Zum Sedimenthaushalt des Sanders im Gletschervorfeld der Pasterze

Die vorliegende Diplomarbeit beschäftigt sich mit der sedimenthaushaltlichen Darstellung des geomorphologischen Materialtransfers im Einzugsgebiet eines proglazialen Sanders. Bestandteile eines Sedimentbudgets sind die Identifiziertung der Sedimentquellen, der Sedimentspeicher und der am Materialtransfer beteiligten Prozesse und ihrer Hauptverlagerngspfade, sowie die Quantifizierung der Prozessraten und der Sedimentein- und austräge. In der gegenständlichen Untersuchung wurde die Materialverlagerung ausgewählter Prozesse quantifiziert, um die erforderlichen Aufwände zu beschränken. Ziel ist die Erstellung eines Sedimenthaushalts der maßgeblich am Materialtransfer beteiligten Prozesse und die Abschätzung der Zusammensetzung des Sedimentspeichers Sander. Das Untersuchungsgebiet liegt unmittelbar südlich des Alpenhauptkammes, im Kärntner Teil der Hohen Tauern und ist Teil des Nationalparks Hohe Tauern. Das Kernstück bildet der „Sandersee“, eine glazifluviale Schwemmfläche, die zum Gletschervorfeld der Pasterze gehört. Die Morphologie des Untersuchungsgebietes zeichnet sich durch große Höhenunterschiede, steile Hänge und glaziale Prägung aus. Der Sander entstand vor mehr als 50 Jahren, als die abschmelzende Gletscherzunge der Pasterze ein Sedimentationsbecken freilegte. Die Geländearbeiten im Einzugsgebiet des Sanders wurden im Sommerhalbjahr 2006 durchgeführt. Es wurde eine geomorphologische Karte erstellt, um die räumliche Lage und Verteilung der im Untersuchungsgebiet vorkommenden Formen und Prozesse zu erheben. Diese Informationen stellen eine wichtige Grundlage für die Quantifizierung des Materialtransfers dar. An insgesamt 6 mehrtägigen Feldaufenthalten fanden gravimetrische Messungen des Abflusses, der Schwebstoffkonzentration und der Lösungskonzentration, sowie des Materialtransfers durch Lawinen statt. Das Volumen von Mur- und Felssturzablagerungen und von Solifluktionsloben wurde ebenfalls abgeschätzt. Neben den im Feld erhobenen Daten fließen außerdem Informationen aus früheren Untersuchungen des Sanders in die vorliegende Arbeit ein. Die Ergebnisse liegen in Form der prozessspezifischen Einzelmessungen, des Sedimenthaushaltes der Ablationsperiode 2006 und einer Abschätzung der Zusammensetzung des Sedimentspeichers Sander vor. Den Neben den im Rahmen dieser Diplomarbeit erhobenen Daten fließen außerdem Informationen aus früheren Untersuchungen des Sanders mit in die ein. Den bedeutendsten Verlagerungspfad für glazifluviale Sedimente im Untersuchungsgebiet stellt das Hauptgerinne, welches den Sander von NW nach SO durchfließt, dar. Die zahlreichen kleinen Seitenbäche sind von untergeordneter Bedeutung. Insgesamt wurden auf diesen Pfaden während der Ablationsperiode 2006 50.000t Schwebstoffe und 2.500t gelöste Stoffe in den Sander ein- und ohne dauerhafte Ablagerung wieder ausgetragen. Die Geschiebefracht wird nach wie vor zur Gänze im Sanderbecken akkumuliert, sie konnte jedoch nicht gemessen werden. Laut Angaben aus der Literatur werden jährlich ca. 15.000t Geschiebe am Sander abgelagert. Der Materialeintrag in den Sander durch Lawinen betrug in der Ablationsperiode 2006 ca. 20t. Während des Untersuchungszeitraumes kam es zu keinem Eintrag von Murmaterial in den Sander. Auf Basis der Ablagerungen aus den letzten 15 Jahren konnte jedoch eine durchschnittliche Materialeintragsrate von ca. 580t/a errechnet werden. Die Ablagerungen aus Muren und Lawinen unterliegen, wie alle grobklastischen Sedimente, am Sander keiner weiteren Umverlagerung mehr. Der Sander stellt daher ein teilweise geschlossenes System dar. Durch Solifluktion werden im Untersuchungsgebiet jährlich 16.600t, durch Sturzprozesse 960t bewegt. Dieses Material gelangt jeodch nicht direkt in den Sander. Die Abschätzung der Materialverlagerung durch Sturzprozesse fand über die Ausweisung ablöserelevanter Flächen und Hangrückverwitterungsraten aus der Literatur statt. Das Sedimentvolumen im Sanderbecken kann mit ca. 1.500.000m3 angenommen werden. Grundlage dieser Schätzung stellt eine 2006 am Sander durchgeführte geophysikalische Erkundung des Untergrunds dar. Der Großteil dieses Raumes, etwa 63%, wird von glazifluvialen Ablagerungen eingenommen. 38% entfallen auf glaziale Ablagerungen, ca. 1% auf Mursedimente. Der Anteil des durch Lawinen eingetragenen Lithosphärenmaterials ist mit ca. 0.02% verschwindend gering. Aufgrund der fraglichen Repräsentativität der erhobenen Daten für den durchschnittlichen Sedimenteintrag seit Entstehung des Sanders sind die Angaben zur Zusammensetzung der Sedimente im Sanderbecken als spekulativ zu betrachten. Die größte Fehlerquelle stellt für die im Rahmen der Diplomarbeit durchgeführten Untersuchungen der kurze Messzeitraum und die dadurch geringe Repräsentativität der Daten dar. Um in zukünftigen Projekten genauere Daten zum Sedimenthaushalt des Sanders zu erhalten, ist ein Zeitrahmen von mehreren Jahren erforderlich.In this study the sedimentbudget of a proglacial sandur is analyzed. Main topic of a sediment-budget-investigation is to identify sediment sources, storage types and geomorphic coupling and to quantify sediment transfer rates. Due to limited temporal resources, aim of this study is the quantification of the major mass wasting processes and the assessment of the components of the sediments stored in the sandur. The study site is located in Carinthia, Austria and is part of the Hohe Tauern National Park. Center of interest is the proglacial sandur, located in the forefield of the Pasterze glacier. The region is characterised by alpine topography - high mountains, deeply incised valleys and steep slopes affected by glaciation. The sandur developed about 50 years ago, when the Pasterze glacier exposed a flat basin on the valley floor. Field studies took place during the ablation period of 2006 from Mai until October. A geomorphic map was derived, to visualize the disposition of geomorphic processes and landforms and the major paths of sediment transfer. Within six field trips - everyone lasting a few days, gravimetric and volumetric field measuremnts of water discharge, solute und suspended load and geomorphic activity of avalanches were carried out. Additionally the volume of debris cones and solifluction lobes was assessed. The results are presented as the specific measurements for every process, as the sediment budget of the ablation period of 2006 and as the assessment of the percental participation of the sediment types stored in the sandur. Data of previous studies of the sandur were used to complete the results of the field measurements. The main transfer path for glaciofluvial sediments is the meltwater stream from the Pasterze glacier, finding its way through the sandur from the northwest to the southeast. The tributaries play a minor role. During the ablation period of 2006 50.000t of suspended load and 2.500t of solutes were transported through the sandur. No long term storage occured in this period of time. Bedload tranport could not be measured, but an storage amount of 15.000t/a was derived for the sandur from literature about former investigations at the Pasterze glacier. Avalanches in spring 2006 delivered about 20t of mostly blocky sediments to the sandur. No debris flow activity could be observed in 2006 but based on the debris cones situated on the surface of the sandur an average accumulation rate of about 580t/a could be derived. The material accumulated by avalanches and debris flows is, as any clastic sediments on the sandur, not subject to further mobilization and therefore the system appears to be partially closed. On the slopes of the drainage basin about 16.600t/a of sediments are mobilized by solifluction and about 960t/a by rockfall. Those masses do not reach the sandur directly. They are stored on the slopes and can be remobilized mainly by debris flows and avalanches. The amount of mass wasting by rockfall was derived from an assessment of proper release areas in combination with rockwall retreat rates from literature. In the sandur basin about 1.500.000m3 of sediments are stored. This assessment is based on some geophysical soundings carried out in 2006. The main part of this volume, about 63%, is allocated by glaciofluvial deposits. 38% belong to moraines and about 1% is material accumulated by debris flows. Only 0.02% of the sediment stored in the entire sandur basin comes from avalanches. A main problem regarding the results of this study is the very short time span of only one summer available for field measurements. Taking this into account, the derived data may not be represantative for the long term average mass transfer and sediment yield in the drainage basin of the sandur. To gain more accurate informations in the future, an investigation time of at least several years seems to be necessary

Effektivität eines gesundheitsorientierten Krafttrainings bei Rückenbeschwerden unter spezieller Betrachtung der Rumpfbeuge- und Rumpfstreckmuskulatur

Ziel der Arbeit war es, die Wirkungen eines medizinischen Krafttrainingsprogramms sowohl auf die Rumpfbeugemuskulatur und Rumpfstreckmuskulatur als auch auf das subjekitve Schmerzempfinden zu überprüfen. Dafür wurde vor Beginn und nach Beendigung des Trainingsprogramms ein Maximalkrafttest und eine Schmerzbefrgaung durchgeführt. Die Ausertung erfolgte im Statisticprogramm Statistica 6.0

Deriving 3d point clouds from terrestrial photographs comparison of different sensors and software

Terrestrial photogrammetry nowadays offers a reasonably cheap, intuitive and effective approach to 3D-modelling. However, the important choice, which sensor and which software to use is not straight forward and needs consideration as the choice will have effects on the resulting 3D point cloud and its derivatives. <br><br> We compare five different sensors as well as four different state-of-the-art software packages for a single application, the modelling of a vegetated rock face. The five sensors represent different resolutions, sensor sizes and price segments of the cameras. The software packages used are: (1) Agisoft PhotoScan Pro (1.16), (2) Pix4D (2.0.89), (3) a combination of Visual SFM (V0.5.22) and SURE (1.2.0.286), and (4) MicMac (1.0). We took photos of a vegetated rock face from identical positions with all sensors. Then we compared the results of the different software packages regarding the ease of the workflow, visual appeal, similarity and quality of the point cloud. <br><br> While PhotoScan and Pix4D offer the user-friendliest workflows, they are also “black-box” programmes giving only little insight into their processing. Unsatisfying results may only be changed by modifying settings within a module. The combined workflow of Visual SFM, SURE and CloudCompare is just as simple but requires more user interaction. MicMac turned out to be the most challenging software as it is less user-friendly. However, MicMac offers the most possibilities to influence the processing workflow. The resulting point-clouds of PhotoScan and MicMac are the most appealing

A high-resolution image time series of the Gorner Glacier – Swiss Alps – derived from repeated unmanned aerial vehicle surveys

Modern drone technology provides an efficient means to monitor the response of alpine glaciers to climate warming. Here we present a new topographic dataset based on images collected during 10 UAV surveys of the Gorner Glacier glacial system (Switzerland) carried out approximately every 2 weeks throughout the summer of 2017. The final products, available at https://doi.org/10.5281/zenodo.2630456 (Benoit et al., 2018), consist of a series of 10&thinsp;cm resolution orthoimages, digital elevation models of the glacier surface, and maps of ice surface displacement. Used on its own, this dataset allows mapping of the glacier and monitoring surface velocities over the summer at a very high spatial resolution. Coupled with a classification or feature detection algorithm, it enables the extraction of structures such as surface drainage networks, debris, or snow cover. The approach we present can be used in the future to gain insights into ice flow dynamics.</p

Journal of Geophysical Research: Earth Surface / The topography of a continental indenter : the interplay between crustal deformation, erosion, and base level changes in the eastern Southern Alps

The topography of the eastern Southern Alps (ESA) reflects indenter tectonics causing crustal shortening, surface uplift, and erosional response. Fluvial drainages were perturbed by Pleistocene glaciations that locally excavated alpine valleys. The Late Miocene desiccation of the Mediterranean Sea and the uplift of the northern Molasse Basin led to significant base level changes in the far field of the ESA and the Eastern Alps (EA), respectively. Among this multitude of mechanisms, the processes that dominate the current topographic evolution of the ESA and the ESA-EA drainage divide have not been identified. We demonstrate the expected topographic effects of each mechanism in a one-dimensional model and compare them with observed channel metrics. We find that the normalized steepness index increases with uplift rate and declines from the indenter tip in the northwest to the foreland basin in the southeast. The number and amplitude of knickpoints and the distortion in longitudinal channel profiles similarly decrease toward the east. Changes in slope of -transformed channel profiles coincide spatially with the Valsugana-Fella fault linking crustal stacking and uplift induced by indenter tectonics with topographic evolution. Gradients in across the ESA-EA drainage divide imply an ongoing, north directed shift of the Danube-ESA watershed that is most likely driven by a base level rise in the northern Molasse basin. We conclude that the regional uplift pattern controls the geometry of ESA-EA channels, while base level changes in the far field control the overall architecture of the orogen by drainage divide migration.(VLID)222030

Global and Planetary Change / Glacial lakes in Austria : distribution and formation since the Little Ice Age

Glacial lakes constitute a substantial part of the legacy of vanishing mountain glaciation and act as water storage, sediment traps and sources of both natural hazards and leisure activities. For these reasons, they receive growing attention by scientists and society. However, while the evolution of glacial lakes has been studied intensively over timescales tied to remote sensing-based approaches, the longer-term perspective has been omitted due a lack of suitable data sources. We mapped and analyzed the spatial distribution of glacial lakes in the Austrian Alps. We trace the development of number and area of glacial lakes in the Austrian Alps since the Little Ice Age (LIA) based on a unique combination of a lake inventory and an extensive record of glacier retreat. We find that bedrock-dammed lakes are the dominant lake type in the inventory. Bedrock- and moraine-dammed lakes populate the highest landscape domains located in cirques and hanging valleys. We observe lakes embedded in glacial deposits at lower locations on average below 2000ma.s.l. In general, the distribution of glacial lakes over elevation reflects glacier erosional and depositional dynamics rather than the distribution of total area. The rate of formation of new glacial lakes (number, area) has continuously accelerated over time with present rates showing an eight-fold increase since LIA. At the same time the total glacier area decreased by two-thirds. This development coincides with a long-term trend of rising temperatures and a significant stepping up of this trend within the last 20years in the Austrian Alps.(VLID)250096

Designing Inter- and Transdisciplinary Research on Mountains: What Place for the Unexpected?

In recent decades, research on mountains has become more inter- and transdisciplinary, but a greater effort is needed if such research is to contribute to a societal transformation toward sustainability. Mountain research centers are a crucial actor in this endeavor. Yet, the literature has not paid sufficient attention to how these centers should (re-)design inter- and transdisciplinary research. In this study, we explored this question with a self-reflexive approach. We analyzed the first 15 months of the Interdisciplinary Centre for Mountain Research (CIRM) of the University of Lausanne (Switzerland) through qualitative data collected via interviews and observation. We used a simple model of inter- and transdisciplinarity at the organizational level of a research center. Special attention was devoted to the individual and collective ability to exploit the unexpected (serendipity). Our results indicate an interdependency between the coconstruction of research objects and the creation of integrative partnerships. They also shed light on the types of institutional resources and integrative methodologies that enhance inter- and transdisciplinary research, as well as their challenges. Our experience shows that implementing inter- and transdisciplinarity requires deep changes in research evaluation procedures, research funding policies, and researchers themselves. Serendipity is in turn shown to play an important role in inter- and transdisciplinarity due to its potential to change the research process in creative ways. We speculate that serendipity offers unique opportunities to capitalize on hidden resources that can catalyze a radical transformation of mountain researchers, research organizations, and society in the face of unprecedented global change

Recent patterns of discharge and sediment output of the Gorner Glacier, Switzerland

Recent climate change is causing rapid retreat of alpine glaciers around the globe. As ice melts and glaciers thin, glacier motion and subglacial processes will change. One of the most relevant aspects for down-valley environments, settlements and infrastructure is the potential change in flow discharge and sediment output. Here we present the results of an ongoing monitoring program at the Gorner Glacier, Switzerland, the second-largest glacier system in the European Alps. During the melt season of 2018 and 2019, stage and turbidity were monitored with a 5 minute frequency along a turbulent section of the glacial river, located approximately 1 km downstream of the glacier terminus. For calibration of the turbidity measurements, daily water samples were obtained with an automated pump sampler, supported by additional intermittent manual sampling. The data is complemented by a discharge time series that also contains information on the flushing of a bedload trap at the hydro power weir located about 2 km downstream of the glacier terminus. The discharge and flushing data have a resolution of 15 minutes. Turbidity and discharge allow estimation of the output of suspended load, while the flushing data inform about bedload. We further measured total organic carbon content of the water samples to infer the water and sediment source. Data suggest a clear seasonal pattern, not only in discharge and sediment output, but also in suspended sediment concentration (SSC). While SSC is high during snow melt and in early summer, it decreases rapidly in July and stays at similar levels until September. This may indicate exhaustion of sediment storage beneath the glacier, but could also result from a change in subglacial regime, e.g. from a decrease in subglacial water pressure due to the progressive opening of subglacial cavities during the melt season. High fractions of organic carbon, presumably due to lateral sediment input from hillslopes, occur during storms throughout the entire season

Journal of Geophysical Research: Earth Surface / Glacial Steady State Topography Controlled by the Coupled Influence of Tectonics and Climate

Glaciers and rivers are the main agents of mountain erosion. While in the fluvial realm empirical relationships and their mathematical description, such as the stream power law, improved the understanding of fundamental controls on landscape evolution, simple constraints on glacial topography and governing scaling relations are widely lacking. We present a steady state solution for longitudinal profiles along eroding glaciers in a coupled system that includes tectonics and climate. We combined the shallow ice approximation and a glacial erosion rule to calculate ice surface and bed topography from prescribed glacier mass balance gradient and rock uplift rate. Our approach is inspired by the classic application of the stream power law for describing a fluvial steady state but with the striking difference that, in the glacial realm, glacier mass balance is added as an altitudedependent variable. From our analyses we find that ice surface slope and glacial relief scale with uplift rate with scaling exponents indicating that glacial relief is less sensitive to uplift rate than relief in most fluvial landscapes. Basic scaling relations controlled by either basal sliding or internal deformation follow a power law with the exponent depending on the exponents for the glacial erosion rule and Glen's flow law. In a mixed scenario of sliding and deformation, complicated scaling relations with variable exponents emerge. Furthermore, a cutoff in glacier mass balance or cold ice in high elevations can lead to substantially larger scaling exponents which may provide an explanation for high relief in high latitudes.J 3976 N-29(VLID)342930