UAV platforms are nowadays a valuable source of data for inspection, surveillance, mapping and 3D modeling issues. New applications in the short- and close-range domain are introduced, being the UAVs a low-cost alternatives to the classical manned a erial photogrammetry. Rotary or fixed wing UAVs, capable of performing the photogrammetric data acquisition with amateur or SLR digital cameras, can fly in manual, semi-automated and autonomous modes. With a typical photogrammetric pipeline, 3D results like DSM/DTM, contour lines, textured 3D models, vector data, etc. can be produced, in a reasonable automated way. The paper reports the latest developments of UAV image processing methods for photogrammetric applications, mapping and 3D modeling issues. Automation is nowadays necessary and feasible at the image orientation, DSM generation and orthophoto production stages, while accurate feature extraction is still an interactive procedure. New perspectives are also addressed.

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Uav photogrammetry for mapping and 3d modeling - current status and future perspectives -

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Permafrost and climate in Europe: Monitoring and modelling thermal, geomorphological and geotechnical responses

This review paper examines thermal conditions (active layer and permafrost), internal composition (rock and ice components), kinematics and rheology of creeping perennially frozen slopes in cold mountain areas. The aim is to assemble current information about creep in permafrost and rock glaciers from diverse published sources into a single paper that will be useful in studies of the flow and deformation of subsurface ice and their surface manifestations not only on Earth, but also on Mars. Emphasis is placed on quantitative information from drilling, borehole measurements, geophysical soundings, photogrammetry, laboratory experiments, etc. It is evident that quantitative holistic treatment of permafrost creep and rock glaciers requires consideration of: (a) rock weathering, snow avalanches and rockfall, with grain-size sorting on scree slopes; (b) freezing processes and ice formation in scree at sub-zero temperatures containing abundant fine material as well as coarse-grained blocks; (c) coupled thermohydro-mechanical aspects of creep and failure processes in frozen rock debris; (d) kinematics of non-isotropic, heterogeneous and layered, ice-rich permafrost on slopes with long transport paths for coarse surface material from the headwall to the front and, in some cases, subsequent re-incorporation into an advancing rock glacier causing corresponding age inversion at

Permafrost creep and rock glacier dynamics

https://www.uibk.ac.at/geographie/personal/kerschner/larstig-qsr.pdf

Latest Pleistocene and Holocene glacier variations in the European Alps

. The mountain cryosphere of mainland Europe is recognized to have important impacts on a range of environmental processes. In this paper, we provide an overview on the current knowledge on snow, glacier, and permafrost processes, as well as their past, current, and future evolution. We additionally provide an assessment of current cryosphere research in Europe and point to the different domains requiring further research. Emphasis is given to our understanding of climate–cryosphere interactions, cryosphere controls on physical and biological mountain systems, and related impacts. By the end of the century, Europe's mountain cryosphere will have changed to an extent that will impact the landscape, the hydrological regimes, the water resources, and the infrastructure. The impacts will not remain confined to the mountain area but also affect the downstream lowlands, entailing a wide range of socioeconomical consequences. European mountains will have a completely different visual appearance, in which low- and mid-range-altitude glaciers will have disappeared and even large valley glaciers will have experienced significant retreat and mass loss. Due to increased air temperatures and related shifts from solid to liquid precipitation, seasonal snow lines will be found at much higher altitudes, and the snow season will be much shorter than today. These changes in snow and ice melt will cause a shift in the timing of discharge maxima, as well as a transition of runoff regimes from glacial to nival and from nival to pluvial. This will entail significant impacts on the seasonality of high-altitude water availability, with consequences for water storage and management in reservoirs for drinking water, irrigation, and hydropower production. Whereas an upward shift of the tree line and expansion of vegetation can be expected into current periglacial areas, the disappearance of permafrost at lower altitudes and its warming at higher elevations will likely result in mass movements and process chains beyond historical experience. Future cryospheric research has the responsibility not only to foster awareness of these expected changes and to develop targeted strategies to precisely quantify their magnitude and rate of occurrence but also to help in the development of approaches to adapt to these changes and to mitigate their consequences. Major joint efforts are required in the domain of cryospheric monitoring, which will require coordination in terms of data availability and quality. In particular, we recognize the quantification of high-altitude precipitation as a key source of uncertainty in projections of future changes. Improvements in numerical modeling and a better understanding of process chains affecting high-altitude mass movements are the two further fields that – in our view – future cryospheric research should focus on.

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The European mountain cryosphere: a review of its current state, trends, and future challenges

This paper describes the three-dimensional reconstruction of the glaciation of two neighboring cirques from the Little Ice Age advance of 1850 up to the present (1997), and the visualization of its spatio-temporal changes during this time period by means of standard methods of cartography and modern computer animation. The glaciers (Goessnitzkees and Hornkees) are located in the Schober group (Hohe Tauern range, Central Alps, Austria). A total of 9 different glacial stages were reconstructed. Computer-based analysis of the given time series was performed using a special digital database for glacier studies. Various numerical and graphical results show the course of deglaciation. Since the glaciers are largely covered by debris, a digital-photogrammetric procedure based on the Least Squares Matching (LSM) algorithm was developed in order to automate the generation of digital terrain models and the computation of three- dimensional flow vectors from the multi-year aerial photographs. This procedure facilitates the combination of aerial photographs of any scale and geometry. Practical results prove the applicability of this method in glacier mapping. The computer animation ("glacier movie") of the glacier retreat has been implemented in the PC-based information system of the Austrian Hohe Tauern National Park for public access.

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Mapping and visualization of the retreat of two cirque glaciers in the austrian hohe tauern national park

Gössnitzkees and Hornkees are two small cirque glaciers (2006: 58.9 and 30.6 ha, respectively) located in the Schober group of the Hohe Tauern range of the Eastern Alps in Austria. Th e glacier history of both glaciers has already been documented for the time period 1850-1997 based on fi eld evidence, historical maps and aerial photographs. Th e temporal change in area, surface height, and volume of both glaciers was presented numerically and graphically. In this paper we intend to extend the observation period to the present. Aerial photographs of 2002 and 2006 covering the area of interest were made available by the Tyrolean regional government and the Austrian Federal Offi ce of Metrology and Surveying, Vienna. A digital photogrammetric workfl ow was applied to the image data provided. Based on these multi-temporal data we computed the volumetric and areal change of both glaciers along with the respective numerical values at elevational intervals of 50 m. Th e change in surface height and area of both glaciers is shown in thematic maps. Th e results include a new orthophoto map at 1:10,000 scale representing the glacial stage of 2006 and an estimation of the equilibrium line altitude.

Documentation of the retreat of Gössnitzkees and Hornkees Glaciers (Hohe Tauern Range, Austrian Alps) for the Time Period 1997-2006 by Means of Aerial Photogrammetry

The surface topography of mountainous areas is often subject to continuous spatio-temporal changes due to gravitational and climatic forces. In this paper we focus on periglacial phenomena, e.g., permafrost creep and other gravitational mass movements (solifluction, etc.) Various in-situ and other non-contact (remote sensing) measurement techniques can be applied in order to derive metric information of surface deformation and flow velocity. In the present work we have investigated the potential of ground-based (terrestrial) photogrammetry for monitoring mountain slopes of local extent (typically 102 103 m) using a low-cost digital camera and applying a digital photogrammetric workflow. A case study has been carried out in the Ötztal Alps, Austria. We selected the Outer Hochebenkar rock glacier since it has been subject to intensive research for many decades. Ground-based photogrammetry is feasible, because photogrammetric baselines can be easily established on the opposite slope, thus allowing multiple stereoscopic coverage of the area of interest. The main task of the case study was to derive 3D displacement vectors of the surface. The paper describes the various pre-processing steps involved, i.e. camera calibration, scanning of the analog photographs and digital resampling for obtaining geometrically refined images. Control points needed for exterior orientation were taken from existing aerial photographs. The measurement of dense fields of displacement vectors is carried out using the inhouse developed ADVM (Automatic Displacement Vector Measurement) software, which was originally developed for the monitoring of rock glaciers using aerial photographs. The results of comparative analysis are presented numerically and graphically. The paper finally summarizes the main findings and specifically addresses the pros and cons of applying low-cost digital consumer cameras in ground-based monitoring tasks in mountainous areas.

Change detection of a mountain slope by means of ground-based photogrammetry: A case study in the Austrian Alps

Documentation of the retreat of a small debris-covered cirque glacier Goessnitzkees, Austrian Alps by means of terrestrial photogrammetry

. Gossnitzkees is a small heavily debris-covered cirque glacier (49.8 ha) located in the Schober Mountains, Hohe Tauern Range, Austrian Alps. Glacier nourishment is mainly due to avalanches descending from its surrounding headwalls. Gossnitzkees is the largest glacier in the Schober Mountains and is highly representative of the other 25 glaciers of this mountain group. All glaciers of this mountain group have receded continuously since 1850. Ongoing atmospheric warming sustains excessive glacier melt. In 1988 a long-term monitoring program was started at Gossnitzkees using terrestrial photogrammetry in order to document and quantify glacier change. The surveys have been repeated from time to time using different types of cameras. Recent surveys date from 2009, 2012, and 2015. The aim of this paper is twofold: firstly, to investigate whether or not the rather complex photogrammetric evaluation process using a conventional photogrammetric workstation (mostly with a limited degree of automation for terrestrial applications) can be replaced by modern fully automated Structure-from-Motion (SfM) based approaches, and secondly, to document and quantify the glacier change at Gossnitzkees based on available information augmented by results obtained from the most recent surveys mentioned. Over the last 27 years (1988-2015) the terminus of Gossnitzkees has receded by 179 m and the glacier ice has melted at a mean annual rate of about 1.5 m/year. The Schober Mountains are in the process of deglaciation and the glaciers will likely disappear within the next two decades. Based on our practical investigations we found out that SfM-based software is in general capable of handling terrestrial photographs in a fully automatic mode supporting challenging glacier studies.

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Viktor Kaufmann

Papers

Mapping and visualization of the retreat of two cirque glaciers in the austrian hohe tauern national park

Documentation of the retreat of Gössnitzkees and Hornkees Glaciers (Hohe Tauern Range, Austrian Alps) for the Time Period 1997-2006 by Means of Aerial Photogrammetry

Change detection of a mountain slope by means of ground-based photogrammetry: A case study in the Austrian Alps

Documentation of the retreat of a small debris-covered cirque glacier Goessnitzkees, Austrian Alps by means of terrestrial photogrammetry

Long-term monitoring of glacier change at gössnitzkees (austria) using terrestrial photogrammetry