Pluri‐decadal evolution of rock glaciers surface velocity and its impact on sediment export rates towards high alpine torrents

Kummert, Mario; Bodin, Xavier; Braillard, Luc; Delaloye, Reynald

doi:10.1002/esp.5231

Cited by 13 publications

(11 citation statements)

References 34 publications

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“…The uncertainties inherent to the 2.5D velocity vectors as derived from change detection between DSM pairs are in a similar range to that found by comparable studies at other rock glacier sites (e.g. Bodin et al, 2018;Fleischer et al, 2021;Kummert et al, 2021). The uncertainty analysis of the velocity vectors is based on an assessment of velocity vectors within stable areas around the rock glacier, which we use as a measure of noise and systematic errors in the data.…”

Section: Sub-seasonal Displacement (2019)supporting

confidence: 56%

Multi-sensor monitoring and data integration reveal cyclical destabilization of the Äußeres Hochebenkar rock glacier

et al. 2023

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Abstract. This study investigates rock glacier destabilization based on the results of a unique in situ and remote-sensing-based monitoring network focused on the kinematics of the rock glacier in Äußeres Hochebenkar (Austrian Alps). We consolidate, homogenize, and extend existing time series to generate a comprehensive dataset consisting of 14 digital surface models covering a 68-year time period, as well as in situ measurements of block displacement since the early 1950s. The digital surface models are derived from historical aerial imagery and, more recently, airborne and uncrewed-aerial-vehicle-based laser scanning (ALS and ULS, respectively). High-resolution 3D ALS and ULS point clouds are available at annual temporal resolution from 2017 to 2021. Additional terrestrial laser scanning data collected in bi-weekly intervals during the summer of 2019 are available from the rock glacier front. Using image correlation techniques, we derive velocity vectors from the digital surface models, thereby adding rock-glacier-wide spatial context to the point-scale block displacement measurements. Based on velocities, surface elevation changes, analyses of morphological features, and computations of the bulk creep factor and strain rates, we assess the combined datasets in terms of rock glacier destabilization. To additionally investigate potential rotational components of the movement of the destabilized section of the rock glacier, we integrate in situ data of block displacement with ULS point clouds and compute changes in the rotation angles of single blocks during recent years. The time series shows two cycles of destabilization in the lower section of the rock glacier. The first lasted from the early 1950s until the mid-1970s. The second began around 2017 after approximately 2 decades of more gradual acceleration and is currently ongoing. Both destabilization periods are characterized by high velocities and the development of morphological destabilization features on the rock glacier surface. Acceleration in the most recent years has been very pronounced, with velocities reaching 20–30 m a−1 in 2020–2021. These values are unprecedented in the time series and suggest highly destabilized conditions in the lower section of the rock glacier, which shows signs of translational and rotational landslide-like movement. Due to the length and granularity of the time series, the cyclic destabilization process at the Äußeres Hochebenkar rock glacier is well resolved in the dataset. Our study highlights the importance of interdisciplinary, long-term, and continuous high-resolution 3D monitoring to improve process understanding and model development related to rock glacier rheology and destabilization.

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Section: Sub-seasonal Displacement (2019)supporting

confidence: 56%

Multi-sensor monitoring and data integration reveal cyclical destabilization of the Äußeres Hochebenkar rock glacier

et al. 2023

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“…11, p = 0.25) there is no significant correlation between mean flow velocity and mean MAAT in the individual time steps, whereas Lobe2 (R 2 = 0.53, p < 0.05) shows a significant relationship.…”

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confidence: 85%

“…Active rock glaciers are a downslope creep phenomenon of mountain permafrost that occurs in areas with high-relief and suitable topoclimatic conditions. [1][2][3] The growing interest of the scientific community in mountain permafrost has led to rapid progress in the understanding of rock glaciers in recent years mainly in the European Alps (e.g., Haeberli et al, 3 Buchli et al, 4 Cicoira et al, 5 Cicoira et al, 6 Gärtner-Roer et al, 7 Kellerer-Pirklbauer and Kaufmann, 8 Kenner et al, 9 Krainer et al, 10 Kummert et al, 11 Marcer et al, 12 and Wagner et al 13 ) but also in other mountain regions such as the Andes (e.g., Rangecroft et al 14 and Schaffer et al 15 ) or the Himalayas (e.g., Jones et al 16 and Knight et al 17 ).…”

Section: Introductionmentioning

confidence: 99%

Combination of historical and modern data to decipher the geomorphic evolution of the Innere Ölgruben rock glacier, Kaunertal, Austria, over almost a century (1922–2021)

Fleischer

Haas

Altmann

et al. 2022

Permafrost & Periglacial

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Rock glaciers are cryo-conditioned downslope-creeping landforms in high mountains.Their dynamics are changing due to external factors influenced by climate change.Although there has been a growing scientific interest in mountain permafrost and thus in rock glaciers in recent years, their historical development, especially before the first alpine-wide aerial image flights in the 1950s, has hardly been researched.

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“…There is no annual accumulation or ablation of ice that would control its dynamics and therefore the advancement of a rock glacier is not linked to a mass balance. While a rock glacier can slowly creep downslope due to gravity, which is mainly controlled by local topography, ground ice would not melt in direct response to the minor advancement of a rock glacier, which is in the orders of centimeters to meters per year [89,103,109].…”

Section: Glacier Vs Rock Glaciermentioning

confidence: 99%

Mountain Permafrost Hydrology—A Practical Review Following Studies from the Andes

et al. 2022

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Climate change is expected to reduce water security in arid mountain regions around the world. Vulnerable water supplies in semi-arid zones, such as the Dry Andes, are projected to be further stressed through changes in air temperature, precipitation patterns, sublimation, and evapotranspiration. Together with glacier recession this will negatively impact water availability. While glacier hydrology has been the focus of scientific research for a long time, relatively little is known about the hydrology of mountain permafrost. In contrast to glaciers, where ice is at the surface and directly affected by atmospheric conditions, the behaviour of permafrost and ground ice is more complex, as other factors, such as variable surficial sediments, vegetation cover, or shallow groundwater flow, influence heat transfer and time scales over which changes occur. The effects of permafrost on water flow paths have been studied in lowland areas, with limited research in the mountains. An understanding of how permafrost degradation and associated melt of ground ice (where present) contribute to streamflow in mountain regions is still lacking. Mountain permafrost, particularly rock glaciers, is often conceptualized as a (frozen) water reservoir; however, rates of permafrost ground ice melt and the contribution to water budgets are rarely considered. Additionally, ground ice and permafrost are not directly visible at the surface; hence, uncertainties related to their three-dimensional extent are orders of magnitude higher than those for glaciers. Ground ice volume within permafrost must always be approximated, further complicating estimations of its response to climate change. This review summarizes current understanding of mountain permafrost hydrology, discusses challenges and limitations, and provides suggestions for areas of future research, using the Dry Andes as a basis.

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Pluri‐decadal evolution of rock glaciers surface velocity and its impact on sediment export rates towards high alpine torrents

Cited by 13 publications

References 34 publications

Multi-sensor monitoring and data integration reveal cyclical destabilization of the Äußeres Hochebenkar rock glacier

Multi-sensor monitoring and data integration reveal cyclical destabilization of the Äußeres Hochebenkar rock glacier

Combination of historical and modern data to decipher the geomorphic evolution of the Innere Ölgruben rock glacier, Kaunertal, Austria, over almost a century (1922–2021)

Mountain Permafrost Hydrology—A Practical Review Following Studies from the Andes

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