May 2019 Monthly Permafrost Alert (PMA) Program

The U.S. Permafrost Association is pleased to announce the availability of an updated searchable database on permafrost-related publications. The American Geosciences Institute, with support from the National Science Foundation, has migrated the previous Cold Regions Bibliography to a new platform. Included are the US Permafrost Association supported Monthly Permafrost Alerts dating back to 2011. The Bibliography is searchable at : www.coldregions.org.

Entries in each category are listed in chronological order starting with the most recent citation.

The May Alert includes 64 additional citations from the 2019 European Geosciences Union General Assembly and 22 from the 2018 EGU Assembly.

The individual Monthly Permafrost Alerts are found on the US Permafrost Association website : http://www.uspermafrost.org/monthly-alerts.shtml.

2019046750 Ploum, Stefan W. (Swedish University of Agricultural Sciences, Department of Forest Ecology and Management, Umea, Sweden); Lyon, Steve W.; Teuling, Adriaan J.; Laudon, Hjalmar and Velde, Ype. Soil frost effects on streamflow recessions in a subarctic catchment: Hydrological Processes, 33(9), p. 1304-1316, sketch map, 52 ref., April 30, 2019.

The Arctic is warming rapidly. Changing seasonal freezing and thawing cycles of the soil are expected to affect river run-off substantially, but how soil frost influences river run-off at catchment scales is still largely unknown. We hypothesize that soil frost alters flow paths and therefore affects storage-discharge relations in subarctic catchments. To test this hypothesis, we used an approach that combines meteorological records and recession analysis. We studied streamflow data (1986-2015) of Abiskojokka, a river that drains a mountainous catchment (560 km²) in the north of Sweden (68° latitude). Recessions were separated into frost periods (spring) and no-frost periods (summer) and then compared. We observed a significant difference between recessions of the two periods: During spring, discharge was linearly related to storage, whereas storage-discharge relationships in summer were less linear. An analysis of explanatory factors showed that after winters with cold soil temperatures and low snowpack, storage-discharge relations approached linearity. On the other hand, relatively warm winter soil conditions resulted in storage-discharge relationships that were less linear. Even in summer, relatively cold antecedent winter soils and low snowpack levels had a propagating effect on streamflow. This could be an indication that soil frost controls recharge of deep groundwater flow paths, which affects storage-discharge relationships in summer. We interpret these findings as evidence for soil frost to have an important control over river run-off dynamics. To our knowledge, this is the first study showing significant catchment-integrated effects of soil frost on this spatiotemporal scale. Abstract Copyright (2019), John Wiley & Sons, Ltd.

DOI: 10.1002/hyp.13401

2019046752 Zhang Zaiyong (Chang'an University, Laboratory of Subsurface Hydrology and Ecological Effects in Arid Regions, Xi'an, China); Wang Wenke; Gong Chengcheng; Wang Zhoufeng; Duan Lei; Yeh, Tian-chyi Jim and Yu Peiyuan. Evaporation from seasonally frozen bare and vegetated ground at various groundwater table depths in the Ordos Basin, northwest China: Hydrological Processes, 33(9), p. 1338-1348, illus. incl. 3 tables, sketch map, 36 ref., April 30, 2019.

In cold climates, the process of freezing-thawing significantly affects the ground surface heat balance and water balance. To better understand the mechanism of evaporation from seasonally frozen soils, we performed field experiments at different water table depths on vegetated and bare ground in a semiarid region in China. Soil moisture and temperature, air temperature, precipitation, and water table depths were measured over a 5-month period (November 1, 2016, to March 14, 2017). The evaporation, which was calculated by a mass balance method, was high in the periods of thawing and low in the periods of freezing. Increased water table depth in the freezing period led to high soil moisture in the upper soil layer, whereas lower initial groundwater levels during freezing-thawing decreased the cumulative evaporation. The extent of evaporation from the bare ground was the same in summer as in winter. These results indicate that a noteworthy amount of evaporation from the bare ground is present during freezing-thawing. Finally, the roots of Salix psammophila could increase the soil temperature. This study presents an insight into the joint effects of soil moisture, temperature, ground vegetation, and water table depths on the evaporation from seasonally frozen soils. Furthermore, it also has important implications for water management in seasonally frozen areas. Abstract Copyright (2019), John Wiley & Sons, Ltd.

DOI: 10.1002/hyp.13404

2019046757 Martin, Leo C. P. (University of Oslo, Department of Geosciences, Oslo, Norway); Nitzbon, Jan; Aas, Kjetil Schanke; Etzelmüller, B.; Kristiansen, H. and Westermann, Sebastian. Stability conditions of peat plateaus and palsas in Northern Norway: Journal of Geophysical Research: Earth Surface, 124(3), p. 705-719, illus. incl. 1 table, sketch map, 56 ref., March 2019.

Peat plateaus and palsas are characteristic morphologies of sporadic permafrost, and the transition from permafrost to permafrost-free ground typically occurs on spatial scales of meters. They are particularly vulnerable to climate change and are currently degrading in Fennoscandia. Here we present a spatially distributed data set of ground surface temperatures for two peat plateau sites in northern Norway for the year 2015-2016. Based on these data and thermal modeling, we investigate how the snow depth and water balance modulate the climate signal in the ground. We find that mean annual ground surface temperatures are centered around 2 to 2.5°C for stable permafrost locations and 3.5 to 4.5°C for permafrost-free locations. The surface freezing degree days are characterized by a noticeable threshold around 200°C.day, with most permafrost-free locations ranging below this value and most stable permafrost ones above it. Freezing degree day values are well correlated to the March snow cover, although some variability is observed and attributed to the ground moisture level. Indeed, a zero curtain effect is observed on temperature time series for saturated soils during winter, while drained peat plateaus show early freezing surface temperatures. Complementarily, modeling experiments allow identifying a drainage effect that can modify 1-m ground temperatures by up to 2°C between drained and water accumulating simulations for the same snow cover. This effect can set favorable or unfavorable conditions for permafrost stability under the same climate forcing. Abstract Copyright (2019), American Geophysical Union. All Rights Reserved.

DOI: 10.1029/2018JF004945

2019048243 Xu Min (Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, State Key Laboratory of Cryospheric Science, Lanzhou, China); Kang Shichang; Wang Xiaoming; Pepin, Nick and Wu Hao. Understanding changes in the water budget driven by climate change in cryospheric-dominated watershed of the northeast Tibetan Plateau, China: Hydrological Processes, 33(7), p. 1040-1058, illus. incl. 10 tables, sketch map, 77 ref., March 30, 2019.

Glacial retreat and the thawing of permafrost due to climate warming have altered the hydrological cycle in cryospheric-dominated watersheds. In this study, we analysed the impacts of climate change on the water budget for the upstream of the Shule River Basin on the northeast Tibetan Plateau. The results showed that temperature and precipitation increased significantly during 1957-2010 in the study area. The hydrological cycle in the study area has intensified and accelerated under recent climate change. The average increasing rate of discharge in the upstream of the Shule River Basin was 7.9´10⁶ m³/year during 1957-2010. As the mean annual glacier mass balance lost -62.4 mm/year, the impact of glacier discharge on river flow has increased, especially after the 2000s. The contribution of glacier melt to discharge was approximately 187.99´10⁸ m³ or 33.4% of the total discharge over the study period. The results suggested that the impact of warming overcome the effect of precipitation increase on run-off increase during the study period. The evapotranspiration (ET) increased during 1957-2010 with a rate of 13.4 mm/10 years. On the basis of water balance and the Gravity Recovery and Climate Experiment and the Global Land Data Assimilation System data, the total water storage change showed a decreasing trend, whereas groundwater increased dramatically after 2006. As permafrost has degraded under climate warming, surface water can infiltrate deep into the ground, thus changing both the watershed storage and the mechanisms of discharge generation. Both the change in terrestrial water storage and changes in groundwater have had a strong control on surface discharge in the upstream of the Shule River Basin. Future trends in run-off are forecasted based on climate scenarios. It is suggested that the impact of warming will overcome the effect of precipitation increase on run-off in the study area. Further studies such as this will improve understanding of water balance in cold high-elevation regions. Abstract Copyright (2019), John Wiley & Sons, Ltd.

DOI: 10.1002/hyp.13383

2019050107 Neumann, Rebecca B. (University of Washington, Department of Civil and Environmental Engineering, Seattle, WA); Moorberg, Colby J.; Lundquist, Jessica D.; Turner, Jesse C.; Waldrop, Mark P.; McFarland, Jack W.; Euskirchen, Eugenie S.; Edgar, Colin W. and Turetsky, Merritt R. Warming effects of spring rainfall increase methane emissions from thawing permafrost: Geophysical Research Letters, 46(3), p. 1393-1401, illus., 50 ref., February 16, 2019.

Methane emissions regulate the near-term global warming potential of permafrost thaw, particularly where loss of ice-rich permafrost converts forest and tundra into wetlands. Northern latitudes are expected to get warmer and wetter, and while there is consensus that warming will increase thaw and methane emissions, effects of increased precipitation are uncertain. At a thawing wetland complex in Interior Alaska, we found that interactions between rain and deep soil temperatures controlled methane emissions. In rainy years, recharge from the watershed rapidly altered wetland soil temperatures, warming the top ~80 cm of soil in spring and summer and cooling it in autumn. When soils were warmed by spring rainfall, methane emissions increased by ~30%. The warm, deep soils early in the growing season likely supported both microbial and plant processes that enhanced emissions. Our study identifies an important and unconsidered role of rain in governing the radiative forcing of thawing permafrost landscapes. Abstract Copyright (2019), . American Geophysical Union. All Rights Reserved.

DOI: 10.1029/2018GL081274

2019048271 Aas, Kjetil Schanke (University of Oslo, Department of Geosciences, Oslo, Norway); Martin, Leo; Nitzbon, Jan; Langer, Moritz; Boike, Julia; Lee, Hanna; Berntsen, Terje K. and Westermann, Sebastian. Thaw processes in ice-rich permafrost landscapes represented with laterally coupled tiles in a land surface model: The Cryosphere (Online), 13(2), p. 591-609, illus. incl. 2 tables, 60 ref., 2019.

Earth system models (ESMs) are our primary tool for projecting future climate change, but their ability to represent small-scale land surface processes is currently limited. This is especially true for permafrost landscapes in which melting of excess ground ice and subsequent subsidence affect lateral processes which can substantially alter soil conditions and fluxes of heat, water, and carbon to the atmosphere. Here we demonstrate that dynamically changing microtopography and related lateral fluxes of snow, water, and heat can be represented through a tiling approach suitable for implementation in large-scale models, and we investigate which of these lateral processes are important to reproduce observed landscape evolution. Combining existing methods for representing excess ground ice, snow redistribution, and lateral water and energy fluxes in two coupled tiles, we show that the model approach can simulate observed degradation processes in two very different permafrost landscapes. We are able to simulate the transition from low-centered to high-centered polygons, when applied to polygonal tundra in the cold, continuous permafrost zone, which results in (i) a more realistic representation of soil conditions through drying of elevated features and wetting of lowered features with related changes in energy fluxes, (ii) up to 2°C reduced average permafrost temperatures in the current (2000-2009) climate, (iii) delayed permafrost degradation in the future RCP4.5 scenario by several decades, and (iv) more rapid degradation through snow and soil water feedback mechanisms once subsidence starts. Applied to peat plateaus in the sporadic permafrost zone, the same two-tile system can represent an elevated peat plateau underlain by permafrost in a surrounding permafrost-free fen and its degradation in the future following a moderate warming scenario. These results demonstrate the importance of representing lateral fluxes to realistically simulate both the current permafrost state and its degradation trajectories as the climate continues to warm. Implementing laterally coupled tiles in ESMs could improve the representation of a range of permafrost processes, which is likely to impact the simulated magnitude and timing of the permafrost-carbon feedback.

DOI: 10.5194/tc-13-591-2019

2019048269 Cao Bin (Lanzhou University, College of Earth and Environmental Sciences, Laboratory of Western China's Environmental Systems, Lanzhou, China); Zhang Tingjun; Wu Qingbai; Sheng Yu; Zhao Lin and Zou Defu. Evaluation and inter-comparisons of Qinghai-Tibet Plateau permafrost maps based on a new inventory of field evidence: The Cryosphere (Online), 13(2), p. 511-519, illus. incl. 2 tables, sketch map, 34 ref., 2019.

Many maps have been produced to estimate permafrost distribution over the Qinghai-Tibet Plateau (QTP), but the errors and biases among them are poorly understood due to limited field evidence. Here we evaluate and inter-compare the results of six different QTP permafrost maps with a new inventory of permafrost presence or absence comprising 1475 field sites compiled from various sources. Based on the in situ measurements, our evaluation results showed a wide range of map performance, with Cohen's kappa coefficient from 0.21 to 0.58 and an overall accuracy between about 55% and 83%. The low agreement in areas near the boundary between permafrost and non-permafrost and in spatially highly variable landscapes highlights the need for improved mapping methods that consider more controlling factors at both medium-large and local scales.

DOI: 10.5194/tc-13-511-2019

2019048272 Chang, Kuang-Yu (Lawrence Berkeley National Laboratory, Climate and Ecosystem Sciences Division, Berkeley, CA); Riley, William J.; Crill, Patrick M.; Grant, Robert F.; Rich, Virginia I. and Saleska, Scott R. Large carbon cycle sensitivities to climate across a permafrost thaw gradient in subarctic Sweden: The Cryosphere (Online), 13(2), p. 647-663, illus. incl. 3 tables, 77 ref., 2019.

Permafrost peatlands store large amounts of carbon potentially vulnerable to decomposition. However, the fate of that carbon in a changing climate remains uncertain in models due to complex interactions among hydrological, biogeochemical, microbial, and plant processes. In this study, we estimated effects of climate forcing biases present in global climate reanalysis products on carbon cycle predictions at a thawing permafrost peatland in subarctic Sweden. The analysis was conducted with a comprehensive biogeochemical model (ecosys) across a permafrost thaw gradient encompassing intact permafrost palsa with an ice core and a shallow active layer, partly thawed bog with a deeper active layer and a variable water table, and fen with a water table close to the surface, each with distinct vegetation and microbiota. Using in situ observations to correct local cold and wet biases found in the Global Soil Wetness Project Phase 3 (GSWP3) climate reanalysis forcing, we demonstrate good model performance by comparing predicted and observed carbon dioxide (CO₂) and methane (CH₄) exchanges, thaw depth, and water table depth. The simulations driven by the bias-corrected climate suggest that the three peatland types currently accumulate carbon from the atmosphere, although the bog and fen sites can have annual positive radiative forcing impacts due to their higher CH₄ emissions. Our simulations indicate that projected precipitation increases could accelerate CH₄ emissions from the palsa area, even without further degradation of palsa permafrost. The GSWP3 cold and wet biases for this site significantly alter simulation results and lead to erroneous active layer depth (ALD) and carbon budget estimates. Biases in simulated CO₂ and CH₄exchanges from biased climate forcing are as large as those among the thaw stages themselves at a landscape scale across the examined permafrost thaw gradient. Future studies should thus not only focus on changes in carbon budget associated with morphological changes in thawing permafrost, but also recognize the effects of climate forcing uncertainty on carbon cycling.

DOI: 10.5194/tc-13-647-2019

2019048261 Coulombe, Stephanie (Polar Knowledge Canada, Cambridge Bay, NU, Canada); Fortier, Daniel; Lacelle, Denis; Kanevskiy, Mikhail and Shur, Yuri. Origin, burial and preservation of late Pleistocene-age glacier ice in Arctic permafrost (Bylot Island, NU, Canada): The Cryosphere (Online), 13(1), p. 97-111, illus. incl. sect., 1 table, sketch map, 81 ref., 2019.

Over the past decades, observations of buried glacier ice exposed in coastal bluffs and headwalls of retrogressive thaw slumps of the Arctic have indicated that considerable amounts of late Pleistocene glacier ice survived the deglaciation and are still preserved in permafrost. In exposures, relict glacier ice and intrasedimental ice often coexist and look alike but their genesis is strikingly different. This paper aims to present a detailed description and infer the origin of a massive ice body preserved in the permafrost of Bylot Island (Nunavut). The massive ice exposure and core samples were described according to the cryostratigraphic approach, combining the analysis of permafrost cryofacies and cryostructures, ice crystallography, stable O-H isotopes and cation contents. The ice was clear to whitish in appearance with large crystals (cm) and small gas inclusions (mm) at crystal intersections, similar to observations of englacial ice facies commonly found on contemporary glaciers and ice sheets. However, the d¹⁸O composition (-34.0±0.4 ppm) of the massive ice was markedly lower than contemporary glacier ice and was consistent with the late Pleistocene age ice in the Barnes Ice Cap. This ice predates the aggradation of the surrounding permafrost and can be used as an archive to infer palaeo-environmental conditions at the study site. As most of the glaciated Arctic landscapes are still strongly determined by their glacial legacy, the melting of these large ice bodies could lead to extensive slope failures and settlement of the ground surface, with significant impact on permafrost geosystem landscape dynamics, terrestrial and aquatic ecosystems and infrastructure.

DOI: 10.5194/tc-13-97-2019

2019048274 Karjalainen, Olli (University of Oulu, Geography Research Unit, Oulu, Finland); Luoto, Miska; Aalto, Juha and Hjort, Jan. New insights into the environmental factors controlling the ground thermal regime across the Northern Hemisphere; a comparison between permafrost and non-permafrost areas: The Cryosphere (Online), 13(2), p. 693-707, illus. incl. 2 tables, 88 ref., 2019.

The thermal state of permafrost affects Earth surface systems and human activity in the Arctic and has implications for global climate. Improved understanding of the local-scale variability in the global ground thermal regime is required to account for its sensitivity to changing climatic and geoecological conditions. Here, we statistically related observations of mean annual ground temperature (MAGT) and active-layer thickness (ALT) to high-resolution (~1 km²) geospatial data of climatic and local environmental conditions across the Northern Hemisphere. The aim was to characterize the relative importance of key environmental factors and the magnitude and shape of their effects on MAGT and ALT. The multivariate models fitted well to both response variables with average R² values being ~0.94 and 0.78. Corresponding predictive performances in terms of root-mean-square error were ~1.31°C and 87 cm. Freezing (FDD) and thawing (TDD) degree days were key factors for MAGT inside and outside the permafrost domain with average effect sizes of 6.7 and 13.6°C, respectively. Soil properties had marginal effects on MAGT (effect size=0.4-0.7°C). For ALT, rainfall (effect size=181 cm) and solar radiation (161 cm) were most influential. Analysis of variable importance further underlined the dominance of climate for MAGT and highlighted the role of solar radiation for ALT. Most response shapes for MAGT ≤&eq;0°C and ALT were non-linear and indicated thresholds for covariation. Most importantly, permafrost temperatures had a more complex relationship with air temperatures than non-frozen ground. Moreover, the observed warming effect of rainfall on MAGT≤&eq;0°C reverted after reaching an optimum at ~250 mm, and that of snowfall started to level off at ~300-400 mm. It is suggested that the factors of large global variation (i.e. climate) suppressed the effects of local-scale factors (i.e. soil properties and vegetation) owing to the extensive study area and limited representation of soil organic matter. Our new insights into the factors affecting the ground thermal regime at a 1 km scale should improve future hemispheric-scale studies.

DOI: 10.5194/tc-13-693-2019

2019048263 Yi, Yonghong (California Institute of Technology, Jet Propulsion Laboratory, Pasadena, CA); Kimball, John S.; Chen, Richard H.; Moghaddam, Mahta and Miller, Charles E. Sensitivity of active-layer freezing process to snow cover in Arctic Alaska: The Cryosphere (Online), 13(1), p. 197-218, illus. incl. 4 tables, 94 ref., 2019.

The contribution of cold-season soil respiration to the Arctic-boreal carbon cycle and its potential feedback to the global climate remain poorly quantified, partly due to a poor understanding of changes in the soil thermal regime and liquid water content during the soil-freezing process. Here, we characterized the processes controlling active-layer freezing in Arctic Alaska using an integrated approach combining in situ soil measurements, local-scale (~50 m) longwave radar retrievals from NASA airborne P-band polarimetric SAR (PolSAR) and a remote-sensing-driven permafrost model. To better capture landscape variability in snow cover and its influence on the soil thermal regime, we downscaled global coarse-resolution (~0.5°) MERRA-2 reanalysis snow depth data using finer-scale (500 m) MODIS snow cover extent (SCE) observations. The downscaled 1 km snow depth data were used as key inputs to the permafrost model, capturing finer-scale variability associated with local topography and with favorable accuracy relative to the SNOTEL site measurements in Arctic Alaska (mean RMSE=0.16 m, bias=-0.01 m) In situ tundra soil dielectric constant (e) profile measurements were used for model parameterization of the soil organic layer and unfrozen-water content curve. The resulting model-simulated mean zero-curtain period was generally consistent with in situ observations spanning a 2° latitudinal transect along the Alaska North Slope (R: 0.6±0.2; RMSE: 19±6 days), with an estimated mean zero-curtain period ranging from 61±11 to 73±15 days at 0.25 to 0.45 m depths. Along the same transect, both the observed and model-simulated zero-curtain periods were positively correlated (R>0.55, p<0.01) with a MODIS-derived snow cover fraction (SCF) from September to October. We also examined the airborne P-band radar-retrieved e profile along this transect in 2014 and 2015, which is sensitive to near-surface soil liquid water content and freeze-thaw status. The e difference in radar retrievals for the surface (~<0.1 m) soil between late August and early October was negatively correlated with SCF in September (R=-0.77, p<0.01); areas with lower SCF generally showed larger e reductions, indicating earlier surface soil freezing. On regional scales, the simulated zero curtain in the upper (<0.4 m) soils showed large variability and was closely associated with variations in early cold-season snow cover. Areas with earlier snow onset generally showed a longer zero-curtain period; however, the soil freeze onset and zero-curtain period in deeper (>0.5 m) soils were more closely linked to maximum thaw depth. Our findings indicate that a deepening active layer associated with climate warming will lead to persistent unfrozen conditions in deeper soils, promoting greater cold-season soil carbon loss.

DOI: 10.5194/tc-13-197-2019

2019049375 Guglielmin, Mauro (Insubria University, Department of Theoretical and Applied Sciences, Varese, Italy); Donatelli, Marco; Semplice, Matteo and Serra Capizzano, Stefano. Ground surface temperature reconstruction for the last 500 years obtained from permafrost temperatures observed in the SHARE STELVIO Borehole, Italian Alps: Climate of the Past, 14(6), p. 709-724, illus. incl. 2 tables, 56 ref., June 2018.

Here we present the results of the inversion of a multi-annual temperature profile (2013, 2014, 2015) of the deepest borehole (235 m) in the mountain permafrost of the world located close to Stelvio Pass in the Central Italian Alps. The SHARE STELVIO Borehole (SSB) has been monitored since 2010 with 13 thermistors placed at different depths between 20 and 235 m. The negligible porosity of the rock (dolostone, < 5 %) allows us to assume the latent heat effects are also negligible. The inversion model proposed here is based on the Tikhonov regularization applied to a discretized heat equation, accompanied by a novel regularizing penalty operator. The general pattern of ground surface temperatures (GSTs) reconstructed from SSB for the last 500 years is similar to the mean annual air temperature (MAAT) reconstructions for the European Alps. The main difference with respect to MAAT reconstructions relates to post Little Ice Age (LIA) events. Between 1940 and 1989, SSB data indicate a cooling of ca. 1 °C. Subsequently, a rapid and abrupt GST warming (more than 0.8 °C per decade) was recorded between 1990 and 2011. This warming is of the same magnitude as the increase in MAAT between 1990 and 2000 recorded in central Europe and roughly doubling the increase in MAAT in the Alps.

DOI: 10.5194/cp-14-709-2018

2019047314 Zhang Zhongqiong (Chinese Academy of Science, Northwest Institute of Eco-Environment and Resources, State Key Laboratory of Frozen Soil Engineering, Lanzhou, China); Wu Qingbai; Xun Xueyi; Wang Boxin and Wang Xunan. Climate change and the distribution of frozen soil in 1980-2010 in northern northeast China: Quaternary International, 467(Part B), p. 230-241, illus. incl. 2 tables, sketch map, 36 ref., February 22, 2018.

Frozen soil is an important environmental factor in cold regions. Permafrost change, driven by a warming climate, will increase the risk of permafrost thawing, i.e., carbon release accelerating, suprapermafrost water lowering, desertification strengthening, and infrastructure destructing. Based on the energy balance between the atmosphere and the soil, mean annual air temperature (MAAT), annual precipitation (AP), and mean annual wind speed (Vs) were selected for the analysis of the patterns of permafrost environment and its dynamics from 1980 to 2010 in northern northeast China. According to data from meteorological stations, MAAT and Vs increased with the decrease of latitude in the study area, whereas AP increased with the increase of longitude. During 1980 to 2010, the average of MAAT, Vs, AP, freezing index (DDF), and thawing index (DDT) in the study area was -0.73°C, 473.5 mm, 2.44 m s^-1, -2696.7°C·d^-1, and 2458.0°C·d^-1, respectively. Compared with the condition in 1980, the area with MAAT less than 0°C decreased by 15.8%, 500 mm isotherms of AP moved to the east, the area with Vs of less than 2.2 m/s was expanding, and the area with DDF larger than DDT decreased by 16.9%. The 0°C isotherm moved to the north and high-altitude direction. The area of permafrost was decreased by 13.67% from 1980 to 2010. However, the area with sparcely island permafrost expanded because of the increase in precipitation, especially in the southeast area. MAAT, Vs, and AP influenced the change and distribution of permafrost, among which MAAT was the dominant factor. The influence of Vs and AP gradually decreased from south to north. Changes in the permafrost environment and distribution would directly affect the vegetation succession and ecological environment. This work will provide basic data for regional research on frozen soil and environment in northern northeast China.

DOI: 10.1016/j.quaint.2018.01.015

2019047309 Boike, Julia (Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Potsdam, Germany); Juszak, Inge; Lange, Stephan; Chadburn, Sarah; Burke, Eleanor; Overduin, Pier Paul; Roth, Kurt; Ippisch, Olaf; Bornemann, Niko; Stern, Lielle; Gouttevin, Isabelle; Hauber, Ernst and Westermann, Sebastian. A 20-year record (1998-2017) of permafrost, active layer and meteorological conditions at a high Arctic permafrost research site (Bayelva, Spitsbergen): Earth System Science Data (ESSD), 10(1), p. 355-390, illus. incl. 8 tables, 73 ref., 2018.

Most permafrost is located in the Arctic, where frozen organic carbon makes it an important component of the global climate system. Despite the fact that the Arctic climate changes more rapidly than the rest of the globe, observational data density in the region is low. Permafrost thaw and carbon release to the atmosphere are a positive feedback mechanism that can exacerbate global warming. This positive feedback functions via changing land-atmosphere energy and mass exchanges. There is thus a great need to understand links between the energy balance, which can vary rapidly over hourly to annual timescales, and permafrost, which changes slowly over long time periods. This understanding thus mandates long-term observational data sets. Such a data set is available from the Bayelva site at Ny-Alesund, Svalbard, where meteorology, energy balance components and subsurface observations have been made for the last 20 years. Additional data include a high-resolution digital elevation model (DEM) that can be used together with the snow physical information for snowpack modeling and a panchromatic image. This paper presents the data set produced so far, explains instrumentation, calibration, processing and data quality control, as well as the sources for various resulting data sets. The resulting data set is unique in the Arctic and serves as a baseline for future studies. The mean permafrost temperature is -2.8°C, with a zero-amplitude depth at 5.5 m (2009-2017). Since the data provide observations of temporally variable parameters that mitigate energy fluxes between permafrost and atmosphere, such as snow depth and soil moisture content, they are suitable for use in integrating, calibrating and testing permafrost as a component in earth system models. The presented data are available in the Supplement for this paper (time series) and through the PANGAEA and Zenodo data portals: time series (URL: https://doi.org/10.1594/PANGAEA.880120, URL: https://zenodo.org/record/1139714) and HRSC-AX data products (URL: https://doi.org/10.1594/PANGAEA.884730, URL: https://zenodo.org/record/1145373 ).

DOI: 10.5194/essd-10-355-2018

2019047344 Makarieva, Olga (Gidrotehproekt, Saint Petersburg, Russian Federation); Nesterova, Nataliia; Lebedeva, Lyudmila and Sushansky, Sergey. Water balance and hydrology research in a mountainous permafrost watershed in upland streams of the Kolyma River, Russia; a database from the Kolyma Water-Balance Station, 1948-1997: Earth System Science Data (ESSD), 10(2), p. 689-710, illus. incl. 8 tables, 82 ref., 2018.

In 2018, 70 years have passed since the beginning of observations at the Kolyma Water-Balance Station (KWBS), a unique scientific research hydrological and permafrost catchment. The volume and duration (50 continuous years) of hydrometeorological standard and experimental data, characterizing the natural conditions and processes occurring in mountainous permafrost conditions, significantly exceed any counterparts elsewhere in the world. The data are representative of mountainous territory of the North-East of Russia. In 1997, the station was terminated, thereby leaving Russia without operating research watersheds in the permafrost zone. This paper describes the dataset containing the series of daily runoff from 10 watersheds with an area from 0.27 to 21.3 km², precipitation, meteorological observations, evaporation from soil and snow, snow surveys, soil thaw and freeze depths, and soil temperature for the period 1948-1997. It also highlights the main historical stages of the station's existence, its work and scientific significance, and outlines the prospects for its future, where the Kolyma Water-Balance Station could be restored to the status of a scientific research watershed and become a valuable international centre for hydrological research in permafrost. The data are available at .

DOI: 10.5194/essd-10-689-2018

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2019049872 Barker, Amanda J. Speciation, transport and mobility of metals in pristine watersheds and contaminated soil systems in Alaska: 249 p., illus. incl. 21 tables, sketch map, 270 ref., Doctoral, 2016, University of Alaska at Fairbanks, Fairbanks, AK.

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2019048509 Aspaas, Andreas (University of Oslo, Department of Geosciences, Oslo, Norway); Krautblatter, Michael; Renard, François and Etzelmüller, Bernd. Effects of glimmer rich rocks on the failure criterion of ice-filled permafrost rock joints [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-14551, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Degrading permafrost is an increasingly important problem in high altitude alpine mountains and Arctic regions around the world because it exerts a primary control on rock falls and landslides in these areas. Rock type dependence on the failure criterion of permafrost rock joints has not yet been studied and the present study focuses on glimmers, which are mica rich rocks with well developed foliation. The shear strength and the cohesion in glimmers are partly controlled by weak hydrogen-bonds due to the presence of OH groups at the surface of hydrated silicate minerals and ice. During shearing, glimmers are expected to release ions at the rock-ice interface, which would increase the surface charge and thereby the cohesion in glimmer rich rocks. We tested this hypothesis, in the framework of the CryoWall project, by shearing glimmer rich rocks sampled from the Ramnanosi active landslide in southwestern Norway, the Nordnesfjellet landslide in northern Norway and the Matterhorn mountain rock falls in the Swiss Alps. In these three areas, the cohesion of the rock volume is partly controlled by the presence of ice in rock joints. The samples sliding surface were grinded with a grinding powder to ensure reproducibility of the initial roughness. A direct shear machine was used to conduct 72 tests on rock-ice-rock sandwich samples. A constant strain rate was applied, provoking fracturing while a constant normal stress equivalent to 4, 8 or 15 meter overburden was maintained. The temperature was controlled at -10, -6 and -2 °C. Results provide a unique dataset that allows defining a rock failure criterion for glimmer rich rocks in the presence of ice. A validation of the failure criterion for permafrost rock joints may improve estimations of the degrading permafrost rock slopes in Arctic and alpine mountain areas, where the effects of global warming are known to be large. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-14551.pdf

2019048515 Baillet, Laurent (Université Grenoble Alpes, Institut des Sciences de la Terre, France); Guyoton, Fabrice; Larose, Eric; Amitrano, David; Rey, Etienne; Helmstetter, Agnès; Jongmans, Denis; Lebreton, Mathieu; Leroy, Gaelle and Scheiblin, Guilhem. Geophysics, geomechanics, geotechnics innovation laboratory (LABCOM); a private/public research project for natural hazard monitoring and warning [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-2825, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

The joint laboratory Geophysics, Geomechanics, Geotechnics Innovation Lab. is a research structure joining the Institute of Earth Sciences (CNRS & Univ. Grenoble Alpes) and the Geolithe private company. This joint laboratory aims at developing new techniques and instrumentation prototypes to monitor natural or artificial instabilities such as landslides, rockfalls, mines or civil engineered structures, but also hazards induced but global warming such as rocky glacier destabilization and other permafrost issues. Among other emerging techniques, we develop: Ambient seismic noise monitoring based on natural resonance frequency analysis for unstable rock mass on cliffs. Ambient seismic noise monitoring using cross-correlation technique to track relative changes of rigidity of the soil, to anticipate landslide acceleration phases. Microseismic monitoring with advanced algorithms for classification of sources and repeaters detection. Ground deformation from RFID tags. Ground deformation from image correlation, laser grammetry and stereo-photogrammetry. We will illustrate these techniques by different field examples. An advantageous specificity of our approach is often to connect observations of the surface (ground deformation from optics or RFID) to observations at depth in the bulk of the material (seismology). [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-2825.pdf

2019048455 Bartsch, Annett (b.geos, Korneuburg, Austria); Strozzi, Tazio; Leibman, Marina; Widhalm, Barbara; Khomutov, Artem; Mullanurov, Damir and Gubarkov, Anatoly. Added value of InSAR derived displacements through combination with in situ observations over continuous permafrost, central Yamal [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-10239, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

The Vaskiny Dachi research station was established in 1988 and is situated on the central Yamal Peninsula in a system of highly dissected alluvial lacustrine-marine plains and terraces. It is located within a region of continuous permafrost where tundra lakes and river flood plains are the most prominent landscape features. Active layer thickness ranges between 40 cm in peat and up to on average 120 cm on sandy, poorly vegetated surfaces. Depths of more than 170 cm can occur. Satellite observations from synthetic aperture radar data including displacements derived using interferometry (InSAR) and surface soil saturation from backscatter information collected from X-, C- and L-band observations (COSMO Skymed, TerraSAR-X, Sentinel-1, ALOS-2 PALSAR-2) are available for 2016 to 2018 through the ESA DUE project GlobPermafrost. Active layer thickness modeled from TerraSAR-X backscatter is also available from a preceding study for this region. The snow free season on Central Yamal has been longer than average on central Yamal in 2016. This is reflected in in situ measurements, including active layer thickness. Further available in situ measurements include ground temperature and subsidence. Air temperature data are available from the meteorological station Mare-Sale. All available years of satellite data have been analyzed to quantify the impact of the 2016 warming. The overall magnitude of subsidence is in the order of in-situ measurements, but it is in general underestimated possibly because space-based observation cannot sense the period right after start of ground thaw and their spatial sampling is not sufficient to capture local scale effects. An offset correction regarding start and magnitude of displacement using in situ measurements is required for interpretation of the InSAR measurements. Results of the modified records show that two phases of thaw and subsequent subsidence can be observed in 2016, what agrees with air temperature observations. Late summer thaw patterns, as enabled in 2016, relate also to surface wetness conditions and increased active layer involving thaw of perennial ice at the top of permafrost. The suggested approach of combining in situ and space based observations may allow for evaluation of the seasonal evolution of modeled thaw depth time series over larger regions, as e.g. anticipated within the framework of the ESA CCI+ Permafrost initiative. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-10239.pdf

2019048496 Bek, Dina (Skolkovo Institute of Science and Technologies, Hydrocarbon recovery, Moscow, Russian Federation); Ilya, Komarov and Artem, Myasnikov. Coupled thermo-elastoplastic model of the layered unconventional reservoirs and low-temperatures formations behavior [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-16393, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

One of the understudied problems of unconventional reservoirs development and operation are the failure mechanisms in the media containing plastic enclaves and layers. The importance of this problem is related to the development of unconventional reservoirs, which may contain a significant amount of clays and kerogen. Considering such formations in the areas of permafrost propagation also the common problem is soils thawing. Due to the interaction between constructions and foundation soil leads to the thawing and therefore, losing its bearing capacity. Apparently, under specific conditions, such formations' failure mechanism is of ductile nature and they are attended by remarkable plastic deformations. Thus, the question about failure mechanisms in the layered formations with great contrast in strength and elastoplastic properties and frozen soils arises. In this research, we are considering the problem of stress-strain redistribution due to the long-term loading and time-dependent effects caused by the mechanical and thermal exposure on the formations. The model is stated as a coupled problem: thermal and mechanical. As a result, we get the coupled model of the processes induced by the mechanical (exploitation and operation of reservoirs) and thermal (thawing or freezing of formations in the permafrost areas) exposures. Which allows solving a wide range of engineering tasks from hydraulic fracturing design and estimation of wellbore stability to the soils thawing, freezing, and thermostabilization. New predictive technique which considers coupled thermo-mechanical problem for the elastoplastic model of soils behavior under specific conditions of layered unconventional reservoirs and low-temperatures. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-16393.pdf

2019048459 Buckel, Johannes (Technical University of Braunschweig, Institute for Geophysics and Extraterrestrial Physics, Brunswick, Germany); Reinosch, Eike and Hördt, Andreas. Analyzing periglacial sediment dynamics under a special climate setting in the Qugaqie Basin (Tibet autonomous region) [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-2101, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Sediment fluxes in the Qugaqie basin at NamCo Lake (Tibetan plateau) underlie a special regional climate setting. The setting is characterized by an intersection of the Westerlies, the South West Asian monsoon (Indian summer monsoon), and the East Asian monsoon. Additionally, sediment fluxes in high mountain areas are controlled by strong temperature variations and a seasonal variability. The elevation of the Qugaqie basin ranges from 4722 (lake level NamCo) up to 6119 m a.s.l., which suggests a strong influence of permafrost and the periglacial process domain throughout the year. It is hypothesized that periglacial processes dominate the sediment flux in the catchment. The aim of the study, embedded in the DFG-sponsored research training group TransTiP, is to describe, differentiate and quantify the controlling factors of sediment flux, especially the sediment transport by periglacial processes. Therefore, different methods have been applied: (1) Mapping: A geomorphological map locates and visualizes sediment storage types, geomorphometric features and active geomorphological processes. (2) Geophysical methods: Electrical resistivity tomography (ERT) identifies permafrost and reveals the subsurface structure of periglacial landforms. (3) Radar remote sensing: To detect surface changes we are using the Interferometric Synthetic Aperture Radar (InSAR) time-series analysis based on ESA's Sentinel-1 satellite data to track periglacial landform creep. The geophysical measurements show zones of high resistivity that can be associated with the occurrence of permafrost, e.g. in moraine deposits. The InSAR time-series analysis detects moving surface areas that are assigned to mapped periglacial landforms. Areas of movement match the mapped periglacial landforms, e.g. rock glaciers and protalus ramparts. Classical field techniques (mapping & geophysics) combined with a new satellite-based surface deformation tracking are suitable to extrapolate ground-based investigations to a larger spatial coverage and leads to a better understanding of the "cold spots" of the permafrost induced sediment dynamics of the Qugaqie basin. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-2101.pdf

2019048446 Carey, Sean (McMaster University, School of Geography and Earth Sciences, Hamilton, Canada); Shatilla, Nadine and Tang, Weigang. High frequency flow and solute dynamics in an alpine discontinuous permafrost catchment [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-11678, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Permafrost and frozen ground play a critical role in the transfer of water and solutes from the landscape to the stream, and in biogeochemical cycling by acting as a cold season or semi-permanent aquitard. Conceptual models of permafrost hydrology have been well defined for over 40 years, yet renewed interest in the face of climate change and rapid degradation of frozen ground has provided an opportunity to revisit previous paradigms. At the same time, new instruments and techniques to understand coupled hydrological and biogeochemical processes have emerged, providing a more nuanced view of northern catchments. In this presentation, multi-year high frequency data sets of water, specific conductance (SpC) and chromophoric dissolved organic matter (CDOM) from Granger Creek, an instrumented alpine watershed with discontinuous permafrost within the Wolf Creek Research Basin, Yukon Territory, Canada, is presented. Snowmelt and rainfall-runoff events were delineated over multiple years and sub-hourly data was used to generate hysteresis loops for several dozen events. The direction and magnitude of these loops for Q-SpC and Q-CDOM suggest strong seasonal controls on the mechanisms of solute export, which vary for weathering ions compared with dissolved organic matter. Dissolved solutes (as represented by SpC) are largely diluted during freshet and storm events, with Q-SpC hysteresis being greatest during period of low-flow in mid-summer when SpC was large. In contrast, CDOM largely exhibited a mobilization signal with large event and inter-annual variability in hysteresis patterns. In both cases, there were unique signals related to season: freshet, mid-summer low flow and fall wetting. High-frequency and hysteresis direction and magnitude suggest changing proximal and distal sources of solutes and organic material in response to active layer thickening, soil moisture and precipitation intensity; highlighting spatial connections among landscape units not previously reported. Evaluation of these patterns at the headwater scale provides alternate hypotheses for how permafrost landscapes may respond to a changing climate. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-11678.pdf

2019048537 Chen Leiyi (Chinese Academy of Sciences, Institute of Botany, Beijing, China); Liu Li; Mao Chao; Qin Shuqi; Blagodatsky, Sergey and Yang Yuanhe. Nitrogen availability regulates topsoil carbon dynamics after permafrost thaw by altering microbial metabolic efficiency [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-4607, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Input of labile carbon may accelerate the decomposition of existing soil organic matter (priming effect), with the priming intensity depending on changes in soil nitrogen availability after permafrost thaw. However, experimental evidence for the linkage between the priming effect and post-thaw nitrogen availability is unavailable. Here we test the hypothesis that elevated nitrogen availability after permafrost collapse inhibits the priming effect by increasing microbial metabolic efficiency based on a combination of thermokarst-induced natural nitrogen gradient and nitrogen addition experiment. We find a negative correlation between the priming intensity and soil total dissolved nitrogen concentration along the thaw sequence. The negative effect is confirmed by the reduced priming effect after nitrogen addition. In contrast to the prevailing view, this nitrogen-regulated priming intensity is independent of extracellular enzyme activities but associated with microbial metabolic efficiency. These findings demonstrate that post-thaw nitrogen availability regulates topsoil carbon dynamics through its modification of microbial metabolic efficiency. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-4607.pdf

2019048479 Christiansen, Hanne Hvidtfeldt (University Centre in Svalbard, Department of Geology, Longyearbyen, Norway) and Strand, Sarah Marie. Permafrost thermal dynamics in periglacial landforms in Svalbard during the last decade [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-10141, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

The permafrost in Svalbard has warmed during the last decade, as the air temperature has increased. Warming has been largest in bedrock sites in western Svalbard at sea level and in a blockfield in the mountains in central Svalbard, typically around 0.1 C/year at 10 m depth. Warming rates of up to 0.2 C/yr has been recorded in ice-wedges in the sedimentary Adventdalen valley lowland. The active layer increased on average by 0.6 cm/yr from 2000 to 2018 in the UNISCALM monitoring site, and seems more controlled by winter air temperatures than summer air temperatures. Future direct online permafrost data availability both for research, education and societal geohazard use is being developed, when the existing permafrost observation boreholes are being extended to 20 m depth and the instrumentation upgraded in several of the periglacial landforms in central Svalbard as part of the ongoing Svalbard Integrated Arctic Earth Observing System, SIOS activities. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-10141.pdf

2019048454 Coperey, Antoine (Université Grenoble Alpes, Institut des Sciences de la Terre, Grenoble, France); Revil, André; Stutz, Benoit; Duvillard, Pierre Allain; Abdulsamad, Feras and Ravanel, Ludovic. Low frequency induced polarization of porous media undergoing freezing; from pore to the field scale [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-370, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Induced Polarization and Electrical Resistivity are non-intrusive geophysical methods that can characterize thermal anomalies (e.g. geothermal system) or monitor thermal changes in different environments (e.g. permafrost). To improve our interpretation of geophysical observables in such environments, we need to understand the thermal dependency of the complex conductivity associated with (or without) a phase change. Thus, nine samples were selected to perform spectral conductivity measurements with respect to temperatures ranging from +20 to -15 C. We selected three clayey soils, two granites, one graphitic tight sandstone and three clay-sand mixes. A total of 12 experiments were conducted, including one soil sample measured at different salinities to provide the impact assessment of salinity on the freezing point and on the complex conductivity response. Complex conductivity spectra were analysed with the dynamic Stern layer polarization model associated to a freezing curve. At low frequencies (< 10Hz) and without phase change, the in-phase and quadrature conductivity increased by 2% per degree, due to the thermal dependence of the charge carrier mobility. The phase change can be reflected by reducing the liquid water content and increasing the pore water salinity (salt segregation) which led to a brutal decay with temperature of the in-phase and quadrature conductivity. The dependencies of in-phase parameters (i.e. bulk, surface conductivity) and quadrature conductivity can be linked by an exponential freezing curve which in turn described the thermal dependence of liquid water content. In addition, one of the soil sample came from an alpine rock glacier from Val-Thorens (Vanoise massif, France), where a 3D induced polarization study was performed. Field and laboratory measurements are consistent, and the ratio between normalized chargeability and surface conductivity is close to dimensionless number R = 0.08. The theory implies that this dimensionless number R is independent of water content and temperature in agreement with laboratory experiments. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-370.pdf

2019048512 Delfini, Stefanie Almazan (Swiss Federal Institute of Technology in Zurich, Department of Earth Sciences, Zurich, Switzerland); Leith, Kerry and Gischig, Valentin. Modelling vibration-induced stresses in tall (11 to 40 m) rock columns partially supported by interstitial ice [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-14900, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

The emergence of alpine rock slope instabilities during periods of strong warming or abnormally high temperatures has been linked to the degradation of interstitial ice and permafrost through a number of mechanisms. Studies seeking a causative link typically suggest the instability results from an increase in driving stress due to the development of high joint water pressures, a loss of rock mass cohesion as interstitial ice melts from joints, or a combination of the two effects. Here, we investigate the potential for critical tensile stresses to form at the base of large (meter-scale) vertical rock columns in response to a combination of increased geometric freedom as ice melts out of a pre-existing fracture separating the column from the stable rock mass, and seismic excitation due to a) ambient seismic noise, or, b) a magnitude Mw 6 earthquake at a focal distance of 60 km. Using a 2D finite element model, we evaluate eigenfrequencies for a range of equivalent rock slope geometries with ice-backed column thicknesses ranging from 2 m to 7 m, heights ranging from 40 m to 11.5 m (respectively), and 100 different ice occupation configurations. Selecting the excitation frequency that produces the largest deformation at the base of the column, we then run two time dependent simulations (for excitation by ambient noise, or an earthquake) for each geometric configuration in order to assess the maximum tensile stress generated at the tip of the fracture separating the column from the stable rock slope. Modelled displacements compare favourably with observations derived from unstable rock columns in the field, while maximum tensile stresses typically increase with a thinning of ice toward the base of the fracture (allowing the column to sway more freely). The maximum tensile stress generated behind a 40 m high, 2 m wide column is 19 MPa when a couple of meters of ice is present near the base of the fracture, while a similar configuration with ambient vibration produces peak tensile stresses of just 1.5 MPa. When ice fills the rear crack, the peak tensile stress for both excitation conditions is just 0.4 MPa. While our model results suggest that ambient vibration is unlikely to generate damage in intact rock at the base of such columns, fatigue may play a role, and reducing the volume of ice behind rock columns may reduce the lifetime of tall, thin columns composed of weak rock. On the other hand, modelled tensile stresses induced by seismic loading are in the range of typical tensile strength estimates for strong rock, and although further work is required, our results suggest the simple increase in geometric freedom due to a reduction of ice in such rock slopes may lead to an increase in earthquake-triggered rock slope failures. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-14900.pdf

2019048472 Dobinski, Wojciech (University of Silesia, Faculty of Earth Sciences, Poland). Two-layered permafrost formation as a result of climate change in a mountainous environment; example from Storglaciaren, Tarfala, northern Sweden [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-2916, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

The most common study of the occurrence of permafrost in the world concerns one layer in the lithosphere inside which the temperature is equal to or lower than 0°C. Like other components of the cryosphere, Permafrost reacts to climatic changes that register in its thermal characteristics. This causes that the temperature course in the permafrost profile is nonlinear, and in specific locations two layers of permafrost can be separated by talik. Such a situation is known for its occurrence in West Siberia. However, climate changes are similar in both the Arctic and Alpine permafrost. ERT research conducted in the Tarfala area, in the forefield of the Storglaciaren, show two high-resistance anomalies separated by a layer of lower resistance. The results of electro resistivity surveys together with previous published results indicate that two layers of permafrost can be distinguished also in the Storglaciaren forefield and probably in Tarfala valley as well. The shallower, discountinuous layer, with thickness ca. 2-6 meters is connected to the current climate, Deeper located second layer, separated with talik, must be significantly older. Its thickness can reach dozens of metres and its existence is probably the result of permafrost formation during early Holocene or even Pleistocene epoch. The occurrence of two-layered permafrost in the Tarfala valley shows that the evolution of mountain permafrost may be seen as analogous to that in Western Siberia. This means that the effect of climate changes gives a similar results in permafrost formation and evolution in both altitudinal and latitudinal extent. The occurrence of two-layered permafrost in Scandes and Western Siberia plain indicates possible analogy in climatic evolution, and gives opportunity to understand them in uniform way. The existence of a two-layer permafrost in the mountain environment of the Scandinavian Mountains should be included in the models that are developed by other authors. Funded by National Science Center (NCN) Poland, UMO-2016/21/B/ST10/02509 Institute of Geophysics PAN and UMO-2012/07/B/ST10 /04268 University of Silesia. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-2916-1.pdf

2019048489 Donner, Anika (University of Würzburg, Institute of Geography and Geology, Germany) and Winkler, Stefan. Periglacial landforms in Jotunheimen, Norway; distribution and causal links to permafrost and other factors [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-5772, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

The high-altitudinal plateaus of Jotunheimen in central South Norway, the mountain region home of Norway's highest summits, create a unique and diverse natural environment. The specific gross morphology of Jotunheimen facilitates the occurrence of a variety of periglacial landforms ranging considerably in both dimension and age. The regional distribution of permafrost is one of the major controlling factors for the altitudinal distribution of these periglacial landforms. The largest individual features of patterned ground, undisputed the regionally most dominant periglacial land-forms, are situated on terrain currently underlain by permafrost. They visually appear to be quite relict, despite the occurrence of permafrost, and the exact timing of their formation remains unknown. This example points to additional factors significantly influencing the periglacial landform assemblage, like topography, ground moisture availability, and the local deglaciation history. The lack of a regional overview regarding periglacial landforms in Jotunheimen exacerbates the need for a profound investigation of their altitudinal zonation and potential causal links to climate, permafrost, (de-)glaciation, and other factors. The compilation of a regional overview based on aerial imagery and a literature review aims, therefore, to reveal further insight into the controlling factors for and mechanisms of periglacial landform development in Jotunheimen. This shall be achieved by creating an altitudinal zonation for periglacial features and highlighting causal links between their spatial/altitudinal distribution and possible influencing factors. In an outlook to future studies this attempt may also provide more detailed information on the regional basal properties of the former Scandinavian ice sheet, the regional/local deglaciation patterns for the Jotunheimen region, and about the exact chronology of formation of the periglacial landforms studied. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-5772.pdf

2019048440 Etzelmuller, Bernd (University of Oslo, Department of Geosciences, Oslo, Norway); Patton, Henry; Schoemacker, Anders; Hubbard, Alun Lloyd; Czekirda, Justyna and Westermann, Sebastian. Permafrost dynamics in Iceland between 18 ka BP and today; model results and geomorphological implications [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-3933, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Periglacial processes and the dynamics of permafrost is a decisive factor for slope stability locally, and for understanding landscape development over longer time scales. Iceland has a highly dynamic landscape because of young bedrock and associated high geomorphological process rates, leading to large material production and frequent gravitational processes in the present periglacial realm. At present, permafrost in Iceland is widespread in mountain settings over c. 800 m a.s.l. and sporadically in palsa mires in the central Highlands. However, during the late Pleistocene and Holocene, the periglacial environment in Iceland must have varied strongly in time and space, with subsequent imprint in the landscape. To evaluate the dynamics of permafrost in Iceland since the onset of the last deglaciation, we used the forcing and output of a 3D, time-integrated ice sheet model to run a transient permafrost model (CryoGRID 2) between the onset of the last deglaciation (c. 18 ka BP) until today. The permafrost model was forced by either modeled sub-glacial temperatures if ice-covered, or air temperatures if the area was deglaciated. The results give insights into the possible age of permafrost in Iceland, distinguish areas with wide-spread paleo-permafrost and let us determine the persistence of permafrost in the different areas. The presentation discusses these results in the light of periglacial processes, landforms and landscape development. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-3933-1.pdf

2019048471 Georgievski, Goran (Helmholtz-Zentrum Geesthacht, Institute of Coastal Research, Hamburg, Germany); Hagemann, Stefan; Sein, Dmitry; Nicolsky, Dmitry; Romanovsky, Vladimir; Onaca, Alexandru; Chetan, Marinela; Urdea, Petru; Drozdov, Dmitry and Gravis, Andrew. Study of the development of extreme events over permafrost areas; SODEEP [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-15867, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

In the frame of the ERA-NET project SODEEP, we examine the impact of climate change on the permafrost degradation and related biophysical feedbacks over various spatial and temporal scales. Our aim is to assess the role of land-atmosphere interactions on the severity and frequency of extreme events over circum-Arctic land areas. Our focus regions are major bio-climatic zones of the Russian Arctic and sub-Arctic, which are not only extremely vulnerable habitats to the permafrost degradation due to climate change, but also exhibit a threat for the global climate due to frozen soil-bounded carbon. The data from long-term in situ observations and field studies as well as medium and high-resolution satellite-borne and aerial observations are combined with a state of the art hierarchy of climate models to identify missing or misrepresented permafrost-relevant key processes in numerical models. The rate of the permafrost temperature rise is different in different climatic zones. The maximum growth rate is observed in the southern tundra, the minimum in the southern forest-tundra and northern taiga, where the permafrost temperature is close to 0°C. The ground temperature rise reduce the bearing capacity. The layers of the "zero curtain" with a thickness of several meters occur at temperatures close to 0°C. Its presence inhibits the degradation of permafrost. Here, we present the project and first results. The latter comprise preliminary results from field campaign and development of a permafrost temperature dynamics and active layer thickness database, processing of optical satellite images (spatio-temporal changes related to lake extent and trend of several multi-spectral indices, i.e. NDVI, NDMI, Tasseled Cap indices based on Landsat and Sentinel-2 images selected from archives and acquired between 1987-2018), as well as the progress in understanding and implementation of permafrost related processes into the regional climate model REMO and simulations with Geophysical Institute Permafrost Laboratory (GIPL) model to reproduce historic permafrost distribution 1960-2009 on the pan-Arctic at 0.5 spatial resolution. Thermal and hydrologic properties of the ground material and snowpack are parameterized using vegetation cover, surface geology and extensive empirical observations. This model will be augmented later in the project with advances in techniques as geographic object-based image analysis for interpretation of remote sensing imagery through automated identification of landscape changes and used to update permafrost scheme in climate models. The approach using empirical regional trends detected from long records was applied for mapping of current and future (2050 and 2100) permafrost temperature. Trends are identified by taking into account the current changes in climate and permafrost characteristics. This work is funded in the frame of ERA-Net plus Russia. TSU is supported by MOSC RF #14.587.21.0048 (RFMEFI58718X0048), AWI and HZG are supported by BMBF (Grant no. 01DJ18016A and 01DJ18016B), and WUT by a grant of the Romanian National Authority for Scientific Research and Innovation, CCDI-UEFISCDI, project number ERANET-RUS-PLUS-SODEEP, within PNCD III. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-15867-2.pdf

2019048502 Golovleva, Iuliia (Lomonosov Moscow State University, Moscow, Russian Federation); Korkina, Elena; Desyatkin, Roman; Bruand, Ary; Verba, Marina and Krasilnikov, Pavel. Formation of structure in the clay soil of taiga zone in Siberia [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-18301, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

lay soil form on river terraces in Siberia under cold environments with seasonal and perennial frost action, which gives the specific appearance of the soil. We studied the cryogenic structure of clay soil in middle taiga zone of Western and Eastern Siberia. The climate of Western Siberia is moderately cold with mean annual temperature -4 -2 °C, mean January temperature -20 °C and mean July temperature +18 C. The annual precipitation is 580 mm. The area has insular permafrost. The climate of Central Yakutia (Eastern Siberia) is more continental with mean annual temperature -10.2 °C, mean January temperature -38.6 °C, and mean July temperature +19.5 °C. The annual precipitation is 238 mm. The area has continuous permafrost. Both are covered with taiga forests with larch, pine and Siberian pine. The parent materials of the studied soils are loams, sandy loams, sands of alluvial and ancient alluvial origin. Soils have brownish and pale colors. They have specific caviar structure in B horizons and cryogenic platy structure consolidated with ice in lower horizons. The latter feature is typical for permafrost-affected soils. Micromorphological study of soil thin sections in transmitted and reflected light showed the presence of numerous rounded aggregates with and without Fe-Mn nodules in the center. Mercury porosity showed the presence of a large number of pores of different configurations, predominantly of small and medium size. The mineralogical composition of clays is characterized by the presence of chlorite-vermiculite, kaolinite and smectite. There are some types of coatings: clay, humus-clay and carbonate. The West Siberian soils are strongly acid and Eastern Siberia soils are neutral-alkaline. Soils were identified as Cambisols, Alisols, Cryosols, and Planosols according to the WRB. We hypothesized that the specific caviar structure may be ascribed to the frost action. Financial Support: This work was supported by the grant of Russian Science Foundation No. 17-17-01293. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-18301-1.pdf

2019048493 Götz, Joachim (University of Graz, Department of Geography and Regional Science, Austria); Salcher, Bernhard and Schrott, Lothar. Short and long term sediment dynamics in an alpine headwater catchment [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-16211, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Mechanisms increasing recent debris flow dynamics are intensively dicussed and often related to global warming and associated permafrost degradation. However, present-day events have been rarely set in relation to the overall Postglacial and Holocene activity by comparing their magnitudes with cumulative landform volumes. Moreover, recent events remain often poorly constrained lacking reliable time-series. The establishment of meaningful frequency-magnitude-relations with respect to the long-term context of actitivy are therefore highly needed to better evaluate and assess the state of present day geomorphic activity. To address this issue we focus on contemporary and postglacial sediment dynamics within a small-scale denudation-accumulation system in the Austrian Alps using a multi-temporal sediment budget approach. The long-term perspective of averaged Holocene debris flow activity is based on the analysis of the sedimentary architecture and the reconstruction of the infill history of a closed, former lake basin in the Hohe Tauern region (Gradenmoos Basin, 4.5 km²). For this, we applied a number of field, lab and modelling techniques involving drill core anyalsis, geophysical prospection and terrestrial laser-scanning (TLS). Early-Holocene radiocarbon ages of our lowest sediment core samples indicate that postglacial sedimentation started after Younger Dryas deglaciation c. 11 ka BP after the related glacier almost entirely emptied the basin. After deglaciation, lake formation maximised trap efficiency for the following 7.5 ka as proved by stratigraphic and palynologic information. This did even not change after the lake was filled around 3.5 ka ago due to the low transport capacity of the trunk stream. The basin fill was quantified via a GIS-based approach (bedrock interpolation, 3D cut-and-fill modelling) combining drill core, geophysical and TLS data. Sediment storage volumes sum up to c. 20 Mm³ corresponding to long-term rates of postglacial sediment yield between 214 and 855 m³/a for three cirques supplying sediment to the basin. Monitoring of short-term sediment dynamics is restricted to the most active cirque subsystem (855 m³/a) feeding a massive coalescing debris cone mainly through debris flows. Here, we quantify present-day sediment supply through TLS-monitoring (time series 2009-2018), different routines of geomorphic change detection (cloud-to-cloud, mesh-to-mesh, as well as raster based), and roughness-based error modelling. In the 9-year study period sediment input was dominated by three huge debris flow events supplying a total volume of c. 81,400 m³, what corresponds to an annual average input of c. 9,000 m³/a to the cone (accompanied by further c. 20,600 m³ redeposition). We discuss drivers of this tenfold increased debris flow dynamics in the past decade with respect to recent permafrost warming/degradation, triggering rainfall thresholds, and the role of perennial snow patches as important links in mountain sediment cascades. Finally, we evaluate the transferability of these findings in the light of the current debate on more frequent extreme events in Alpine environments. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-16211.pdf

2019048469 Grenier, Christophe (Institut Pierre Simon Laplace, Laboratoire des Sciences du Climat et de l'Environnement, France); Costard, François; Anbergen, Hauke; Bense, Victor; Chanzy, Quentin; Coon, Ethan; Collier, Nathaniel; Ferry, Michel; Frampton, Andrew; Frederick, Jennifer; Gonçalvès, Julio; Holmén, Johann; Jost, Anne; Kokh, Samuel; Kurylyk, Barret; McKenzie, Jeffrey; Molson, John; Mouche, Emmanuel; Orgogozo, Laurent; Pannetier, Romain; Pohl, Eric; Rivière, Agnès; Rühaak, Wolfram; Scheidegger, Johanna; Selroos, Jan-Olof; Therrien, René; Vidstrand, Patrik and Voss, Clifford. Interfrost project phase 2; updated experiment design for validation of cryohydrogeological codes (frozen inclusion) [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-15194, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Recent field and modelling studies indicate that a fully-coupled, multi-dimensional, thermo-hydraulic (TH) approach is required to accurately model the evolution of permafrost-impacted landscapes and groundwater systems. However, the relatively new and complex numerical codes being developed for coupled non-linear freeze-thaw systems require validation. This issue was first addressed within the InterFrost IPA Action Group, by means of an intercomparison of thirteen numerical codes for two-dimensional TH test cases (TH2 & TH3). The main results (cf. Grenier et al. 2018 and wiki.lsce.ipsl.fr/interfrost) demonstrate that these codes provide robust results for the test cases considered. The second phase of the InterFrost project is devoted to the simulation of a cold-room reference experiment based on test case TH2 (Frozen Inclusion). In a first implementation phase of the experimental setup, the initial frozen inclusion was inserted in the setup prior to the complete filling of the porous medium and the flow initiation. The thermal evolution of the system was monitored by thermistors located at the center of the initial inclusion and along the downgradient centerline. This setup provided optimal conditions to control the initial experiment geometries but resulted in slight differences in the initialization time for different experiments. We present a second implementation strategy that considers "in place" generation of an initial frozen inclusion through a cooling coil. The initial frozen inclusion is obtained after the initial cooling time and its initial thermal state is measured by means of an array of thermistors. In a second step, the flow is initiated, and the thermal evolution is monitored through an array of 11 thermistors (within the initial position and downgradient). The experimental setup and monitoring results as well as preliminary simulation results are presented. Derived results and conclusions from this exercise form the basis for the next phase within the InterFrost validation exercise. Grenier, C. et al. 2018. Groundwater flow and heat transport for systems undergoing freeze-thaw: Inter-comparison of numerical simulators for 2D test cases. Adv. Wat. Res. 114: 196-218. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-15194.pdf

2019048442 Grünberg, Inge (Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Potsdam, Germany); Cable, William L.; Antonova, Sofia; Lange, Stephan and Boike, Julia. Soil temperature and thaw depth differences associated with tundra vegetation types at Trail Valley Creek, NWT, Canada [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-13037, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Climate, vegetation, and permafrost are coupled through various positive and negative feedback loops in the Arctic and Subarctic. Many of these feedback mechanisms are still poorly quantified, in particular with respect to vegetation density or biomass. For instance, climate warming facilitates shrub densification and range expansion. The shrub canopies in-turn shade the ground surface during the summer, keeping permafrost cooler, while during the winter the canopies trap more snow, insulating the surface and keeping the ground (and permafrost) warmer. We investigated the feedback of vegetation change on permafrost conditions and local climate at the Trail Valley Creek study site, near tree-line, in Northwest Canada (133.50 W, 68.74 N). In particular, we quantified the effect of vegetation on the soil surface temperature and thaw depth through shading in summer and through snow collection in winter. We combine local field measurements of vegetation, climate, and permafrost with spatially resolved data from repeated aerial surveys of high resolution imagery and laser scanning. Our results show that winter ground surface temperatures below tall shrubs are on average 2 C warmer than below lichen tundra due to the snow layer being twice as deep. However, delayed spring onset and soil shading in summer result in shallower thaw depths below tall shrubs (47cm on average) as compared to lichen tundra (61cm on average). Our results highlight the complex interactions between vegetation and permafrost involving snow, the surface energy budget and soil properties. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-13037.pdf

2019048437 Harper, Joel (University of Montana, Department of Geosciences, Missoula, MT) and Meierbachtol, Toby. The impacts of Greenland ice sheet basal conditions on regional permafrost and groundwater flow [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-11297, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Permafrost typically exists in regions impacted by past or present glacier and ice sheet coverage. Consequently, the thermal and physical conditions at the bed of ice masses can often form important controls on permafrost and associated groundwater flow dynamics. Here we present a conceptual overview of the Western Greenland ice sheet basal conditions, from ice divide-to-margin, with regards to regional permafrost and groundwater flow fields. Our understanding is based on ice sheet modeling combined with detailed field observations conducted along a 325 km long transect of the ice sheet as part of the "Greenland Analogue Project". We drilled 36 boreholes to the bed of the ice sheet to measure ice temperature, ice deformation and basal sliding, and subglacial water pressure and transmissivity. Simulations incorporate heat transport and higher-order physics for ice flow in three dimensions, data assimilation for constraining model results with climate and surface velocity data fields, and are forced by boundary conditions uniquely constrained by observational data. Our results suggest that between the central ice divide and the ice sheet margin, the bed transitions between four differing thermo-hydrologic regimes. Each zone has different physical conditions and plays contrasting roles in the regional groundwater flow field. We discuss the permafrost conditions beneath the ice sheet and two remaining uncertainties in transitional zones that impact permafrost and groundwater flow conditions. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-11297.pdf

2019048534 Hauck, Christian (University of Fribourg, Department of Geosciences, Fribourg, Switzerland); Mollaret, Coline and Hilbich, Christin. Comparison of long-term refraction seismic and ERT monitoring to detect and quantify ground ice loss at alpine permafrost sites [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-11161, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Geophysical monitoring has become more and more popular in permafrost environments due to its remarkable success to detect permafrost thawing and associated spatio-temporal changes in the ground ice content. Hereby, geoelectric methods such as Electrical Resistivity Tomography (ERT) are usually applied due to the strong differences in the electrical properties between frozen and unfrozen state. However, also seismic properties change markedly upon freezing/thawing and time-lapse refraction seismic tomography has been shown to be applicable to permafrost over smaller time scales (e.g. Hilbich 2010). The reason why only few studies employ long-term seismic monitoring in permafrost is probably due to the higher logistical effort that is required. At two permafrost monitoring sites in the Swiss Alps yearly refraction seismic surveys are conducted since more than 10 years, in addition to standard borehole temperature, climatic and ERT measurements. Data sets are recorded using a comparatively small geophone spacing of 2 meter and a limited number of geophones and shot points (24/ 20). Measurement geometry is held constant and a sledgehammer is used as source. The monitoring aim is to image the interannual changes of the depth of the active layer, i.e. the maximum thaw depth of the near-surface layer in summer as well as differences in ice content within the permafrost layer below. In this contribution we will focus on two 10-year long seismic data sets, their interpretation with respect to climate-induced thawing, as well as on an evaluation of the advantages and disadvantages of seismic monitoring compared to the more standard ERT monitoring. The results will also be analysed with respect to their suitability for future ERT-seismic joint inversion approaches in a monitoring context (cf. Mollaret et al. EGU 2019, Wagner et al. EGU 2019). References: Hilbich, C.: Time-lapse refraction seismic tomography for the detection of ground ice degradation, The Cryosphere, 4, 243-259, URL: https://doi.org/10.5194/tc-4-243-2010, 2010. Mollaret, C., Wagner, F., Hilbich, C., Hauck, C.: Alpine permafrost field applications of a petrophysical joint inversion of refraction seismic and electrical resistivity tomography to image the subsurface ice content, EGU abstract, CR2.3 session, 2019. Wagner, F., Mollaret, C., Gunther, T., Uhlemann, S., Dafflon, B., Hubbard, S.S., Hauck, C., Kemna, A.: Characterization of permafrost systems through petrophysical joint inversion of seismic and geoelectrial data, EGU abstract, SM4.4 session, 2019. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-11161.pdf

2019048481 Hilger, Paula (Norwegian Geological Survey, Trondheim, Norway); Etzelmüller, Bernd; Myhra, Kristin Saeterdal; Hermanns, Reginald L.; Jacobs, Benjamin; Krautblatter, Michael; Magnin, Florence and Westermann, Sebastian. Permafrost is a crucial factor for paraglacial landscape modifications in glaciated mountain regions [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-8679, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Ground temperatures in steep slopes are a well-recognized factor for slope stability. Rock walls with cold permafrost tend to be stable due to additional cohesion provided by ice bonds. A warming of such rock faces influences the ice rheology in rock joints and decreases tensile and compressive stresses in rock masses. During transitions between glaciation and inter-glaciation many steep mountain slopes encounter repeatedly strong cooling and warming, leading to permafrost aggradation and degradation over relatively short time periods depending on regional deglaciation patterns. We hypothesize that this dynamic and the related irreversible rock fatigue is a major factor for slope destabilisation after deglaciation in addition and in concert to debuttressing. To test this hypothesis, we have employed a 2D heat flow model over glacial-interglacial cycles, which subsequently has been input into a thermo-mechanical stability model. In addition, emerging sliding planes and deposits from major rockslides were dated using cosmogenic nuclides. The results indicate the development of progressive rock-slope failure modulated by permafrost development that acts to transiently influence the mechanical stability of bedrock. Permafrost dynamics may therefore be an overlooked factor for understanding valley forming and modifying processes during glacial-interglacial transitions, while at the same time influencing present-day rock-fall processes in deglaciated areas. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-8679.pdf

2019048467 Hinzman, Alexa (Vrije Universiteit Amsterdam, Department of Earth and Climate, Amsterdam, Netherlands); Sjoberg, Ylva; Lyon, Steve and van der Velde, Ype. Changing hydrological connectivity in the Arctic [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-14789, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

In regions where subsurface flow is controlled by seasonally frozen ground or permafrost, identifying where and when hydrological connectivity increases during thawing periods is necessary to understand source areas, flow pathways and river flows. The degree of connectivity (i.e. water flow between surface, subsurface and between stores of water within the subsurface) controls water chemistry and streamflow dynamics. With current anthropogenic climate change, Arctic and sub-Arctic regions will continue to warm, frozen grounds will thaw and flow paths open to allow increased subsurface flow. This increase in connectivity is expected to result in a change of the storage-discharge relationship of watersheds. As spring snowmelt occurs earlier, subsurface connectivity is predicted to establish earlier and continue later into the summer. However, it is still unclear if the increase in temperatures actually deepen hydrologic connectivity or create a shift of unfrozen extent of connectivity to earlier in the year? We use recession flow analysis on 16 watersheds to determine when and how much of a shift in storage-discharge relationships has occurred within Northern Sweden. Our research shows a wide-spread trend of significant increase in non-linearity of the storage-discharge relationship which we relate to an increase in hydrologic connectivity, in arctic watersheds over the last 50 years. Moreover, we find that during this period, cold winter temperatures affect the storage-discharge relationship differently than warm winters. The relationship is more nonlinear in warm winters than cold winters and cold winters effect the hydrologic connectivity to start increasing later into spring. These results strengthen our hypothesis that trends in storage-discharge relationships are valuable indicators for persistent changes in hydrological connectivity induced by thawing in a warming Arctic. Our results lead to a better understanding of how streamflow in arctic watersheds have changed as seasonal freezing of grounds diminishes. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-14789.pdf

2019048532 Huang Yadong (Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, Lanzhou, China) and Jin Huijun. Spatiotemporal variations of freezing and thawing index in northern northeast China [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-11858, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

University of Chinese Academy of Sciences, Beijing, China Northern Northeast (NNE) China is the second largest permafrost region in China, only second to Qinghai-Tibet Plateau. The permafrost in NNE China presents high temperature and thin thickness, and the degradation is being accelerated due to climate warming and anthropogenic activities. The mean annual air temperature (MAAT), mean annual ground surface temperature (MAGST), annual air freezing index (AFI), annual ground surface freezing index (GFI), annual air thawing index (ATI) and annual ground surface thawing index (GTI) in NNE China were calculated based on ground surface and air temperatures of 27 selected stations. The results indicated that the MAAT and MAGST were higher compared to decades ago, averaged 1.74 and 0.43 , with an increasing rate of 0.568 and 0.643/10a, respectively. The AFI, GFI, ATI and GTI ranges were 1757 3619 d, 1685 3925 d, 1896 3288 d and 2426 3869 d, respectively, and the multiyear average were 2502 d, 2602 d, 2662 d and 3238 d, respectively. AFI and GFI exhibited decreasing trend and the rate were 117.6 d/10a and 111 d/10a. However, thawing index exhibited increasing trend and the liner tendency of ATI/GTI were 89.5 d/10a and 111 d/10a. The strong liner relationship between MAAT and freezing and thawing index were also observed. The results will help us better comprehend the temporal and spatial variation of NNE permafrost and provide scientific basis for permafrost forecast. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-11858.pdf

2019048470 Jacobs, Benjamin (Technical University of Munich, Chair of Landslide Research, Munich, Germany); Leinauer, Johannes; Myhra, Kristin Saeterdal and Krautblatter, Michael. Short- and long-term thermal and mechanical transition in Norwegian permafrost rock walls [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-15460, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

The frequency of landslides in permafrost rock walls has significantly increased in the last decades. Since permafrost degradation is strongly linked to a decrease in rock strength and overall rock mass stability, high-altitude rock walls are prone to permafrost related instabilities in the context of global climate warming. In Norway, seven out of 300 mapped instable rock walls are classified as high-risk sites of which at least two (Gamanjunni and Mannen) are believed to be situated in permafrost conditions. Here we use laboratory-calibrated 2D and 2.5D electrical resistivity tomography, rock mechanical testing as well as thermal and mechanical modelling to (i) gain insights into the current thermal and mechanical dynamics of these two high-risk sites and (ii) to show how long-term thermal changes over the Lateglacial / Holocene affect the evolution of rock wall instabilities. In this study, we investigate two of Norway's top risk rock wall instabilities to evaluate how short-term (10 to 100 a) thermal variations can influence the local mechanical regime and, interestingly, vice versa. 2D and 2.5D electrical resistivity tomographies, which we calibrated for temperature using samples from site, reveal the existence of permafrost with a strong influence of slowly changing topographic features such as active landslide scarps and fissures. The results of over 100 rock mechanical tests of samples from both test sites show a 15 to 20 % strength reduction upon thaw. This data can be used to set up mechanical models in order to analyze the current local mechanical regime. Both test sites, however, show a long-term (0.1 to 10 ka) history of rock wall instability, hence the long-term trajectory of the thermal and mechanical transition should not be neglected. We use the output of a long-term transient heat flow model (CryoGrid2D) in combination with a multi-stage continuum mechanical model on a fjord scale level to show how the evolution of rock wall temperatures since deglaciation affects the long-term stability of steep fjord flanks. Here we show the short-term thermal impact on local rock wall stability and vice versa in the context of long-term thermal and mechanical evolution of extreme fjord topographies. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-15460-1.pdf

2019048457 Jiang Huiru (Sichuan University, State Key Laboratory of Hydraulics and Mountain River, China); Zhang Wenjiang; Yang Kun and Chen, Deliang. Investigating the sensitivity of soil freeze/thaw dynamics to environmental conditions at different scales in the central Tibetan Plateau [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-472, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Widespread soil thaw has been observed in the Tibetan Plateau (TP) with regional warming, and a better understanding of the environmental sensitivity of these changes is critical for projecting hydro-ecological responses to future climate conditions. In this study, we used a multi-scale soil temperature and moisture networks from the Asia-Australia Monsoon Project sites within the Tibetan Plateau domain (CAMP-Tibet) and Central Tibetan Plateau Soil Moisture and Temperature Monitoring Network (CTP-SMTMN), as well as a process model, to investigate the sensitivity of soil freeze/thaw (F/T) dynamics to environmental conditions in the central TP region. The results showed that model simulated soil temperatures generally agreed well with the observations, with RMSE lower than 1.3 [U+2103] and 2.0 [U+2103] for CAMP-Tibet and CTP-SMTMN sites, respectively. Relatively large errors in the CTP-SMTMN sites were likely due to the uncertainties in the deep soil parameterization, where no soil moisture observations were available below 40 cm depth. The analysis on the relationships between the soil F/T dynamics and environmental conditions showed that maximum frozen depths (MFDs) were significantly influenced by elevation (R=0.48, p<0.005), soil moisture content (R=0.57, p<0.005), and SOC content (R=0.46, p<0.005). However, the main factors affecting MFDs vary at different scales. Even though the elevation which indicates temperature differences is the first-order factor controlling the MFD at the regional scale, soil moisture also plays an important role regulating MFD at local scale. Soil thaw onset is more closely associated with environmental factors examined than soil freeze onset at the seasonally frozen ground (SFG) study sites. Since F/T dynamics may be different between SFG and permafrost regions, more analysis is still needed to evaluate the potential differences of soil F/T sensitivity to environmental factors in these two regions. Our study highlights the importance of soil moisture in affecting soil F/T dynamics in central TP region, which should be properly addressed in future studies in soil F/T and permafrost modelling for the TP region. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-472.pdf

2019048474 Johansson, Emma (Swedish Nuclear Fuel and Waste Management Company, Solna, Sweden); Lindborg, Tobias; Selroos, Jan-Olof and Liljedahl, Lillemor Claesson. The GRASP project -periglacial hydrology and biogeochemistry studies bridging the gap between the academic and industrial worlds [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-10916, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Long term climate development - e.g. up to 100 000 years or more - is rarely an issue for societal questions and planning. However, the nuclear waste management industry needs to demonstrate safety for humans and the environment for time scales way beyond common standards. This demand, together with a general scientific interest in climate and landscape development, provides an opportunity for cooperation between industrial organisations and the scientific community. By using specific site analogues, the conceptual understanding of site behaviour and future climate development can be explored for long time scales. Here we summarize and present methods used and data collected in the Greenland Analogue Surface Project (GRASP). GRASP is a catchment-scale field study of the periglacial area in the Kangerlussuaq region, West Greenland, focusing on hydrological and biogeochemical processes in the landscape. The site investigations were initiated in 2010 and have so far resulted in three separate data sets published in ESSD (Earth system and Science Data) focusing on i) meteorological data and hydrology, ii) biogeochemistry, and iii) geometries of sediments and the active layer, respectively. The three data sets, which are freely available via the PANGAEA data base, enable conceptual and coupled numerical modelling of hydrological and biogeochemical processes during present-day conditions. The results of such modelling are discussed in terms of short and long term changes in properties and process rates due to possible changes in climate conditions. Quantification and assumptions on future change are often based on model predictions. Such models require cross-disciplinary data of high quality; however, such data rarely exist. Biogeochemical processes in the landscape are highly influenced by the hydrology, which in turn is intimately related to permafrost processes. Thus, a multidisciplinary approach is needed when collecting data and setting up field experiments aiming at increasing the understanding of these processes. An important asset of the GRASP data is that all data are collected within the same, relatively small, catchment area. This implies that measurements are more easily linked to the right source area or process. Despite the small catchment area, it includes the major units of the periglacial hydrological system; a lake, a talik, a supra- and sub-permafrost aquifers, allowing biogeochemical processes in each of these units to be studied. The data from GRASP are used both with the aim to increase knowledge of present day periglacial hydrology and biogeochemistry, and also with the aim to predict hydrological and biogeochemical consequences due to future climate change. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-10916-1.pdf

2019048456 Keil, David (University of Vienna, Institut für Geographie und Regionalforschung, Vienna, Austria); Lachner, Johannes; Schenk, Julia; Scandroglio, Riccardo; Krautblatter, Michael and Kraushaar, Sabine. Tracing permafrost in proglacial springs; first results from two alpine research areas [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-1547, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Permafrost degradation is related to an increase of natural hazards in the European Alps. The AlpSenseBench project aims at an analysis of natural hazards in four alpine catchments applying a multiscale monitoring concept.. In this study, the proglacial region of the Vernagtferner glacier (~3000m asml) and the Zugspitze summit (~2700m asml) are focus areas to determine the impact of permafrost degradation on rock fall activities, slope stability and the future water balance of Alpine catchments. Both areas have been object of extensive geo electrical monitoring in order to detect permafrost. Here, we analyze waters from the glacier, snow, precipitation and springs from the same area in monthly time intervals in order to hydro-chemically detect and characterize permafrost thawing from bedrock and unconsolidated moraine sediments. The water analysis includes stable isotope signatures D²H and D¹⁸O and the radioactive Iodine nuclide 129I for the relative age determination. The results show the spatial distribution of springs possibly fed by permafrost melt water and allow quantitative implications about its seasonal variability. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-1547.pdf

2019048473 Kröhn, Klaus-Peter (Gesellschaft für Anlagen- und Reaktorsicherheit, Geological Disposal, Germany). Permafrost hydrology related to nuclear waste repositories in Germany [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-7957, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Deep geological disposal of nuclear waste implies (1) storage at a depth of several hundred metres below surface and (2) a safety assessment that covers a long period of time. In Germany a time span of 1,000,000 years has to be considered. One of the main concerns for such a repository is the detrimental effect of groundwater on the technical and geotechnical barriers, e.g. waste canisters. For the design of the repository, a good knowledge of the local and regional groundwater system is therefore required. This knowledge forms also the basis for predicting radionuclide migration in case of leakage from a damaged waste canister. Potential sites in Germany have been identified in the North German lowlands and in Southern Germany within or adjacent to the Alpine foothills. During recent cold stages like the Weichselian glacial (Wurm glacial stage for the Alpine region) these sites experienced partly permafrost conditions, partly coverage by an ice shield. Ground freezing to a large lateral as well as vertical extent has thus to be assumed under these conditions. This may have led to radically different groundwater flow systems compared to those prevailing during warm stages with presently hard to predict consequences for the potential migration of radionuclides through the geosphere. However, work on groundwater flow systems under cold stage conditions has not gone to great detail in Germany yet. As a first step in that direction, changes in the underground due to freezing under permafrost conditions would have to be addressed. Only at a later stage and based on sound understanding of the geohydrology under permafrost conditions, the effect of an approaching ice cap and the subsequent ice coverage can be treated as this introduces additional levels of complexity and is preceded by permafrost conditions anyway. Neglecting mechanical effects from expansion during freezing and assuming no water flow, ground freezing is a thermal problem that is basically controlled by the mean sur-face temperature, heat production from earth's core and the thermal properties of the geological units. Much more challenging is the simulation of the development of taliki which is a delicate process and requires a thermo-hydraulic (TH-)coupling. Open taliki connect deep aquifers with the rock surface and thus form a key feature in a frozen groundwater flow system. However, development of an open talik may be influenced by the groundwater flow system to an unknown extent which would make this process site specific. These tasks are intended to be tackled with the code d3f++ which is well suited for this purpose as it is capable of modelling TH-groundwater flow and just needs to be advanced to cope with freezing of water in granular porous media. The general strategy is to start out with simple models in terms of physical complexity while preferably sticking to generic models in order to increase the general understanding of the processes involved. Wherever possible, a comparison with in-situ investigations will be sought. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-7957.pdf

2019048486 Kunz, Julius (University of Wuerzburg, Institute of Geography and Geology, Germany) and Kneisel, Christof. Glacier-permafrost-interaction at a thrust moraine complex in the Val Muragl (Swiss Alps); investigations using electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-15420, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Several studies have proofed the existence of an interaction between glacier and permafrost by geophysical surveying and have verified the presence of polygenetic ground ice in several moraine complexes in the European Alps. Exemplarily, the presence of massive polygenetic ground ice within the large thrust moraine complex of the upper Val Muragl (Swiss Alps) was confirmed. However, so far no other structures indicating an interaction of the glacier and sub- and proglacial permafrost were detected inside this moraine complex. The contribution presents results from recent surveying of ERT and GPR in the Val Muragl. The aim of these geophysical investigations is the detection of the present-day extent of the massive ice core and the identification of internal sedimentological structures that would indicate a glacier-permafrost interaction. The GPR surveys were performed using a PulseEKKO Pro system with two unshielded 50 MHz antennas. The ERT surveys we conducted using a Syscal Pro Switch resistivity imaging system with 36 electrodes and an electrode spacing of 5 m. The results of the ERT measurements enabled a clear delineation of the actual extent of the massive ice core and showed a zone of very high electrical resistivity values in the central and proximal part of the moraine body. The high electrical resistivity values reach more than 1 M m and give evidence on a polygenetic origin of the massive ice core. In contrast, the GPR imaging revealed boundaries of different substrate zones within the moraine complex that are partly even visible at the surface. In the radargrams these zones appeared as linear reflectors that dipped towards the proximal side of the moraine complex. The course and the extent of the detected boundaries between the different substrate zones indicated the presence of several shear planes within the moraine body. The combination of ERT and GPR surveying could contribute to a better understanding of the internal structure of the moraine complex in the Val Muragl. The geophysical data make the presence of polygenetic massive ice core likely and indicated as well substrate boundaries inside the moraine body that were interpreted as shear planes. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-15420.pdf

2019048443 Lamontagne-Hallé, Pierrick (McGill University, Department of Earth and Planetary Sciences, Montreal, Canada); McKenzie, Jeffrey; Kurylyk, Barret; Chen, Lin and Zipper, Samuel. Designing realistic surface boundary conditions for groundwater models in permafrost regions [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-1700, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

The presence of permafrost strongly influences the storage and movement of groundwater by confining ground-water flow to the unfrozen zones above and below permafrost and in taliks (i.e. perennially unfrozen zones). Permafrost thaw due to climate warming modifies hydrological processes by increasing hydraulic conductivity by several orders of magnitude. To improve our knowledge on the impact of climate change on northern hydrology and on the role of groundwater flow on permafrost thaw, groundwater modelling tools have been developed during the last decade to include freezing and thawing processes and its impact on soil properties. These models have revealed new insights into Arctic hydrological systems, but considerable uncertainty remains regarding the design and parameterization of surface boundary conditions that represent thermal and hydrologic climate change phenomenon at the land surface. The employed boundary conditions are usually very limited and not adapted to cold regions. Herein, we develop different sets of thermal and hydrologic surface boundary conditions adapted specifically for cold regions. These include a seasonally varying recharge boundary condition and a surface energy balance that considers different surface processes. We then test these boundary conditions in saturated and unsaturated conditions and compare the simulation outcomes with models in a similar setting using traditional boundary condition forms. From these analyses, we determine which boundary conditions exert a strong influence on the model outcomes and provide recommendations for which boundary conditions to use depending on the setting. This study provides the first guidelines to develop realistic and effective conceptual and numerical groundwater models in cold regions and will allow stakeholders to apply these models for different purposes such as managing water resources in the Arctic. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-1700.pdf

2019048441 Lebedeva, Liudmila (Melnikov Permafrost Institute, Yakutsk, Russian Federation); Gustafsson, David; Makarieva, Olga and Agafonova, Svetlana. Changing river ice and frozen ground in eastern Siberia; present state and future scenarios [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-11156, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Large part of Eastern Siberia is covered by permafrost and is accessible only by rivers in summer and ice roads in winter. They critically depend on ice formation dates and thickness. Ground thawing, subsidence, thermokarst and other hazardous cryogenic processes could lead to failure of infrastructure. The study aimed at assessment of current and future climate-induced changes of river ice and active layer depth in Central Yakutia. Hydrological models Hydrograph and HYPE were employed to simulate active layer depth and river ice respectively with ensembles of bias-corrected CMIP5 climate model outputs (1971-2100) as forcing representing the emission scenarios RCP4.5 and RCP8.5. Air temperature in Yakutsk has increased from -10.4 C (1951-1978) to -8.7 C (1979-2012). It is expected to further increase by 3.5 C and 6.6 C according to RCP4.5 and RCP8.5 by the end of XXI century. The mean ice thickness of the Lena River at Yakutsk in March and April has decreased in March and April during the period 1955-2015 by 20-35%. River breakup is shifting to earlier dates at a rate of 1.2 days per decade (1939-2015). Ground temperature and thawing depth are relatively stable for the period 1982-2012. Hydrograph model was applied in a lumped way to simulate active layer depth. The dominant landscapes in Central Yakutia are larch forest with sandy soil, pine forest with sandy soil, larch forest with loamy soil, alas depressions covered by grassland with loamy soil, inter-alas areas covered by larch and birch forests, and marsh. Model parameters were estimated based on field data that is representative for above-mentioned landscapes. Validated on the historical observations Hydrograph model was used for future projection. According to RCP4.5 practically no changes of active layer depth are expected in alas and interalas areas. Deepening of active layer in marshes, pine and larch forests with sandy soils for period 2071-2100 would reach 47-66 cm comparative to 2011-2040. According to extreme RCP8.5 scenario permafrost would completely thaw in upper 5 m in three landscapes with sandy soils while thawing depth would increase only by 15-27 cm in other three landscapes with loamy soils. Simulation results suggest relatively high resilience of alas, interalas areas and larch forests with loamy soils to future warming. The Arctic-HYPE model was applied to simulate ice depths and freeze-up and break-up dates at river ice road crossings in the Lena, Aldan and Viluy rivers. Local observations from the Lena river at Tabaga, Yakutsk and Khangalassy were used for critical model improvements. Projections towards the end of XXI century under RCP4.5 and RCP8.5 suggests that the ice cover period is likely to be one month shorter than today, both through earlier break-up and later ice formation dates, and reduction of annual maximum ice depth would be in the range 40 to 70 cm. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-11156.pdf

2019048480 Lilleoren, Karianne (University of Oslo, Department of Geosciences, Norway); Etzelmüller, Bernd and Dehls, John. Towards a national inventory of continuous rock glaciers movement in Norway based on InSAR [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-4124, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Creeping permafrost landforms in Norway are widely distributed over the country. While in southern Norway features originated from ice-cored moraines dominate in high elevation, northern Norway has clusters of both active and relict rock glaciers derived mainly from talus slope deposits. Mapping of these features was mainly based on interpretation of aerial photos of varying quality and resolution, which opens for misinterpretation of both type and activity status, along with lacking observations. E.g., in the northern part of Finnmark in Northern Norway, a group of rock glaciers exists close to sea level, and has been mapped as relict features in our inventory. Since 2015, we have investigated one of these rock glaciers (Ivarsfjord rock glacier) more closely using high resolution (10 cm) SfM, DEM comparison and ERT surveys, revealing a significant displacement pattern indicating an active rock glacier. The Geological Survey of Norway (NGU) has recently published a nationwide database of radar interferometry measurements (InSAR; URL: https://insar.ngu.no/). The data is collected from the Sentinel 1-satellites, part of the EU Copernicus program, and data exist from October 2014, with a temporal resolution of up to 6 days during the snow-free season. The database is openly available, and has until now be used to identify unstable rock slope areas and vertical movement of buildings and infrastructure. To evaluate the activity of Norwegian rock glaciers we systematically compared the InSAR database to our existing rock glacier inventory. The high correspondence between the existence of rock glaciers and large ground displacement verifies the inventory interpretations. The field measurements from the Ivarsfjord rock glacier correspond to a large degree to the InSAR-derived displacements. Further, areas of large displacement in the InSAR dataset were investigated more closely, and in this way several areas of rock glaciers previously not mapped were discovered. Here we will present the result of our dataset comparison in terms of activity classification, flow velocities and their variations in time and space in Norway. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-4124.pdf

2019048529 MacDougall, Andrew (St. Francis Xavier University, Department of Climate & Environment, Antigonish, Canada). Limitations of the 1% experiment as the benchmark idealized experiment for carbon cycle evaluation in Earth system models [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-7984, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Idealized climate change simulations are used as benchmark experiments to facilitate the comparison of ensembles of climate models. In the Fifth phase of the Climate Model Intercomparison Project (CMIP5) the 1% experiment was used to compare Earth System Models with full representations of the global carbon cycle. However the 1% experiment was never intended for such a purpose and implies a rise in atmospheric CO₂ concentration at double the rate of the instrumental record. Here we examine this choice by using an intermediate complexity climate model to compare the 1% experiment to an idealized CO₂ pathway derived from a logistic function. The comparison shows three key differences in model output when forcing the model with the Logistic experiment. (1) The model forced with the logistic experiment exhibits a transition of the land biosphere from a carbon sink to a carbon source, a feature absent when forcing the model with the 1% experiment. (2) The ocean uptake of carbon comes to dominate the carbon cycle as emissions decline, a feature that cannot be captured when forcing a model with the 1% experiment. (3) The permafrost carbon feedback to climate change under the 1% experiment forcing is less than half the strength of the feedback seen under logistic experiment forcing. Using the logistic experiment also allows smooth transition to zero or negative emission states, allowing these states to be examined without sharp discontinuities in CO₂ emissions. Given the limitations of the 1% experiment as the benchmark experiment for carbon cycle intercomparisons, adding a logistic or similar idealized experiment to the protocol of the CMIP7 is recommended. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-7984-1.pdf

2019048498 Majdanski, Mariusz (Polish Academy of Sciences, Institute of Geophysics, Warsaw, Poland); Marciniak, Artur; Owoc, Bartosz; Kowalczyk, Sebastian and Dzierzek, Jan. Uncertainty driven multi-method seismic analysis in near-surface imaging; case studies [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-6607, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Near-surface imaging is often performed with a single method like multi-channel analysis of surface waves or first breaks traveltime tomography. This approach is easy to execute and gives fast results. However, such a limited approach use only a part of available data. This results in limited recognition of sub-surface structures with high uncertainties, that leads to difficult interpretations. This work presents a multi-method approach that utilises both refraction and reflection components of seismic data. Moreover, it uses a sequence of interpretation techniques combining multi-channel analysis of surface waves, ground penetrating radar, wide-angle travel-time tomography, and reflection imaging to recognize details in sub-surface structures. Additionally, the uncertainty driven approach allows to estimate uncertainty at each processing stage and propagate it through the multi-method path to estimate its final value. The application of this approach is presented for two case studies, one high arctic study to recognize the shape of the permafrost in the area between a retreating glacier and the seashore, the other one more typical geological study of Quaternary fluvial sediments. Both case studies clearly show that the combination of several methods gives better, more detailed and less uncertain results, while additional processing cost for already existing data is proportionally not significant. Additionally, all field works have been executed with different acquisition geometries, and this work presents the influence of the particular type of acquisition of each interpretation technique. This research was funded by National Science Centre, Poland (NCN) Grant UMO-2015/19/B/ST10/01833. Part of this work was supported within statutory activities No. 3841/E-41/S/2018 of the Ministry of Science and Higher Education of Poland. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-6607.pdf

2019048510 Mamot, Philipp (Technical University of Munich, Chair of Landslide Research, Munich, Germany); Krautblatter, Michael; Scandroglio, Riccardo and Eppinger, Saskia. A thermo-mechanically coupled failure model for degrading permafrost rock slopes based on laboratory and field data [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-5291, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Instability and failure of permafrost-affected rock slopes have significantly increased coincident to rising air temperature in the last decades. Most of the observed failures in permafrost-affected rock walls are likely triggered by the mechanical destabilisation of warming bedrock permafrost including ice-filled joints. To anticipate failure in a warming climate, we need to better understand how rock-ice mechanical processes affect rock slope destabilisation and failure with temperatures increasing close to 0 C. Warming permafrost in rock slopes decreases the shear resistance along rock joints (considering ice or soil infillings and cohesive rock bridges) as well as the compressive and tensile strength of saturated intact bedrock (Krautblatter et al., 2013). For the first time, we mechanically model the weakening of a degrading permafrost rock slope considering a change from the frozen to the unfrozen state. For this, we combine the temperature distribution in a rock slope with a temperature-dependent mechanical failure model. We calibrate this model with a shallow, ice-supported rockslide of approximately 10.000 m³ at the permafrost-affected Zugspitze summit crestline (2885 m a.s.l.), Germany, using frozen and unfrozen rock-ice-mechanical parameters. For this, we performed a set of laboratory studies on a broad spectrum of mechanical properties of thawing bedrock and rock joints with Wetterstein limestone from the Zugspitze. The tested mechanical properties of the intact bedrock contain the uniaxial compressive strength (sc), the tensile strength (st) and the Young's modulus (E). Investigated rock joint properties involve the shear strength of rock joints filled with ice and rock joints without infilling (Mamot et al., 2018). A temperature-dependent strength reduction could be shown for all investigated parameters. Tomographies of electrical resistivity (ERT) and seismic refraction (SRT) of the Zugspitze summit crest were used to identify the spatial distribution of permafrost within the rock slope. Modelling is performed with the two-dimensional Universal Distinct Element Code (UDEC) which simulates and represents the mechanical behaviour of discontinuous media - an assemblage of discrete rock blocks separated from each other by discontinuities. The model shows a decreasing factor of safety and higher displacement rates as soon as thawing sets in. The combination of thermal and mechanical information as input data for numerical failure models helps scientists and engineers to anticipate for the first time the strength reduction of degrading permafrost rock slopes. Krautblatter, M., Funk, D., Gunzel, F. K. (2013). Why permafrost rocks become unstable: a rock-ice-mechanical model in time and space. Earth Surface Processes and Landforms 38: 876-887. Mamot, P., Weber, S., Schroder, T. and Krautblatter, M. (2018): A temperature- and stress-controlled failure criterion for ice-filled permafrost rock joints. The Cryosphere 12: 3333-3353. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-5291.pdf

2019048504 Manseau, Frederic (Laval University, Department of Geography, Quebec, QC, Canada); Bhiry, Najat; Molson, John and Cloutier, Danielle. Stream turbidity within degrading permafrost terrain in the Tasiapik Valley, Umiujaq region, Nunavik [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-2753, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Permafrost degradation caused by rising temperatures has had a significant impact on northern ecosystems. For example, it contributes to greenhouse gas emissions, increased recurrence of landslides, and changes in water resources. Sediment migration to the soil surface has also been observed during soil settlement caused by thawing permafrost. Soil settlement increases the flow of water, which is enriched in organic matter and mineral sediments, toward streams and lakes, resulting in increased suspended sediment load and increased river turbidity. Furthermore, during flood episodes in spring and high rainfall in autumn, the loose sediment is supported and transported toward the river by surface runoff. This increase in turbidity can have negative effects on the trophic chain, especially on fish as a result of the abrasion of their gills. Variations in river turbidity have been examined in several studies (Lawler et al., 2006; Hamilton and Luff-man, 2009). However, in the context of current and future climate change, there is limited knowledge about the effects of variations in river turbidity associated with permafrost degradation. Thus, the objective of this research is to track variations in river turbidity in the periglacial context in relation to environmental field parameters. The Tasiapik Valley is located 5 km east of the village of Umiujaq, Nunavik (Canada). A central stream drains the valley which contains discontinuous and degrading permafrost mound and surface water ponds. The stream collects water from tributaries originating from the northern slopes of the valley and flows into Lake Tasiujaq, which is part of Tursujuq National Park. The surrounding environment is a unique and important place for fishing and outdoor activities both for the Umiujaq community and for the increasing number of tourists. In addition, the valley is the subject of numerous scientific and environmental research projects being conducted by the Centre d'Etudes Nordiques (CEN; Centre for Northern Studies) of Université Laval. Characterization of the local environment has already been completed through geomorphological surveys, while sedimentological analyses of fluvial samples will be carried out. Turbidity data are being collected during the river's frost-free period using submersible turbidity meters. These measurements will be analyzed and correlated with weather data from the CEN VDT-SILA meteorological station in order to examine the relationship between variations in turbidity and environmental parameters such as air temperature and precipitation. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-2753.pdf

2019048452 Marciniak, Artur (Polish Academy of Sciences, Institiute of Geophysics, Warsaw, Poland); Owoc, Bartosz; Wawrzyniak, Tomasz; Nawrot, Adam; Glazer, Michal; Osuch, Marzena; Dobinski, Wojciech and Majdanski, Mariusz. Recognition of the varying permafrost conditions in the SW Svalbard by multiple geophysical methods [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-377, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

In recent years, rapid climatic changes and their impact are widely visible and recognizable around the world. The Atlantic sector of the Arctic is the place of the strongest observed changes. As a result, such changes are already destabilizing the arctic systems including the glaciers and the permafrost that strongly affects the Arctic's physical and biological systems. In the presented work, we applied multiple geophysical methods and tools, to recognize horizontal and vertical distribution as well as ongoing changes in the seasonally and perennially frozen ground. The study site, located near the Polish Polar Station in the Hornsund (Svalbard), is unique due to its location between sea-shore and mountainous ridges and close presence of the retreating Hans Glacier. Such an environment allows for conducting research encompassing various dynamical cryospheric, geological and other environmental processes. The monitoring of the ground temperature variations in the several boreholes, with detailed ERT, GPR and MASW modeling, allow for recognition and analyses of the active layer spatial variability and the permafrost changes in this area. The seismic recognition, based on the dense 2D seismic reflection and refraction methods, allows for the direct comparisons between observations conducted during the summer and winter seasons. Results obtained by those methods are directly targeted to visualize not only the active layer thickness but also the permafrost which until today is unknown in the area of Southern Spitsbergen. Additionally, the comparison of the data-set quality between two seasons allowed to select the best conditions for future data acquisition. The recognition of vertical and horizontal changes of the permafrost as well as the active layer depth provided unique information about the thermal ground conditions. Obtained results, gives us the opportunity for explanation of seasonal changes which were observed, measured, and modeled. This information allows for better understanding of the geophysical processes responsible for the cryospheric and geological processes occurring in the study site, and further better estimation of the climate change impacts on the environment SW Spitsbergen. This research was funded by National Science Centre, Poland (NCN) Grant UMO-2016/21/B/ST10/02509. Part of this work was supported within statutory activities No. 3841/E-41/S/2018 of the Ministry of Science and Higher Education of Poland. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-377.pdf

2019048487 Miesen, Floreana (University of Bonn, Department of Geography, Bonn, Germany); Dahl, Svein Olaf and Schrott, Lothar. Assessing glacier-permafrost coupling from scratch; thermokarst processes in an ice-cored moraine, Snohetta, Dovrefjell, Norway [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-17718, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Albeit often located in the same area and climatic zone, phenomena regarding permafrost and glaciers are often studied separately. Various landforms, however, express a clear interaction of these regimes, such as ice-cored moraines. Being of glacial origin, ice-cored moraines constitute a permafrost environment. Reworking by periglacial processes is often directed both by glacial meltwater impacts and freeze-thaw dynamics. Aiming to seek a coupling element in a glacial-periglacial landscape, surface- and near-surface hydrology was considered along a basin featuring a polythermal glacier, a glacier lake and an ice-cored moraine complex at the north-eastern flank of the Snohetta massif, Dovrefjell, South Norway. This study provides insight from very first field observations including a snapshot of spatial variability of stable oxygen isotopes as tracers along meltwater pathways combined with short-term observations of glacier lake dynamics by remote sensing. First results suggest a periodical drainage of the lake along preferential subsurface pathways, with subsequent thermal erosion of the ice-core and the development of thermokarst structures within the moraine. This constitutes a spatially heterogeneous pattern and a division of the moraine complex in a stable, eastern part and a degrading, western part. Whether the ice-cored moraine provides a barrier or a pathway to meltwater exiting the glacier, is both determined by dynamics and patterns of glacial discharge and active layer depth within the moraine, suggesting a two-fold threshold for lake drainage. The ice-cored moraine therefore provides an intriguing example of studying the transient glacier-permafrost interface in a changing climate. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-17718-1.pdf

2019048492 Mithan, Huw (Univeristy of Dundee, Department of Geography and Environmental Science, Dundee, United Kingdom); Hales, Tristram and Cleall, Peter. Topographic and ground-ice controls on shallow landslides in Arctic permafrost [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-15999, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Arctic landscapes are experiencing enhanced permafrost thaw due to a rapidly warming climate. More frequent extreme summer temperatures and rainfall events drive heat quicker and deeper into ice-rich permafrost soils. Higher heat fluxes increase the active layer depth and facilitate rapid thawing of ground-ice, resulting in more vigorous hillslope surface processes such as shallow permafrost landslides called active layer detachments (ALDs). Such increase in the rate of surface processes threaten Arctic infrastructure and are an important mechanism for delivering sediment, organic carbon, and other nutrients to Arctic rivers and lakes. However, little is currently known about the topographic controls and ground-ice conditions needed to generate ALDs on Arctic hillslopes. We used satellite imagery to map 150 ALDs in a 100 square kilometre study area of the Brooks Range, Alaska. We compared the distribution of ALDs to the drainage network to determine any topographic constraints. Our topographic results show that the majority of mapped ALDs are coincident with the drainage network, suggesting that they initiate in areas of topographic convergence. However, not all of the drainage network experienced ALD failures suggesting an additional mechanistic control on ALD intimation. We then modified a two-dimensional slope stability model to assess the temporal and spatial impact of excess pore-pressures generated by thawing ice lenses on slope stability. Our analysis shows that if ice lenses are too small or have low relative connectivity the slope remains stable. However, the conditions required to initiate ALDs is the rapid thawing of highly concentrated ground ice at depth. Therefore, we suggest that future ALD potential may be better understood through field measurements of ground ice distribution on Arctic hillslopes. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-15999.pdf

2019048447 Molson, John (Laval University, Department of Geology & Geological Engineering, Quebec, Canada); Dagenais, Sophie; Ghias, Masoumeh Shojae; Cochand, Marion; Albers, Britt; Therrien, René; Fortier, Richard and Lemieux, Jean-Michel. Numerical modelling of coupled groundwater flow and permafrost thaw under climate change; applications to monitored field sites at Umiujaq (Nunavik, Quebec) and Iqaluit (Nunavut), Canada [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-12376, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Numerical simulations have been completed at two monitored field sites in northern Canada to investigate the behavior of coupled groundwater flow and permafrost thaw in the context of climate change. The numerical model, HEATFLOW/3D, includes groundwater flow and heat transport with latent heat, and temperature-dependent water density and viscosity, relative permeability, thermal conductivity and unfrozen water content. Analytical solutions and numerical benchmarks from the Interfrost consortium (wiki.lsce.ipsl.fr/interfrost) were used for model validation. The first site, near the village of Umiujaq in Nunavik, northern Quebec, Canada, is located in a small two square kilometre catchment containing degrading permafrost. A two-dimensional vertical-plane cryo-hydrogeological numerical model was developed for the site based on a 3D geological model which included up to 30 m of Quaternary sediments composed of sands, gravels and marine silts, as well as fractured bedrock. Field-based groundwater recharge and observed air temperatures were applied as components of the surface boundary conditions, while model calibration was based on detailed observed temperature profiles and ground heat fluxes. The simulations suggest that both supra- and sub-permafrost groundwater flow is contributing to permafrost thaw, driven by increasing air temperatures. The relatively short and rapid flow paths were consistent with the observed hydro-geochemical signatures dominated by Ca-HCO₃ water types. Cooled sub-permafrost groundwater flow maintains cold temperatures in the downgradient discharge zone. Model calibration and predictive simulations based on IPCC climate warming projections suggest the active zone thickness is increasing by 12 cm/yr while the base of the permafrost is thawing at a rate of about 80 cm/year, with complete permafrost thaw by around the year 2040. The second site is located at the Iqaluit airport, in Nunavut, northern Canada, where permafrost degradation is contributing to deformation of the airport taxiway. In comparison to the Umiujaq site, Iqaluit lies in the continuous permafrost zone where thermal conduction and supra-permafrost groundwater flow play active roles in permafrost dynamics. The same HEATFLOW/3D code was applied to the Iqaluit site, in a 2D vertical plane across the taxiway. At this site, the insulating effect of snow cover on the taxiway shoulders is shown to significantly affect permafrost thaw dynamics. Despite increasing mean air and ground surface temperatures over time, groundwater cooling along the permafrost table is paradoxically shown to temporarily increase the height of the permafrost table in downgradient areas. The simulations suggest that the maximum depth of the active layer will increase from 2 m in 2012 to 8.8 m in 2100 and, over the same time period, thaw settlement along the airport taxiway will increase from 0.11 m to at least 0.17 m. In both the Umiujaq and Iqaluit models, a quantitative parameter sensitivity analysis showed that variations in the hydraulic and thermal conductivity of the uppermost soil layers and the shape of the unfrozen water saturation function had the most significant effects on permafrost degradation. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode] hydro-geochemical signatures dominated by Ca-HCO₃ water types.

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-12376.pdf

2019048538 Morel, Xavier (Centre National de Recherches Météorologiques, Toulouse, France); Decharme, Bertrand; Delire, Christine; Krinner, Gerhard; Lund, Magnus; Hansen, Birger and Mastepanov, Mikhail. Investigating peat soil carbon and methane emissions with a new process-based model and new data from Nuuk (Greenland) [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-15464, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Permafrost soils and arctic wetlands methane emissions represent an important challenge for modeling the future climate. We present a new process-based model designed to represent the main thermal, hydrological, and biogeochemical processes related to these emissions for general land surface modeling, and a new soil carbon dataset from a greenlandic peatland, close to Nuuk. The multilayer scheme, embedded in the ISBA land-surface model, represents carbon pools, vertical carbon dynamics (advection and cryoturbation processes), and both oxic and anoxic organic matter decomposition. It also represents the soil gas processes for CH₄, CO₂, and O₂ through the soil column. Although this model has been validated on three climatically distinct arctic sites - two in Greenland (Nuuk and Zackenberg) and one in Siberia (Chokurdakh) - where it realistically reproduces methane and carbon dioxide emissions from both permafrosted and non-permafrosted sites, the modeled soil carbon stocks and profiles were not evaluated due to the lack of soil carbon data on these sites. This shortcoming had to be addressed, as carbon profiles are one of the primary drivers for CO₂ and CH₄ soil production. Hence, we measured for the first time soil carbon stocks and profiles at the Nuuk peatland. These new measurements are in the range of those encountered in arctic peatlands. Comparing these stocks and profiles with the modeled carbon stocks shows some shortcomings of the new discretized soil carbon model, in particular for the soil carbon vertical dynamics processes. Sensitivity experiments on the vertical dynamics and the soil carbon decomposition rates show that our model is able to reproduce fairly well both carbon profiles and greenhouse gases emissions from the Nuuk peatland. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-15464.pdf

2019048458 Müller, Jakob (University of Vienna, Department of Geography and Regional Research, Austria); Lachner, Johannes; Groh, Till; Blöthe, Jan Henrik and Kraushaar, Sabine. Quantifying permafrost degradation using combined stable isotopes (²H and ¹⁸O) and anthropogenic ¹²⁹I isotope chemistry in rock-glacier meltwaters [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-1408, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Rock glaciers are very prominent features of alpine permafrost that potentially contain important water resources in alpine regions. In the European Alps, where glaciers are diminishing under the rising temperatures, the importance of underground ice stored in permafrost bodies is on the rise. In this respect, rock glaciers receive increasing attention, as their distinct surface morphology and creeping movement attests to significant ice-contents below their active layer. How much of this ice is melting during warm summers and how these melting processes affect the hydrological cycle of alpine rivers is largely unknown. Our study uses a hydro-chemical approach to estimate the fraction of total discharge contributed by rock-glacier meltwaters in the Kaiserbergtal valley, located in the crystalline Otztaler Alps, Austria. The upper Kaiserbergtal valley has a surface area of 3 km² and hosts several active rock glaciers in elevations above 2500 m a.s.l., but is devoid of any glacier ice. Here we installed two gauging stations to monitor discharge, one located close to the terminus of the largest rock glacier, a second station further downstream that receives discharges from the entire catchment. In addition, we collected monthly water samples from rain, lakes, snow, glacier ice (adjacent catchment), and rock glacier discharge throughout the summer of 2018 in order to determine their stable isotope signatures ¹⁸O and ²H, as well as the anthropogenic isotope ¹²⁹I. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-1408-1.pdf

2019048483 Onaca, Alexandru (West University of Timisoara, Department of Geography, Timisoara, Romania); Ardelean, Adrian; Magori, Brigitte; Voiculescu, Mircea; Ardelean, Florina; Gachev, Emil and Sirbu, Flavius. Permafrost investigations in the Rila and Pirin mountains, Bulgaria [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-5864, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

This study assesses the possible occurrence of permafrost in the Bulgarian highest mountains using thermal and geophysical measurements. Although both Rila and Pirin Mountains rise to nearly 3000 m, the possibility of permafrost occurrence in these mountain ranges has not been investigated so far. Generally, in marginal periglacial environments, permafrost occurrence is patchy and highly dependent on site-specific characteristics. However, the conditions of enhanced preservation of permafrost in marginal periglacial environments as in the case of the highest mountains in the Balkan Peninsula, are still poorly understood. A total of 20 thermistors were scattered on the surface of ten selected rock glaciers in the Rila and Pirin Mountains to examine the near-surface thermal regime and to determine whether the microclimatic factors at the ground surface are suitable for hosting permafrost. Measurements of the bottom temperature of the winter snow cover were performed at the end of cold season, whereas the temperature of several springs seeping from rock glaciers was measured in late summer. All the thermal measurements were conducted during two different hydrological seasons (2016-2017 and 2017-2018). Conventional geophysical investigations (electrical resistivity tomography and ground penetrating radar) were used to get subsurface information regarding permafrost occurrence within the selected rock glaciers and talus slopes. The preliminary thermal and geophysical results revealed that patches of relict permafrost may occur at altitudes above 2400-2500 m where the pronounced shadow effect of the ridges and the actual climatic conditions allow the preservation of long-lasting snow patches. Based on our observations and measurements the sites where permafrost is probable to occur are characterized by large boulders at the surface, reduced income of solar radiation and a very efficient cooling effect of the blocky surface. Acknowledgement: This work was supported by a grant of Ministry of Research and Innovation, CNCS - UEFISCDI, project number PN-III-P1-1.1-PD-2016-0172, within PNCDI III. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-5864.pdf

2019048445 Orgogozo, Laurent (Université de Toulouse, Géosciences Environnement Toulouse, Toulouse, France); Prokushkin, Anatoly S.; Pokrovsky, Oleg S.; Grenier, Christophe; Quintard, Michel; Viers, Jérôme and Audry, Stéphane. Water and element fluxes in an experimental watershed in a permafrost-dominated, forested area of Central Siberia; insights from geochemical observations and thermo-hydrological modeling [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-7838, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

The biogeochemical transfers in the catchment of the Kulingdakan stream, which is a small tributary of the Kochechum river in the Yenisei basin, have been studied for more than a decade. Measurements of the chemical composition of the waters in the stream and in the other compartments of the watershed, such as mineral soil or litter horizons for instance, have been done. Along with these hydrogeochemical observations, characterizations of the chemical compositions of the constituents of the compartments themselves have been performed. The vegetation cover properties, heterogeneity and elemental composition have also been carefully assessed. This knowledge (e.g.: [1], [2]) allowed to build a conceptual hydrological scheme of the water fluxes in this Kuling-dakan catchment, characterized by a strong impact of active layer dynamics. The main feature of this hydrological scheme is the high variability along slopes aspect, as summarized in Orgogozo et al. (2014) [3]. This conceptual scheme has then been investigated by cryohydrogeological numerical modeling [4]. The numerical study confirms the transfer mechanisms inferred by the biogeochemical studies, and allows to point out more precisely the impact on the fluxes of matter of the vegetation cover and especially of the dynamics of transfer processes within the root layers. The impact of evapotranspiration on water fluxes is studied numerically, which highlights a strong sensitivity to the variability of rooting depth and corresponding evapotranspiration at the slopes of different aspects in the catchment. On the basis of these results the potential evolution of the fluxes of water and elements from the slopes to the stream in the Kulingdakan watershed under climate change is briefly discussed using a substituting space-for-time approach (e.g.: [5]). [1] Bagard M-L et al. Geochimica et Cosmochimica Acta. 2013;114:169-187. [2] Viers J et al. Biogeo-chemistry. 2013;113:435-449. [3] Orgogozo L et al. in 'Permafrost: Distribution, Composition and Impacts on Infrastructure and Ecosystems', ed. Pokrovksy OS, Nova Publishers. 2014:153-172. [4] Orgogozo L et al. Permafrost Periglac. Accepted. [5] Kirpotin SN et al. Int J Environ Stud. 2018;75(3): 385-394. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-7838-1.pdf

2019048519 Pan, Mengdi (German Research Center for Geosciences, Helmholtz Center Potsdam, Potsdam, Germany); Wang, Yi; Mayanna, Sathish; Schleicher, Anja; Spangenberg, Erik; Schicks, Judith and Li Xiaosen. Changes of permeabilties as a result of hydrate dissociation in sand-clay sediment from Qilian Mountain permafrost, China [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-17102, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Permeability is known as a key factor affecting the effectiveness of gas production from a natural gas hydrate reservoir. In addition to the lithological effects of the hydrate-bearing sediment itself, the formation and dissociation processes of gas hydrate in the sediments may also have an influence on the permeability. In this study, samples from a gas hydrate reservoir in the Qilian Mountain permafrost (borehole DK-8 and SK-2 in northern Muli coalfield) were taken for the permeability experiments. Permeabilities were measured before hydrate formation, with hydrate and also after hydrate dissociation. The presence of solid methane hydrate in the pores lowers the permeability depending on hydrate saturation. However an unexpected high permeability decrease was observed after the dissociation of methane hydrate. Six kinds of permeability tests were carried out to detect the reason for formation damage after hydrate dissociation. The results indicate that the fresh water released from the hydrate dissociation may cause an activation and following the migration of fine particles which block the pore throats and finally result in a decrease of permeability. Scanning Electron Microscopy (SEM) analysis on the filter papers which attached on the inlet and outlet of the core sample provides visible evidence on fine migration. In our study we present the experimental results of the permeability tests under different conditions and discuss the potential reasons for our observations. One possible explanation for this phenomenon may be that the release of fresh water causes an increase in the double layer thickness at the water mineral surfaces and therefore increase the repulsion forces between rock particles. This process can release small particles which were attached to the surface of bigger sediment grains. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-17102.pdf

2019048449 Piovano, Thea Ilaria (University of Aberdeen, School of Geosciences, Aberdeen, United Kingdom); Tetzlaff, Doerthe; Carey, Sean; Shatilla, Nadine; Smith, Aaron and Soulsby, Chris. Spatially distributed tracer-aided modelling of dynamics in storage and water ages in a permafrost influenced catchment [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-160, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Permafrost strongly controls hydrological processes in cold regions, and our understanding of how changes in seasonal and perennial frozen ground disposition and linked storage dynamics affects runoff generation processes remains limited. Storage dynamics and water redistribution are affected by the seasonal variability and spatial heterogeneity of frozen ground, snow accumulation and melt. Stable isotopes are useful to quantify the dynamics of water sources, flow paths and ages, yet few studies have employed isotope data in permafrost-influenced catchments. Here, we applied the model STARR (Spatially distributed Tracer-Aided Rainfall-Runoff model) which facilitates fully distributed simulations of hydrological storage dynamics and runoff process, isotopic composition and water ages. We adapted this model to a subarctic catchment in Yukon Territory, Canada, with a time variable implementation of field capacity to include the influence of thaw dynamics. A multi-criteria calibration based on streamflow, snowpack and isotopes was applied to validate three years of daily data. The integration of isotope data in the spatially distributed model provided the basis to quantify spatio-temporal dynamics of water storages and ages underlying the importance of thaw layer dynamics in mixing and damping the melt signal. By using the model conceptualisation of spatio-temporal variant storages, this study demonstrates the value of tracer-aided modelling to capture thaw layer dynamics and to quantify storage and age dynamics in permafrost environment for the first time. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-160-1.pdf

2019048468 Romanovskaya, Maria (Lomonosov Moscow State University, Department of Dynamic Geology, Moscow, Russian Federation); Romanovsky, Vladimir and Kuznetsova, Tatyana V. The possible consequences of increasing greenhouse gases released as a result of climate warming [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-14914, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

It is well known that an enormous amount of organic material is sequestered in permafrost and the overlaying active layer. Some estimates say the amount of carbon in the permafrost is more than two times than there is in atmospheric carbon dioxide (Romanovsky V.E. et al., 2018). The presence of a significant amount of organic matter, microbes, and water and low oxygen concentrations under impermeable caps of ice and glacier beds creates very good conditions for greenhouse gas production (Burns R. et al., 2018). These facts raise concerns associated with an increased release of greenhouse gases caused by modern climate warming. Our study area occupies the southern part of the Middle Russian Upland (the East European Plain). It has experienced several Quaternary glaciations. The results of our comprehensive geological and geomorphological exploration and analysis of the area have clearly shown that this upland was formed under the influence of the Don, Dnepr, Moscow, and Valdai Glaciations (Romanovskaya M.A. et al., 2017, 2018). The facts of the presence of permafrost and its degradation during the late Pleistocene and Holocene are established here as well. The area is located within of the equilibrium permafrost zone as it is shown on the map of the Last Permafrost Maximum (LPM) (Vandenberghe J. et al, 2014). Our finest and most detailed study of a cross-section of the Quaternary deposits was carried out at the multilevel archaeological site Divnogorie-9 (50 36'49" N, 39°30'31"E), known for the discovery of an enormous amount of fossilized horse bones. This section exposed several brownish paleosol layers. Radiocarbon dating of the fossils and paleosol layers found at the site led to estimates of 14-12 ka BP (Lavrushin et al., 2010). At 30 km from the Divnogorie site, another world famous archeological site of mammoth remnants - the Borshchevo-Kostenki site is located (51 23'40" N, 39°30'31"E, 38-18 ka BP). The development of such a large population of grazers at the study area in the late Pleistocene and Holocene tells us about the presence of rich grassy vegetation and rich organic soils here at that time. Our measurements of the present-day concentrations of organic carbon in the paleosol layers have shown very small amounts of the organic carbon, comparable to the sensitivity of the measurements method. This data allows us to make an optimistic conclusion that climate warming caused by the decomposition of organic material in thawing permafrost and under disappearing ice sheets had already had a place in Quaternary history in this area and has not led to particularly devastating global consequences. However, on a regional scale, the related changes had a disastrous effect on the local flora and fauna. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-14914-6.pdf

2019048475 Scandroglio, Riccardo (Technical University of Munich, Institute of Astronomical and Physical Geodesy, TU Munich, Munich, Germany); Heinze, Markus; Schröder, Tanja; Pail, Roland and Krautblatter, Michael. A first attempt to reveal hydrostatic pressure in permafrost-affected rock slopes with relative gravimetry [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-12870, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Progressive failure of rock faces in periglacial environments (e.g. Piz Cengalo in 2017) are controlled by rock and ice mechanics but also by hydro- and cryostatic stresses. One of the most important but still unknown factors is the contribution of water in terms of hydrostatic pressure. Its presence has often been registered in major rock failures but it has never been quantified. Infiltration from rainfall or snow/ice melting could create extreme pressure peaks, especially when permafrost seals fractured rock. Climate change consequences like increase of air temperature and intensification of precipitations can amplify the magnitudes and pose a high risk for humans and infrastructures. We present here a new approach to the problem, using relative gravimetry measurements. The detected changes in the local gravity field are attributed to changes in the water content of the surrounding rocks, for low-porosity rocks to water in its fractures. From 2014 to 2019 we monthly monitored relative gravimetry values on the summit of the Zugspitze (Germany, Wetterstein limestone), a few hundred meters away from an area of big touristic interest with thousands of daily visitors. In our case study a Scintrex CG-5 relative gravimeter with accuracy of 1 Gal=10 8m=s² was used at 18 stations mainly located in a tunnel at 2700m above sea level, where we have been measuring permafrost since 11 years. Contemporary Electrical Resistivity Tomography allowed us to quantify precisely permafrost extension for each campaign. Additional continuous information from 25 rock and air temperature sensors, weather data from two DWD-stations and two discharge measurements in the tunnel help to describe, for the first time, the dynamic of water inside the massive and consequently estimate hydrostatic pressure. Here we present the methodology used to detect hydrostatic pressure changes in permafrost-affected rock, the dataset obtained at our fully instrumented test site at the Zugspitze, and we evaluate the feasibility of the gravimetric approach and its potential of a joint interpretation with ERT and complementary data. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-12870.pdf

2019048451 Schroeder, Tanja (Technical University Munich, Chair of Landslide Research, Munich, Germany); Scandroglio, Riccardo; Stammberger, Verena; Wittmann, Maximilian and Krautblatter, Michael. The effects of the hot summers of 2015 & 2018 on the spatial-temporal permafrost evolution at the Zugspitze [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-12223, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

In the context of climate change, permafrost degradation becomes a key variable in understanding rock slope failures in high mountain areas. Warming of permafrost changes the thermal and mechanical properties of rock, effecting the stability of steep rock faces. Electrical Resistivity Tomography (ERT) is the predominant permafrost monitoring technique in high mountain areas. Its high temperature sensitivity for frozen vs. unfrozen conditions, combined with the resistivity-temperature laboratory calibration on Wettersteinkalk (Zugspitze) (Krautblatter et al. 2010) gives us quantitative information on site-specific rock wall temperatures (Magnin et al. 2015). Here, we present the effects of the hot summers of 2015 and 2018 on the spatial-temporal permafrost evolution at the Zugspitze in the realm of a 11 year monitoring program. Measurements were taken at the Kammstollen along the northern Zugspitze rock face. Two high-resistivity bodies along the investigation area reach resistivity values 10^4:5 Wm (~0.5 °C), indicating frozen rock, displaying a core section with resistivities 104:7 m (~2 °C) (Krautblatter et al., 2010). Seasonal variability is seen by laterally aggrading and degrading marginal sections (Krautblatter et al., 2010). The mean rock temperature of the entire core section shows a 2 months phase-shift between solar radiation forcing and thermal rock wall response. Further locally restricted short-term warming patterns along fracture zones are contributed to precipitation and percolating cleft water. Our preliminary results are: ERT-derived rock temperatures reproduce the natural temperature field in the rock wall and can be validated via a simple thermal model. The 2 months phase-shift between thermal rock wall response and solar radiation forcing is attributed to the climatic signal propagation time and conductive energy transport. Net solar radiation, the heat balance of the rock surface is the modulating factor of temporal rock wall temperature evolution, with water availability as an important driving factor. The 11 year monitoring program enables the validation of the resistivity-temperature relationship for natural rock walls and displays seasonal and singular effects due to environmental factors and extreme weather events. The hot summers of 2015 & 2018 show a significant warming over the entire rock wall and especially in local highly fractured zones through the centre of the permafrost lens. 2018 marks the year with the highest permafrost core temperatures and smallest areal extent yet recorded. We further present an approach for a coupled thermo-geophysical model for conductive heat transfer in permafrost rock walls on local scale. We aim to link apparent resistivities, the ground thermal regime and meteorological forcing as seasonality and long-term climate change to validate the ERT and project future conditions. Krautblatter, M., Verleysdonk, S., Flores-Orozco, A. & Kemna, A. (2010): Temperature- calibrated imaging of seasonal changes in permafrost rock walls by quantitative electrical resistivity tomography (Zugspitze, German/Austrian Alps). J. Geophys. Res. 115: F02003. Magnin, F., Krautblatter, M., Deline, P., Ravanel, L., Malet, E., Bevington, A. (2015): Determination of warm, sensitive permafrost areas in near-vertical rockwalls and evaluation of distributed models by electrical resistivity tomography. J. Geophys. Res. Earth Surf., 120, 745-762. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-12223.pdf

2019048463 Sjoberg, Ylva (Stockholm University, Department of Physical Geography and the Bolin Center for Climate Research, Stockholm, Sweden); Rudy, Ashley; Siewert, Matthias; Paquette, Michel; Bouchard, Frédéric; Malenfant-Lepage, Julie and Fritz, Michael. Building on each other's work; impact and inspiration of permafrost research from 1998 to 2017 [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-6851, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Research on permafrost has intensified in recent years, due to enhanced warming in the Arctic and in alpine regions, and the direct feedbacks between thawing permafrost and climate. To explore how scientists build on existing knowledge on permafrost and identify which studies inspire more research, we analyzed scientific articles published over two decades, before (1998-2007) and after (2008-2017) the 4th International Polar Year (2007/2008). We compared this bibliometric data to results from an online survey in which respondents were asked to list the most influential and inspiring publications on permafrost in their view. While publications per year have more than doubled for multidisciplinary geosciences from 1998 to 2017, permafrost publications have increased more than six-fold for the same period, according to bibliometric data from Web of Science. Permafrost publications have increased the most in journals focusing on biogeosciences (e.g. Journal of Geophysical Research - Biogeosciences) but also in the broader geoscience and science journals (e.g. Geophysical Research Letters, Nature), reflecting a shift towards more carbon-cycle focused research in later years. From the survey, many listed books as the most influential publications and comments also revealed that conferences, photographs, movies and (non-science) books inspire permafrost researchers. Keeping track on how knowledge is collectively built within a scientific discipline and community, can help us to identify how to design impactful studies and how to coordinate research efforts in a time when high quality and impact research is badly needed. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-6851.pdf

2019048497 St. Amour, Arianne B. (Université Laval, Center of Northern Studies, Canada) and Allard, Michel. Permafrost characterization using ground penetrating radar (GPR) for territorial development, Inukjuak, Nunavik [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-12132, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

With climate warming affecting the high latitudes, there is a growing need of knowledge concerning the cryostratigraphy and the stability of permafrost for land use planning in the inhabited environments. Since a strong demographic growth is occurring in the community of Inukjuak, there is an increasing need for housing development and municipal infrastructure. It is therefore essential to proceed to high resolution permafrost characterization (about 100 m²) to support urban land use planning and to select foundation designs for buildings in accordance with local permafrost conditions. The main objective of this project is to map the depth to bedrock, the distribution of surface geological units and strata and the zones of ice-rich permafrost zones in the community area and to provide necessary information for selecting the best choices of foundation designs such as pads, piles to bedrock, adjustable studs and thermosiphons throughout the urban area. To achieve this goal, a total of 21 km of GPR profiles surveyed in the summers of 2015 and 2017 were interpreted with the help of other sources of information such as analysis of aerial photographs, surficial geology maps, excavations, drill holes and field observations. Although some sectors of the Inukjuak area are underlain by thaw sensitive permafrost, some other ones such as the southern sector of the community on marine sands have bedrock at rather shallow depths, i.e. between 3.5 and 6.5 m below the surface. The compilation of permafrost data and the map of depth to bedrock shall help decision making for the community and the supporting regional government and will be a tool to develop an adaptation strategy to climate change. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-12132-1.pdf

2019048466 Verdonen, Mariana (University of Eastern Finland, Department of Geographical and Historical Studies, Finland); Tarolli, Paolo; Korpelainen, Pasi; Kolari, Tiina; Tahvanainen, Teemu and Kumpula, Timo. Application of UAS in the analysis of the spatial distribution of active layer thickness in palsa mounds [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-13158, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Palsas, peat-covered mounds with perennially frozen core, occur in the zone of discontinuous and sporadic permafrost, and are often the southernmost patches of permafrost in the Northern Hemisphere. Previous studies have reported degradation of palsas due to warming climate and increasing precipitation. However, the degree of changes seems to vary largely, mainly due to different microclimatic conditions, vegetation cover as well as their shape and height above surrounding peatland surface. In this study, we applied Unmanned Aerial System (UAS) to better understand the effects of different variables on current and future state of these permafrost features. UASs were used to collect ultra-high resolution optical data (RGB and NIR) alongside the field observations, such as active layer thickness (ALT) measurements and vegetation plots in July 2018 from three peatlands in Finnish Lapland at different altitudes: 1) Nierivuoma (68 48'N, 22 15'E; 440 m a.s.l.), 2) Rommaeno (69 01'N, 21 34'E; 550 m a.s.l.) and 3) Balsalahku (68 56'N, 21 35'E; 730 m a.s.l.). The orthomosaics, and Digital Elevation Models (DEM), derived by photogrammetric technique at 0.03 - 0.05 m grid cell resolution improve notably our ability to delineate palsa mounds from the surrounding peatland surface and explore their attributes, in comparison to previously available aerial imagery (1960 - 2012) and 2 m resolution DEM from Airborne Laser Scanning (2016). Combining these datasets with UAS data and field measurements provided a new approach for mapping of the palsas, and estimating the ALT at palsa peatlands not covered by field investigations. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-13158-1.pdf

2019048500 Voigt, Christian (German Research Centre for Geosciences, Global Geomonitoring and Gravity Field, Potsdam, Germany); Pflug, Hartmut; Förste, Christoph and Flechtner, Frank. The Zugspitze geodynamic observatory Germany; installations and first data analysis [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-8605, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

The Zugspitze Geodynamic Observatory Germany (ZUGOG) has been setup on the summit of mountain Zugspitze at an altitude of almost 3000 m during 2018 with the main scientific objective to obtain a better understanding of seasonal and long-term mass redistributions in the European Alps. This knowledge is known to be very important, e.g. with regard to water storage and its high sensitivity to climate change, but not very advanced due to sparse data availability. ZUGOG is connected to the Environmental Research Station Schneefernerhaus as the home base of a large research consortium operating a dense sensor network for almost 20 years as well as providing technical support and infrastructure. It is accessible all around the year with cable cars. In September 2018, the Observatory Superconducting Gravimeter (SG) 052 has been installed at ZUGOG after removal from Sutherland, South Africa, as one of two SGs operating in parallel and refurbishment at the manufacturer GWR. This former laboratory of the Max Planck Society on the summit of Zugspitze has no mass variations above the sensor, no snow accumulation on the roof and a largely increased gravimetric footprint due to the high altitude. Moreover, this location fits very well into the central European network of SGs. In addition, a GNSS station has been setup as well as meteorological and hydrological sensors in the local vicinity. The completed installations are described, and the first months of data are analysed with regard to noise characteristics, drift and signal separation. This location offers a large variety of connections to other scientific groups and disciplines, which are discussed. These include episodic absolute and monthly relative gravimetric observations with the continuous SG observations filling an important gap in the concept of hybrid gravimetry. From a hydrological perspective, the conditions of the Research Catchment Zugspitze are very suitable being regarded as a natural lysimeter. In addition to the point measurements of individual storage compartments of the hydrological sensor network, the SG provides the total water storage variations from a bird's eye perspective on the summit in the sense of hydrogravimetry. These will also be applied for the validation of GRACE Follow-On. For the monitoring of mountain permafrost in Zugspitze, geoelectric and seismic observations but also permanent temperature observations are used. The SG on the summit directly above the permafrost supports the analysis of seasonal and long-term evolution of permafrost and allows for joint interpretation with complementary geophysical observations. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-8605-1.pdf

2019048439 Voss, Clifford (U. S. Geological Survey, Menlo Park, CA). Cryohydrogeologic systems analysis using numerical simulation [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-5902, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Numerical simulators developed over recent years have the capability of simulating the physical subsurface processes that occur in cold regions associated with flow of water through geologic fabrics containing seasonal or permanent subsurface ice. These are the powerful tools required for analyses that develop basic understanding of cryohydrogeologic processes and to help understand possible impacts of human activities and infrastructure and changes in climate on water quantity, water quality, surface morphology, and ecosystems. One of the earliest-developed cryohydrogeology simulation tools is the U.S. Geological Survey (USGS) SUTRA saturated-unsaturated groundwater flow and energy transport code. SUTRA was first developed in the 1980's and was enhanced in 2006 to simulate saturated freeze/thaw processes and more-recently saturated-unsaturated freeze/thaw processes. This simulator is informally known as the SutraICE code, and it has been used in USGS cooperative projects with co-authors both within and outside USGS to study a variety of cold-regions systems in the ensuing years, as described below. SutraICE has been employed to study seasonal ground ice in peatlands and bogs, groundwater discharge controlling fish habitats in streams (thermal refugia), groundwater discharge and baseflow in alpine watersheds (where quantity and timing may be impacted by climate change), and soil freezing dynamics at high latitudes. SutraICE has also been employed to study processes in permafrost terrains including lake formation and sub-lake taliks, permafrost-vegetation interaction, active-layer dynamics, groundwater flow and baseflow to streams, development of perennial thaw zones (taliks) and carbon mobilization potential, permafrost-groundwater-surface water relations and ecology in arctic water tracks, permafrost peatlands and bogs, climate change impacts on permafrost distribution and fate, and for basic studies of the dynamics of permafrost-groundwater processes. In addition, SutraICE is being used to study glaciers, firn and snow, focusing on firn aquifers in Greenland, and, meltwater recharge fate and ice-layer formation in firn. SutraICE also has had technological applications including freeze/thaw groundwater simulation code intercomparison and ground-truthing geophysical inversion approaches for defining subsurface ice content from electrical measurements. These studies have provided basic new knowledge of cryohydrogeologic system dynamical behavior and have led to improved understanding of practical implications in a variety of cold-regions settings, highlighting the great value of numerical simulation approaches for cryohydrogeologic systems analysis. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-5902.pdf

2019048535 Wagner, Florian M. (University of Bonn, Institute of Geosciences and Meteorology, Bonn, Germany); Mollaret, Coline; Günther, Thomas; Uhlemann, Sebastian; Dafflon, Baptiste; Hubbard, Susan S.; Hauck, Christian and Kemna, Andreas. Characterization of permafrost systems through petrophysical joint inversion of seismic and geoelectrical data [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-15670, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Characterizing the spatiotemporal distribution of liquid water, ice, and air pore fractions is crucial for a process-based understanding of permafrost systems and their hazard potential upon climate-induced degradation. While borehole information is expensive and limited to discrete locations, geophysical techniques offer opportunities to image permafrost in a non-invasive manner at high spatial and temporal resolution. Seismic and geoelectrical methods are sensitive to the phase change of water between its liquid, frozen, and gaseous states and are therefore widely used in cryospheric geophysical applications. We present an approach that uses apparent resistivities and seismic traveltimes simultaneously in a petro-physically coupled joint inversion to estimate the volumetric fractions of liquid water, ice, and air. By formulating the inverse problem in terms of the petrophysical target parameters, the underlying petrophysical relations (including volume conservation) as well as non-geophysical data (e.g., information on water content inferred from soil moisture measurements) can be honored during parameter estimation. We demonstrate advantages and limitations of the approach based on a synthetic model. In comparison to post-inversion transformation of conventional tomograms, the joint inversion leads to quantitatively improved and physically plausible images, but does not overcome some inherent petrophysical ambiguities (e.g., between ice content and porosity). We further apply the approach to a field data set acquired in a watershed near Teller, Alaska, during the summer of 2018. The resulting tomograms exhibit lateral changes in liquid water and ice content, which are in agreement with changes in vegetation, topography, soil moisture, and temperature. While ambiguity in the absolute values remains in the absence of additional laboratory and borehole information, the spatial distributions are consistent. Through spatial clustering of water, ice, air, and rock contents, we developed a conceptual subsurface model, which could provide a basis for the parameterization of process models that simulate the dynamics and evolution of permafrost environments. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-15670.pdf

2019048444 Walvoord, Michelle (U. S. Geological Survey, Lakewood, CO); Wickland, Kimberly; Minsley, Burke and Striegl, Robert. Hydrologic and biogeochemical significance of perennial thaw zones in degrading permafrost [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-2436, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Studies spanning arctic and boreal regions provide observations and physically-based models describing the deepening of the active layer in response to climate warming. A growing number of data and model-based studies document the development of perennial thaw zones, or supra-permafrost taliks, below the depths of seasonal ice as the next stage in top-down permafrost thaw evolution. Discerning the presence and movement of water (or lack thereof) in these actively thawing zones and their hydraulic connectivity are of high interest as these hydrologic characteristics affect biogeochemical cycling and the lateral transport of dissolved constituents, including organic carbon, released from permafrost. The strength of the permafrost-carbon feedback, for example, is critically dependent on coupled hydrologic and biogeochemical processes in shallow thawed zones. Our recent examination of soils in interior Alaska, USA, reveals a larger potential yield of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) from near-surface Holocene permafrost soils upon thaw than previously recognized. In parallel, cryohydrogeologic modeling and geophysical observations in these settings suggest that perennial thaw zones may be more prevalent than previously thought. All lines of evidence suggest that more attention toward lateral hydrologic transport of permafrost DOC and TDN is warranted in expanding the typical one-dimensional view of the permafrost-carbon feedback. While side-by-side comparison of hydrology and biogeochemistry studies in permafrost systems help construct critical conceptual building blocks, advances in more fully integrated approaches are needed toward quantitatively constraining current and projected lateral hydrologic export of aqueous constituents, including DOC and TDN, influenced by thawing permafrost. Material presented here from site-based research in Alaska describes necessary steps toward such advances. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-2436.pdf

2019048508 Weber, Samuel (Swiss Federal Institute of Technology in Zurich, Computer Engineering and Networks Laboratory, Zurich, Switzerland); Beutel, Jan; Gruber, Stephan; Hasler, Andreas and Vieli, Andreas. Cross validation of a multi-modal dataset describing temperature-induced rock slope dynamics [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-17046, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Rock slope destabilization due to warming or thawing permafrost poses a risk to the safety of local communities and infrastructure in populated mountain regions. The analysis of fracture kinematics in the context of local temperature evolution in the longer-term is a common approach aiming to identify its forcing (e.g. Wegmann and Gudmundsson, 1999, Matsuoka and Murton, 2008, Blikra and Christiansen, 2014). Hasler et al. (2012) and Weber et al. (2017) analyzed fracture dilatation data measured at Matterhorn Hornligrat at 3500 m a.s.l. and suggest thawing related processes, such as meltwater percolation into fractures to cause irreversible displacement. However, this finding so far has not been backed up by data from different instruments or analysis methods. Hence, misinterpretation of the existing data can not reliably be excluded. Based on further data consisting of surface displacements measured with D-GPS, inclinometers, ambient seismic vibrations and ground resistivity captured and compiled over a period of ten years, we apply a multi-data cross validation technique to detect and quantify temperature-induced rock slope dynamics and identify the components of derived process knowledge that predict behaviour across differing observation methods. The combined analysis of this multi-modal dataset allows to further develop and analyse our limited understanding of the dominant processes governing rock slope stability, in our case a steep bedrock mountain permafrost buttress. Based on this evidence we conclude that the kinematics observed at the surface in the winter/re-freezing period is negligible compared to those observed during spring initiated by the thawing and mobilization of fluid water w.r.t. to destabilization and precursory signs of rockfall at a larger scale. Therefore, future research should focus on the quantification of water supply, distribution and mobility both in the frozen and fluid state. References Blikra, L. H. and Christiansen, H. H.: A field-based model of permafrost-controlled rockslide deformation in Northern Norway, Geomorphology, 208, 34-39, doi: 10.1016/j.geomorph. 2013.11.014, 2014. Hasler, A., Gruber, S., and Beutel, J.: Kinematics of steep bedrock permafrost, J. Geophys. Res., 117, F01 016, doi: 10.1029/2011JF001981, 2012. Matsuoka, N. and Murton, J.: Frost weathering: Recent advances and future directions, Permafrost and Periglacial Process., 19, 195-210, doi: 10.1002/ppp.620, 2008. Weber, S., Beutel, J., Faillettaz, J., Hasler, A., Krautblatter, M., and Vieli, A.: Quantifying irreversible movement in steep, fractured bedrock permafrost on Matterhorn (CH), The Cryosphere, 11, 567-583, doi: 10.5194/tc-11-567-2017, 2017. Wegmann, M. and Gudmundsson, G. H.: Thermally induced temporal strain variations in rock walls observed at subzero temperatures, in: Advances in cold-region thermal engineering and sciences, edited by Hutter, K., Wang, Y., and Beer, H., vol. 533, pp. 511-518, Springer Berlin Heidelberg, doi: 10.1007/BFb0104208, 1999. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-17046-2.pdf

2019048464 Westermann, Sebastian (University of Oslo, Department of Geosciences, Oslo, Norway); Strozzi, Tazio; Wiesmann, Andreas; Aalstad, Kristoffer; Fiddes, Joel; Kääb, Andreas; Obu, Jaroslav; Seifert, Frank Martin; Grosse, Guido; Heim, Birgit; Matthes, Heidrun; Nitze, Ingmar; Rinke, Annette; Hugelius, Gustaf; Palmtag, Juri; Barboux, Chloé; Delaloye, Reynald; Kroisleitner, Christine and Bartsch, Annett. Circumpolar mapping of permafrost temperature and thaw depth in the ESA permafrost CCI project [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-10479, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Permafrost is an Essential Climate Variable (ECV) within the Global Climate Observing System (GCOS), which is characterized by subsurface temperatures and the depth of the seasonal thaw layer. Complementing ground-based monitoring networks, the Permafrost CCI project funded by the European Space Agency (ESA) 2018-2021 will establish Earth Observation (EO) based products for the permafrost ECV spanning the last two decades. Since ground temperature and thaw depth cannot be directly observed from space-borne sensors, we will ingest a variety of satellite and reanalysis data in a ground thermal model, which allows to quantitatively characterize the changing permafrost systems in Arctic and High-Mountain areas. As recently demonstrated for the Lena River Delta in Northern Siberia, the algorithm uses remotely sensed data sets of Land Surface Temperature (LST), Snow Water Equivalent (SWE) and landcover to drive the transient permafrost model CryoGrid 2, which yields ground temperature at various depths, in addition to thaw depth. For the circumpolar CCI product, we aim for a spatial resolution of 1km, and ensemble runs will be performed for each pixel to represent the subgrid variability of snow and land cover. The performance of the transient algorithm crucially depends on the correct representation of ground properties, in particular ice and organic contents. Therefore, the project will compile a new subsurface stratigraphy product which also holds great potential for improving Earth System Model results in permafrost environments. We present simulation runs for various permafrost regions and characterize the accuracy and ability to reproduce trends against ground-based data. Finally, we evaluate the feasibility of future "permafrost reanalysis" products, exploiting the information content of various satellite products to deliver the best possible estimate for the permafrost thermal state over a range of spatial scales. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-10479.pdf

2019048450 Wicky, Jonas (University of Fribourg, Department of Geosciences, Fribourg, Switzerland) and Hauck, Christian. Air convection within the active layer of an alpine rock glacier; a numerical modelling approach [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-4274, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

In an Alpine setting coarse blocky surface material with underlying permafrost is widespread. The interconnected voids allow for air convection. This influences the thermal regime of the underlying permafrost. Rock glaciers are one of the main permafrost landforms, also often covered with coarse blocky material, and thus influenced by air convection. Previous 1D-modelling approaches were able to reproduce this effect using sink- or source terms or other parametrizations. We switch to a 2D domain to explicitly model and solve the governing equations for air convection within the ground. The model solves for heat conduction coupled with air flow described as a Darcian flow with the Boussinesq approximation to account for natural convection. We use a simplified geometry of a rock glacier to solve the equations in transient model runs. Long-term monitoring data from the Swiss Permafrost Monitoring Network PERMOS serves for model forcing and validation. Our results show that convection has a great influence on ground temperatures in the active layer and the underlying permafrost. Seasonal patterns develop. During wintertime, when the thermal gradient between the active layer and air temperature is negative, the air stratification within the active layer is thermally unstable. The onset of vertical convection cells can be observed and the ground cools very efficiently. Whereas during summer, air circulation is weak and mainly driven by gravity. Summer heat transfer is thus mainly conductive. The modelling results fit quite well to the measured borehole data. During winter, the intense ground cooling, which cannot be explained by conduction only, is well represented. In the context of a changing climate and degrading permafrost in the Alps, a thorough understanding of these processes is important. Our modelling results show that landforms covered with coarse blocks react differently to changing atmospheric conditions. This is of great importance to understand and predict the development and extent of Alpine permafrost in future. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-4274.pdf

2019048495 Yin Zhenhua (Chinese Academy of Sciences, Northwest Institute of Eco-Environment and Resources, China). Experiment study of mechanical properties of cement solidified soil in negative temperature [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-11642, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Serious differential settlement often occurs in engineering and construction built in permafrost regions due to the existence of warm and ice-rich frozen soil. In order to prevent the disaster of thaw collapse, the mechanical properties of frozen soil can be improved by adding cement and additives. In this paper, three different cements(SAC, OPC and MPC) are used to solidify warm and ice-rich frozen soil. The compressive properties and unconfined compressive strength of cement-solidified soil under the action of different cement contents and curing ages are studied. Meanwhile, the mechanism of solidification was analyzed by measuring the change of water content and analyzing the product by scanning electron microscope. The results show that the addition of all kinds of cements reduced the moisture content of the frozen soil. However just the cement-solidified warm and ice-rich frozen soil by SAC and OPC can eliminate the thaw collapse and deformation. OPC has little effect on the solidification of warm and ice-rich frozen soil. This suggests that not all kinds of cements can be used to solidify warm and ice-rich frozen soil. It provides a theoretical basis for cement-solidified frozen soil. And it is of great significance to the prevention and control of disaster of thaw collapse in permafrost regions. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-11642.pdf

2019048436 Zang, Carina (Heidelberg University, Department of Geography, Germany); Schmidt, Susanne and Dame, Juliane. Isotopic signatures of glacier, permafrost and streams in the Trans-Himalaya of Ladakh, India [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-17169, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

Heidelberg University, South Asia Institute, Department of Geography, Germany The importance of glaciers, permafrost and seasonal snow contribution to stream flow in the upper Indus Basin is a frequently discussed topic on the large scale as well as on the regional scale of Ladakh, where the agriculture depends on the melt water runoff of these water sources. A variety of methodological approaches exists in order to estimate the contribution of these different water sources to the runoff. Due to the lack of meteorological and discharge data in many high mountain regions, large scale input data for hydrological models can be derived from remote sensing data. However, their low spatial resolution cannot capture small scale processes caused by the steep topography. Therefore, additional ground-truth information on the cryosphere through natural tracers is highly valuable. Modern possibilities of analysing stable water isotopes allow for a resource efficient way of gathering information in mountain regions. In this study snap shot samples were collected in 62 locations in three tributaries of the Indus River in Ladakh. The sampling was planned with the aim of covering the major sources for stream flow including glacier melt, springs (most likely melt water from permafrost), streams, groundwater and snow. Measured stable water isotopes range from -16.04 h to -10.39 h for d¹⁸O and -110.81 h to -69.88 h for d²H. Based on the results from different water sources a local meteorological water line was calculated: d²H = 7.85 x d¹⁸O + 10.34. The results show a major dependence on the east to west distribution of sampling locations especially for glacier melt water. Snow samples are more depleted than other sources. Results from springs are highly heterogenic ranging from -14.29 to -10.94 for d¹⁸O and -106.76 and -74.37 for d²H. In contrast to the broad range of sampling elevation (3,470 to 5,380 m) the results only show a weak correlation to elevation. The measured values directly sampled from glacier meltwater shows some interesting variation. While glaciers in the valleys of Stok and Leh exhibit a similar range for d¹⁸O and d²H (between -14.34 to -13.91 for ¹⁸O and -98.97 to -97.37 for d²H) the results from glaciers in the Igoo Valley are significantly more enriched (d¹⁸O > -11.61 and d²H > -77.86). These results can help to increase the understanding of underlying processes in the local cryosphere and possible expected changes in the future due to global warming. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-17169.pdf

2019048460 Zhang Wenjiang (Sichuan University, Department of Hydrology, Chengdu, China) and Liu Li. Investigating the soil heat simulation of the Variable Infiltration Capacity (VIC) model in the Tibetan Plateau [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-6344, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

The most extensive coverage of middle-latitude permafrost (~1,200,000 km²) developed in the Tibetan Plateau (TP), the largest highland in the world and the so-called third pole. This region is highly sensitively subjected to persistent climate warming because the annual air temperature is much more near water freezing point (i.e. 0 °C) in the TP than in the circum-Arctic regions. Therefore, it is important to simulate and understand the dynamics of soil freeze/thaw for projecting the trajectory of land surface process in the TP. In the study, the capability in soil heat simulation was investigated for the Variable Infiltration Capacity (VIC) model against in-situ observations of two soil temperature profiles (respectively with the depths of 6.1 and 10.0 m) in the TP. Our results showed the VIC seriously underestimated soil temperature at both profiles, with the RMSE ranging between 2.0 and 5.5 °C, which generally increased with soil depth significantly. The simulation bias was not highly sensitive to the parameterization of soil heat transfer. It was likely the marked under-estimation of land surface temperature that led to the serious bias in the soil heat simulation of the VIC model. We will further examine the reason underlying the serious bias and plan to make necessary modification so as to produce reliable simulation of soil heat transfer in the TP. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-6344.pdf

2019048477 Zhou Zhiwei (Chinese Academy of Sciences, Institute of Geodesy and Geophysics, Wuhan, China); Jiang Liming; Liu Lin; Wang Hansheng and Zhang Tingjun. Rapid development of permafrost thermokarst landforms detected by repeated Unmanned Aerial Vehicle surveys in the northeastern Qinghai-Tibetan Plateau [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-14231, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

The number and area of thermokarst landforms are continuously increasing on the Qinghai-Tibet Plateau due to climate warming and anthropogenic disturbance since 1950s. To quantify the development of thermokarst land-forms, we investigated sinkhole, thermal erosion gullies and slump-gully-complex three types of hillslope process thermokarst landforms by differencing high-resolution digital terrain models (DSMs) acquired by Unmanned Aerial Vehicle in 2016 and 2017 summers. Different development patterns are observed in these three types of thermokarst landforms: the sinkhole presents up to -5 m/year subsidence rate, the erosion gully shows up to 15 m/year headwall retreat rate, while the subsidence and headwall retreat rate of slump-gully-complex falls in between of the other two types. The results show that the Qinghai-Tibet Plateau is undergoing rapid thermokarst landforms development. The fast development of thermokarst landforms will likely amplify the ecological, geomorphology, environment and engineering-related hazards impacts. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-14231.pdf

2019048438 Zwinger, Thomas (CSC-IT Center for Science, Espoo, Finland); Hartikainen, Juha and Cohen, Denis. A high-resolution coupled permafrost; ice sheet model [abstr.]: in European Geosciences Union general assembly 2019, Geophysical Research Abstracts, 21, Abstract EGU2019-10311, 2019. Meeting: European Geosciences Union general assembly 2019, April 7-12, 2019, Vienna, Austria.

We present a recently developed high-resolution permafrost model. Based on continuum thermodynamics, the model consists of several sub-modules representing heat-transfer within ice, water and soil, saturated groundwater flow, salinity transport as well as deformation and stress-distributions of the solid constituents (i.e. ice, soil and bedrock). Within these sub-modules, we introduce important coupling mechanisms, such as effects of permafrost on glacier sliding and hydraulic conductivity of soil and bedrock, effects of solutes on the development of permafrost, and changes in hydrological conductivity by bedrock deformation. Implemented in the Finite Element code Elmer, this package provides the possibility to couple the permafrost to a high-resolution glacier or ice-sheet model (Elmer/Ice) that accounts for all stress components (full-Stokes). This makes it possible to study detailed processes at places that need high resolutions, such as ice-sheet margins where permafrost may play an important role in controlling the basal ice temperature, or geologically strongly varying bedrocks where permeability changes as a result of permafrost formation or degradation can significantly alter groundwater flow paths. The model is tested on benchmark problems for sub-module coupling as well as problems in combination with either advancing or retreating glaciation. [Copyright Author(s) 2019. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: https://meetingorganizer.copernicus.org/EGU2019/EGU2019-10311.pdf

2019045938 Cherian-Hall, Amaya S. (Quest University Canada, Squamish, BC, Canada). Thermokarst lake evolution in a discontinuous permafrost zone near Whitehorse YT, Canada [abstr.]: in Geological Society of America, 2018 annual meeting & exposition, Abstracts with Programs - Geological Society of America, 50(6), Abstract no. 248-8, November 2018. Meeting: Geological Society of America, 2018 annual meeting & exposition, Nov. 4-7, 2018, Indianapolis, IN.

Discontinuous permafrost underlies sections of the Takhini River valley (TRV), located near Whitehorse YT, Canada. The TRV is a major agricultural area and highway corridor. Landforms in this area are dynamic due to localized frost heave and permafrost thaw. In the Yukon, climate change studies show an annual average temperature increase of 2°C in the past 50 years--more than double the average increase in southern Canada (Streicker, 2016). While permafrost degradation is expected to increase over time as a direct result of this increase in air temperature (Streicker, 2016), previous studies suggest that vegetation, organic layer thickness, snow depth and soil moisture content are the more important variables for permafrost persistence in discontinuous permafrost zones (Burn, 1997). With permafrost melt we can expect increased ground instability and shifting topography and drainage patterns. This is visually observable through the reshaping of existing thermokarst landforms as well as the creation of new ones. The TRV floor is comprised of glaciolacustrine sediments deposited during the late Wisconsinan McConnell Glaciation (Hughes, 1989), and hosts clusters of thermokarst lakes--lakes formed by melting ice lenses resulting in ground subsidence. We visually characterized these lakes in the field and via aerial imagery (select years 1946 to 2016) for changes over time. We assessed qualitative characteristics such as lake size, structure and bank erosion. We did not observe any consistent temporal variation in lake formations that would correlate with increasing annual temperature. We did however determine that the aspect of thermokarst lake banks was a major contributor to erosion with south aspect banks showing significantly more activity. Further study can elucidate whether or not this is linked to increased sun exposure and heating resulting in earlier annual snow melt and elevated permafrost thaw rates.

2019048552 Bartsch, Annett (Zentralanstalt für Meteorologie und Geodynamik, Vienna, Austria); Pointner, Georg; Widhalm, Barbara; Dvornikov, Yury; Leibman, Marina; Heim, Birgit and Nitze, Ingmar. Monitoring lakes and cryogenic processes in Siberia with Sentinel-1 and 2 data [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-15889, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

Lakes and ponds are ubiquitous features of the arctic tundra landscape. They are often associated with thermokarst phenomena (thaw lakes). Their changes over time are expected to reflect changes in permafrost. Satellite data are commonly used to analyze spatial and temporal patters of tundra lakes. High spatial as well as temporal resolution is required. Both SAR as well as optical data can be utilized. Features of interest are not only size and shape but also bathymetric and associated properties. The latter specifically includes ground fast lake ice along shallow shelfs and can be derived from SAR. Of further interest are degradation features along the lake rims. They require sufficient spatial resolution in order to map them. The Yamal peninsula is mostly underlain by continuous permafrost. The distribution of lakes is largely related to the patterns of marine terraces. A comprehensive dataset of land surface features from long term in situ and high resolution satellite data is available for central Yamal. We have utilized Sentinel-1 as well as Sentinel-2 data for mapping of these lakes and their surroundings. A lake map has been derived from Sentinel-2 within the framework of the ESA DUE GlobPermafrost project as part of the landcover prototype development. Major challenges have been frequent cloud cover, seasonal lake change, sediments in lakes of floodplains and with erosional features as well as reflectance properties of high arctic lakes within wetland areas. Two years of data (summer 2016 and 2017) have been required for complete coverage of the area of interest. Post processing has been required for treatment of artefacts due to cloud masking effects. Results are also compared to acquisitions from the Spot5Take campaign from 2015 as well as a trend product from Landsat (30m) spanning 1998-1999 and 2000-2015. It can be demonstrated that the spatial resolution of Sentinel-2 and SPOT (10m) is sufficient to identify erosional features along the lake margins, but quantification of changes from year to year require more detail. Trends in greenness can be observed in Landsat after 2000, what indicates initiation during this time period. C-band SAR data as available from Sentinel-1 provide year to year changes in ground fast ice conditions and reveal differences in lake bathymetry among the terraces. There are however a range of phenomena on larger lakes which impact the ground-fast ice detection. These features can be identified in both, Sentinel-1 and Sentinel-2 data. Our results exemplify some challenges of landcover mapping in permafrost regions, but also detail the information gain from using Sentinel-1 and Sentinel-2 data. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-15889.pdf

2019048547 Choi, Yeonjin (Korea Polar Research Institute, South Korea); Kang, Seung-Goo; Jang, U. Geun; Hong, Jong Kuk; Jin, Young Keun; Chung, Woo Keen and Shin, Sung-Ryul. AVO analysis to gas hydrates BSR in the continental shelf of Canadian Beaufort Sea [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-13844, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

Gas hydrates are ice-crystalline solid containing gas molecules entrapped within rigid cage of water molecule (Sloan, 1998). Gas hydrates can be existed in the permafrost area on the polar region or marine environments under low temperature (<15°) and high pressure condition (>5MPa) known as the gas hydrate stability zone (GHSZ. Gas hydrates are getting attention as a potential energy resource, but it is recognized for influence of global climate change and geohazard to seafloor. In 2014, expedition ARA05C using Korean ice breaker RV ARAON carried out in collaboration with the Korea Polar Research Institute (KOPRI), Geological Survey of Canada (GSC), Monterey Bay Aquarium Research Institute (MBARI), and Bremen University (BARUM). This expedition was conducted to understand degrading permafrost and gas hydrates, fluid flow and degassing, seismic stratigraphy, and associated geohazards of the Beaufort shelf and slope region. During the expedition, we acquired the multi-channel seismic data (MCS) using the 8-array air-gun and 120 channels streamer (1.5 km). A total of 998 L-km MCS data with 19,962 shots were obtained along 23 lines. Riedel et al. (2017) identified for the first time the bottom simulating reflector (BSR), which is a gas hydrate-related seismic event, in the study area. AVO analysis is very useful geophysical techniques used to determine the rock properties in onshore and offshore oil and gas exploration (Tinivella et al. 2008). In many studies, AVO analysis have shown good results in identification effect of gas hydrates and free gas (Wood et al., 2008). In this study, we conducted the Amplitude versus Offset(AVO) analysis and seismic inversion to examine detailed properties from the BSR occurred in the study area. Our study is aimed 1) to identify the gas hydrates and free gas distribution, 2) to estimate the rock properties for investigation of GHSZ, 3) to show AVO characteristics of gas hydrates and free gas. For AVO analysis, we conducted the gradient analysis, AVO attribute inversion, cross-plotting, and attribute volume calculation. P-wave velocity model and acoustic impedance model were reconstructed by sparse spike inversion. Our inversion results show existence of the low velocity zone by free gas, and its distribution. Reference Riedel, M., Brent, T. A., Taylor, G., Taylor, A. E., Hong, J.-K., Jin, Y.-K., and Dallimore, S. R., (2017), Evidence for gas hydrate occurrences in the Canadian Arctic Beaufort Sea within permafrost-associated shelf and deep-water marine environments, Mar. Petrol. Geol, 81, p.66-78. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-13844-1.pdf

2019048563 D'Amico, Michele (University of Torino, Department of Agriculture, Forest and Food Sciences, Italy); Pintaldi, Emanuele; Giardino, Marco; Freppaz, Michele and Bonifacio, Eleonora. Soils in Pleistocene large-scale sorted striped and blockstreams and their paleoclimatic implications [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-19001, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

Because of extensive Pleistocene glaciations, which erased most of the previously existing soils, slope steepness and climate conditions favoring soil erosion, most soils observed on the Alps (and in other mid-latitude mountain ranges) have developed during the Holocene. However, in few sites, particularly in the outermost sections of the Alpine range, Pleistocene glaciers covered only small and scattered surfaces, and ancient soils could be preserved for long periods of time on stable surfaces. In many cases, these soils retain good memories of Quaternary periglacial activity. We described and sampled soils developed in large-scale sorted stripes and blockstreams of some locations in the Western Italian Alps (Piemonte Region, Italy). The elevation of the sampling sites ranged between 600 and 1600 m a.s.l., under present-day lower montane Ostrya carpinifolia, montane Fagus sylvatica forests or montane heath/grazed grassland, on metamorphic lithological units such as quartzite, serpentinite and gneiss. Within the sampling areas, the relict blockfields/blockstreams and sorted stripes were strongly developed and well preserved. The soils preserved in such relict Quaternary periglacial landforms normally showed stratification of different layers (units), separated by structural discontinuities, evidencing different depositional settings and different pedogenic development degree. Soil wedge casts, involutions, strong cryogenic granulometric sorting and deep organic-matter rich layers characterized all the observed soils. Compact and dense layers with strong platy/lenticular structural aggregation, sometimes associated with redoximorphic Fe oxide cementation (plinthic or placic horizons), was often observed along structural discontinuities. Thus, geomorphology and soil properties evidence the widespread presence of permafrost during cold Pleistocene phases, with different active layer thicknesses in different climatic phases. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-19001.pdf

2019048543 De Mendoza, Ignacio Hermoso (Université du Québec à Montréal, Sciences de la Terre et de l'Atmosphère, Montreal, QC, Canada); Beltrami, Hugo; Mareschal, Jean-Claude and MacDougall, Andrew. Lowering the bottom boundary in land models; implications for permafrost stability [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-1094, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

Earth System Models (ESMs) currently use very shallow bottom boundaries (~3-45m) for the land subsurface. These depths are an order of magnitude smaller than the depths required to fully capture thermal changes propagating from the surface for the centennial time scales associated with climate change. This depth limitation limits the propagation of energy into the subsurface, thus shallow bottom boundaries and the lack of geothermal gradient in current land surface models, could introduce uncertainties in the estimates of the land surface energy balance and the thermal evolution of the subsurface. We have modified the Community Land Model version 4.5 (CLM4.5) by introducing a crustal heat flux as bottom boundary condition and increasing the depth of the lower boundary from 42m to 342m. We have compared the thermal regime of the subsurface with that of the unmodified CLM4.5 under the atmospheric forcings for the 20^th century followed by 300 years of a high emission future scenario (RCP 8.5). Our results suggest that the bottom boundary of the unmodified CLM4.5 is too shallow to fully capture the thermal signal propagating from the surface and reflects considerable energy back to the surface, resulting in higher underground temperatures, which may adversely influence the simulated stability of regions of permafrost and the associated release of stored carbon. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-1094.pdf

2019048548 Dessens, Olivier (University College London, London, United Kingdom). Impact of climate feedback on the energy/economic system; impacts of permafrost thawing under low emissions scenarios [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-17925, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

In this study we are focusing on the largest single feedback processes examined by AR5: Permafrost thawing. We examine the impacts on the energy-economic system of the emissions of carbon dioxide from permafrost under climate change. Permafrost is a large reservoir of carbon held in frozen soil of high latitude land. The thawing of permafrost in a warmer climate will exert a positive feedback through the additional release of carbon dioxide; permafrost feedbacks are shown to exhibit substantial dependence to specific warming level pathways. We implement a very recently publish formulation of permafrost feedback which is a scenario dependent function derived from explicit modelling of permafrost with different land surface schemes and regional climate change patterns from Burke et al. 2017. The socio-economic model used throughout this study is TIAM-UCL. This is a 16 region global optimisation integrated assessment model with a strong focus on the energy system. We study the permafrost feedback outcomes on emission levels, carbon prices and energy system changes under the 2 C global target from the Paris Agreement and different climate and permafrost sensitivities. We find that, even under a low emissions scenario limiting warming to below 2 C over the century, the thawing of permafrost may have a considerable impact on the economics and technological choices of mitigation. In the worst case scenario, when the climate and the permafrost both present strong sensitivities to carbon emissions and warming respectively, the carbon budget over the century can drop by almost 4% resulting in a 30% rise in carbon prices. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-17925.pdf

2019048544 Dobinski, Wojciech (University of Silesia, Sosnowiec, Poland). Definition of permafrost in AAG the international encyclopedia of geography; connection of glacial and periglacial environment [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-7063, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

Permafrost is defined as the thermal state of the ground or rock that remains below 0 C for at least two consecutive years. This definition in the initial period of permafrost studies included both periglacial and glacial environments because ice was widely regarded as a rock analogous to all other rocks found on Earth. Nowadays, although ice is still classified in the collection of minerals and progressive specialization in scientific development caused the disconnection of glaciology and periglacology. It is obvious, however, that ice always remains frozen and that its great accumulations in the form of glaciers and ice sheets are stable enough to meet the definition of permafrost. For this reason, it is obvious that the permafrost encompass also those components of the cryosphere. The geophysical profile of glacial permafrost, however, will differ from that which is appropriate in the periglacial environment. First, glacial permafrost will not have active layer which remains seasonally at the positive temperature above the permafrost table. Secondly, together with the thermal classification of glaciers, which is characterized by cold ice and temperate ice layers, there is also a distinction between two types of glacial permafrost. The first - completely frozen, includes the layer of cold ice, usually located above, and the second layer of temperate ice remaining in the state of pressure melting point, that is, not completely frozen. Freezing however is not required in the definition of permafrost but only a negative temperature, and the temperature of the melting point is always below 0 C. Such definition of permafrost has been published in The International Encyclopedia of Geography published in the Collaboration of the American Association of Geographers and Wiley publishing house (Dobinski 2017) and may serve as a starting point in the re-integration of the geographical environment in a uniform approach to the study of all components of the cryosphere especially the two most important: permafrost and glaciers. In addition, this definition, like other earth sciences, has a broader and more universal character, because it can be applied to a correct understanding of the cryosphere on other celestial bodies whose surface is made of an icy-lithosphere. Dobinski W. 2017: Permafrost - definition and extent. In.: Richardson D., Castree N., Goodchild M.F., Kobayashi A., Liu W., and Marston R.A., (eds). The International Encyclopedia of Geography. John Wiley & Sons, Ltd. DOI: 10.1002/9781118786352.wbieg0277 1-9 [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-7063.pdf

2019048559 Felbauer, Lucia (University of Vienna, Department of Geography and Regional Research, Vienna, Austria); Poppl, Ronald and Weidinger, Johannes Thomas. Investigations on climate-induced paraglacial changes in a glacier retreat area with special consideration of proglacial lakes; a case study from the Dachstein Group [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-10181, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

Since the end of the Little Ice Age global warming results in a still ongoing retreat of glaciers in the Alps. After their retreat, glaciers leave behind large amounts of easily erodible sediments and a highly vulnerable paraglacial landscape system characterized by morainic material and continuously sedimenting lakes. In addition, the debut-tressing of rockwalls and the decay of permafrost in the high mountain regions facilitates mass movements of potential disastrous consequences, such as rock falls and debris flows. Therefore, it is highly important to investigate how glacial retreat influences sediment dynamics in proglacial areas. In the presented work glacier retreat and associated sediment dynamics were investigated for the Hallstatter Glacier in the Dachstein group (Upper-Austria) by analyzing remote sensing data, focusing on proglacial lakes. Glacial retreat from the period of 1950 to 2012 was documented by interpreting aerial photographs, further mapping and quantifying geomorphic change in the glacial retreat area from 1950 to 2015 via field observations and GIS analyses. First results will be presented at the EGU General Assembly 2018. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-10181.pdf

2019048565 Friedl, Barbara (University of Salzburg, Department of Geoinformatics, Salzburg, Austria); Hölbling, Daniel; Dittrich, Jirathana; Tiede, Dirk; Saemundsson, Thorsteinn; Gugmundsson, Snaevarr and Pedersen, Gro B. M. Delineation of rock avalanche deposits on glaciers from different remote sensing data [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-13689, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

Glacial headwall retreat is often related to slope movement processes such as rock falls or rock avalanches from the over steepened cliffs. Due to the effects of climate change it is expected that such events will occur more frequently in future, especially in subarctic regions where permafrost degradation, the relief of slopes as a result of glacier recession, and changes in the ice cover will render slopes more susceptible to mass movements. In order to evaluate the effects of climate change with respect to the size and frequency of rock falls/avalanches in glacial environments, it is essential to have detailed historical inventories. Regarding this, the use of remote sensing data shows a high potential for the spatio-temporal identification of rock fall/avalanche deposits on glaciers, especially over large and inaccessible areas. In this case study, we focus on the detection of major rock fall/avalanche deposits in the Vatnajokull National Park located in southeast Iceland, which contains - beyond the Polar Regions - the largest glacier in Europe, the Vatnajokull ice sheet. Many outlet glaciers, each with distinct characteristics, are part of this massive ice sheet. Three major rock fall/ rock avalanche events on outlet glaciers (Morsarjokull, Svinafellsjokull and Svoludalsjokull) are investigated in this study. The main aim is to semi-automatically delineate sediment depositions on glacier tongues originated from mass wasting by means of object-based image analysis (OBIA) using various remote sensing data. In OBIA, pixels are grouped into objects (usually based on spectral of functional homogeneity) that serve as basis for the classification. OBIA enables the semi-automated detection and classification of complex natural phenomena due to its capability to address spectral, spatial, textural and contextual properties of target classes and allows the integration of different data sets and data derivatives. Post-event remote sensing data, i.e. optical satellite images (e.g. SPOT-5, Landsat), synthetic aperture radar (SAR) data (e.g. TerraSAR-X, Sentinel-1) and digital elevation models (DEMs - e.g. ArcticDEM, Tandem-X DEM), are used independently as basis for the analyses. Band ratios of optical data, texture descriptive features of SAR and DEM data, and normalized SAR backscatter and coherence values are applied for the delineation of rock fall/avalanche deposits. Classification accuracy is assessed by comparing outcomes to reference polygons obtained from visual image interpretation. The results derived from the various data sources are evaluated with respect to achieved accuracy metrics and transferability to other sensors with different spectral or spatial resolutions. By doing so, the most suitable remote sensing data for delineating rock fall/avalanche deposits on glaciers using OBIA will be identified. In further consequence, a detailed inventory of past rock falls/avalanches could be compiled applying the developed classification routines on historical and recent remote sensing data. Better knowledge about the occurrence, location and size of rock falls/avalanches onto glaciers is useful to estimate the regional effects of climate change and can have implications for glacier tourism, which is an important economic factor in Iceland. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-13689.pdf

2019048550 Haas, Antonie (Alfred Wegener Institut, Helmholtz Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany); Grosse, Guido; Heim, Birgit; Walter, Andreas; Immerz, Antonia; Schäfer-Neth, Christian; Muster, Sina; Laboor, Sebastian; Bartsch, Annett and Seifert, Frank Martin. PerSys - WebGIS-based permafrost data visualisation system for ESA GlobPermafrost [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-11925, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

ESA DUE GlobPermafrost (www.globpermafrost.info) provides a remote sensing data service for permafrost research and applications. This service comprises of the generation of remote sensing products for various regions and spatial scales, and specific infrastructures for visualisation, dissemination and access to datasets. PerSys is the ESA GlobPermafrost geospatial information service for publishing and visualisation of information and data products to the public. Data products are described and searchable in the PerSys Data Catalogue, a core component of the Arctic Permafrost Geospatial Centre (APGC), established within the framework of ERC PETA-CARB at AWI. The data visualisation employs the AWI WebGIS-infrastructure maps@awi (URL: http://maps.awi.de), a highly scalable data visualisation unit within the AWI data-workflow framework O2A, from Observation to Archive. WebGIS technology in maps@awi supports the project-specific visualisation of raster and vector data products of diverse spatial resolutions and remote sensing sources. This is a prerequisite for the visualisation of the wide range of GlobPermafrost remote sensing products like: Landsat multispectral index trends (Tasseled Cap Brightness, Greeness, Wetness; Normalized Vegetation Index NDVI), Arctic land cover (e.g., shrub height, vegetation composition), lake ice grounding, InSAR-based land surface deformation, rock glacier velocities and a spatially distributed permafrost model output with permafrost probability and ground temperature per pixel. All WebGIS projects are adapted to the products specific spatial scale. For example, the WebGIS 'Arctic' visualises the Circum-Arctic products. Higher spatial resolution products for rock glacier movements are visualised on regional scales in the WebGIS projects 'Alps', 'Andes' and 'Central Asia'. GIS services were created and designed using ArcGIS for Desktop (10.4) and finally published as a Web Map Service (WMS), an internationally standardized format (Open Geospatial Consortium (OGC)), using ArcGIS for Server (10.4). The project-specific data WMS as well as a resolution-specific background map WMS are embedded into a GIS viewer application based on Leaflet, an open-source JavaScript library. The GIS viewer application was adapted to interlink all WebGIS projects, and especially to enable their direct accessibility via the GlobPermafrost Overview WebGIS project. The PerSys WebGIS is accessible via the GlobPermafrost project webpage and linked to the respective product groups as well as on maps@awi (maps.awi.de). All GlobPermafrost data products will be DOI-registered and archived in PANGAEA. In future, PerSys will integrate and visualise more data from permafrost researchers other than GlobPermafrost. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-11925-3.pdf

2019048546 Hauck, Christian (University of Fribourg, Department of Geosciences, Fribourg, Switzerland); Kemna, Andreas; Weigand, Maximilian; Wagner, Florian; Pellet, Cécile; Mollaret, Coline; Hoelzle, Martin and Hilbich, Christin. Monitoring spatio-temporal infiltration pattern and its interaction with permafrost thaw using electrical resistivity and self-potential measurements at Schilthorn, Swiss Alps [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-10780, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

The permafrost evolution and ground ice conditions have been investigated in detail at the long-term monitoring station Schilthorn, Northern Swiss Alps, over the past 20 years. Results show warm permafrost conditions close to the freezing point over at least 100 metres depth, a high interannual variability of the active layer depth, but a clear increasing trend of active layer thickness reaching almost 10m in recent years. In addition to borehole temperature measurements, an energy balance station, distributed soil moisture and ground temperature sensors, geophysical monitoring installations are used to monitor the spatio-temporal variability of ground ice conditions and provide ground truth data for hydro-thermal model simulations. Geophysical monitoring techniques include autonomous electrical resistivity tomography (ERT) measurements, yearly refraction seismic measurements and recently installed continuous self potential (SP) measurements to monitor the permafrost hydrology (Hilbich et al. 2008, 2011, Kemna et al. 2016). Numerical model simulations consistent with borehole data showed the occurrence of deep infiltration processes within the active layer, but also within the permafrost, suggesting low and/or heterogeneous ice contents within the permafrost (Scherler et al. 2010). In this contribution, we will use the combination of geophysical data (ERT, SP) with the distributed soil moisture data to analyse spatio-temporal infiltration patterns and address the question of its potential impact on active layer deepening and permafrost thaw. In addition, the relative frequency of infiltration events due to summer precipitation, snow melt and upslope processes detected by the different methods will be compared and analysed over several years. Hilbich, C., Hauck, C., Hoelzle, M., Scherler, M., Schudel, L., Volksch, I., Vonder Muhll, D. and R. Maus-bacher, 2008. Monitoring mountain permafrost evolution using electrical resistivity tomography: A 7-year study of seasonal, annual, and long-term variations at Schilthorn, Swiss Alps, J. Geophys. Res., 113, F01S90, doi:10.1029/2007JF000799. Hilbich, C., Fuss, C. and Hauck, C., 2011. Automated time-lapse ERT for improved process analysis and monitoring of frozen ground, Permafrost and Periglacial Processes 22(4), 306-319, DOI: 10.1002/ppp.732. Kemna, A., Weigand, M., Wagner, F., Hilbich, C. and Hauck, C., 2016. Monitoring the Dynamics of Water flow at a High-Mountain Permafrost Site Using Electrical Self-Potential Measurements. American Geophysical Union, Fall General Assembly 2016, abstract #H34A-06. Scherler, M., Hauck, C., Hoelzle, M., Stahli, M. and Volksch, I., 2010. Meltwater infiltration into the frozen active layer at an alpine permafrost site. Permafrost and Periglacial Processes 21: 325-334, DOI: 10.1002/ppp.694. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-10780.pdf

2019048566 Jacobs, Benjamin (Technical University of Munich, Department of Civil, Geo and Environmental Engineering, Munich, Germany); Myrha, Kristin S.; Leinauer, Johannes and Krautblatter, Michael. Thermal and mechanical modelling of massive rock slope failure following fjord deglaciation [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-13699, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

During the last decade, more than 300 unstable rock walls have been systematically identified throughout Norway, of which five are classified as high-risk instabilities with respect to high hazard scores and anticipated casualties. At these five sites long-term permafrost degradation following glacial retreat seems to significantly influence large-scale rock instability. Here we combine thermal and mechanical modelling of extreme fjord topographies over the Pleniglacial / Lateglacial / Holocene to demonstrate how permafrost degradation controls long-term rock slope failure. Recent movement rates, however, show a strong link to hydraulic conditions such as hydraulic head and infiltration rates. In this study, we investigate two of Norway's high-risk sites to model and evaluate thermal and hydraulic forcing on historic and recent rock slope instabilities. Critical rock mass parameters, such as uniaxial compressive strength, tensile strength and elasticity in frozen and unfrozen state were obtained by using over 100 specimens from site for rock mechanical testing. The results show a 15 to 20% strength reduction upon thaw. These test results and results of a long-term transient heat flow model (CryoGrid2D) were transferred into a continuum mechanical model on a fjord scale level. Our thermal assumptions of recent rock wall temperature dynamics were confirmed by temperature-calibrated 3D electrical resistivity tomography. On a slope scale, 2D electrical resistivity tomography reveals hydraulic forcing since surface features such as large fissures can be attributed to zones of increased infiltration. Here we show the first attempt on long-term stability modelling of steep fjord rock walls following deglaciation. This work helps understanding the often-observed time lag between deglaciation and rock wall failure by adding laboratory-tested rock mechanical implications of permafrost development and degradation to the picture. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-13699.pdf

2019048545 Ji Duoying (Beijing Normal University, College of Global Change and Earth System Science, Beijing, China) and Sun Wenbin. Tibetan Plateau permafrost change during the past 40 years [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-7403, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

Permafrost is a climatologically important feature of the Tibetan Plateau, and it has been treated as an indicator of climate change and is highly sensitive to climate changes. Changes in permafrost are likely to influence local energy exchanges, hydrological processes and carbon budgets and hence global climate system. In this study, we use the regional climate model WRF forced by ERA-interim to study how the Tibetan Plateau permafrost changes during the last four decades, and diagnose the permafrost extent, active layer thickness and related soil organic carbon budget changes. The WRF model used in this study adopts several permafrost focused features on land surface processes, such as surface organic layer, deep soil column representation, and vertical resolved soil organic carbon dynamics. We also compare the regional climate model WRF simulated historical Tibetan Plateau permafrost change with results from six offline land surface models participated in Permafrost Carbon Network Model Intercomparison Project (PCN-MIP). This study indicates that the WRF model could well simulate the regional climate and environmental change over the Tibet Plateau, although more efforts still need to put on improving its parameterization schemes on land-atmosphere interaction. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-7403.pdf

2019048583 Kotelevets, Dmitry (Lomonosov Moscow State University, Moscow, Russian Federation); Vasil'chuk, Jessica; Alexeev, Sergei and Zolotaya, Lyudmila. Complex study of permafrost mounds in Sentsa River (Russian Federation) valley by geophysical methods [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-807, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

Permafrost covers a considerable area of the Northern Hemisphere and over 65 percent of the territory of Russia and is possible place for the formation of specific permafrost landforms such as lithalsas - mineral-rich permafrost mounds with ice lenses. The understanding of lithalsa geomorphology is important for the Arctic and mountain regions, which contain technical-engineering constructions for several reasons. Firstly, such landforms represent potential hazard while ice melting. Secondly, lithalsa are geomorphological indicators of past and present conditions of the formation of permafrost mounds. Such landforms also can indicate recent climatic or environmental influences. The study is considering the results of the examination of genesis and configuration of lithalsas in Sentsa river valley (East Sayan Mountains, Russia). The climatic conditions of the region are appropriate for their formation and existing the annual average air temperature varies from -4 C -6 C, and the average July air temperature varies from +9 C to +11.5 C. A complex study of two lithalsas (80 and 30 meters in diameter) was carried out in summer 2017 on a surface of 150x350m. We performed electric survey in a modification of profile vertical electrical sounding (VES). The total amount of electric measurements consists of 28 points with a step of 15 m. Obtained data was interpreted considering the geological data from two boreholes (20 and 15 m depth), that allowed us to create geoelectric sections for each of the lithalsa mounds. Additionally to define the geomorphological structure of the upper part of the section the kappametry examination of a vertical profile of 10 soil pits (1.5 m depth) was performed. Total amount of measurements of the magnetic susceptibility (c) is more than 500. The results of kappametry examination were also used for the dividing the soil profile into horizons. Obtained geoelectric sections for two lithalsas allowed us to build a 3D model of mounds and define the contours of ice lenses. The lenses are defined by isometric zones of high electrical resistivity from 18000 to 30000 Ohm meters on a background of loamy sediments with low resistivity around 80-300 Ohm meters. Due to the complex geophysical research it was established, that ice lenses are at the depth of 4 meters and are 10 meters thick. The largest of the studied lithalsas occurred to have two separate perennial ice-cores. This can be the sign of the formation of two separate lithalsas and subsequent fusion due to the close position. Russian science foundation (grant No. 14-27-00083) and Russian Foundation for Basic Research (grant No. 16-05-00115) supported the research. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-807.pdf

2019048555 Kuschel, Erik (University of Natural Resources and Life Sciences, Department of Civil Engineering and Natural Hazards, Vienna, Austria); Zangerl, Christian; Prokop, Alexander; Tolle, Florian; Bernard, Eric and Friedt, Jean-Michel. Landslide characterisation based on multi-temporal terrestrial laser scanning in the cirque of the Austre Lovenbreen [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-7444, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

The slopes surrounding the Austre Lovenbreen glacier (79 N, Ny-Alesund, Svalbard) were selected to study the occurrence, spatial distribution and temporal evolution of landslide processes in the high arctic. In addition, the impact of ongoing glacier retreat and warming-induced permafrost degradation on landslide formation mechanisms is investigated by analyses of multi-temporal terrestrial laser scanning (TLS) data and geological field surveys. The cirque of Austre Lovenbreen glacier is located in the basement rocks of the Kongsvegen Group which is composed of the Nielsenfjellet, Steenfjellet and the Bogegga Formation. For this study particular focus is placed on low strength and penetrative foliated phyllites of the Nielsenfjellet Formation. The area was chosen because this rock type is prone for different landslide processes including deep-seated rock slides, shallow soil slides, solifluction, rock avalanches and falls. In the study area, the landslide inventory was mapped during a field survey in 2017 and by the analysis of multi-temporal TLS data. TLS was performed annually since 2012 and provide high resolution digital elevation models of the slopes and thus enable the detection of topographical changes induced by landslides. Ortho-images, aerial photographs taken since 1936 and ground based photographs taken during the field campaign provide additional information about the different slope processes. With the help of differential maps derived from terrestrial laser scanning and photogrammetric models slope and landslide processes are identified and mapped using geographic information systems. During the field campaign several shallow translational soil slides with depths ranging from 1-5 m were observed. The basal shear zones of the soil slides were formed directly on the contact between the soil layer and an underlaying glacier ice layer. The frequently occurrence of these type of failure mechanisms at different heights of the slopes shows that the underlaying ice layer can be found up to 100 m above the Austre Lovenbreen valley glacier as was shown through previous GPR studies conducted in the area. Field observations suggest that formation of the shallow soil slides is related to a mass loss of the valley glacier i.e. loss of the retaining effect at the foot and/or the reduction of shear strength at the contact between the soil and ice layer most probably due to temperature increase and water infiltration. Furthermore, on all slopes solifluction sheets and lobes were observed indicating active shallow soil creep. Surprisingly, no characteristic structures indicating deep-seated rock slides were found in the area even though the slopes are steep and composed of intensively fractured low-strength phyllitic rock masses. The presented study provides a preliminary insight into landslide processes that occur in slopes of the high arctic affected by glacier retreat and permafrost degradation. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-7444.pdf

2019048579 Lebedeva, Liudmila (Melnikov Permafrost Institute, Yakutsk, Russian Federation); Bazhin, Kirill; Khristoforov, Ivan and Makarieva, Olga. Suprapermafrost taliks in the Shestakovka River watershed, continuous permafrost environment, investigated by GPR and ERT techniques [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-15744, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

Continuous permafrost is usually considered as impermeable frozen ground. It is often assumed that surface flow and flow in the shallow active layer (AL) are main sources of river runoff in permafrost basins. Although existence of taliks is acknowledged, their distribution, genesis, evolution and role in surface-subsurface water interactions remain unresolved issues. The research objective is to estimate taliks distribution, depth and geometry in the Shestakovka River research watershed, Eastern Siberia, using electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) geophysical techniques. The Shestakovka River watershed with area 170 km² is located in 20 km to south-west of Yakutsk within the erosion-denudational slope of the ancient accumulative plain with absolute elevation of 150-280 m. The permafrost thickness is 200-400 m. The upper 40 m of the section are represented by quartz-feldspar sands with rare inclusions of silty sandy loam and loam. The climate is cold and dry with mean annual air temperature -9.5 °C, precipitation 240 mm/year. Dominant landscapes are pine (47% of the watershed area) and larch (38%) forest. AL thickness in the pine forest could reach 3-4 m. Water-saturated suprapermafrost taliks were occasionally found on the gentle slopes covered by pine forests. Larch forests are characterized by cold permafrost with AL thickness up to 1 m. To estimate the talik abundance fourteen profiles 300 m long each were selected on the gentle slopes covered by pine forests. GPR measurements in May 2017 showed that there are water-saturated suprapermafrost taliks at eight profiles out of fourteen. Typically taliks were discovered in the depth interval from 2.5 to 10 m. If assume that selected profiles are representative for pine forest landscape of the watershed we conclude that 28% of the watershed area could be occupied by taliks. The high fraction of taliks containing suprapermafrost groundwater suggests possible importance of groundwater pathways for the river runoff generation even for the small watershed in continuous permafrost zone. Six profiles (five with taliks and one without) were selected for more time-consuming ERT measurements and repeated investigations in September 2017 when AL thickness reaches maximum. Joint interpretation of GPR and ERT results, taliks depth, geometry and relations of talik distributions to topography and landscape features will be discussed in the paper. Understanding of groundwater storages and its seasonal dynamics could advance concepts of runoff generation that underlay hydrological, hydrogeological and permafrost modelling strategies and future projections. The study was partially supported by Russian Foundation for Basic Research, projects No 17-05-00926, 16-35-60082 mol_a_dk. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-15744.pdf

2019048574 Makarieva, Olga (Gidrotehproekt, St. Petersburg, Russian Federation); Nesterova, Nataliia; Lebedeva, Lyudmila and Sushansky, Sergey. The Kolyma water-balance station; the history of a research watershed in a mountainous permafrost environment from 1947 to 2017 [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-924, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

In 2017 we celebrate 70 years since work on organizing the Kolyma Water-Balance station (KWBS) began. This hydrological and permafrost research catchment has accumulated standard and experimental data unique both in terms of their amount and duration. It includes 50 years of continuous daily meteorological and streamflow data for main meteorological plot and runoff gauge of KWBS and daily data of shorter periods for another two meteorological sites and 9 runoff gauges (Makarieva et al., 2017). The dataset is important because it characterizes the natural settings, which, on the one hand, are nearly ungauged, and on the other hand, are representative for the vast mountainous territory of Eastern Siberia and North-East Russia. The Kolyma water balance station (KWBS) was established on October 15, 1947 and was initially known as the Itrikanskaya runoff station of the Dalstroy (Far North Construction Trust organized in 1931) Hydrometeorological Service. At the end of the 1940s and early 1950s, technical staff of the station were mainly former convicts. During the first few years, the workers of the station built houses for themselves, collected firewood and organized the household. The working day lasted till 10 or 11 p.m. Since there was no electricity, they used kerosene lamps filled with a mixture of petrol and salt. In summer 1956 there were only 13 people left at the station, some of them were taken to help with haymaking to prepare hay for their subsidiary holding that consisted of two cows and a horse. In 1957 the station was handed over to the jurisdiction of the Kolyma Hydro-meteorological service administration, and in 1958 it was partially connected to electricity. At that time there were active steps taken toward fitting out the station with new types of devices and equipment, engaging new specialists in hydro-meteorology. In 1976 the station hosted a delegation of USA scientists. They highly praised the professional and personal qualities of the station's staff members. According to Slaughter and Bilello (1977), the data recorded at the KWBS, were unique and unprecedented for world practice. In 1997, the station was terminated, thereby leaving Russia without operating research watersheds in the permafrost zone. Nowadays, the resumption of continuous observations and research at the Kolyma station appears to be a critical task due to increased interest in the natural processes of the Arctic region. Present-day data, following the KWBS long-term observations series, could become a valuable indicator of climate change and a basis for studying its impact on the state of the permafrost and its associated hydrological regime. The report will have the outlines the prospects for future of the station, where the KWBS could be restored to the status of a scientific research watershed and become a valuable international center for hydrological research in permafrost. Makarieva, O., Nesterova, N., Lebedeva, L., Sushansky, S.: Water-balance and hydrology research in a mountainous permafrost watershed in upland streams of the Kolyma River, Russia: database from the Kolyma Water-Balance Station, 1948-1997, Earth Syst. Sci. Data Discuss., URL: https://doi.org/10.5194/essd-2017-125, in review, 2017 [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-924.pdf

2019048575 Makarieva, Olga (St. Petersburg State University, Institute of Earth Scienses, St. Petersburg, Russian Federation); Vinogradova, Tatyana; Nesterova, Natalya and Lebedeva, Lyudmila. The principle of universality as the only way to overcome hydromythology in hydrological modelling [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-1059, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

The issue of this session is not new and has been raised as a real problem for future development of hydrology not only by Pomeroy et al (2011), but by Beven and continuously by Makarieva (previously Semenova) with coauthors starting from EGU 2009. Here we would like to bring attention to the universality principle (UP) in hydrological modelling as the only way to overcome the charms of hydromythology. UP implies the possibility to simulate hydrological processes from elementary slope scale up to the basins of any size within the framework of a single methodological approach and unified parameterization. As pointed by Pomeroy et al. (2011) the more advanced physically-based descriptions of "surface" processes may be justified where there is sufficient information, in ungauged basins they can be conceptualized. However, physically-based descriptions of the subsurface processes (the Richard's, Saint-Venant and Boussinesq equations) do not lead to realistic simulations of sub-surface hydrology in any cases, causing nonlinearity, uniqueness, uncertainty, equifinality and scale problems. Hydrograph is a Russian process-based model which core is the concept of runoff elements allowing for description of surface and subsurface water movement at any scale (Vinogrdov et al., 2011). The probable idealization - hierarchical sequence of layers of runoff elements arrangement which take part in river inflow - is proposed. The following empirical facts are taken into account: the decrease of infiltration capacity of water-holding rocks and outflow rate and the simultaneous increase of water storage with the depth in groundwater aquifers. Each level in the system of runoff elements is characterised by two hydraulic parameters, relaxation time and rate of out-flow, water storage. Runoff elements can be easily identified with the natural formations. Surface runoff elements depending on natural conditions but mainly on inclination can be measured from shares and ones up to tens of thousands square meters. Underground runoff elements can be much greater. The conceptual parameters of runoff elements can be assessed based on the results of specific studies at research catchments and transferred from small (slope)-scale to watershed- and basin-scale modelling. Mountainous areas of North-Eastern Russia are characterized by variety of landscapes, climatic conditions. But this region has almost none specific observational data due to it remoteness. For area of more than mln km², there were only two research watersheds during historical period. This is the high-altitude Suntar-Hayata station at the Suntar river basin (1957-1959) and the Kolyma water balance station at the Kolyma river basin (1948-1997). Based on that data we developed the database for the mountainous areas of the Yana, Indigirka and Kolyma rivers which includes GIS of main landscapes and their parameters for the Hydrograph model. The model parameters were verified at the scale of soil column to small watersheds in different permafrost landscapes. We applied developed parameterization scheme for 30 basins with available flow data with areas from 0.3 to 90 000 km² without change. The satisfactory results of this study show the possibility for scale-free modelling with adequate to natural processes conceptualizations. They will be reported. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-1059.pdf

2019048584 Marciniak, Artur (Polish Academy of Sciences, Institute of Geophysics, Warsaw, Poland); Owoc, Bartosz; Grzyb, Jaroslaw; Glazer, Michal; Dobinski, Wojciech and Majdanski, Mariusz. Seismic tomography and MASW analysis of the results of Spitsbergen seismic experiment; case study [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-280, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

In recent years, polar studies become theme of interest of many fields of modern geosciences. Seismic experiment conducted in front of Hans Glacier in Horsund region of Svalbard, aims to recognize changes in permafrost during different seasons of the year. This work is the first part of the larger experiment, where complex interpretation of borehole temperatures, ERT and climate projections will be jointly analyzed to model future changes in the deep permafrost in the area of retreating glacier. In this step we present active geophysical measurements with the first data processing recorded in the summer season. Seismic tomography, and MASW methods were conducted to receive initial information about subsurface from 3 seismic lines. Application of different seismic methods to the data set, is aimed to obtain velocity field for further seismic imaging, and to uncertainty estimation of the results. Moreover authors obtained information about V_S30 profile, and were able to estimate occurrence of possible low velocity zones. For validation of received data, forward modeling of the results obtained from seismic tomography and MASW were calculated, and compared with the real data. That step was a final test, if the received results comprises in a border of uncertainty with real data-set. As a final result authors will compare those results with second data set collected in the winter season, which can be highly usable to understand changes in permafrost during year cycle. Moreover, comparison of received seismic data with information from ERT tomography profiles performed paralleled to seismic lines, should delivered very accurate and certain final models, based on multiple methods with estimated uncertainty for proper data correlation. This research was funded by National Science Centre, Poland (NCN) Grant UMO-2015/21/B/ST10/02509. Part of this work was supported within statutory activities No. 3841/E-41/S/2017 of the Ministry of Science and Higher Education of Poland. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-280-3.pdf

2019048564 Morino, Costanza (Open University, School of Environment, Earth & Ecosystem Sciences, Milton Keynes, United Kingdom); Conway, Susan J.; Balme, Matthew; Saemundsson, Sorsteinn; Helgason, Jon Kristinn; Jordan, Colm; Hillier, John and Argles, Tom. How permafrost degradation can affect the dynamics of landslides; two case studies in northern Iceland [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-14359, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

Permafrost degradation can severely affect slope stability in periglacial environments. However, its role in conditioning mass movements in Iceland, and in particular landslides involving loose deposits, is not well constrained. Landslides are a direct threat to many towns in Iceland, and triggering factors of these hazardous events include heavy precipitation, rapid snowmelt, seismic activity and permafrost thaw (e.g., Saemundsson et al., 2003; Saemundsson et al., in press). Here, we present two case studies of landslides induced by degrading permafrost in Iceland, whose source materials comprised ice-cemented talus deposits. We describe and quantify the morphometric characteristics of these landslides, which reveal different dynamic processes, and how the thawing of ground ice could have affected their emplacement. As degrading permafrost is predicted to increasingly affect mountain regions in the future, improving our knowledge on this type of landslides is important, as they could be a further source of risk for local population in Iceland and other mountainous periglacial areas. References: Saemundsson, T., Petursson, H.G., Decaulne, A., 2003. Triggering factors for rapid mass movements in Iceland, in: D., R., C.L., C. (Eds.), International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction, and Assessment, Proceedings, 3rd International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction, and Assessment. 167-178. Saemundsson, S., Morino, C., Helgason, J.K., Conway, S.J., Petursson, H.G.. The triggering factors of the Moafellshyrna debris slide in northern Iceland: intense precipitation, earthquake activity and thawing of mountain permafrost. Sci. Total Environ. in press. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-14359.pdf

2019048541 Romanenko, Fedor (Moscow State University, Faculty of Geography, Moscow, Russian Federation); Shabanova, Natalia; Volobuyev, Vasilii; Shilovtseva, Olga and Lugovoy, Nikolay. Thermal regime of Kola Peninsula and Franz-Josef Land in view of permafrost and geomorphological processes evolution in XX and XXI centuries [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-11828, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

Lots of Arctic environmental processes and systems are affected by permafrost. Our field works were aimed to observe some of them like coastal dynamics linked to thermodenudation and thermoabrasion at Franz-Josef Land and relief processes linked to sporadic and insular permafrost in Kola Peninsula. The presence and state of permafrost depends on regional "thermal potential": year sums of daily positive and negative temperatures. Within the climate change the change of the permafrost state and related processes is expected. We investigated all the available observation data at the regions mentioned above and completed them with CRU4.1 and reanalysis (ERA Interim) data. Our data samples cover the period from 1897 to 2016. Air temperature analysis at the stations of the southern part of Kola has revealed its quasi-cyclic changes with the period of about 70 years, characterized by a distinctly seen linear trend of average mean annual air temperature increase with the rate of about 1.0°C per 100 years. In all seasons, the linear air temperature trend is positive; in winter it is the most significant. The modern warming has an uneven distribution over the Kola Peninsula increasing from the west to the east: in Kandalaksha it is almost unseen, while on Sosnovets Island it becomes statistically significant. Nevertheless, up to the current day the warming strength is not enough to melt the sporadic permafrost located in the Kola Peninsula southern part which was expected to disappear even in the previous warming of 1930-40^th [1]. At Franz-Josef land the warming is extremely rapid: about 4°C per 50 years (compared to 1,2-1,7 °C at Kola Peninsula). Still this record breaking warming is provided by winter temperature growth, while summers' temperatures, which are crucial for cryogenic processes, remain stable since 1958. In the same time, we do observe coastal dynamics activization in recent 10-20 years which must be explained by ice-free (abrasion) period extension. The work was executed with the support of the Russian Science Foundation (project 14-37-00038). Reference: [1] Lavrova M.A., 1935 A note about found permafrost on the southern coast of Kola Peninsula // Proceedings of the Commission on permafrost studies. Vol. IV. [in Russian]. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-11828.pdf

2019048542 Steinert, Norman (Universidad Complutense de Madrid, Department of Earth Science, Astronomy and Astrophysics, Madrid, Spain); González-Rouco, Jesus Fidel; Hagemann, Stefan; De Vrese, Philipp; Garcia-Bustamante, Elena; Jungclaus, Johann; Lorenz, Stephan and Melo-Aguilar, Camilo. Increasing the depth of a land surface model; implications for the subsurface thermal and hydrological regimes [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-17035, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

The representation of the thermal and hydrological state in Land Surface Models (LSMs) is crucial to have a realistic simulation of subsurface processes and the coupling between the atmo-, lito- and biosphere. An important factor for the LSM realism is the depth of the soil allocating space for subsurface processes and hence, land-climate feedbacks. This work addresses the influence of soil depth on the long-term climate variability and land-climate coupling. The concept of soil depth used herein is twofold, defining it as available space for energy storage on the one hand, and water storage on the other hand. Changes in any of them influence the simulation of land-air interactions and subsurface phenomena, e.g. energy/moisture balance and storage capacity, freeze/thaw cycles or permafrost evolution. The "thermal depth" refers to the depth of the zero-flux Bottom Boundary Condition Placement (BBCP). There is evidence for the current generation Earth System Models (ESM) inaccurately simulating subsurface thermodynamics by having LSM components with a BBCP too close to the surface. In shallow LSMs, the amplitude and phase of the energy propagation with depth and the spatial (vertical) and temporal variability of subsurface temperatures are distorted. In this study, we increase the BBCP into JSBACH - the LSM component of the MPI ESM. Four subsurface layers are added progressively to increase the soil depth from 10m (5 layers) to 275m (9 layers). The depth of the BBCP has also implications for the hydrological regime, in which the soil moisture is sensitive to depth changes in the thermal scheme. The "water depth" is specified by the parameter datasets that characterize the spatial distribution of root and bedrock depths. Thus, it defines the space for water storage available for hydro-climate interactions. We use two different datasets of soil parameters to assess the sensitivity JSBACH, with major implications for the vertical distribution of soil moisture. Both in the cases of BBCP and water depth changes, we explore the sensitivity of the LSM from the perspective of changes in the soil thermodynamics, energy balance and storage as well as the effect of including freezing and thawing processes. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-17035-1.pdf

2019048551 Widhalm, Barbara (Zentralanstalt für Meteorologie und Geodynamik, Vienna, Austria) and Bartsch, Annett. Sentinel-1 data for frozen soil applications [abstr.]: in European Geosciences Union general assembly 2018, Geophysical Research Abstracts, 20, Abstract EGU2018-19678, 2018. Meeting: European Geosciences Union general assembly 2018, April 8-13, 2018, Vienna, Austria.

Frozen soil C-band backscatter has been shown of high value for landcover characterization and soil organic carbon estimation in tundra environments. Due to the incidence angle dependence of Synthetic Aperture Radar (SAR) backscatter values, a normalization to a common incidence angle is required for these applications. Angular signatures of radar backscatter depend on surface roughness and vegetation cover and are thus variable in heterogeneous environments. For the derivation of location specific normalization functions multiple acquisitions from overlapping orbits are required. Within the ESA DUE GlobPermafrost project, which aims at analyzing large regions across the Arctic, we developed a simpler method for C-band Sentinel-1 data which can be applied for single scenes. As stable dielectric properties are necessary in this case, this method of deriving the normalization function is applicable for frozen conditions. Examples which demonstrate the utility of Sentinel-1 derived frozen surface data will be presented. [Copyright Author(s) 2018. CC Attribution 4.0 License: https://creativecommons.org/licenses/by/4.0/legalcode]

URL: http://meetingorganizer.copernicus.org/EGU2018/EGU2018-19678.pdf

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2019048166 Hanssen-Bauer, Inger (Norwegian Meteorological Institute, Norway); Forland, Eirik J.; Hisdal, Hege; Maver, S.; Sando, Anne Britt; Sortebera, Asgeir; Adakudlu, M.; Andresen, J.; Bakke, J.; Beldring, S.; Benestad, R.; Bill, W.; Bogen, J.; Borstad, C.; Breili, K.; Breivik, O.; Borsheim, K. Y.; Christiansen, Hanne Hvidtfeldt; Dobler, A.; Engeset, R.; Frauenfelder, R.; Gerland, S.; Gjelten, H. M.; Gundersen, J.; Isaksen, K.; Jaedicke, C.; Kierulf, H.; Kohler, J.; Li, H.; Lutz, J.; Melvold, K.; Mezghani, A.; Nilsen, F.; Nilsen, I. B.; Nilsen, J. E. O.; Pavlova, O.; Ravndal, O.; Risebrobakken, B.; Saloranta, T.; Sandven, S.; Schuler, T. V.; Simpson, M. J. R.; Skogen, M.; Smedsrud, L. H.; Sund, M.; Vikhamar-Schuler, D.; Westermann, S. and Wong, W. K. Climate in Svalbard 2100; a knowledge base for climate adaptation: NCCS Report, Rep. No. 1/2019, 207 p. (Norwegian sum.), illus. incl. tables, sketch map, 202 ref., 2019. Includes appendices.

URL: https://www.miljodirektoratet.no/globalassets/publikasjoner/M1242/M1242.pdf

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