The first consistent inventory of rock glaciers and their hydrological catchments of the Austrian Alps

AbstractA first consistent and homogenized polygon-based inventory of rock glaciers of the Austrian Alps is presented. Compiling previous inventories and updating them by using digital elevation models (1 m grid resolution) derived from airborne laser scanning yield a dataset of 5769 rock glaciers in a ca. 48400 km2 large area. A consistent methodological approach for assigning attributes, stored in a detailed attribute table, was developed and applied here to improve comparability and reproducibility. The majority (60 %) of the studied landforms is considered to be relict (no permafrost); the remaining 40 % may still contain permafrost ice and are thus classified as intact. Rock glaciers range in elevation from 476 to 3312 m a.s.l. and cover a total area of 303 km2. The distribution of rock glaciers is mainly related to the topography of the Austrian Alps and related effects such as past glaciation history.In addition, a comprehensive analysis of the hydrological catchment areas of all individual rock glaciers was carried out. A hydrological catchment analysis in rock glacier areas is of great interest for sustainable water management issues in alpine catchments as these landforms represent shallow aquifer systems with a relatively high storage and thus buffer capability, especially in crystalline bedrock areas. A total area of almost 1280 km2 is drained through rock glaciers.The presented rock glacier and rock glacier catchment inventories provide an important basis for further research, particularly for a better understanding of the hydrogeology and geomorphology of alpine catchments and their potential alteration in the light of climate change, but also in terms of paleoglaciation and deglaciation in the Alpine Lateglacial to Holocene period. As such, the inventories are seen as an important base to stimulate further research.

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Active rock glaciers as shallow groundwater reservoirs, Austrian Alps

Grundwasser ◽

10.1007/s00767-020-00455-x ◽

2020 ◽

Vol 25 (3) ◽

pp. 215-230 ◽

Cited By ~ 1

Author(s):

Thomas Wagner ◽

Alexander Brodacz ◽

Karl Krainer ◽

Gerfried Winkler

Keyword(s):

Groundwater Resources ◽

Water Discharge ◽

Shallow Groundwater ◽

Shallow Aquifer ◽

Ground Ice ◽

Discharge Data ◽

Austrian Alps ◽

Rock Glaciers ◽

Permafrost Ground ◽

Alpine Catchments

Abstract Rock glaciers are the most prominent landforms of alpine permafrost and comprise complex shallow aquifer systems in (high) alpine catchments. Recession analyses of groundwater discharge of four active rock glaciers that contain permafrost ground ice show that they have a base flow component of the order of a few liters per second, similar to that of a relict rock glacier in which permafrost ground ice is absent. This is related to an unfrozen (fine-grained) base layer with a thickness of about 10 m. Based on a threshold analysis of precipitation events and event water discharge, depressions atop the bedrock or the permafrost table seem to play only a minor role in storing groundwater. This important finding has rarely been documented, but is highly relevant for optimal groundwater resources management in sensitive (high) alpine catchments and ecosystems. All the rock glaciers analyzed here are located in the Austrian Alps and represent the nationwide sites where suitable discharge data are available. The analysis highlights the hydrogeological importance of these discrete permafrost-derived debris accumulations as complex shallow groundwater bodies with important—but limited—storage and buffer capabilities.

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GEOMATIC METHODS APPLIED TO THE CHANGE STUDY OF THE LA PAÚL ROCK GLACIER, SPANISH PYRENEES

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-2-w13-1771-2019 ◽

2019 ◽

Vol XLII-2/W13 ◽

pp. 1771-1775

Author(s):

A. Martínez-Fernández ◽

E. Serrano ◽

J. J. Sanjosé ◽

M. Gómez-Lende ◽

A. Pisabarro ◽

...

Keyword(s):

Laser Scanning ◽

Satellite System ◽

Ice Age ◽

Rock Glacier ◽

Glacier Surface ◽

The North ◽

Spanish Pyrenees ◽

Gnss Receivers ◽

Rock Glaciers ◽

Global Navigation Satellite

Abstract. Rock glaciers are one of the most important features of the mountain permafrost in the Pyrenees. La Paúl is an active rock glacier located in the north face of the Posets massif in the La Paúl glacier cirque (Spanish Pyrenees). This study presents the preliminary results of the La Paúl rock glacier monitoring works carried out through two geomatic technologies since 2013: Global Navigation Satellite System (GNSS) receivers and Terrestrial Laser Scanning (TLS) devices. Displacements measured on the rock glacier surface have demonstrated both the activity of the rock glacier and the utility of this equipment for the rock glaciers dynamic analysis. The glacier has exhibited the fastest displacements on its west side (over 35&thinsp;cm&thinsp;yr&minus;1), affected by the Little Ice Age, and frontal area (over 25&thinsp;cm&thinsp;yr&minus;1). As an indicator of permafrost in marginal environments and its peculiar morphology, La Paúl rock glacier encourages a more prolonged study and to the application of more geomatic techniques for its detailed analysis.

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Disaggregating surface change mechanisms of a rock glacier using terrestrial laser scanning point clouds acquired at different time scales

10.5194/esurf-2020-55 ◽

2020 ◽

Author(s):

Veit Ulrich ◽

Jack G. Williams ◽

Vivien Zahs ◽

Katharina Anders ◽

Stefan Hecht ◽

...

Keyword(s):

Laser Scanning ◽

Point Clouds ◽

Rock Glacier ◽

Glacier Surface ◽

Terrestrial Lidar ◽

Surface Change ◽

Relative Contribution ◽

Rock Glaciers ◽

Change Mechanisms ◽

Glacier Flow

Abstract. Topographic change at a given location usually results from multiple processes operating over different timescales. However, interpretations of surface change are often based upon single values of movement, measured over a specified time period and in a single direction. This work presents a method to help separate surface change mechanisms related to the deformation of an active rock glacier, drawing on terrestrial lidar monitoring at sub-monthly intervals. We derive 3D topographic changes across the Äußeres Hochebenkar rock glacier in the Ötztal Alps. These are presented as the relative contribution of surface change during a three-week period of snow-free conditions (2018) to the annual surface change (2017–2018). They are also separated according to the direction perpendicular to the local rock glacier surface (using point cloud distance computation) and the direction of rock glacier flow, indicated by movement of individual boulders. In a 1500 m2 sample area in the lower tongue section of the rock glacier, the contribution of the three-week period to the annual change perpendicular to the surface is 20 %, as compared to 6 % in the direction of rock glacier flow. This shows that different directions of surface change are dominant at different times of the year. Our results demonstrate the benefit of more frequent lidar monitoring and, critically, the requirement of novel approaches to detecting change, as a step towards interpreting the mechanisms that underlie the surface change of rock glaciers.

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Rock Glacier Appearance Level and Rock Glacier Initiation Line Altitude: A Methodological Approach to the Study of Rock Glaciers

Arctic and Alpine Research ◽

10.2307/1551495 ◽

1988 ◽

Vol 20 (2) ◽

pp. 160 ◽

Cited By ~ 41

Author(s):

Ole Humlum

Keyword(s):

Methodological Approach ◽

Rock Glacier ◽

Rock Glaciers

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Altitudinal dependency of snow amounts in two small alpine catchments: can catchment-wide snow amounts be estimated via single snow or precipitation stations?

Annals of Glaciology ◽

10.3189/172756411797252248 ◽

2011 ◽

Vol 52 (58) ◽

pp. 153-158 ◽

Cited By ~ 39

Author(s):

Thomas Grünewald ◽

Michael Lehning

Keyword(s):

Laser Scanning ◽

Snow Water Equivalent ◽

Altitudinal Gradients ◽

Mountainous Regions ◽

Winter Snow ◽

Catchment Areas ◽

Scale Models ◽

Snow Water ◽

Snow Distribution ◽

Alpine Catchments

AbstarctThe spatial distribution and the local amount of snow in mountainous regions strongly depend on the spatial characteristics of snowfall, snow deposition and snow redistribution. Uniform altitudinal gradients can only represent a part of these influences but are without alternative for use in larger-scale models. How well altitudinal gradients represent the true snow distribution has not been assessed. We analyse altitudinal characteristics of snow stored in two high-alpine catchments in Switzerland. Peak winter snow depths were monitored using high-resolution airborne laser scanning technology. These snow depths were transferred to snow water equivalent by applying simple density estimations. From these data, altitudinal gradients were calculated for the total catchment areas and for selected subareas characterized by different accumulation patterns. These gradients were then compared with gradients resulting from automated snow depth measurements obtained from several snow stations on different height levels located in the catchments, and with estimations from climatological precipitation gradients. The analysis showed that neither precipitation gradients nor flat-field stations estimate catchment-wide snow amounts accurately. While the climatological gradient showed different trends for different areas and years, the snow stations tended to overestimate mean snow amounts.

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Conventional and UAV-Based Aerial Surveys for Long-Term Monitoring (1954–2020) of a Highly Active Rock Glacier in Austria

Frontiers in Remote Sensing ◽

10.3389/frsen.2021.732744 ◽

2021 ◽

Vol 2 ◽

Author(s):

Viktor Kaufmann ◽

Andreas Kellerer-Pirklbauer ◽

Gernot Seier

Keyword(s):

Laser Scanning ◽

Temperature Data ◽

General View ◽

Rock Glacier ◽

Aerial Surveys ◽

Multi Temporal ◽

Rock Glaciers ◽

Ice Content ◽

Creep Velocity

Rock glaciers are creep phenomena of mountain permafrost. Speed-up has been observed on several rock glaciers in recent years and attributed to climate change. Although rare, related long-term studies are nevertheless essential to bring a climate perspective to creep velocity changes. In the present study, we focused on changes both in the surface creep velocity and volume of the Leibnitzkopf rock glacier (Hohe Tauern Range, Austria) in the period 1954–2020. We applied 3D change detection using aerial images of both conventional (12 epochs between 1954 and 2018) and unmanned aerial vehicle (UAV)-based aerial surveys (2 epochs, 2019 and 2020), and combined this with ground and air temperature data. Photogrammetric processing (structure-from-motion, multi-view stereo) of the multi-temporal dataset resulted in high-resolution digital orthophotos/DOPs (5–50 cm spatial resolution) and digital elevation models/DEMs (10–50 cm grid spacing). Georeferencing was supported by five externally triangulated images from 2018, bi-temporal aerial triangulation of the image data relying on stable ground around the rock glacier, measured ground control points (2019 and 2020), and measured camera locations (PPK-GNSS) of the UAV flight in 2020. 2D displacement vectors based on the multi-temporal DOPs and/or DEMs were computed. Accuracy analyses were conducted based on geodetic measurements (2010–2020) and airborne laser scanning data (2009). Our analyses show high multi-annual and inter-annual creep velocity variabilities with maxima between 12 (1974–1981) and 576 cm/year (2019–2020), always detected in the same area of the rock glacier where surface disintegration was first observed in 2018. Our volume change analyses of the entire landform for the period 1954–2018 do not indicate any significant changes. This suggests little permafrost ice melt and/or general low ice content of the rock glacier. Analyses of the temperature data reveal a close relationship between higher temperatures and rock glacier acceleration despite the high probability of low ice content. This suggests that hydrogeological changes play an important role in the rock glacier system. The paper concludes with a summary of technical improvements and recommendations useful for rock glacier monitoring and a general view on the kinematic state of the Leibnitzkopf rock glacier.

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Estimated hydrologic characteristics of shallow aquifer systems in the Valley and Ridge, the Blue Ridge, and the Piedmont Physiographic Provinces based on analysis of streamflow recession and base flow

Professional Paper ◽

10.3133/pp1422b ◽

1996 ◽

pp. B1-B58 ◽

Cited By ~ 17

Author(s):

A.T. Rutledge ◽

T.O. Mesko

Keyword(s):

Base Flow ◽

Shallow Aquifer ◽

Blue Ridge ◽

Aquifer Systems

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Observations on a Debris-Covered Polar Glacier “Whisky Glacier”, James Ross Island, Antarctic Peninsula, Antarctica

Journal of Glaciology ◽

10.1017/s002214300000887x ◽

1987 ◽

Vol 33 (115) ◽

pp. 300-310 ◽

Cited By ~ 25

Author(s):

T.J.H. Chinn ◽

A. Dillon

Keyword(s):

Antarctic Peninsula ◽

Rock Glacier ◽

Freezing Front ◽

Extensive Area ◽

Free Zone ◽

Rock Glaciers ◽

James Ross Island ◽

Polythermal Glacier ◽

Powerful Mechanism

Abstract“Whisky Glacier” on James Ross Island, Antarctic Peninsula, comprises anévéand clean ice trunk surrounded by an extensive area of debris-covered ice resembling a rock glacier. The debris-free trunk of the glacier abuts abruptly against the broad, totally debris-covered tongue at a number of concentric zones where debris-laden beds crop out at the surface in a manner similar to the “inner moraine” formations of many polar glaciers.Ice structures and foliation suggest that “Whisky Glacier” is a polythermal glacier which is wet-based under the debris-free zone, and dry-based under the debris-covered zone. It is surmised that the glacier sole crosses the freezing front close to where the basal debris beds are upwarped towards the surface. Here, basal water is confined, and freezes to the under side of the glacier in thick beds of regelation ice which are uplifted to the surface along with the debris-laden beds. Ablation losses effectively cease beneath the blanket of debris covering the tongue.The transition from wet-based to dry-based conditions at the glacier sole is a powerful mechanism for entraining debris into a glacier and, in the case of “Whisky Glacier”, for lifting debris to the surface. It is suggested that this may be a mechanism for forming some polar rock glaciers.

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