Evidence of glacier-permafrost interactions associated with hydro-geomorphological processes and landforms at Snøhetta, Dovrefjell, Norway

Glacier-permafrost interactions are investigated to understand glacial-hydrological influence along a partly glacierised valley on the NE flank of the Snøhetta massif, Dovrefjell, southern Norway. Of particular interest is how processes are controlled by a hydrological connection between landforms. Field mapping identified an ice-marginal landsystem comprising a polythermal glacier, a proglacial lake, an ice-cored moraine complex and a river-lake with perennial frost mounds. A clear interaction between glacial and periglacial processes was observed in transitional landforms, most prominently in the ice-cored moraine which constitutes a permafrost environment that is directly reworked by glaciofluvial processes. The role of this interaction in controlling seasonal, partial drainage of the proglacial lake was assessed using remote sensing-based observations of lake surface size evolution and seasonal surface subsidence. Results suggest a two-fold threshold for lake drainage: Depending on the dynamics of glacial discharge and active layer depth, the ice-cored moraine may either act as a barrier or a pathway to meltwater exiting the glacier. This demonstrates the importance of meltwater dynamics in controlling landform evolution in a glacial-periglacial landscape. To further assess the importance of surface and subsurface hydrology in linking glacial and periglacial domains, water stable oxygen isotope ratios across the study area were studied to map the flow of meltwater from glacier to permafrost. Results include a model of the surface and subsurface hydrology in the catchment and promote a conceptual understanding of water as a thermal, hydraulic and mechanical agent of transient glacier-permafrost interaction operating at heterogeneous timescales.publishedVersio

Ice content and interannual water storage changes of an active rock glacier in the dry Andes of Argentina

The quantification of volumetric ice and water contents in active rock glaciers is necessary to estimate their role as water stores and contributors to runoff in dry mountain catchments. In the semi-arid to arid Andes of Argentina, active rock glaciers potentially constitute important water reservoirs due to their widespread distribution. Here however, water storage capacities and their interannual changes have so far escaped quantification in detailed field studies. Volumetric ice and water contents were quantified using a petrophysical four-phase model (4PM) based on complementary electrical resistivities (ERT) and seismic refraction tomographies (SRT) in different positions of Dos Lenguas rock glacier in the Upper Agua Negra basin, Argentina. We derived vertical and horizontal surface changes of the Dos Lenguas rock glacier, for the periods 2016?17 and 2017?18 using drone-derived digital elevation models (DEM). Interannual water storage changes of −36 mm yr−1 and +27 mm yr−1 derived from DEMs of Difference (DoD) for the periods 2016?17 and 2017?18, respectively, indicate that significant amounts of annual precipitation rates can be stored in and released from the active rock glacier. Heterogeneous ice and water contents show ice-rich permafrost and supra-, intra- and sub-permafrost aquifers in the subsurface. Active layer and ice-rich permafrost control traps and pathways of shallow ground water, and thus regulate interannual storage changes and water releases from the active rock glacier in the dry mountain catchment. The ice content of 1.7?2.0 × 109 kg in the active Dos Lenguas rock glacier represents an important long-term ice reservoir, just like other ground ice deposits in the vicinity, if compared to surface ice that covers less than 3 % of the high mountain catchment.Fil: Halla, Christian. Universitat Bonn; AlemaniaFil: Blöthe, Jan Henrick. Universitat Bonn; AlemaniaFil: Tapia Baldis, Carla Cintia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Trombotto, Dario Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Hilbich, Christin. University Of Fribourg; AlemaniaFil: Hauck, Christian. University Of Fribourg; AlemaniaFil: Schrott, Lothar. Universitat Bonn; Alemani

Erdoberflächenprozesse im Hochgebirge – Der Einfluss des Klimawandels

Der Einfluss des Klimawandels auf Erdoberflächenprozesse zeigt sich im Hochgebirge in vielfältiger Weise, ist jedoch hinsichtlich der kurz-, mittel- und langfristigen Auswirkungen bislang nicht allumfassend untersucht. Neben den klimatischen Einflussfaktoren kommen auch die veränderte Landnutzung durch den Menschen oder systeminterne Faktoren (z.B. Klüfte im Fels) zum Tragen. Zählen besonders kleine Gletscher (< 4 km²) zu geeigneten Klimaindikatoren, weil sie auf klimatische Veränderungen schnell durch sichtbare Längenänderungen reagieren, sind Auswirkungen an Berghängen oder in Felswänden im Gebirgspermafrost oft erst nach Jahren oder mit aufwändiger und präziser Messtechnik nachzuweisen und können häufig nicht ausschließlich auf den Klimawandel zurückgeführt werden. Dennoch gibt es Anzeichen dafür, dass viele Prozesse im Hochgebirge sowohl in der Häufigkeit des Auftretens als auch in ihrer Intensität zunehmen und somit zu tiefgreifenden Veränderungen und neuen Gefahren und Risiken führen werden. Der folgende Beitrag zeigt exemplarisch den Einfluss des Klimawandels auf die geomorphologische Wirkung von gravitativen Massenbewegungen, Schneelawinen, periglazialen, glazialen und fluvialen Prozessen im Hochgebirge. Earth surface processes in high mountain regions – the influence of climate change: The impact of climate change on earth surface processes in mountain systems can be observed in many ways, however, our knowledge regarding short-, medium-, and long-term effects is still limited. In addition to climatic factors, changes in land use or internal factors (e.g. fissures in rock) need to be considered as well. While small glaciers (< 4 km²) are very good indicators for climatic variations showing dramatic changes in lengths and volume, impacts on mountain slopes or on rock walls under permafrost conditions are much more difficult to identify, sometimes after years or only with sophisticated measurement techniques, and not always related to climate warming. Nevertheless, there is evidence that many processes in mountain areas do increase in frequency of occurrence and in magnitude which will cause profound changes with new hazards and risks. The following chapter exemplifies how climate changes affects various geomorphological processes, such as gravitational mass movements, avalanches, periglacial, glacial and fluvial processes in high mountains

Map of permafrost distribution for Austria, Europe

This dataset contains a simulation of regional permafrost distribution for Austria based on the Permakart 3.0 modell developped by Schrott et al. (2012). The original model was created and calibrated using validation data from the Hohe Tauern range only. Here we used the same modelling parameter and extended the simulation to the entire Austrian Alps. Please note: The simulation was not validated for other parts of the country and may be erronous. Furthermore, the field evidence was collected between 2009 and 2011 and may not be valid anymore. The raster dataset contains values from 0-100 representing a pseudo-probability of permafrost occurence. For more information on the modell and field data please refer to the original publication (see "Related to" Reference)

Evidence of glacier-permafrost interactions associated with hydro-geomorphological processes and landforms at Snøhetta, Dovrefjell, Norway

Glacier-permafrost interactions are investigated to understand glacial-hydrological influence along a partly glacierised valley on the NE flank of the Snøhetta massif, Dovrefjell, southern Norway. Of particular interest is how processes are controlled by a hydrological connection between landforms. Field mapping identified an ice-marginal landsystem comprising a polythermal glacier, a proglacial lake, an ice-cored moraine complex and a river-lake with perennial frost mounds. A clear interaction between glacial and periglacial processes was observed in transitional landforms, most prominently in the ice-cored moraine which constitutes a permafrost environment that is directly reworked by glaciofluvial processes. The role of this interaction in controlling seasonal, partial drainage of the proglacial lake was assessed using remote sensing-based observations of lake surface size evolution and seasonal surface subsidence. Results suggest a two-fold threshold for lake drainage: Depending on the dynamics of glacial discharge and active layer depth, the ice-cored moraine may either act as a barrier or a pathway to meltwater exiting the glacier. This demonstrates the importance of meltwater dynamics in controlling landform evolution in a glacial-periglacial landscape. To further assess the importance of surface and subsurface hydrology in linking glacial and periglacial domains, water stable oxygen isotope ratios across the study area were studied to map the flow of meltwater from glacier to permafrost. Results include a model of the surface and subsurface hydrology in the catchment and promote a conceptual understanding of water as a thermal, hydraulic and mechanical agent of transient glacier-permafrost interaction operating at heterogeneous timescales

Bio-climate affects hillslope and fluvial sediment grain size along the Chilean Coastal Cordillera

Sediment dynamics in river catchments are controlled by tectonics, climate, and biota effecting material production on hillslopes and transport of sediment from their source to the catchment outlet. Tectonics create topography and control erodibility of the bedrock material, whereas climate controls the efficiency of weathering and transporting processes. In contrast, the effects of biota (i.e. vegetation) are more ambiguous. Vegetation accelerates bio-chemical weathering and effects mass wasting through uprooting, trapping and stabilizing hillslope material. Furthermore, vegetation exerts a strong control on the grain size distribution of hillslope sediments and thus on sediment rooting through catchments. In this study we compare grain size distributions of hillslope and channel sediments collected in four headwater catchments located in the Chilean Coastal Cordillera covering a strong bio-climatic gradient. 76 volumetric bulk samples were taken with grain sizes ranging from clay (d = 0.3 μm) to boulders (d > 300 mm). Results show that the production of fine material is strongly dependent on bio-chemical weathering intensity and hence humidity. The coarse fraction in hillslope material and channel sediments increases from arid to sub-humid conditions, presumably reflecting a higher intensity of mass wasting processes. Channels show varying degrees of armouring reflecting nonselective and thus transport-limited conditions under arid climate that are contrasted by relatively well sorted and armoured channel sediments in the humid and vegetated catchments, indicating size selective and supply-limited transport conditions. Channel grain sizes generally show high similarity to hillslope grain sizes of the same catchment, revealing the strong dependency of channel sediments on hillslope supply, at least in headwater catchments, transferring a bio-climatic control from the hillslopes to the channel system

Permafrost in den argentinischen Anden, ein bedeutender Wasserspeicher

Die semi-ariden Zentralanden Argentiniens werden durch eine weitfl ächige erbreitung von Permafrost und eine große vertikale Erstreckung von periglazialen Formen und Prozessen charakterisiert. Große Blockgletscherkomplexe mit eisreichem Permafrost werden in den Trockengebieten der Anden als bedeutende Wasserspeicher für die Zukunft angesehen. Die argentinische Regierung hat 2010 ein Gesetz zum Schutz der Gletscher und der periglazialen Höhenstufe erlassen, um diese Naturressourcen zu schützen. Die vorliegende Studie hat das Ziel, die Verbreitung der Blockgletscher aufzuzeigen und die wenig bekannten Eisgehalte dieser Periglazialformen zu quantifi zieren.Fil: Christian Halla. Universitat Bonn; AlemaniaFil: Jan Henrik Blöthe. Universitat Bonn; AlemaniaFil: Trombotto, Dario Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Lothar Schrott. Universitat Bonn; Alemani

Surface velocity fields of active rock glaciers and ice‐debris complexes in the Central Andes of Argentina

Rock glaciers and transitional ice‐debris complexes predominate the Central Andean landform assemblage, yet regional studies on their state of activity and their kinematics remain sparse. Here we utilize the national glacier inventory of Argentina to quantify surface velocity fields of 244 rock glaciers and 51 ice‐debris complexes, located in the Cordón del Plata range, Argentina. Applying a feature‐tracking approach to repeated RapidEye satellite imagery acquired between 2010 and 2017/18, we find mean displacement rates between 0.37 and 2.61 m year−1 for 149 landforms, while for the remaining 146 features, surface movement remains below our level of detection. We compare our satellite‐derived velocity fields with ground‐truth data from two local field sites and find closely matching results in magnitude and spatial distribution. With average displacement of one‐third of the active rock glaciers and ice‐debris complexes exceeding 1 m year−1, the region hosts an exceptional number of fast‐flowing periglacial landforms, compared to other mountain belts. Using a random forest model, we test the predictive power of 25 morphometric and topoclimatic candidate predictors for modelling the state of activity of rock glaciers and ice‐debris complexes on two different scales. For entire landforms and individual landform segments, constructed along displacement centrelines, we can predict the state of activity with overall accuracies of 70.08% (mean AUROC = 0.785) and 74.86% (mean AUROC = 0.753), respectively. While topoclimatic parameters such as solar radiation and elevation are most important for entire landforms, geometric parameters become more important at the scale of landform segments. Despite tentative correlations between local slope and surface kinematics, our results point to factors integrating slope and distance to the source to govern local deformation. We conclude that feature tracking in optical imagery is feasible for regional studies in remote regions and provides valuable insight into the current state of the Andean cryosphere. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons LtdOur study quantifies the surface kinematics of 295 rock glaciers and ice‐debris complexes in the Central Andes using feature tracking in optical satellite imagery. We find nearly half of these are actively moving, with high average rates between 0.38 and 2.36 m year−1. Using a random forest modelling approach, we find topoclimatic predictors to have the highest importance for predicting the state of activity of entire landforms, while geometric predictors become more important on the scale of individual landform segments.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Deutsches Zentrum für Luft‐ und Raumfahrt http://dx.doi.org/10.13039/50110000294