Visualization of tectonic structures in shallow-depth high-resolution ground-penetrating radar (GPR) profiles   总被引：3，自引：0，他引：3  

Martin Meschede  Ulrich Asprion  & Klaus Reicherter 《地学学报》1997,9(4):167-170

Ground-penetrating radar (GPR) is applied to detect subsurface tectonic structures and to map the geometry of faulted blocks. Tectonic interpretations from a profile crossing the graben fault and a grid in a second-order graben structure providing a 3D data set are correlated to the structural inventory of the outcrop. Folded layers of the roll-over anticline are identified by continuous curved reflectors and an increasing dip towards the main graben fault. Faults are indicated by arrays of reflector terminations. Variations in the water and clay content caused by karstification and brecciation on fault planes are displayed by changing amplitudes of the detected signal. The 3D visualization of the second-order graben structure with a grid of GPR profiles illustrates the local stress pattern which coincides with structural observations in the outcrop and photo lineations.  相似文献   

Access and Assimilation: Pivotal environmental information challenges     

Benking Heiner  Kampffmeyer  B. Ulrich 《GeoJournal》1992,26(3):323-334

The world-wide environmental exchange of information is hampered by difficulties bridging terminologies and languages so that trans-cultural, cross-sectoral, and multi-dimensional information can be made available in a usable form at low cost. The alternative concepts and elements described are planned to contribute to HEMIS, UNEP-HEMs world-wide information and reference system. The potential content includes: environmentally relevant organizations, activities, systems, methods, data sources, qualities, and access methods. The key design element is a multi-lingual thesaurus which has harmonization effect resulting from the structuring and strategic access to information. Documentation and retrieval is another concern beside the provision of tools to ease identification, dissemination, and validation of information. The maintenance of validated source data and documents will reduce the volumes of requested information and thereby counteract the present information overkill.  相似文献   

Mapping mountains: Vegetation in the Himalaya     

Ulrich Schweinfurth 《GeoJournal》1992,27(1):73-83

The author deals with the vegetation of the Himalayas taking his 1957 map as basis of the presentation. This map by way of vegetation first opened insigh into the hitherto unknown landscape structure of the mountain system, thereby revealing, for instance, the phenomeon of the inner valleys and the climatically dry valleys, in particular as well as the areas vegetationwise still unknown. Progress in our knowledge of the vegetation in the Himalayas since publication of the 1957 map is carefully recorded showing, above all, the advancement of our knowledge in Nepal since. In contrast to expectations, research was unable to concentrate on all the gaps in our knowledge as demonstrated on the 1957 map owing to political conditions prevailing.  相似文献   

Phase transitions in leucite: Order parameter behaviour and the Landau potential deduced from Raman spectroscopy and birefringence studies     

David C. Palmer  Ulrich Bismayer  Ekhard K. H. Salje 《Physics and Chemistry of Minerals》1990,17(3):259-265

Hard mode Raman Spectroscopy and optical birefringence studies have been used to evaluate the temperature behaviour of order parameters for the cubictetragonal phase transition in leucite. There is a strong temperature-dependence of Raman line frequencies near 498 cm^–1 and 529 cm^–1, and the optical birefringence decreases towards zero on heating. Above the transition temperature leucite still shows slight birefringence, which correlates with the persistence of the 200 X-ray reflexion at these temperatures, and is not compatible with the ideal cubic symmetry. Quantitative observations of the temperature evolution of Raman line-frequencies and the birefringence are consistent with an order parameter showing T _1g symmetry, and a nearly-tricritical phase transition behaviour. The results of earlier X-ray and DSC studies imply the operation of an additional order parameter, with E _g symmetry; this is observed, but its influence on the transition behaviour is significant only at temperatures close to T _c. The two order parameters are related via linear-quadratic or biquadratic coupling. We develop the form of the Landau Potential for leucite — including both order parameters and their couplings — to discuss the present observations and previous structural data.  相似文献   

Grain boundary wetness of partially molten dunite     

Shangshang Mu  Ulrich H. Faul 《Contributions to Mineralogy and Petrology》2016,171(5):40

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Towards the assimilation of tree-ring-width records using ensemble Kalman filtering techniques     

Walter Acevedo  Sebastian Reich  Ulrich Cubasch 《Climate Dynamics》2016,46(5-6):1909-1920

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The East African Rift System and the impact of orographic changes on regional climate and the resulting aridification     

Anja Sommerfeld  Kerstin Prömmel  Ulrich Cubasch 《International Journal of Earth Sciences》2016,105(6):1779-1794

Several proxy data indicate an aridification of the East African climate during the Neogene, which might be influenced by the orographic changes of the East African Rift System (EARS) induced by tectonic forcing during the last 20 million years. To investigate the impact of the orography and especially of the rifts, the regional climate model CCLM is used, covering the EARS with Lake Victoria in the centre of the model domain. CCLM is driven by the ERA-Interim reanalysis and applied with a double-nesting method resulting in a very high spatial resolution of 7 km. The resolution clearly shows the shoulders and rifts of the western and eastern branch of the EARS and the Rwenzoris within the western branch. To analyse the orographic influence on climate, a new technique of modifying the orography is used in this sensitivity study. The shoulders of the branches are lowered and the rifts are elevated, resulting in a smoothed orography structure with less altitude difference between the shoulders and rifts. The changes in 2 m-temperature are very local and associated with the changes in the orography. The vertically integrated moisture transport is characterised by less vortices, and its zonal component is increased over the branches. The resulting amount of precipitation is mainly decreased west of the western branch and increased in the rift of the western branch. In the eastern branch, however, the changes in the amount of precipitation are not significant. The changes in the precipitation and temperature patterns lead to a shift of biomes towards a vegetation coverage characterised by more humid conditions in the northern part of the model domain and more arid conditions in the South. Thus, the aridification found in the proxy data can be attributed to the orographic changes of the rifts only in the northern model domain.  相似文献   

Über eine scheinbare Anomalie der Temperaturdifferenz Luft-Wasser     

Ulrich Roll 《Ocean Dynamics》1949,2(4):134-137

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Gibt es eine «kritische Windgeschwindigkeit» für Prozesse an der Grenzfläche Wasser-Luft?     

Dr. Hans Ulrich Roll 《Pure and Applied Geophysics》1952,21(1):110-126

Zusammenfassung Eineabsolute «kritische Windgeschwindigkeit» für Prozesse an der Grenzfläche Wasser-Luft scheint nicht zu existieren. Unsere Beobachtungen liefern jedoch Anzeichen für das Vorhandenseinrelativer «kritischer Windgeschwindigkeiten, die vom Ueberströmungsweg, bzw. von der Wellenlaufstrecke abzuhängen scheinen. Diese relativen «kritischen Windgeschwindigkeiten» sind durch folgende-Merkmale gekennzeichnet: Aenderung der Struktur der Meeresoberfläche (glatt-rauh); Umschlag der laminaren Wassergrenzschicht zur Turbulenz; Ueberbrechen der Schwerewellen; Minimum des Widerstandskoeffizienten der Meeresoberfläche.

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Summary It seems that there is no absolute «critical wind speed» for air-sea boundary processes. From our observations it may, however, be referred that there are relative values of the «critical wind speed» which seem to depend on the fetch. These relative values of the «critical wind speed» are characterized by the following marks: The sea surface pattern is changed (smooth-rough);, the boundary layer in water turns from laminar to turbulent flow; the gravity waves break; the resistance coefficient of the sea surface has a minimum.

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Über Größenunterschiede der Meereswellen bei Warm- und Kaltluft     

Hans Ulrich Roll 《Ocean Dynamics》1952,5(2-3):111-114

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