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.