Showing papers by "Viktor Kaufmann published in 2007"

10 years of monitoring of the Doesen rock glacier (Ankogel group, Austria) - A review of the research activities for the time period 1995 - 2005

Abstract: Doesen rock glacier (46°59' N, 13°17' E, altitude range 2339-2650 m) is located in the Ankogel group of the Hohe Tauern range in Austria. The first permafrost related studies including geomorphological mapping and geophysical investigations were carried out in the early 1990s by the Institute of Geography and Regional Science of the University of Graz. In 1995, the Institute of Remote Sensing and Photogrammetry and the Institute of Navigation and Satellite Geodesy (both Graz University of Technology) commenced geodetic, photogrammetric and cartographic work in order to obtain information on the kinematic state of the rock glacier and to create more accurate maps of the area of interest. Furthermore, satellite-based differential SAR interferometry was applied to obtain additional geomorphometric information. In this paper we want to (1) give a short summary of the work carried out in the last 10 years, based mainly on literature references, and will (2) present an analysis of the photogrammetric and geodetic measurements carried out at Doesen rock glacier using tables, graphs and thematic maps. The geodetic analysis will include 34 object points and additional points of 4 profile lines of the rock glacier. These points were measured every year in August during the last 10 years, with one interruption in 2003. INTRODUCTION Doesen rock glacier (46°59'12" N, 13°17'08" E) is located in the Ankogel group of the Hohe Tauern range, Austria. It is situated at the end of the glacially shaped, W-E oriented inner Doesen valley (cp. Figures 1-3). Rock glaciers are creep phenomena of mountain permafrost and are composed of rocks and interstitial ice. Active rock glaciers creep downslope by force of gravity due to internal deformation of the ice. Sliding may also be possible at certain shear horizons. Due to the above mentioned dynamics, the surfaces of rock glaciers often show characteristic flow features, such as furrows and ridges, reminiscent of lava flows (see also Barsch, 1996). Doesen rock glacier ranges from 2339 m to 2900 m ASL. The latter value is taken from Doesener Spitz, which is the highest point of the surrounding mountains in the S, SE and E of the rock glacier from where the rock glacier is nourished by weathered material, which is of crystalline type, predominantly granitic gneiss (cp. Figure 2). The frontal slope of the rock glacier is approx. 35-40° steep. The length of the whole permafrost body is about 1000 m, the width varies between 150 and 300 m. In 1993 Gerhard K. Lieb from the Institute of Geography and Regional Science of the University of Graz started a research initiative on mountain permafrost in Austria with a special geographical focus on the Eastern Austrian Alps. He compiled an inventory of some 1450 rock glaciers of the area of interest by means of geomorphological mapping. For more details see Lieb (1996) and Lieb (1998). Lieb selected the inner Doesen valley as a study area for closer in-situ investigations on the distribution of mountain permafrost and on rock glaciers. It should be mentioned that Doesen rock glacier is one of the largest active rock glaciers of his inventory. Multi-disciplinary research work funded by the Austrian Science Fund (FWF) comprised not only GIS-based analysis of various field measurements, special geophysical soundings, and cartographic tasks but also geodetic and photogrammetric activities. A detailed description of the results obtained is given in a monograph published by Lieb (see e.g. Lieb, 1996; Schmöller and Fruhwirth, 1996; Kaufmann, 1996). KAUFMANN et al.: 10 YEARS OF MONITORING OF THE DOESEN ROCK GLACIER (ANKOGEL GROUP, AUSTRIA) ... Lieb estimated the mean thickness of the Doesen rock glacier at 30-40 m based on geophysical soundings. He also calculated the total volume of the rock glacier to be approx. 15×10 m. The ice volume is estimated at 6×10 m. A "rock glacier educational trail" has been installed in the Doesen valley in a follow-on project funded by the Hohe Tauern National Park. People who are interested can walk this trail, which ends near the snout of Doesen rock glacier. A folder gives detailed information on the various aspects of landscape development along the trail, permafrost related subjects, and also rock glaciers (Nutz, 2005). In this paper we intend (1) to summarize all mapping and geomorphometric projects (initial work and follow-on projects) carried out on Doesen rock glacier and (2) to present some new geodetic and photogrammetric results obtained from recent investigations. The authors concentrated on setting up a long-term (geomorphometric) monitoring program using various observation techniques for obtaining precise and reliable information on the spatio-temporal evaluation of the surface of Doesen rock glacier. All work described in the following pages was carried out under the leadership of the Institute of Remote Sensing and Photogrammetry of the Graz University of Technology (TU Graz) in cooperation with the Institute of Navigation and Satellite Geodesy of TU Graz and the Institute of Digital Image Processing of Joanneum Research, Graz. Chapter 2 presents the photogrammetric work, while the geodetic surveys are described in chapter 3. The application of radar interferometry and the cartographic work are briefly outlined in chapters 4 and 5, respectively. Chapters 6 to 8 cover the analysis of the photogrammetric and geodetic results with concluding remarks. PHOTOGRAMMETRIC SURVEYS 1954-1998 Aerial photogrammetry is one of the most powerful techniques for obtaining area-wide three-dimensional (3D) information of high mountain environments. Modern digital photogrammetric techniques and, especially, the digital photogrammetric workstation (DPW) have led to the so-called "democratization" of photogrammetry, which made this technology available to a broader user community. Geographical information systems (GIS) now enable not only indirect but also direct input of data using stereo viewing functionality. The application of photogrammetry to rock glacier monitoring is very much advanced and well documented in literature (cp. Kääb, 2005; Kaufmann and Ladstädter, 2004). Aerial photographs of several data takes (1954-1998) covering the study area were acquired from the Austrian Federal Office of Metrology and Surveying, Vienna (see Table 1). Table 1. Aerial photographs used in the study. date photos image scale focal length flying height type of film 1954 3 1 : 16,300 210 mm 5930 m black-and-white 1969 2 1 : 29,700 153 mm 7040 m black-and-white 17.9.1975 5 1 : 19,800 153 mm 5520 m black-and-white 15.8.1983 5 1 : 46,400 153 mm 9580 m black-and-white 15.8.1993 5 1 : 11,300 215 mm 4930 m color infrared 1.9.1997 2 1 : 14,000 152 mm 4640 m black-and-white 10.9.1998 2 1 : 33,400 153 mm 7600 m black-and-white date of acquisition unknown acquisition between 29.9. and 12.10. data acquisition by Bildflug Fischer, Graz, Austria KAUFMANN et al.: 10 YEARS OF MONITORING OF THE DOESEN ROCK GLACIER (ANKOGEL GROUP, AUSTRIA) ... Figure 1. Location of Doesen rock glacier in the Ankogel group, Hohe Tauern range, Austria. Large parts of the Ankogel group are within the Hohe Tauern National Park ( ). The Russian KFA-1000 space photograph (spectrozonal film emulsion) on the right hand side shows the same area indicating relief and landcover. The photograph (no. 21528, original scale 1:410,000) was taken from the MIR space station on 25 September 1991 during the Austrian-Russian AUSTROMIR project. The photograph shown is not an exact orthoimage. The study area is indicated by a box. A closeup of this area is shown in Figure 2. (The KFA-1000 photograph was provided by R. Kalliany, Graz.) The photogrammetric evaluation of the aerial photographs 1954-1993 is described in Kaufmann (1996, 1997, and 1998). The task was to derive high resolution digital terrain models (DTMs) with a grid spacing of 2.5 m for a selected area partly covering the Doesen rock glacier (see Figure 2, white box) for 1954, 1975, 1993, and 1997, and for the whole study area (as shown in Figure 2) using the aerial photographs of 1975. 3D feature collection was performed using an analytical stereoplotter DSR-1 of Kern. At this stage of photogrammetric work, photographs were scanned in parts – disk space was still a limiting factor at that time – using a VX3000 scanner of Vexcel Imaging Austria, and orthophotos were produced using the in-house developed software GAMSAD (Kaufmann, 1984). In order to derive a dense field of 3D deformation vectors some 600 distinct corner points of rocks/boulders on the rock glacier surface were traced in the multi-temporal stereomodels of 1954-1997 and measured with care. High quality measurements were achieved (cp. Figure 4), although work was quite troublesome and tedious, since the more convenient technique of simultaneous multi-temporal point transfer (cp. Kääb, 1996) was not available at that time. The identification of multi-temporal homologous points was facilitated by prediction based on previous measurements. From the experience gained in previous work, a much more efficient solution for measuring 3D displacement vectors based on digital photogrammetric techniques was proposed by Kaufmann (1996). The idea was to apply high accuracy image matching algorithms, e.g. least squares matching, to multi-temporal "pseudo-orthophotos", which are prerectified aerial photographs. This concept has several advantages as described in Kaufmann and Ladstädter (2004). KAUFMANN et al.: 10 YEARS OF MONITORING OF THE DOESEN ROCK GLACIER (ANKOGEL GROUP, AUSTRIA) ...

Paraglacial Talus Slope Instability in Recently Deglaciated Cirques (Schober Group, Austria)

Abstract: This paper presents observations on the paraglacial landscape adjustment in two recently deglaciated and neighbouring cirques (Kogele cirque/Kc and Hinteres Langtal cirque/HLc) in the Schober Group, Hohe Tauern Range, Central Austrian Alps (46°59’N, 12°47’E). During the Little Ice Age advance in the mid 19th century, both studied cirques have been covered by small glaciers and large perennial snow fi elds. Since then, these cryospheric landscape elements gradually disappeared almost completely at the surface leaving large talus slopes at the base of the headwalls behind. The evolution of surfaces covered by glaciers and perennial snow has been reconstructed for the years 1834, c.1850, 1872/73, 1928/29, 1969, 1982, 1997, and 1998 by using geomorphological evidences (terminal and lateral moraines), historical maps, and aerial photographs. Today, only few small patches of superfi cial glacier ice and perennial snow are found in radiation-sheltered locations. At both cirques, a number of vegetation-free small-scale and tongue-shaped landforms (STL) have evolved from these slope sediments during the last decades (Kc n=9, HLc n=13). Thus, all STLs are very young geomorphic features caused by paraglacial slope adjustment processes. Spatial distribution, geometry and possible genesis of the features in relation to the deglaciation history are discussed. It is suggested that the coverage of glacier ice by debris could possibly be a crucial process for the ice nourishment of the rock glacier Hinteres Langtalkar.

Photogrammetrische und geodätische Dokumentation der Hangrutschung Blaubachgraben (Gemeinde Krimml, Salzburg) für den Zeitraum 1953 - 2006.

Abstract: Dieser Beitrag beschreibt die photogrammetrischen und geodätischen Arbeiten zur Erfassung der Kinematik der Hangrutschung im Blaubachgraben (Gemeinde Krimml, Salzburg, Österreich) für den Zeitraum 1953 bis 2006. Das dargestellte Methodenspektrum zielt darauf ab, einerseits mit Luftbildzeitreihen das zeitlich zurückliegende Bewegungsverhalten des Rutschhanges flächendeckend und andererseits die aktuelle Bewegung durch geodätische Einzelpunktmessung zu erfassen.