<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "The search for and location of inhomogeneities in seasonal snowpacks utilizing ground-penetrating radar"^^ . "The location of singular objects or layered transitions below the surface and properties thereof in the ground are a pivotal topic in geosciences. In mountainous regions is the investigation of objects and layer transitions specifically of interest for the seasonal snowpack, primarily to reduce the threat to humans and infrastructures by natural hazards. Snow avalanches are a major natural hazard causing numerous fatalities throughout the world and they are a direct consequence of snowpack conditions. The annual fatality numbers of avalanches are fairly constant for the last 30 years, while in other fields such as e.g. road traffic these numbers decreased significantly. It can be assumed that the permanent enhancements in active and passive safety systems in road traffic are the reason for the decrease in victim numbers. In the field of professional search and rescue operations or accident prevention in avalanches such as hazard forecast, enhancements of instrumentations are marginal for the last three decades. The present study describes two different assessments for the use of ground-penetrating radar (GPR) systems to improve the instrumentation for the location of buried avalanche victims and the prediction of avalanches. Consequently, it demonstrates the feasibility of radar systems for the detection of inhomogeneities in seasonal snowpacks. With regard to the improvement of current methods to search and locate buried avalanche victims, which are not equipped with a location device (e.g. avalanche beacon), the main objective is to shorten search time. The assessment of this thesis was therefore to use helicopter-borne non-invasive location methods. To simulate helicopter flights, test arrangements were designed to perform field tests from above the surface. I developed methods to measure from 6--12 m above the snow cover. To measure non-invasively, the arrangement is based on pulsed radar technology. To shorten search time and to minimize the influence of man-made error possibilities, an automatic location software was developed. The results of the field tests present the answers of the fundamental questions for an airborne location operation and enabled the development of a location algorithm. Measurements showed, that the sidewise detectable range of 3--5 m of an antenna set-up with one transmitter -- receiver pair is rather small for the given flight height of 6 to 12 m. Furthermore, the reflection amplitude of the snow surface decreases almost linearly with the flight height. Unfortunately, in wet snow avalanches a buried object in the snowpack does not appear as typical reflection pattern and is therefore not explicitly locatable. The developed software algorithm proved to be sufficient for all applied test arrangements in dry snow conditions. The algorithm is able to distinguish between buried victims in the snowpack and reflections caused by only air holes within the snow cover. Further implementations on helicopters can be achieved, based on these results, but more field tests are necessary to adapt the software to the rougher flight conditions in helicopters. Concerning the observation of stratigraphic inhomogeneities within a snowpack, this thesis showed that a record of specific snowpack conditions from beneath the snow cover is feasible with GPR. The assessment of the present work is to provide snowpack information in avalanche endangered slopes and to follow the temporal evolution of the snowpack over a whole season. Two different kinds of field measurements in dry and wet snow conditions were performed to ascertain the GPR set-up, which provides the best trade-off between penetration depth and layer resolution. On the one hand, temporally singular measurements at different locations, concerning altitude, snowpack conditions and climatic regions in the European Alps, enabled the determination of capable test arrangements. On the other hand, a temporal monitoring of the snow cover at a fixed position over several months, facilitated the record of the change of specific parameters in the snowpack. In terms of system parameters, antennas with a center frequency of about 800--900 MHz are able to penetrate and adequately record stratigraphic transitions in dry and wet snow conditions. The radar-measured snow height in dry snow using a mean wave speed value for the conversion of the two-way travel time was in a good agreement to the probed snow depth and arose in an uncertainty slightly higher than of ultrasonic sensors. In terms of snowpack parameters, the recorded signals of the various snow covers were in good agreement with the measured snow properties. For dry snow conditions, the appearance and the manner of reflections recorded in the snow cover corresponded to the size and the algebraic sign of the gradient in snow density. Moisture in the snowpack attenuates the radar signal significantly. This thesis presents encouraging results of the use of impulse radar technology for the location of inhomogeneities in seasonal snowpacks. Parts of the presented results and methodologies (e.g. the automatic location algorithm) are possibly easily adaptable in related areas of geoscientific research and could also provide advances in other, non-snow related fields."^^ . "2009" . . . . . . . . "Achim"^^ . "Heilig"^^ . "Achim Heilig"^^ . . . . . . "The search for and location of inhomogeneities in seasonal snowpacks utilizing ground-penetrating radar (PDF)"^^ . . . "Dissertation_AchimHeilig2009v2.pdf"^^ . . . "The search for and location of inhomogeneities in seasonal snowpacks utilizing ground-penetrating radar (Other)"^^ . . . . . . "indexcodes.txt"^^ . . . "The search for and location of inhomogeneities in seasonal snowpacks utilizing ground-penetrating radar (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "The search for and location of inhomogeneities in seasonal snowpacks utilizing ground-penetrating radar (Other)"^^ . . . . . . "preview.jpg"^^ . . . "The search for and location of inhomogeneities in seasonal snowpacks utilizing ground-penetrating radar (Other)"^^ . . . . . . "medium.jpg"^^ . . . "The search for and location of inhomogeneities in seasonal snowpacks utilizing ground-penetrating radar (Other)"^^ . . . . . . "small.jpg"^^ . . "HTML Summary of #10022 \n\nThe search for and location of inhomogeneities in seasonal snowpacks utilizing ground-penetrating radar\n\n" . "text/html" . . . "550 Geowissenschaften"@de . "550 Earth sciences"@en . .