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171.
Joachim Bartz 《International Journal of Earth Sciences》1949,37(1):113-114
Ohne Zusammenfassung 相似文献
172.
173.
Christian Dumperth Joachim Rohn Alexander Fleer Jin-Ge Wang Wei Xiang Karsten Zimmermann 《山地科学学报》2016,13(10):1701-1710
Semi qualitative index based methods using rankings and ratings are commonly used in susceptibility estimations over a wide area. However, generalized ranking and ratings are not applicable for one single landslide. This paper gives an easy and transferable approach to a susceptibility assessment of Huangtupo landslide (P.R. China), using raster addition without taking account for ranking and ratings. Slope, aspect, curvature, location and drainage buffer distance raster data sets have been obtained out of open source digital elevation models using ESRI’s ArcGIS. These conditioning factor raster data sets have been translated into raster data sets including simple yes or no criteria, referring to triggering or not. Subsequently they have been added by raster math to acquire a simple raster overlay map. After that this map is compared to initial displacement measurements, obtained by using a ground based synthetic aperture radar device. Acquired data is recalculated to a raster data set using the same spatial extent, to provide the possibility of comparison of the two raster data sets. The results reveal, that 76.35% of all measured movements occur in areas where raster cells include three or more conditioning factors, indicating that easy raster math operations can lead to satisfying results in local scale. 相似文献
174.
Joachim Kuhlemann Klaas van der Borg Paul D. Bons Martin Danišík Wolfgang Frisch 《International Journal of Earth Sciences》2008,97(3):549-564
A study of erosion rates by in-situ 10Be concentrations in granites of Miocene high-elevation paleosurfaces in Corsica indicates maximum erosion rates between 8
and 24 mm/kyear. The regional distribution of measured erosion rates indicates that the local climatic conditions, namely
precipitation, the petrographic composition of granites, and the degree of brittle deformation govern erosion rates. Chemical
erosion dominates even at elevations around 2,000 m in presently subalpine climate conditions. Field evidence indicates that
erosion operates by continuous dissolution and/or disintegration to grains (grusification). The erosion rates are relatively
high with respect to the preservation of inferred Early Miocene landscapes. We infer temporal burial in the Middle Miocene
and significantly lower erosion rates in the Neogene until ∼3 Ma to explain the preservation of paleosurfaces, in line with
fission track data. Valley incision rates that are a magnitude higher than erosion rates on summit surfaces result in relief
enhancement and long-term isostatic surface uplift. On the other hand, widening and deepening of valleys by cyclic glaciation
progressively destroys the summit surface relics.
相似文献
Wolfgang FrischEmail: |
175.
Modelling sediment and total phosphorus export from a lowland catchment: comparing sediment routing methods 下载免费PDF全文
Shenglan Lu Brian Kronvang Joachim Audet Dennis Trolle Hans Estrup Andersen Hans Thodsen Ann van Griensven 《水文研究》2015,29(2):280-294
Bank erosion is the main source of suspended sediment (SS) and diffuse total phosphorus (TP) in many lowland catchments. This study compared a physically based sediment routing method (Physical method), which distinguishes between stream bed and bank erosion, with the original sediment routing method (Original method) within the Soil and Water Assessment Tool (SWAT) version 2009, for simulating SS and TP losses from a lowland catchment. A SWAT model was set up for the lowland River Odense catchment in Denmark and calibrated against observed stream flow and phosphate (PO4) loads. On the basis of an initial calibration of hydrological and PO4 parameters, the SWAT model with the Original method (Original model) and the SWAT model with the Physical method (Physical model) were calibrated separately against observed SS and TP loads. The SWAT model simulated daily stream flow well but underestimated PO4 loads. The Physical model simulated daily SS and TP better than the Original model. The simulated contribution of bank erosion to SS in the Physical model (99%) was close to the estimated contribution from in situ erosion measurements (90–94%). Compared with the Original method, the Physical method is not only more conceptually correct but also improves model performance. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
176.
Eva Leitholdt Christoph Zielhofer Stefanie Berg‐Hobohm Katharina Schnabl Britta Kopecky‐Hermanns Jens Bussmann Joachim W. Hrtling Klaus Reicherter Katrin Unger 《Geoarchaeology》2012,27(1):88-104
The Central European watershed passes through the southern Franconian Jura in Bavaria, Germany. This principal watershed divides the Rhine/Main catchment and the Danube catchment. In the early Middle Ages, when ships were an important means of transportation, Charlemagne decided to connect these catchments by the construction of a canal known as the Fossa Carolina. In this paper, we present for the first time 14C data from the Fossa Carolina fill and document a high‐resolution stratigraphic record of the Carolingian and post‐Carolingian trench infilling. Our results provide clear evidence for peat layers in different levels of the trench infill, suggesting a chain of ponds. However, the majority of these peat layers yield mid‐Medieval and younger ages. The period of major peat growth was during the Medieval climatic optimum. Therefore, our preliminary results do not prove the use of the trench during Carolingian times. However, first results from the reconstruction of the Carolingian trench bottom support the hypothesis that the Fossa was primarily planned as a navigable chain of ponds and not as a continuous canal. In the eastern part of the trench, a dam is located that was postulated in former studies to be part of a barrage for supplying the Carolingian canal with water. New 14C data indicate much younger ages and do not support the Carolingian barrage concept. 相似文献
177.
Dieter Pudlo Viktor Reitenbach Daniel Albrecht Leonhard Ganzer Ulrich Gernert Joachim Wienand Bernd Kohlhepp Reinhard Gaupp 《Environmental Earth Sciences》2012,67(2):369-384
In the framework of the German R&D joint project CLEAN (CO2 large-scale enhanced gas recovery in the Altmark natural gas field), Rotliegend reservoir sandstones of the Altensalzwedel block in the Altmark area (Saxony-Anhalt, central Germany) have been studied to characterise litho- and diagenetic facies, mineral content, geochemical composition, and petrophysical properties. These sands have been deposited in a playa environment dominated by aeolian dunes, dry to wet sand flats and fluvial channel fills. The sediments exhibit distinct mineralogical, geochemical, and petrophysical features related to litho- and diagenetic facies types. In sandstones of the damp to wet sandflats, their pristine red colours are preserved and porosity and permeability are only low. Rocks of the aeolian environment and most of the channel fill deposits are preferentially bleached and exhibit moderate to high porosity and permeability. Although geochemical element whole rock content in these rocks is very similar, element correlations are different. Variations in porosity and permeability are mainly due to calcite and anhydrite dissolution and differences in clay coatings with Fe-bearing illitic-chloritic composition exposed to the pore space. Moreover, mineral dissolution patterns as well as compositions (of clays and carbonate) and morphotypes of authigenic minerals (chlorite, illite) are different in red and bleached rocks. Comparison of the geochemical composition and mineralogical features of diagenetically altered sandstones and samples exposed to CO2-bearing fluids in laboratory batch experiments exhibit similar character. Experiments prove an increase in wettability and water binding capacity during CO2 impact. 相似文献
178.
Induced magnetic fields provide the unique possibility to sound the conductive interior of planetary bodies. Such fields are caused by external time-variable magnetic fields. We investigate temporal variations of the jovian magnetospheric field at multiple frequencies at the positions of the Galilean moons and analyze possible responses due to electromagnetic induction within multi-layered interior models of all four satellites. At the jovian satellites the magnetic field varies with the synodic rotation period of Jupiter’s internal field (about 10 h), fractions of this period (e.g., 1/2 and 1/3) due to higher order harmonics of the internal field, the orbital periods of the satellites (∼40 h at Io to ∼400 h at Callisto) and the solar rotation period (about 640 h) and its harmonics due to variabilities of the magnetopause field. To analyze these field variations, we use a magnetospheric model that includes the jovian internal field, the current sheet field and fields due to the magnetopause boundary currents. With this model we calculate magnetic amplitude spectra for each satellite orbit. These spectra provide the strengths of the inducing signals at the different frequencies for all magnetic components. The magnetic fields induced in the interiors of the satellites are then determined from response functions computed for different multi-layer interior models including conductive cores and ocean layers of various conductivities and thicknesses. Based on these results we discuss what information about the ocean and core layers can be deduced from the analysis of induction signals at multiple frequencies. Even moderately thick and conductive oceans produce measurable signal strengths at several frequencies for all satellites. The conductive cores cause signals which will be hardly detectable. Our results show that mutual induction occurs between the core and the ocean. We briefly address this effect and its implications for the analysis of induced field data. We further note that close polar orbits are preferable for future Jupiter system missions to investigate the satellites interiors. 相似文献
179.
Harry Enke Matthias Steinmetz Hans-Martin Adorf Alexander Beck-Ratzka Frank Breitling Thomas Brüsemeister Arthur Carlson Torsten Ensslin Mikael Högqvist Iliya Nickelt Thomas Radke Alexander Reinefeld Angelika Reiser Tobias Scholl Rainer Spurzem Jürgen Steinacker Wolfgang Voges Joachim Wambsganß Steve White 《New Astronomy》2011,16(2):79-93
We present status and results of AstroGrid-D, a joint effort of astrophysicists and computer scientists to employ grid technology for scientific applications. AstroGrid-D provides access to a network of distributed machines with a set of commands as well as software interfaces. It allows simple use of computer and storage facilities and to schedule or monitor compute tasks and data management. It is based on the Globus Toolkit middleware (GT4).Chapter 1 describes the context which led to the demand for advanced software solutions in Astrophysics, and we state the goals of the project.We then present characteristic astrophysical applications that have been implemented on AstroGrid-D in chapter 2. We describe simulations of different complexity, compute-intensive calculations running on multiple sites (Section 2.1), and advanced applications for specific scientific purposes (Section 2.2), such as a connection to robotic telescopes (Section 2.2.3). We can show from these examples how grid execution improves e.g. the scientific workflow.Chapter 3 explains the software tools and services that we adapted or newly developed. Section 3.1 is focused on the administrative aspects of the infrastructure, to manage users and monitor activity. Section 3.2 characterises the central components of our architecture: The AstroGrid-D information service to collect and store metadata, a file management system, the data management system, and a job manager for automatic submission of compute tasks.We summarise the successfully established infrastructure in chapter 4, concluding with our future plans to establish AstroGrid-D as a platform of modern e-Astronomy. 相似文献
180.
Naki Akçar Susan Ivy-Ochs Vasily Alfimov Anne Claude Hans R. Graf Andreas Dehnert Peter W. Kubik Meinert Rahn Joachim Kuhlemann Christian Schlüchter 《Swiss Journal of Geoscience》2014,107(2-3):337-347
The Swiss Deckenschotter (“cover gravels”) is the oldest Quaternary units in the northern Swiss Alpine Foreland. They are a succession of glaciofluvial gravel layers intercalated with glacial and/or overbank deposits. This lithostratigraphic sequence is called Deckenschotter because it “covers” Molasse or Mesozoic bedrock and forms mesa-type hill-tops. Deckenschotter occurs both within and beyond the extent of the Last Glacial Maximum glaciers. The Swiss Deckenschotter consist of two sub-units: Höhere (Higher) and Tiefere (Lower) Deckenschotter. Although the Höhere Deckenschotter sub-unit (HDS) is topographically higher than the Tiefere Deckenschotter, it is older. The only available age for the Swiss Deckenschotter is 2.5–1.8 Ma based on mammal remains found in HDS at the Irchel site. In this study, we present an exposure age for the topographically lowest HDS, calculated from a cosmogenic 10Be depth-profile. Our results show that the first phase of the Deckenschotter glaciations in the Swiss Alps terminated at least 1,020\(_{ - 120}^{ + 80}\) ka ago, which is indicated by a significant fluvial incision. This line of evidence seems to be close to synchronous with the beginning of the Mid-Pleistocene Revolution, when the frequency of the glacial-interglacial cyclicity changed from 41 to 100 ka and the amplitude from low to high, between marine isotope stages 23 and 22. 相似文献