrost thaw and carbon emissions from space, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3281, https://doi.org/10.5194/egusphere-egu25-3281, 2025.
In the Central Mongolian mountains, the presence of permafrost is intimately linked to local topography and ecosystem setting. Permafrost in these areas is generally found on north-facing slopes, and it is an important element of the hydrological regime, contributing to water availability and downstream ecosystem function. Currently, these linked systems are under increased pressure from both intensified land use and climate warming. This includes disturbances from herd animals, who modify the surface energy balance at grassland sites by changing vegetation structure in summer and snow cover in winter. However, the effect of livestock grazing and trampling on the ground thermal regime in these marginal permafrost areas is largely unknown. In this study, we investigate how semi-nomadic pastoralism impacts surface cover and associated ground temperatures at grassland sites in Central Mongolia. We survey vegetation and snow cover in summer and winter and monitor ground surface temperatures (GSTs) over 14 months at plots featuring different grazing intensities (intensely and ungrazed), as well as topographic aspects (north- and south-facing). We find that plots subject to intense grazing feature lower vegetation density and height, reduced snow cover and an absence of surface litter layers. Overall, intensely grazed plots display an intensified annual cycle of GSTs compared to ungrazed plots, with GSTs at a south-facing site up to +5.1°C warmer in summer and up to -5.4°C colder in winter. We further find the impact of grazing on GST to depend on topographic aspect, and at a north-facing site we observe lower seasonal differences in GST of +1.4°C and -2.5°C between grazed and ungrazed plots. At our study sites the seasonal differences in GST largely cancel each other out, with the net effect depending on spring and autumn conditions. These results suggest that surface conditions at grassland sites can be managed by regulating the disturbances caused by livestock, which in turn can modify the ground thermal dynamics. For example, a cooling of ground temperatures can possibly be achieved through shielding areas from grazing during the growing season while allowing or even promoting grazing and trampling in the snow season. Such livestock management could potentially offset current and future surface warming in marginal permafrost areas, contributing to sustained local water availability and ecosystem function.
How to cite: Zweigel, R. B., Dashtseren, A., Temuujin, K., Sharkhuu, A., Webster, C., Lee, H., and Westermann, S.: Disturbance by livestock impacts ground temperatures in marginal permafrost areas in Central Mongolia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17283, https://doi.org/10.5194/egusphere-egu25-17283, 2025.
Thawing permafrost increasingly threatens the integrity of legacy sites from resource exploration and extractive industries. In the Northwest Territories, Canada, over 200 sumps containing drilling wastes within permafrost pose considerable environmental and health risks to local ecosystems and populations relying on the land for subsistence. Exploratory drilling activities have caused long-term disturbances to permafrost terrains and tundra vegetation, necessitating continued monitoring and research. This study investigates the complex interactions between legacy oil well disturbances, permafrost thaw, and vegetation changes. Using a combination of field-based and remote sensing techniques, we mapped and assessed the impacts of four drilling mud sumps located along the Inuvik-Tuktoyaktuk Highway (Northwest Territories, Canada). Multispectral drone surveys were conducted at the sites to produce high-resolution orthophotos, digital elevation models, landcover and vegetation index maps. Additionally, we measured the active layer thickness, percent cover of plant functional types, and canopy height within vegetation plots distributed along transects that covered both undisturbed and disturbed terrains. Here, we present preliminary findings from these investigations, including statistical and spatial analyses of the gathered data. Decades after decommissioning, the disturbances caused by the drilling mud sumps, coupled with permafrost degradation processes, continue to affect plant communities, shrub growth and vegetation productivity.
How to cite: Scheer, J. and Siewert, M.: Mapping the impacts of legacy oil wells and permafrost thaw on vegetation in the Northwest Territories, Canada, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19570, https://doi.org/10.5194/egusphere-egu25-19570, 2025.
As the Arctic warms at nearly four times the global average, the thawing of ice-rich permafrost is destabilizing the ground and amplifying thermokarst-related mass-wasting events, including active-layer detachment failures (ALDs). ALDs are translational landslides that occur during summer thaw and are very common across the Arctic in both continuous and discontinuous permafrost areas, most typically in ice-rich unconsolidated sediments. These events are becoming increasingly common and pose significant risks to the region's topography, vegetation, hydrology, infrastructure integrity, and carbon exchange. This study investigates the susceptibility of ALDs in permafrost regions under current climate conditions, with a particular focus on Alaska and the Northwest Territories of Canada. Using the Maxent statistical model, we developed a susceptibility map for ALDs across the study area, providing valuable insights into the spatial distribution of ALD-prone zones. Our analysis revealed high-susceptibility regions in critical areas, including the Brooks Range, Franklin Mountains, and West Crazy Mountains in Alaska, as well as the areas around Dawson City and Mackenzie River regions in Canada. A particular concern is the vulnerability of linear infrastructure, with significant portions (39% in total) of roads and pipelines located in high to very high susceptibility zones. These findings underscore the broader implications of climate change in the Arctic regions, particularly the destabilization of permafrost. They highlight the necessity of adapting infrastructure and management strategies to mitigate the growing risks associated with ALD events.
How to cite: Makopoulou, E., Karjalainen, O., Lipovsky, P., Blais-Stevens, A., and Hjort, J.: Active-layer detachment failures and the vulnerability of infrastructure in Alaska and northwestern Canada, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16368, https://doi.org/10.5194/egusphere-egu25-16368, 2025.
Permafrost underlying the central Qinghai-Tibetan Plateau has experienced significant degradation in recent decades due to the warming climate. Retrogressive thaw slumps (RTSs), a typical form of abrupt permafrost disturbance, retreat rapidly and can impact the local environment for decades before stabilizing. Previous studies have revealed rapid growth of RTSs in the central plateau, with their areas and numbers increasing by 154% and 70% from 2016 to2022, respectively. To gain a deeper understanding of the long-term activity and distribution of RTSs, we utilized multi-source satellite imagery, including Keyhole (1965–1984), Landsat (1984–2015), WorldView (2006–2013), and PlanetScope (2016–2024), to trace their activities over six decades. We manually delineated RTSs on high-resolution (<5 m) satellite images in 1965–1984 and 2016–2024. To fill the temporal gap between 1984 and 2016, we acquired 30-m-resolution Landsat imagery and applied deep learning-based heatmap regression to estimate RTS areas.
We identified 126 RTSs affecting 108 ha areas in 1965; while after sixty years, the number and affected areas increased by 4.48 and 13.9 times. Notably, around 50 new RTSs developed between 1970 and 1973. Since then, the activity of RTSs has slowed, with numbers increasing slightly from 274 to 287 in 1973-2010. However, from 2010 to 2013, the number rose to 324, affecting 482 ha. Between 2016 and 2017, RTSs surged from 407 to 697, impacting 1,167 ha. By comparing the average air temperatures from station records for the thawing season (from June to August), we found that the episodically rapid growth of RTSs during 1970–1973, 2010–2013, and 2016–2017 was associated with high summer temperatures.
In conclusion, we compiled a comprehensive timeseries of RTS evolutions in the central Qinghai-Tibetan Plateau, based on which we found that the active initiation of RTSs may be attributed to high summer temperatures. However, a more detailed analysis incorporating other climatic and environmental factors is necessary. Based on the long-term evolution of RTSs, we will further enhance our analysis of their changing numbers and areas to gain a quantitative understanding of the decadal evolution of these hillslope thermokarst landforms on the central Qinghai-Tibetan Plateau.
How to cite: Xia, Z., Zhao, Z., and Liu, L.: 60-year evolution of retrogressive thaw slumps on the central Qinghai-Tibet Plateau, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8116, https://doi.org/10.5194/egusphere-egu25-8116, 2025.
Retrogressive thaw slumps (RTS), a common type of thermokarst landslide in Arctic permafrost, have been increasing both in number and distribution in recent years. As RTS are characterized by their dynamic behaviour, a main controlling factor is the ice availability and the sediment properties. Most RTS described in previous studies occur within fine grained permafrost sediments, a multi-layered geological setting, as in this study, uncommon for RTS.
The study site is located near the Zackenberg Research in Northeast Greenland, within sediments deposited since the Last Glacial Maximum (LGM), including a salt-rich marine layer. In recent years, two RTS have developed on the eastern riverbank in a multi-facies geological setting. To investigate the RTS, the geological subsurface model, and the threat to the station, five quasi-3D profiles were measured using electrical resistivity tomography (ERT). The surveys were combined with stratigraphic analysis, core drilling and laboratory tests. To better delineate the extent of the marine layer, whose high salt content strongly affects the geophysical measurements, additional ERT calibrations were performed under laboratory conditions. The combined results highlight the significant influence of a saline marine silt on the geomorphology, permafrost state (unfrozen vs. frozen), and the behaviour of RTS.
How to cite: Eppinger, S., Lorentzen, T. H., Angelopoulos, M., Marcer, M., Ingeman-Nielsen, T., and Krautblatter, M.: Investigating Retrogressive Thaw Slumps in Saline Permafrost (East Greenland) using Electrical Resistivity Tomography, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18451, https://doi.org/10.5194/egusphere-egu25-18451, 2025.
The Arctic is warming, resulting in permafrost degradation. Beavers are rapidly colonizing the Arctic tundra and altering the landscape, which can further increase permafrost thaw. While surface changes caused by beaver ponds have been shown using remote sensing imagery, the subsurface changes caused by beaver ponds remain theoretical and undocumented. Here, we used ground-penetrating radar (GPR) to non-invasively measure permafrost table depth under beaver pond complexes in northwestern Alaska and quantify the rate of permafrost thaw based on pond age in beaver and non-beaver-affected waterbodies. GPR measurements were collected in August 2024 along transects at 11 sites associated with beaver ponds. These included six sites near Nome on the Seward Peninsula, characterized by discontinuous permafrost with low to moderate ground-ice content, and five sites near Kotzebue on the Baldwin Peninsula, characterized by continuous permafrost with high ground-ice content. An antenna frequency of 160 MHz was used inside a packraft, and measurements were recorded at 0.3 s intervals. We also measured thaw depth (average of 0.5 m +/- 0.2 m) using a probe around the water bodies to calibrate the radar velocity (0.05 m/ns) within the thawed layer. Our results show deeper thaw beneath old (>20 years) beaver ponds and shallower thaw beneath young (~1 year) beaver ponds. Permafrost tables are more clearly identified in radargrams in sites with continuous permafrost and high ground-ice content compared to sites with discontinuous permafrost and low ground-ice content. This study quantifies the effects of beaver engineering on permafrost degradation, enhancing our understanding of the Arctic beaver pond environment and the future of the Arctic tundra ecosystems in a changing climate.
How to cite: Sriharan, J., Rangel, R. C., Jones, B. M., Loranty, M. M., Tape, K. D., Glass, T. W., Zavoico, S., Kehoe, P., Johnston, S. E., Clark, J. A., and Maio, C. V.: Investigating permafrost degradation below beaver ponds using ground-penetrating radar in northwestern Alaska, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13067, https://doi.org/10.5194/egusphere-egu25-13067, 2025.
The rapid thawing of Arctic permafrost is driving significant changes in both the hydrological and carbon cycles, with critical implications for surface wetness and ecosystem processes. These changes are contributing to increased surface wetness, which, in turn, accelerates permafrost degradation and alters ecosystem dynamics. Understanding the feedback mechanisms governing these processes is essential for predicting future impacts, as seasonal variations in wetness directly influence permafrost stability and carbon fluxes. This study integrates in-situ measurements and satellite-based observations to investigate wetness variability across the Arctic, providing a comprehensive assessment.
In-situ soil moisture records, collected across diverse permafrost regions in North America and Eurasia, were combined with high-resolution land cover data from the circumarctic Land Cover Units (CALU) v2.0 dataset and other variables (ground temperature etc.) from ESA CCI Permafrost records. This approach aims to identify the processes and key drivers of wetness variability and quantify wetting/drying trends. To gain deeper insights into the mechanisms governing these dynamics, land cover is incorporated as a critical variable to understand its role in influencing wetness dynamics, including processes such as vegetation growth and permafrost thaw including related disturbances. Statistical analyses were conducted to assess biases in satellite-based soil moisture retrievals and to evaluate the significance of the observed trends. Preliminary findings reveal considerable biases in satellite retrievals.
Further on, surface deformation and subsidence are associated with permafrost thaw. They can be investigated with interferometric synthetic aperture radar (InSAR) utilizing data from e.g. Sentinel-1 and ALOS-2 PALSAR. These deformation patterns provide critical insights into surface wetness. The findings of this study advance understanding of the current and future impacts of climate change on Arctic ecosystems, particularly in relation to surface wetness dynamics, permafrost stability, and land-atmosphere interactions.
How to cite: Radha Krishnan, S. R., Widhalm, B., Bartsch, A., and Göckede, M.: Wetness Dynamics and Permafrost Thaw Across the Arctic: An Integrated Analysis based on In-Situ and Satellite-Based Soil Moisture Datasets, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10955, https://doi.org/10.5194/egusphere-egu25-10955, 2025.
Climate change is affecting high latitude ecosystems in unprecedented ways as temperature increases more than two times higher than the global average. Large stocks of carbon sequestered in permafrost may be released as the region –that historically has been a carbon sink– appears to be turning into a source of carbon to the atmosphere. Therefore, it is of great importance to properly account for changes in the carbon cycle. Of note is that even if we are aware of the quantities of carbon release, there is a large difference in warming potential between carbon dioxide and methane, the latter is a far stronger short term greenhouse gas.
Here we present work on two ESA projects which aim to address gaps in our knowledge of Arctic methane release: AMPAC-net and the CCI RECCAP-2 project.
AMPAC-net is an ESA contribution to AMPAC, the 'Arctic Methane and Permafrost Challenge', which is a cooperation between ESA and NASA. Key topics include the combination of remote sensing with in-situ measurements for high latitude methane detection. The RECCAP2-CCI ‘REgional Carbon Cycle Assessment and Processes’, is in Phase 2 of ESA's 'Climate Change Initiative'. The overarching aim is to improve carbon budgets for the global stock take, with our sub-project focusing on permafrost region wetlands. As part of these research projects, we have reviewed past, current and required future state of methane monitoring and modeling in high latitudes. After an initial overview of past work, we follow with an analysis of the current state of Arctic methane research. Many projects aim to improve our understanding directly, but also indirectly for example by improved wetlands classification. We also highlight and discuss a major research challenge: the large discrepancy between top-down and bottom-up carbon budgets in high latitudes. We present our initial steps towards addressing this issue in a set of experiments where we use updated Arctic specific priors for methane inversions. Finally, we give an overview of high priority knowledge gaps that will need further addressing, and advise on how to move forward.
How to cite: Pallandt, M., Bartsch, A., Goeckede, M., and Hugelius, G.: Assessing the ability of high latitude methane monitoring and modeling systems to detect climate driven changes , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9514, https://doi.org/10.5194/egusphere-egu25-9514, 2025.
Northern high latitudes have experienced pronounced warming throughout the last decades, with particularly high temperatures during winter and spring. Due to Arctic Amplification, the Arctic region is warming four times faster than anywhere else. Permafrost, a crucial component of arctic ecosystems, is particularly sensitive to increasing air temperatures and changes in the snow regime. In the last decade, satellite-derived land surface temperature (LST) products combined with snow cover information and land cover data have been increasingly used for permafrost modelling. For example, the CryoGrid community model, a ground thermal model, is used within the frame of the ESA Permafrost Climate Change Initiative (CCI) project to produce permafrost extent maps on a hemispheric scale. These maps and permafrost modelling outputs are based on Moderate Resolution Imaging Spectroradiometer (MODIS) LST data. A drawback is that MODIS LST products have only been available since 2001, which prevents differentiating multi-decadal climate trends from decadal-scale climate oscillations.
To leverage the historic Advanced Very High-Resolution Radiometer (AVHRR) sensors series, a new pan-Arctic LST dataset has been developed using EUMETSAT’s AVHRR Fundamental Data Record (FDR). The pan-Arctic AVHRR LST product covers a period from 1981 to 2021 and has a spatial resolution of approximately 4 km. It incorporates snow cover information derived from fractional snow cover and snow water equivalent data, allowing for accurate emissivity and temperature retrievals over snow and ice. To obtain AVHRR LST data at a spatial resolution similar to the MODIS LST dataset (~ 1 km) and allow for intercomparison of the permafrost modelling outputs, the AVHRR pan-Arctic LST dataset is downscaled to a spatial resolution of 1 km. Recent advances in spatiotemporal fusion and super-resolution models offer new solutions to downscale thermal infrared (TIR) data, allowing obtaining LST data at a high spatial and temporal resolution. Guided super-resolution (SR) is another downscaling strategy that only relies on a low-resolution source and a high-resolution guide. It returns a high-resolution version of the source. In the case of the AVHRR LST downscaling, the guide comprises information derived from land cover, elevation models, and canopy height data. Downscaling results of the pan-Arctic LST dataset based on guided deep anisotropic diffusion for the region of the Yamal Peninsula (Siberia) and along the Alaska Highway in the Yukon (Canada) showed promising results. The downscaling methodology demonstrated its potential for capturing the complexities of typical permafrost landscapes.
How to cite: Dupuis, S., Metzger, N., Westermann, S., Schindler, K., Göttsche, F.-M., and Wunderle, S.: Benefits of downscaled satellite-derived land surface temperature for permafrost modelling in the northern high latitudes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5216, https://doi.org/10.5194/egusphere-egu25-5216, 2025.
Understanding the dynamics and influences of permafrost under a warming climate heavily relies on numerical simulations. However, this task presents significant challenges as the state-of-the-art land surface models are found weak ability in representing permafrost processes. Here, we introduce the Flexible Permafrost Model (FPM), a land surface scheme designed model especially for permafrost applications. This model serves as a flexible platform to explore novel structures and parameterizations for a variety of permafrost processes. The FPM accounts for both vertical and lateral heat flow at and below the soil surface, while also describing the energy exchange with the atmosphere by considering radiative and turbulent fluxes. To demonstrate the utility of FPM for supporting permafrost studies, we apply the model to the simulations of global-scale permafrost extent and fine-scale permafrost island dynamics. Our simulation results are found reasonable against published permafrost extent and in situ observations, indicating FPM can serve as a stand-alone simulation tool for permafrost studies.
How to cite: Cao, B., Sun, W., and Guo, X.: Flexible Permafrost Model: a new process-based permafrost model for cross-scale studies, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5394, https://doi.org/10.5194/egusphere-egu25-5394, 2025.
The intense warming of Arctic soils make them vulnerable to permafrost degradation, with critical implications for the global carbon cycle and regional ecosystems. However, the increasing temperature is not the only factor affecting permafrost degradation. Water availability changes in the Arctic considerably affect the soil moisture and ice presence and subsequently thermal structure in permafrost regions. The interaction between soil hydrology and thermodynamics is still poorly represented by most of the CMIP6 land surface models (LSMs), mainly in terms of the soil depth, vertical resolution, and coupling between hydrology and thermodynamics.
Using a modified version of the MPI Earth System Model (MPI-ESM), we investigate the sensitivity of permafrost to changes in soil hydrology and thermodynamics. Three different model configurations were tested to simulate varying hydrological states under future warming. Enhanced soil depth and vertical resolution within the land surface model, JSBACH, were also incorporated to capture fine-scale dynamics. The findings reveal that deepening JSBACH reduces the intensity of near-surface warming, reducing the deep permafrost degradation area by 3.1 million km2 and constraining the active layer thickness deepening by the end of the 21st century under high-emission scenarios. However, hydrological configurations significantly influence model outcomes, with DRY and WET setups producing temperature offsets of up to 3°C and varying active layer thicknesses by 1–2 meters. The results highlight the crucial role of hydro-thermodynamic interactions in shaping permafrost dynamics.
How to cite: González-Rouco, F., García-Pereira, F., Meabe-Yanguas, N., Steinert, N. J., de Vrese, P., Lorenz, S., and Jungclaus, J.: Permafrost sensitivity to modified soil hydro-thermodynamics in MPI-ESM, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15648, https://doi.org/10.5194/egusphere-egu25-15648, 2025.
Permafrost in the Arctic and Subarctic regions contains a significant amount of carbon from ancient vegetation and animals remaining and started to thaw at an alarming rate due to global warming and the Arctic amplification, posing significant risks of releasing ancient carbon into the atmosphere and affecting global carbon neutrality. However, the magnitude and rates of carbon release from permafrost at a global scale remain unclear. Among the various processes associated with permafrost thaw, mass movements such as retrogressive thaw slumps (RTSs) play a critical role in transforming local hydrology, geomorphology, and ecosystems and moving soil organic carbon from permafrost to the environment. To advance the understanding of carbon release from permafrost, we utilized high-resolution (2 m) topographic change data (DEM differences) and multi-temporal/source satellite imagery to identify RTSs and estimate the carbon mobility during the RTS development. Specifically, we (1) delineated regions of elevation loss from 2-meter-resolution topographic change data using the Segment Anything Model, (2) fine-tuned a vision-language model (e.g., CLIP) model and used it to classify areas of elevation loss into RTS-induced and others using multi-temporal/source satellite imagery, and (3) calculated the volume of matter removed from permafrost using the DEM difference and estimated the carbon mobility using the northern circumpolar soil carbon database. The DEM difference was derived from approximately 200 TB of ArcticDEM, covering all land in the Arctic and SubArctic (https://doi.org/10.18739/A2ZS2KF4B). This is a newly funded project that started in January 2025, and we will present some preliminary results and look forward to the collaboration and contribution from Arctic scientists and carbon experts.
How to cite: Huang, L.: Estimating the carbon mobility from permafrost using DEM difference derived from ArcticDEM at a pan-Arctic scale, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5034, https://doi.org/10.5194/egusphere-egu25-5034, 2025.
Retrogressive thaw slumps are a well-known arctic geohazard, which often occur in ice-rich permafrost. Thaw slumps can be triggered by warming and/or anthropogenic influences. Consequences of thaw slumps include changes to the landscape, impacts to infrastructure, sediment and solute loads to watersheds, and release of stored carbon, among other effects. Many studies on thaw slumps in nature include external monitoring through use of time-lapse photography, unmanned aerial vehicle (UAV), and lidar surveys. While field studies using external monitoring equipment provide high quality information about the extent and consequence of thaw slumps, direct observations of thermal and mechanical mechanisms occurring behind the scarp normally remain hidden. Recent advances at Royal Military College of Canada (RMC) used physical modeling to examine cold regions phenomena with a geotechnical centrifuge. Geotechnical centrifuges apply elevated gravity to small-scale models to create stress-equivalent environments and allow for direct observation of subsurface displacements from digital images of the model's side profile. Instrumentation in thaw slump physical models includes internal temperature measurements using fiber optics and scarp face temperature measurements using a thermal camera. Preliminary results indicate that the thaw slump physical models are conceptually capturing key behaviours observed from external field measurements. Typically, warming begins at the face and surface leading to thawing and and episodic thaw slump events. Failed material migrates downward and away from the intact block. This mechanism repeats until the final slump occurs . Internal displacements, measured using digital image corellation (DIC), show corellation with co-located temperature measurements. Results also show higher ice contents and taller scarps tend to lead to shear failure while lower ice contents and shorter scarps tend to fail via a toppling mechanism. Outcomes of the research will provide a practical analysis tool for analyzing thaw slumps as well as fundamental understanding of pre-failure permafrost mechanics.
How to cite: Siemens, G., Mardani, A., Beddoe, R., Eichhorn, G., and Rugwizangoga, C.: Physical modelling of thaw slumps in a geotechnical centrifuge , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13451, https://doi.org/10.5194/egusphere-egu25-13451, 2025.
Permafrost in high latitudes has been particularly affected by global warming. Its extent is decreasing rapidly, and that can have a significant effect on coastal communities. Because of the ice mixed with sediments, those coasts are affected by important erosive processes, differing from those affecting lower latitudes (Lantuit et al., 2012). The number of studies on coastline dynamics is significant, however the majority have been completed using remote sensing data. Over the last decade numerical models have also been developed (Barnhart et al., 2014) but few studies have tried physical modelling of coastal permafrost (Korte et al., 2020). Physical modelling allows for the observance of the erosional processes during the experiments in the controlled environment. The purpose of this study was to use experimental modelling to improve the knowledge on the processes and the main parameters involved in coastal permafrost weathering.
For a first set of experiments, permafrost blocks were created in the M2C cold rooms (Caen University, France) using a cubic box made of Polyvinyl chloride (PVC). The blocks were 30 cm high and 50 cm wide. They were placed in the M2C wave flume (17 m long and 50 cm wide). For the experiments presented here, only regular wave conditions were used. While the block was degrading, it was monitored with several instruments to document its morphological and thermal evolution, along with the hydrodynamic conditions. Their purpose is to observe the changes in permafrost erosion under different experimental configurations (wave height, water height, water temperature, sediment type) to quantify the influence of each parameter on the erosion process. As predicted by different models (Dupeyrat et al., 2011; White et al., 1980) the water temperature remains the critical parameter for the erosion rate, but the granulometry, linked to the porosity and ice structure also has an important impact. Coarser blocks erode at a slower rate. As the block degrades, a cone of loose sediments is formed alongside the receding frozen part. Wave action tends to lower the cone’s slope angle and increase the frequency of gravity-driven processes, as well as creating scallop patterns on the exposed permafrost surface.
These experiments were compared to a complementary study carried out in a cubic static water tank. The permafrost blocks were smaller (30 cm high and 30 cm wide) and allowed for the testing of the influence of salinity on the degradation of the blocks. The results in the static water tank could then be compared with the wave flume tests. This comparison allowed for the quantification of the mechanical component of the erosion process while also expanding the test series to include the influence of water temperature and salinity. Salinity seems to only have a small impact on the block’s erosion rate in our setup, compared to the water temperature.
How to cite: Clément, J., Font, M., Stolle, J., Mouazé, D., and Lagniel, E.: Experimental modelling of coastal permafrost weathering in two different setup : a wave flume and a static water tank., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20294, https://doi.org/10.5194/egusphere-egu25-20294, 2025.
The Arctic is experiencing rapid warming, leading to prolonged ice-free periods, increased storm activity, and intensified coastal erosion. These changes release organic matter-rich permafrost into the nearshore marine environment, where it either degrades to CO₂ or is transported further for potential burial on the continental shelf. However, only 5% of all sediment samples in the Arctic Ocean have been collected from the nearshore zone (depths shallower than 10 meters), suggesting that this zone has been significantly under-sampled and understudied in the global carbon cycle and along the land-ocean continuum. This study addresses this gap by investigating OC redistribution and transformation in the nearshore zone of the Canadian Beaufort Sea coast.
We collected sediment samples from five locations adjacent to eroding permafrost coasts along the Canadian Beaufort Sea coast across two shallow zones: the surf zone (0–2 m depth) and the nearshore zone (2–5 m depth). Additional samples included four shelf sediments (30–55 m depth), a sediment trap (2.2 m depth), and surface water samples. The samples were hydrodynamically fractionated (into low and high density with cutoff of 1.8 g/cm³; and subsequently size-fractionated) and analysed for their carbon (C), nitrogen (N), and δ¹³C content. We compare our results with an earlier study that characterized eroding permafrost coastal material.
Our findings indicate that in eroding permafrost, the majority of OC is stored in the LD and HD<38 μm fractions, contributing 69±22% and 20±18% of OC, respectively. Fluvial material, as shown by sediment trap analysis, also retains most of its OC in the LD (56%) and HD<38 μm (32%) fractions. In contrast, surf zone sediments (0–2 m depth) predominantly store OC in the HD>200 μm and HD>63 μm fractions, which contribute up to 39±23% and 28±18% of total OC, respectively, while the LD fraction accounts for only 19±24%. In slightly deeper nearshore waters (2–5 m depth), OC distribution shifts, with a larger fraction in HD<38 μm (41±23%) and HD>63 μm (27±26%), and the LD fraction increasing to 28±18%. On the inner shelf, OC distribution undergoes a clear shift, with the HD<38 μm fraction becoming the dominant contributor, representing 86±2.4% of total sediment OC. Scanning Electron Microscopy (SEM) images confirm that vascular plant material can be found in the high-density (usually more mineral) fractions, particularly in the high-density (63–200 μm) fraction. These findings highlight the redistribution and transformation of vascular plant material into high-density coarse fractions, which can undergo further degradation. It further highlights the importance of shallow Arctic coastal zones in the global carbon cycle, emphasizing their role in the redistribution, transformation, and burial of terrestrial organic carbon. By focusing on these underrepresented zones, this research provides critical insights into Arctic OC dynamics under the influence of climate-driven changes.
How to cite: van Crimpen, F., Madaj, L., van Genuchten, J., Tesi, T., Whalen, D., Scharffenberg, K., Bröder, L., Fritz, M., and Vonk, J.: Bridging the Gap: Nearshore zones as key mediators in Arctic land-ocean carbon fluxes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16304, https://doi.org/10.5194/egusphere-egu25-16304, 2025.
Posters on site: Mon, 28 Apr, 16:15–18:00 | Hall X5
Wildfires have important effects on hydrothermal regimes of boreal permafrost. However, they are not yet systematically and extensively studied in Northeast China, except those discrete measurements during the early 1990s. Since 2017, a series of study sites have been built for continuous observation on ground hydrothermal regimes at ten sites of three fire severity (unburned, light burn and severe burn) in three areas (Mo’he, Alongshan and Mangui) on the western flank of the northern Da Xing’anling Mountains, Northeast China. An integrated dataset was compiled with sub-datasets on ground temperatures, soil moisture contents, and active layer thickness (ALT). The study results show evident impacts of wildfires manifested as rapid ground warming, thickening active layer and drying shallow soils. Moreover, the thermally affected depth of wildfires has exceeded 20 m, and ALT has increased by as much as 2.75 m eight years after the severe burn. Post-fire changes were more pronounced in ground temperatures at depths of 0-6 m. In addition, changes in ground hydrothermal regimes became greater with increasing fire severity, and the fire influences lasted more than 30 years. Rapid warming and thawing of permafrost and subsequent loss of SOC after wildfires could have a positive feedback effect on climate warming. Therefore, this study can provide basic data for studies and action plan to support the carbon neutralization initiative and for assessment of ecological safety and management of the permafrost environment.
How to cite: Li, X., Wang, H., Jin, H., He, R., Luo, D., Li, Z., and Zhang, J.: Monitoring of ground hydrothermal regimes and active layer thickness during 2017-2022 in some previously burned areas in hemiboreal forests in Northeast China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2193, https://doi.org/10.5194/egusphere-egu25-2193, 2025.
The permafrost types in the Arctic and Qinghai-Tibet Plateau (QTP) are different, resulting in significant differences in their thermal characteristics. Soil thermal conductivity (STC) is a key physical parameter in land surface processes that controls the storage and conduction of heat in soil, and it is of great significance for simulating the thermal state of frozen soil. Here,a comparative study on STC of the active layer surface soil between the Arctic tundra and alpine meadow in hinterland of the QTP was conducted. Results show that the STC of the Arctic tundra and the alpine meadow in hinterland of the QTP exhibit an opposite patterns. During study period, monthly average STC of the Arctic tundra varied significantly with seasons, reaching a maximum of 1.989 Wm-1K-1 in cold season and a minimum of 0.761 Wm-1K-1 in warmer season, with an annual average of 1.541 Wm-1K-1. For Arctic tundra, STC in frozen state was 1.787 Wm-1K-1, while in the unfrozen state, it was 0.802 Wm-1K-1. In contrast, the monthly average STC for alpine meadow in the hinterland of the QTP showed opposite pattern, with the minimum value of 0.933 Wm-1K-1 occurred in January and the maximum value of 1.375 Wm-1K-1 occurred in September, and an annual average of 1.151 Wm-1K-1. In frozen state STC was 0.962 Wm-1K-1 while in unfrozen state such value was 1.341 Wm-1K-1. Field observation experiments in both regions found that STC is strongly dependent on soil moisture content. The initial frozen water content of the Bylot tundra in the Arctic was approximately 0.531 m3m-3 (0.495~ 0.565 m3m-3), while that of the Tanggula alpine meadow in the hinterland of the QTP was 0.142 m3m-3 (0.167~0.115 m3m-3), only 26.7% of the Arctic tundra. This significant difference in initial frozen water content is the main reason for the difference in STC between the two regions. Additionally, rapid changes in unfrozen water content have a great impact on STC during freezing process. For the Arctic tundra observation site, the STC increased by 0.273 Wm-1K-1 (0.247~0.300 Wm-1K-1) for every 0.100 m3m-3 decrease in unfrozen water content. While for the alpine meadow of the QTP, the STC decreased by 0.163 Wm-1K-1 for every 0.100 m3m-3 decrease in unfrozen water content. On average, in the Arctic tundra, the STC of the active layer surface decreases with increasing soil liquid water content, while in the alpine meadow of the QTP, it increases with increasing soil liquid water content. In frozen state for Arctic tundra, the contribution of soil ice content and unfrozen water to thermal conductivity is 75.6% and 5.2%, respectively. It can be seen that STC of the Arctic tundra active layer is mainly controlled by the ice content. As for the QTP meadow, such values were 25.9% and 41.8%, respectively. That means unfrozen water content is the dominant factor for STC changes in the QTP meadow. Furthermore, the Kerstern number scheme was optimized based on the STC data obtained from in-situ observations and KD2 Pro dehumidification experiments of soil samples under different soil moisture conditions.
How to cite: Li, R., Wang, S., Wu, T., Tang, S., Liu, W., and Wu, X.: A comparative investigation on the in-situ thermal conductivity between Arctic tundra and alpine meadow in the hinterland of the Qinghai-Tibet Plateau, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5655, https://doi.org/10.5194/egusphere-egu25-5655, 2025.
Solifluction processes inherent in Arctic environments introduce a layer of complexity when estimating both current and future soil carbon dynamics and fluxes. This intricacy extends to the assessment of hillslope stability and infrastructure resilience. Understanding the dynamic interplay of factors in the Arctic landscape requires a meticulous examination of triggers and drivers behind soil movement in hillslopes with discontinuous permafrost. In this study, we made use of a novel dense monitoring approach to obtain vertically resolved, continuous observations of soil movement and temperature at tens of locations across multiple adjacent hillslopes throughout two successive thawing seasons to better understand the mechanisms at play.
Results show substantial soil movements, with surface deformations reaching up to 344 mm in the second year. The upper parts of the watershed exhibited the greatest movements, with thaw depth, slope angle, and thermal conditions identified as key factors influencing solifluction. Thaw depth played a central role, triggering deformation by impacting water pressure at the thawing front. Soil temperature influenced both thawing and freezing processes, affecting soil cohesion and internal friction, which are critical for slope stability. A Factor of Safety proxy based on observed data has been developed and proved useful for assessing slope stability and understanding the effects of soil thermal conditions on deformation. This study provides new insights into the triggers of hillslope movements, contributing to the broader understanding of soil redistribution in Arctic environments and the implications for future landscape and infrastructure resilience in these regions.
How to cite: Fiolleau, S., Uhlemann, S., Wielandt, S., and Dafflon, B.: Solifluction Processes in a Discontinuous Permafrost Arctic Landscape: Insights from Two Years of Dense Monitoring, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6618, https://doi.org/10.5194/egusphere-egu25-6618, 2025.
Under a climate warming, wildfires have been occurring frequently in the boreal permafrost regions. Wildfires can lead to rapid degradation of permafrost, triggering significant changes in soil nutrients. Since 2016, we have systematically established a network for studying soil nutrients (0-3.6 m in depth) and hydrothermal state of the active layer and permafrost (0-20 m in depth) in some previously burned areas in the northern Da Xing’anling (Hinggan) Mountains in Northeast China. The datasets included soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), soil moisture content (SMC), ground temperatures and active layer thickness (ALT). The data were collected from eight sites in four burned areas with two categories of fire severity (severely burned and unburned) from 2016 to 2022. The research showed that wildfires cause rapid degradation of permafrost and evident changes in soil nutrients. At depths of 0-4 m, ground temperatures were 0.5-9.9oC higher at the burned sites than those at the unburned sites. At depths of 12-20 m, the differences were 0-2.1oC between at the burned and unburned sites, and less than those at depths of 0-4 m. ALTs were 0.13-2.75 m deeper at the burned sites than those at the unburned sites. SMC values were lower at the burned sites than those at the unburned sites. Wildfires affected the ground freeze-thaw processes in permafrost regions, delaying the ground freezing or advancing the ground thaw by about a month. A large amount of SOC and TN were stored in the active layer and near-surface permafrost layer, especially in the soil organic layer. At depths of 0-1.5 m at the unburned sites, average contents of SOC and TN were 1.5-3.9 and 1.6-3.5 times those at the severely burned sites, respectively, and 2.5-2.9 and 1.5-2.0 times those of at the slightly burned sites, respectively. The contents of TP and TK also changed significantly in different burned years. With increasing fire severity, changes in the ground hydrothermal regimes and soil nutrient contents became more obvious. Moreover, 30 years after fire, there were still remarkable difference in ground hydrothermal regimes and soil nutrient contents between the burned and unburned sites. Wildfires lead to rapid ground warming and great loss of SOC, and the effects may last for at least 30 years.
How to cite: Jin, H., Li, X., and Wang, H.: An integrated dataset of ground hydrothermal regimes and soil nutrients monitored during 2016-2022 in Northeast China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7727, https://doi.org/10.5194/egusphere-egu25-7727, 2025.
Modeling climate-driven changes in permafrost, particularly surface subsidence caused by melting ground ice, remains a significant challenge for Earth System Models (ESMs) due to high spatial and temporal heterogeneity inherent in permafrost dynamics.
In this study, we investigate permafrost subsidence using the latest InSAR satellite data on ground displacement. With its meter-scale resolution, InSAR data provides a unique opportunity to examine the highly heterogeneous nature of permafrost subsidence unprecedented sampling density and coverage area. Statistical analyses were conducted on high-resolution data from PALSAR-2, covering five regions: Central North Slope, Inuvik region, Noatak River Basin, Yamal, and Yukon-Kuskokwim Delta.
Our findings reveal that permafrost subsidence exhibits consistent statistical properties. The Exponential Weibull distribution (EWD) emerged as the best-fit model across all regions and scales, effectively capturing the skewed and heavy-tailed nature of subsidence distributions. Correlation analyses between subsidence and potential driving factors, including climatic variables derived from ERA5-Land, soil class, and topography, showed low direct correlations. Additional analysis of clustered subsidence distributions in relation to local environmental conditions was performed to explore cross-regional commonalities.
Furthermore, we identified key requirements and limitations for improving permafrost subsidence analyses using InSAR data. First, the quality of observation data does not significantly improve beyond a certain threshold of sample size and resolution. While larger datasets produce smoother histograms, the overall shape of the distribution remains unchanged. Second, results from a series of Kolmogorov-Smirnov (K-S) tests show that subsidence data reliability is insensitive to any Gaussian distributed noises.
These insights highlight some robustness in the statistical nature of permafrost subsidence while emphasizing the need to focus on other factors, such as temporal and spatial coverage, to advance future analyses on permafrost subsidence under climate impacts. Additionally, the choice of data filters plays a critical role, as effective filtering can preserve large-scale patterns while mitigating atmospheric artifacts.
This study provides a statistical perspective on utilizing InSAR data to gain new insights into permafrost subsidence, while identifying current data limitations that urgently need to be addressed.
How to cite: Liu, Z., Widhalm, B., Bartsch, A., Kleinen, T., and Brovkin, V.: Statistical Analyses of Permafrost Subsidence Based on High-resolution InSAR Data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8727, https://doi.org/10.5194/egusphere-egu25-8727, 2025.
Depth-to-bedrock (DTB) determines soil thickness in land surface models and controls the active depth of hydrological and biogeochemical processes, particularly important in permafrost regions where soil thickness affects both hydrologic and heat transfer. In this study, we evaluate the sensitivity of permafrost hydrothermal regime to DTB parameterization in Community Land Model version 5.0 (CLM5.0) by comparing two datasets: DTB_P (default DTB in CLM5.0, developed by Pelletier) and DTB_SG (Shangguan-derived DTB) over three sites (BLH, TGL, and XDT) and the Qinghai-Tibet Plateau (QTP). Through four experiments with increasing soil thickness, we find significant sensitivity of permafrost simulations to DTB, shallow DTB_P results in excess water being redistributed and overestimated active layer thickness (ALT) at three sites (9.1 m and 10.5 m at BLH and TGL, exceeding 42 m at XDT), while deeper DTB_SG improves simulations by enhancing soil column's water storage capacity and extending the depth of soil-parameterized heat transfer, where both thermal conductivity and heat capacity vary with soil properties rather than using constant bedrock values. At the regional scale, implementation of DTB_SG significantly reduces mean ALT from 8.83 m to 3.11 m across the QTP and from 9.04 m to 2.55 m in the Three Rivers Source Region, producing more realistic spatial patterns and temporal variations. We conclude that while soil liquid water simulations stabilize beyond 4.0 m, greater soil thickness continues to benefit thermal processes, establishing a minimum DTB threshold of 4.0 m for reliable permafrost simulations in the QTP.
How to cite: Chen, Z. and Luo, S.: Sensitivity of Permafrost Hydrothermal Regime to Depth-to-Bedrock in Land Surface Modeling: A Case Study of the Qinghai-Tibet Plateau, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8789, https://doi.org/10.5194/egusphere-egu25-8789, 2025.
Both field and satellite observations found a significant greening earth under global warming since the early 1980s, even surprisingly at the permafrost regions. However, the holistic effect of vegetation greening on permafrost at global scale remain unclear. This study employs a well-trained ensemble machine learning model, developed using extensive ground temperature measurements, high-quality climate, topographic, soil, and leaf area index (LAI) data, to assess the effect of vegetation greening on permafrost ground temperature and extent. Our model results show that vegetation greening on the permafrost will lead to a warming in mean annual ground temperature (MAGT) by 0.02-0.01 °C, a reduction in the area of permafrost by 6.7-2.5×104 km2 compared to the scenario without LAI increasing, under four shared socioeconomic pathways by the end of this century. This found indicate that the impact of vegetation greening on permafrost at global scale is negligible. However, the impact at regional or local scales is substantial under both SSP1-2.6 and SSP5-8.5, with the heating effect in most shrub-tundra areas averaging 0.2±0.1°C (potentially reaching up to 0.8°C). In contrast, the effect in grassland tundra areas is predominantly cooling, with an average of 0.1±0.05°C (potentially reaching up to 0.6°C), and only occurring under SSP5-8.5. Such multi-scale effects will have implications for climate, the carbon cycle, and projection of permafrost dynamics.
How to cite: Ran, Y.: Future vegetation greening on permafrost dynamics, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9437, https://doi.org/10.5194/egusphere-egu25-9437, 2025.
Circumpolar permafrost landscapes are undergoing rapid transition and are strongly affected by climate warming. In these high latitude regions, the rising temperatures are disrupting the thermal equilibrium of the ground, influencing the Arctics moisture levels (wetting / drying) which is driving significant changes in hydrological regimes. The Arctic is a water-rich region with abundant freshwater systems. An important feature of large rivers is their discharge of globally significant quantities of freshwater, dissolved organic carbon, and other materials into the Arctic Ocean, while lakes and rivers also contribute to the global emission of carbon dioxide and methane to the atmosphere.
For this study, three different Arctic river systems were investigated: the Mackenzie (Canada), the Ob (Russia) and the Lena (Russia). We mapped river systems at different levels of detail and localized floodplain-related areas by combining Digital Elevation Model (DEM) analysis with land cover maps (CALU). The floodplain areas are described by the fraction distribution of different land cover units. For example, the majority of the detected units showed water as the dominant unit. After filtering out the water areas, the remaining floodplain areas primarily consisted of wetland. We also separated the areas according to their bioclimate subzones (CAVM) which showed no significant differences in wet/dry units between the subzones; in all cases, wet areas were the majority.
This work contributes to the mapping and characterization of rivers in the Arctic, with a focus on identifying, describing, and analyzing floodplains in relation to river systems. The results will enhance the understanding of Arctic hydrology, providing a foundation for further analysis of the wetting and drying in the Arctic which is the focus of the ERC project Q-Arctic.
Datasets:
- CALU: Bartsch, A., Khairullin, R., Efimova, A., Widhalm, B., Muri, X., von Baeckmann, C., Bergstedt, H., Ermokhina, K., Hugelius, G., Heim, B., Leibman, M., & Gruber, C. (2024). Circumarctic Landcover Units (2.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.14235736
- CAVM: Walker, D. A., Raynolds, M. K., Daniëls, F. J., Einarsson, E., Elvebakk, A., Gould, W. A., Katenin, A. E., Kholod, S. S., Markon, C. J., Melnikov, E. S., Moskalenko, N. G., Talbot, S. S., Yurtsev, B. A., and other members of the CAVM Team (2005). The Circumpolar Arctic vegetation map, J. Veg. Sci., 16, 267–282, https://doi.org/10.1111/j.1654-1103.2005.tb02365.x
How to cite: von Baeckmann, C., Bartsch, A., Bergstedt, H., Widhalm, B., and Stacke, T.: Investigation of three different river systems and floodplain areas in Arctic permafrost regions., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10741, https://doi.org/10.5194/egusphere-egu25-10741, 2025.
Permafrost extends offshore in the Arctic as submarine permafrost. Near the edge of stable, continuous permafrost offshore, fresh groundwater flux contributes to regions of actively deforming thermokarst. Large-magnitude (up to ~30 m) sinkholes have been observed to form over less than a decade, posing a significant threat to offshore infrastructure. Additionally, having recently been discovered in sub-Arctic environments, thermokarst formation may be possible in a wider range of conditions than previously thought. It is critical to understand the evolution of degrading submarine permafrost, thermokarst, and the critical parameters necessary to predict the locations and magnitudes of seabed impacts.
We present acoustic sub-bottom profile (3.5 kHz Chirp) data collected in the Canadian Beaufort Sea, highlighting observations just offshore of a well-studied, actively deforming thermokarst field near the shelf edge. We map a seismic horizon that marks the top of ice-bearing sediment in the active thermokarst region; seaward, this horizon becomes a choppy unconformity punctuated by low-amplitude reflections that we interpret as fluid escape pathways. Beneath this horizon, an acoustically transparent layer persists seaward until characteristically and abruptly gaining coherent layering. We map the seaward edge of the acoustically transparent layer and interpret it as paleothermokarst. Laminated shallow seismic stratigraphy and a deep continuous acoustic basement surface are also characteristic of the interpreted paleothermokarst zone and absent from active thermokarst regions. The seaward edge of interpreted paleothermokarst has remarkably consistent seafloor depths at our mapped crossings (-372 m ± 34 m), suggesting an influence of depth-related processes controlling this edge. Lowstand sea level (-120 m) and potentially colder bottom-water temperatures may have allowed lowstand thermokarst to form ~187 m deeper than the thermokarst along the Canadian Beaufort margin today (which has seaward edge depths of -185 m ± 24 m). We suggest that the locus of active thermokarst (de)formation has moved landward over time in response to rising sea level, and expect the most active deformation at the landward edge of the thermokarst field.
How to cite: Walton, M., Obelcz, J., Hong, J. K., Paull, C., Hill, T., Lee, T., Wood, W., and Brake, V.: Evidence for Arctic paleothermokarst and melt features controlled by sea-level rise in regional sub-bottom profile data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12562, https://doi.org/10.5194/egusphere-egu25-12562, 2025.
Lakes and drained lake basins (DLBs) cover 50% to 75% of the landscape in permafrost lowland regions of Alaska, Siberia, and Canada. Lakes and DLBs of different ages create a heterogeneous and dynamic mosaic of terrain units, providing unique habitats for flora and fauna. Lakes and drained lake basins play a crucial role in the permafrost landscape and ecosystem processes, influencing permafrost dynamics, the hydrologic regime, and biogeochemical processes including carbon cycling and greenhouse gas emissions. Depending on time passed since drainage of a given DLB, characteristics like surface roughness, vegetation, moisture, and abundance of ponds may vary between basins. Spatial heterogeneity within a single basin also varies between basins of different age, climatic subzone and underlying surficial geology. The mosaic of vegetative and geomorphic succession within DLBs and the distinct differences between DLBs and surrounding areas can be discriminated with remote sensing and used to derive a landscape-scale classification.
Here we present an update from the circumpolar DLB mapping effort with a focus on regional differences in DLB distribution and DLB characteristics made visible by this systematic approach. We use the novel pan-Arctic assessment on DLB occurrence and the ESA Permafrost_cci circumpolar landcover unit data to assess the inter and intra-DLB spatial heterogeneity of surface characteristics, comparing different regions across the Arctic. Building on existing research, we utilize parameters like landcover patchiness, pond abundance and wetland distribution to infer relative age of different basins within a defined region. Different regions across the Arctic show different landcover distributions within basins, highlighting the importance for region-specific analysis when studying these landscape features. First results show distinct differences between DLBs of different geographic regions areas of differing surficial geology, based on the landcover occurring within basins and other surface properties. Comprehensive mapping and characterizing of DLBs on a circumpolar scale will allow for improved parametrization of regional to pan-Arctic modelling efforts and improve our understanding of DLBs as a crucial landform in Arctic permafrost landscapes.
How to cite: Bergstedt, H., Bartsch, A., von Baeckmann, C., Jones, B. M., Breen, A., Wolter, J., Farquharson, L., Grosse, G., and Kanevskiy, M.: Regional differences in drained lake basin distribution and surface characteristics across the Arctic , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15630, https://doi.org/10.5194/egusphere-egu25-15630, 2025.
The northern part of Western Siberia has been identified as one of the hotspot areas of climate change across the Arctic. This region is rich in typical permafrost features (thaw lakes, thaw slumps and polygonal features) and stretches across the current transition zone from continuous to discontinuous permafrost for more than 1200 km. These features are characterized by distinct wetness patterns which are expected to alter with permafrost thaw. Remote sensing has been shown of high value for monitoring this region in the past. This included e.g. landcover and ground subsidence analyses. A main constraint for satellite observations is, however, the spatial resolution when working over such large areas. UAV and VHR satellite observations are only available locally but can be used to investigate the impact of the scale mismatch of permafrost features and satellite observations.
A recently developed landcover dataset and subsidence (Sentinel-1) records were investigated for this study. The Circumpolar Landcover Unit (CALU) Database provides highly detailed landcover information with a spatial resolution of 10 meters and consists of 23 thematic units. This level of detail is needed for various applications addressing climate change impacts and ecological research. The used retrieval scheme of landcover units employed provides an unprecedented level of detail. The landcover units have been derived by fusion of satellite data using Sentinel-1 (synthetic aperture radar) and Sentinel-2 (multispectral). These units reflect gradients in moisture and vegetation structure. The available spatial detail of CALU has been already shown to provide the means to assess the complexity of lowland permafrost regions, specifically related to thaw lake variations.
The original CALU database covered the Arctic north of the tree line. The latest version extents towards south, providing additional detail within the tundra-taiga. In addition, about a third of the original extend has been reprocessed (including parts of Western Siberia). Numerous issues of the previous version like data gaps, processing artefacts and minor misclassification cases were addressed.
Eventually, the satellite derived information has been compared to VHR data, specifically for polygonal tundra. A database including a range of relevant properties (e.g. low centered versus high centered polygons) has been created for this purpose, covering 25 sites sized 1x1 km with polygonal peatlands spread for 30 kilometers from north to south in the northern part of the Pur-Taz interfluve. Permafrost properties of this area are rapidly changing: while it was considered to be continuous in 1991, it is now discontinuous according to CCI Permafrost data. Statistics based on wetness gradients and landcover for polygonal and non-polygonal features were analyzed. Differences in typical wetness gradients between these features were found to be more pronounced in subsidence retrievals than in landcover.
CALU: Bartsch, A., Khairullin, R., Efimova, A., Widhalm, B., Muri, X., von Baeckmann, C., Bergstedt, H., Ermokhina, K., Hugelius, G., Heim, B., Leibman, M., & Gruber, C. (2024). Circumarctic Landcover Units (2.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.14235736
How to cite: Khairullin, R., Widhalm, B., Gruber, C., von Baeckmann, C., Radha Krishnan, S. R., Bartsch, A., and Khomutov, A.: Permafrost feature and wetness gradient monitoring in Northern Western Siberia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16275, https://doi.org/10.5194/egusphere-egu25-16275, 2025.
Extreme heat events can significantly impact the active-layer thermal conditions of permafrost, yet there is still lack of a comprehensive evaluation of extreme heat events across the permafrost region of the Northern Hemisphere (PRONH). We used six indices to quantify the spatio-temporal patterns and variations of extreme heat events in PRONH under historical (1991–2020) and projected future (2021–2100) periods. Furthermore, we compared the trend of extreme heat events among four types of permafrost and discussed their potential impacts on permafrost dynamics. The results
indicated that, variations in extreme heat events were not significant across most regions during the historical period. Under high-emission scenarios, the Arctic and Tibet Plateau regions exhibit the rapid increases, and extreme heat events may become the norm in these areas. The northern Greenland permafrost region demonstrates a dual-sided extrusion warming process, with increases in air temperatures accompanied by decreases in the annual highest temperatures. Continuous permafrost will experience more extreme heat events in the future, while the increase of extreme heat events in discontinuous, sporadic, and isolated permafrost is relatively slow but their intensity remains considerable. Due to their scattered distribution, those permafrost types are more susceptible to extreme heat events, potentially leading to higher degradation risks in these regions.
How to cite: Feng, H., Su, B., Zhao, H., Zhang, T., and Xiao, C.: Increasing Extreme Heat Events in the Permafrost Region of the Northern Hemisphere, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21061, https://doi.org/10.5194/egusphere-egu25-21061, 2025.
