Viktor Kaufmann

Estimation of rock glacier surface deformation using SAR interferometry data

The detection and quantification of surface deformation of an active rock glacier using the differential synthetic aperture radar (SAR) interferometry (D-InSAR) technique is presented. An average deformation rate of -6 mm/35 days in the radar line of ight was estimated for the summer of 1992. The maximum deformation rate, -18 mm/35 days, was identified at the upper part of the rock glacier, whereas the deformation rate at the snout of the rock glacier was about -10 mm/35 days. The spatial distribution of the surface deformation in the D-InSAR displacement map is smooth and supports the idea that ice is the stress-transferring medium in rock glaciers.

Recent and Holocene dynamics of a rock glacier system: The example of Langtalkar (Central Alps, Austria)

The Hinteres Langtalkar rock glacier (Gössnitztal, Hohe Tauern, Austria) has been part of a complex transportation system of debris and ice since the beginning of the Holocene and shows the highest creep rates of all rock glaciers measured in the Hohe Tauern Range. Results of movement analysis show that the entire rock glacier behaves very differently at different zones and that sudden temporal and spatial changes of velocity rates are a typical feature. Zones with high rates occur close to rather inactive zones and zones with low rates have rapidly accelerated within recent years. The increase in movement rates over time is probably caused by topography. These studies – especially the measurement of surface velocities and elevational changes – allow a differentiation of the rock glacier and a first attempt of a morphogenetic interpretation. In this context, it is important that the innermost part of the cirque was covered by a small cirque glacier during the Little Ice Age advance. This cirque glacier created a moraine complex which contributes to the material supply of the rock glacier. A first estimation of transportation rates is possible with the help of the measurement results available, leading to an estimation of a probable age of at least 4000 years.

Estimation of alpine permafrost surface deformation using InSAR data

The detection of an active rock glacier and the quantification of the observed surface movement as well as its temporal change using the D-InSAR method are presented. An average deformation rate of -7.7 mm/35 days in the radar line-of-sight, in the summer of 1992, was estimated. Whereas, the corresponding geodetic measurement, vertical component of 3D flow velocity, was about -8.0 mm/35 days. Additionally, the spatial distribution of the rock glacier surface deformation derived from the D-InSAR data matches the photogrammetric and geodetic generated results to a very high degree.

Velocity Changes of Rock Glaciers and Induced Hazards

Recent observations and geodetic measurements in the European Alps show that changes are occurring on rock glacier dynamics, ranging from moderate velocity variations to strong acceleration or even total collapse. These changes can be related to the ground temperature and to climate warming. In most cases, rock glaciers do not represent any serious hazard, except the instability of their surface and local rockfalls at the steep front. The surface movements, though moderate, can nevertheless cause damages to sensible infrastructures like cableways or buildings, if these are not designed to adapt to surface movements. The strong accelerations observed on some rock glaciers, however, induce a change of magnitude, and may threaten in some cases downslope areas. Thus, the presence of active or inactive rock glaciers with high ice content must be considered not only with regard to present conditions and dynamics, but with respect to possible evolutions due to climate change.

UAS-Based Change Detection of the Glacial and Proglacial Transition Zone at Pasterze Glacier, Austria

Glacier-related applications of unmanned aircraft systems (UAS) in high mountain regions with steep topography are relatively rare. This study makes a contribution to the lack of UAS applications in studying alpine glaciers in the European Alps. We transferred an established workflow of UAS-based change detection procedures to Austria’s largest glacier, the Pasterze Glacier. We focused on a selected part of the glacier tongue and its proglacial vicinity to obtain detailed knowledge of (i) the behavior of a lateral crevasse field, (ii) the evolution of glacier surface structures and velocity fields, (iii) glacier ablation behavior and the current glacier margin, and (iv) proglacial dead ice conditions and dead ice ablation. Based on two UAS flight campaigns, accomplished in 2016 (51 days apart), we produced digital elevation models (DEMs) and orthophotos with a ground sampling distance (GSD) of 0.15 m using Structure-from-Motion (SfM) photogrammetry. Electrical resistivity tomography (ERT) profiling was additionally conducted in the proglacial area. Results indicate distinct changes in the crevasse field with massive ice collapses, rapid glacier recession, surface lowering (mean of −0.9 m), and ice disintegration at the margins, calculated degree day factors on the order of −7 to −11 mm d−1·°C−1 for clean ice parts, and minimal changes of the debris-covered dead ice in the proglacial area. With this contribution we highlight the benefit of UAS in comparison to commonly used terrestrial methods and satellite-related approaches.

Glaciological Studies at Pasterze Glacier (Austria) Based on Aerial Photographs

This chapter describes and analyses glacier recession observed at Pasterze Glacier, Hohe Tauern Range, Austria, for the time period 2003–2009. Pasterze Glacier is the largest glacier of the entire Eastern Alps, and it is highly indicative of ongoing glacier melt in the Alps. We evaluated three glacier stages (2003, 2006 and 2009) and the glaciological changes between them. The quantitative analysis is based on aerial surveys carried out during the summer of these years. The photogrammetric workflow provided high resolution datasets, such as digital elevation models and orthophotos of each stage. We evaluated the extent, surface elevation, flow velocity field, supraglacial debris cover, and geomorphological changes at the glacier surface and the adjacent paraglacial environment. The main numerical results can be summarized as follows: the glacier covered 17.3 ± 0.1 km2 in 2009, the mean surface elevation change was −1.31 ± 0.07 m a−1 for the period 2003–2009, the glacier surface flow velocity in two test areas at the glacier tongue decelerated from 2003–2006 to 2006–2009 (−4 % and −31 %), and the debris cover of the glacier tongue increased from 63 % (2003) to 72 % (2009). We conclude that Pasterze Glacier is far from equilibrium and that its glacier tongue will turn into a large dead ice body in the near future.

Deglaciation and its impact on permafrost and rock glacier evolution: New insight from two adjacent cirques in Austria

Glaciers and permafrost are strongly linked to each other in mid-latitude mountain regions particularly with polythermal glaciers. This linkage is not only climatically defined but also in terms of geomorphic and glaciological processes. We studied two adjacent cirques located in the Central Austria. We focussed on the deglaciation since the Little Ice Age (LIA) maximum (c.1850CE) and its relevance for permafrost and rock glacier evolution since then. One cirque is occupied by a glacier remnant whereas the second one is occupied by an active rock glacier which was partly overridden by a glacier during the LIA. We applied a multidisciplinary approach using field-based techniques including geoelectrics, geodetic measurements, and automatic monitoring as well as historic maps and photographs, remote sensing, and digital terrain analysis. Results indicate almost complete deglaciation by the end of the last millennium. Small-scale tongue-shaped landforms of complex origin formed during the last decades at finer-grained slope deposits below the cirque headwalls. Field evidences and geophysics results proved the existence of widespread sedimentary ice beneath a thin veneer of debris at these slopes. The variable thickness of the debris layer has a major impact on differential ablation and landform evolution in both cirques. The comparison of digital elevation models revealed clear mass losses at both cirques with low rates between 1954 and 2002 and significantly higher rates since then. The central and lower part of the rock glacier moves fast transporting sediments and ice downvalley. In contrast, the upper part of the rock glacier is characterised by low debris and ice input rates. Both effects cause a significant decoupling of the main rock glacier body from its nourishment area leading eventually to rock glacier starvation. This study demonstrates the importance of a decadal-scale and multidisciplinary research approach in determining the development of alpine landforms over both space and time.

Topographic mapping of the volcano Nevado Ojos del Salado using optical and microwave image data

Abstract The area of interest is located at the border between Chile and Argentina at 27°10’ S. latitude and 68°30’ W. longitude in the High Cordillera of the Andes and includes the second‐highest mountain of America, the Nevado Ojos del Salado. Although the official Chilean altitude is given as 6,880 m, other figures can be found in the literature and various other maps. Situated in a picturesque volcanic terrain rising above the Puna de Atacama, Nevado Ojos del Salado is not only interesting from a geomorphological point of view, it is, e.g., the worlds highest volcano, but also has recently become a much‐favored destination of the mountaineering world. Unfortunately, this area is not covered by reliable and publicly available maps at scales larger than 1:250,000. Therefore, this paper describes the methods employed in and results obtained from topographic mapping of this remote area using spaceborne as well as airborne remotely sensed data. Exploiting Space Shuttle Earth‐viewing photographs, ERS‐1 Syn...

Documentation of the Glacier Retreat in the Eastern Part of the Granatspitz Mountains (Austrian Alps) Using Aerial Photographs for the Time Period 2003-2009

Abstract This paper documents ongoing glacier retreat in the eastern part of the Granatspitz Mountains (Hohe Tauern Range, Austrian Alps) for the time period 2003–2009 using aerial photogrammetry. Aerial photographs of 2003, 2006, and 2009 were made available by the Hydrological Service of the Regional Government of Salzburg, the Federal Office of Metrology, Surveying and Mapping, Vienna, and the Regional Government of the Tyrol, respectively. High resolution multi-temporal digital elevation models and digital orthophotos of the area of interest were derived using digital photogrammetric methods to provide a sound basis for glaciological research. Glacier outlines of the three glacial stages were mapped interactively. Temporal change in area and surface height of the glaciers mapped clearly document glacier retreat. Glacier mass balance based on the geodetic method was calculated for Stubacher Sonnblickkees (Glacier). Mean annual specific net balance amounts to −656 mm w.e. for the time period 2003–2009, with a mass balance gradient of 324 mm w.e. (100 m)−1 and an equilibrium-line altitude of 2995 m a.s.l. Digital orthophoto maps and other thematic maps, e.g. showing surface height change, were prepared to support further data interpretation. Both the study area and its spatio-temporal change were visualized with special emphasis on the glaciers in a computer generated video film. Another film (exposure 29 August 2011) shows the lower part of Stubacher Sonnblickkees and its surroundings for reasons of comparison.

Photogrammetric Tools For Panoramic Sector Scan Imagery In The VIDARS Analysis Station

Computer-assisted photo-interpretation is a recent development supported by the advent of numerous interpretation stations. A unique universal station is VIDARS--manufactured by the Richards Corporation of McLean, Virginia--since it has recently been equipped with a new software system that incorporates complex photogrammetric mensuration capabilities. Photo-interpreters typically find it difficult to perform mensuration tasks; therefore the implementation of the photogrammetric functions must not burden the user with a need to understand photogrammetric theories. This paper illustrates a difficult application of VIDARS to sector-scan panoramic film (Long Range Aerial Panoramic--LORAP) imagery and will show how well the user can perform target positioning tasks within his interpretation work.