Joint inversion of groundwater flow,heat, and solute state variables: a multipurpose approach for characterization and forecast of karst systems     

Kavousi  Alireza  Reimann  Thomas  Wöhling  Thomas  Birk  Steffen  Luhmann  Andrew J.  Kordilla  Jannes  Noffz  Torsten  Sauter  Martin  Liedl  Rudolf 《Hydrogeology Journal》2023,31(4):1005-1030

Characterization of karst systems and forecast of their state variables are essential for groundwater management and engineering in karst regions. These objectives can be met by the use of process-based discrete-continuum models (DCMs). However, results of DCMs may suffer from inversion nonuniqueness. It has been demonstrated that the joint inversion of observations regulated by different natural processes can tackle the nonuniqueness issue in groundwater modeling. However, this has not been tested for DCMs thus far. This research proposes a methodology for the joint inversion of hydro-thermo-chemo-graphs, applying to two small-scale sink-to-spring experiments at Freiheit Spring, Minnesota, USA. In order to address conceptual uncertainty, a multimodel approach was implemented, featuring seven mutually exclusive variants. Spring hydro-thermo-chemo-graphs, for all the variants simulated by MODFLOW-CFPv2, were jointly inverted using a weighted least squares algorithm. Subsequently, models were compared in terms of inversion and forecast performances, as well as parameter uncertainties. Results reveal the suitability of the DCM approach for simultaneous inversion and forecast of hydro-physico-chemical behavior of karst systems, even at a scale of meters and seconds. The estimated volume of the tracer conduit passage ranges from approximately 46–51 m³, which is comparable to the estimate from the flood-pulse method. Moreover, it was demonstrated that the thermograph and hydrograph contain more information about aquifer characteristics than the chemograph. However, this finding can be site-specific and should depend on the analysis scale, the considered conceptual models, and the hydrological state, which are potentially affected by minor unaccountable processes and features.

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Local Extremes in the Lidar‐Derived Snow Cover of Alpine Glaciers          下载免费PDF全文

Kay Helfricht  Michael Lehning  Rudolf Sailer  Michael Kuhn 《Geografiska Annaler: Series A, Physical Geography》2015,97(4):721-736

Snow deposition and redistribution are major drivers of snow cover dynamics in mountainous terrain and contribute to the mass balance of alpine glaciers. The quantitative understanding of inhomogeneous snow distribution in mountains has recently benefited from advances in measuring technologies, such as airborne laser scanning (ALS). This contribution further advances the quantitative understanding of snow distribution by analysing the areas of maximum surface elevation changes in a mountain catchment with large and small glaciers. Using multi‐annual ALS observations, we found extreme surface elevation changes on rather thin borders along the glacier margins. While snow depth distribution patterns in less extreme terrain have presented high inter‐annual persistence, there is little persistence of those extreme glacier accumulations between winters. We therefore interpret the lack of persistence as the result of a predominance of gravity‐driven redistribution, which has an inherently higher random component because it does not occur with all conditions in all winters. In highly crevassed zones, the lidar‐derived surface elevation changes are caused by a complex interaction of ice flux divergence, the propagation of crevasses and snow accumulation. In general, the relative contribution of gravitational mass transport to glacier snow cover volume was found to decrease for glaciers larger than 5 km² in the investigated region. We therefore suggest that extreme accumulations caused by gravitational snow transport play a significant role in the glacier mass balance of small to medium‐size glaciers and that they may be successfully parameterized by simple mass redistribution algorithms, which have been presented in the literature.  相似文献   

Zeta potential of porous rocks in contact with mixtures of monovalent and divalent electrolytes     

Luong Duy Thanh  Rudolf Sprik  Xuan Ca Nguyen 《Geophysical Prospecting》2019,67(5):1354-1368

The zeta potential is one of the most important parameters influencing the electrokinetic coupling. Most reservoir rocks are saturated or partially saturated by natural water containing various types of ions (mostly monovalent and divalent ions). Therefore, understanding how the zeta potential behaves for mixtures of electrolytes is very important. In this work, measurements of the zeta potential for four different silica-based samples saturated by seven different mixtures of monovalent and divalent electrolytes are then carried out at a fixed ionic strength. It is seen that the magnitude of the measured zeta potential decreases with increasing divalent cation fraction. The experimental results are then explained by a model developed for mixtures of monovalent and divalent electrolytes. The result shows that the theoretical model is able to reproduce the main trend of the variation of the zeta potential with divalent cation fractions. Additionally, the model can fit the experimental data reported in literature well for reasonable values of the input parameters.  相似文献   

Natural hazard prevention and the mountain land risk reduction in the Western Carpathians     

Peter Maas Rudolf Ondrasik Libor Jansky 《山地科学学报》2005,2(3):202-210

The Western Carpathians are located out of world main natural hazardous zones. Human casualties are related more to snow avalanches in connection with mountain hiking, some individuals yearly by flooding and rarely by forest fires. Economic lost about 0.1 to 0.2 %, exceptionally up to 0.8 % of the gross domestic product （GDP） proportionally to the Carpathian regions of particular countries. Natural disasters are linked, except of the above mentioned events, to infrequent small and medium scale earthquakes, landslides, and erosion. Records of the most harmful natural events are found in archives since the 16^th century. Their systematic study and factor analysis started from the end of the 19^th century, and protective measures and organization of impact mitigation developed during the 20^th century to minimize the risk.  相似文献   

Incipient devitrification of impact melt particles at Bosumtwi crater,Ghana: Implications for suevite cooling history and melt dispersion     

Rudolf Vlja  Kalle Kirsime  Christian Koeberl  Daniel Boamah  Juho Kirs 《Meteoritics & planetary science》2019,54(10):2557-2572

The petrographic, mineralogical, and geochemical compositions of the incipient devitrification products in impact melt fragments found in outer suevites at the Bosumtwi impact crater were studied to reconstruct the postimpact environmental constraints on the suevite formation and to refine its cooling history. Our study shows that devitrified melt/particles contain numerous microlitic crystals and crystal aggregates of different shapes derived from rapid cooling. The matrix of melt/particles in Bosumtwi suevites contains abundant Mg‐hercynite (pleonaste)‐type spinels with sizes rarely exceeding a few micrometers. High nucleation density of microlites suggests rapid crystallization under strong undercooling in the presence of abundant volatiles. Although the Bosumtwi impact event took place in a continental environment, the possible sources for elevated fluid/volatile content could have been the groundwater in the deeply weathered and fractured‐jointed Birimian basement, dewatering of abundant hydrous phases in weathered crust or hydrothermally altered basement, and the shale/phyllite–greywacke lithologies in the target rocks. Our results show that enough volatiles were present in the target rocks at the time of impact for the effective impact melt dispersion observed in Bosumtwi impactites.  相似文献   

Collected Rain Water as Cost-Efficient Source for Aquifer Tracer Testing     

Felix Tritschler  Martin Binder  Falk Händel  Diana Burghardt  Peter Dietrich  Rudolf Liedl 《Ground water》2020,58(1):125-131

Locally collected precipitation water can be actively used as a groundwater tracer solution based on four inherent tracer signals: electrical conductivity, stable isotopic signatures of deuterium [δ²H], oxygen-18 [δ¹⁸O], and heat, which all may strongly differ from the corresponding background values in the tested groundwater. In hydrogeological practice, a tracer test is one of the most important methods for determining subsurface connections or field parameters, such as porosity, dispersivity, diffusion coefficient, groundwater flow velocity, or flow direction. A common problem is the choice of tracer and the corresponding permission by the appropriate authorities. This problem intensifies where tracer tests are conducted in vulnerable conservation or water protection areas (e.g., around drinking water wells). The use of (if required treated) precipitation as an elemental groundwater tracer is a practical solution for this problem, as it does not introduce foreign matters into the aquifer system, which may contribute positively to the permission delivery. Before tracer application, the natural variations of the participating end members' tracer signals have to be evaluated locally. To obtain a sufficient volume of tracer solution, precipitation can be collected as rain using a detached, large-scale rain collector, which will be independent from possibly existing surfaces like roofs or drained areas. The collected precipitation is then stored prior to a tracer experiment.  相似文献   

Remote sounding of atmospheres: (Cambridge planetary science series). J.T. Houghton,F.W. Taylor,and C.D. Rodgers. Cambridge Univ. Press,New York/Cambridge/London, 1984. 343 pp., $67.50     

Rudolf A. Hanel 《Icarus》1985,61(2):346-348

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The contribution of satellite geodesy to the geosciences     

Rudolf Sigl Dr.-Ing 《GeoJournal》1984,8(4):341-362

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Instrumentelle Aufnahme und elektronische Auswertung von tektonischen Flächen und Linearen     

Prof. Dr. Rudolf E. Adler 《International Journal of Earth Sciences》1969,59(1):152-162

Zusammenfassung In der vorliegenden Arbeit wird kurz über die Möglichkeit berichtet, tektonische Untersuchungen auf der Grundlage detaillierter geologisch-tektonischer Kartierungen durch eine eingehende elektronische Bearbeitung von statistisch erhobenen tektonischen Daten sowie gegebenenfalls auch durch eine stereographisch-photogrammetrische Aufnahme derartiger Daten zu ergänzen.

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This paper deals with the possibility to complete tectonic investigations, which are based on detailed geological field mapping, by electronic computation of statistically obtained tectonic data as well as by stereographic-photogrammetric plotting of such data.

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Résumé L'auteur démontre la possibilité de compléter des recherches tectoniques basées sur des levés géologiques, par une computation électronique des dates tectoniques obtenues par des méthodes statistiques, ainsi que par un levé stéréographique-photogrammétrique de telles dates.

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Die vorliegende Arbeit stellt die erweiterte Fassung eines Vortrages dar, den der Verfasser auf der Frühjahrstagung der Geologischen Vereinigung in Karlsruhe am 20.2.1969 gehalten hat.  相似文献   

Zur Kontrolle der Auswertung von Ionogrammen     

Rudolf Eyfric 《Pure and Applied Geophysics》1958,40(1):157-163

Zusammenfassung 1. Pflüfung der Auswertbläter auf Widerspruchslosigkeit-2. Kontrolle mit grob-statistischen Methoden-3. Kontrolle gegen andere Stationen.

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Summary 1. Test on self-consistency of scaling-2. Test with rough statistical methods-3. Test against distant stations.

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Ionosphären-Institut Breisach im Fernmeldetechnischen Zentralamt der Deutschen Bundespost,Breisach/Rh.

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In Klammern werden die üblichen Code Nummern gegeben.  相似文献