Verbessertes Unpersönliches Mikrometer für Das Zirkumzenital     

Ivo Baueršíma  Josef Šuráň 《Studia Geophysica et Geodaetica》1963,7(3):209-227

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Der Untere Buntsandstein des Germanischen Beckens     

Dr. Josef Paul 《International Journal of Earth Sciences》1982,71(3):795-811

Zusammenfassung Das Germanische Becken, das sich von der südlichen Nordsee bis nach Polen erstreckte, sank vom Perm bis einschließlich Trias mehr oder minder kontinuierlich ab. Die Absenkung wurde im Unteren Buntsandstein durch die Ablagerung von Klastika kompensiert, die vornehmlich aus dem sich hebenden südlichen Vorland herantransportiert wurden. Im allgemeinen nehmen die Korngrößen in Richtung Becken-Mitte ab, entsprechend der Entfernung zum Liefergebiet.In der Becken-Mitte bildete sich ein flacher, leicht übersalzener Playa-See, der häufig trockenfiel. Zu den Bändern hin herrschte ein fluviatiles Regime (braided rivers). Mariner Einfluß ist im zentralen und westlichen Teil nicht nachweisbar.Eingeschaltet in die sonst klastische Abfolge des Buntsandsteins sind zahlreiche niveaubeständige Oolith-Horizonte, die sich auf weite Entfernung korrelieren lassen. Das Maximum ihrer Verbreitung liegt südlich der Becken-Achse. Sie sind wahrscheinlich isochron sedimentiert worden und bildeten sich bei größerer Kalkübersättigung des Wassers und bei nachlassender oder fehlender Sedimentation von Klastika.Die fazielle Analyse der Oolith- und der sie begleitenden Stromatolith-Horizonte legt eine diskontinuierliche Zufuhr von Klastika nahe, die durch die unterschiedliche Hebungsintensität des Vorlandes gesteuert wird.

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The center of the Germanic Basin extended from the North Sea to Poland. The basin subsided more or less continuously from Permian to Triassic times. Subsidence was compensated during the Lower Buntsandstein by the deposition of clastic material, which arrived mainly from southern directions. Grain-sizes decrease toward the center correspondingly with the distance to the supplying area.The depositional environment of the basin was a shallow slightly hypersaline playa lake or inland sabkha with frequent periods of desiccation. Braided rivers dominated toward the rims. There is no marine influence in the central and western part of the basin.Numerous oolite-beds are intercalated in the usually clastic sequence of the Lower Buntsandstein. They occur within and mainly south of the basin center and can be traced over distances of more than 100 km and are used as marker horizons. They are associated with stromatolites and most likely deposited isochronously.Facies analysis suggests a discontinuous supply of clastic material to the basin, which is controlled by the temporally changing intensity of the uplift of the foreland. Oolites and stromatolites were formed during the intervals.

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Résumé La centre du bassin germanique s'étendait de la Mer du Nord jusqu'en Pologne. Le bassin subsidant de façon plus ou moins continue du Permien jusqu'en Triasique. Cette subsidence du Buntsandstein inferieur était compensé par la sedimentation clastique. Les sediments étaient provenaient principalement de la bordure meridionale du bassin en voie de soulèvement. Avec la distance de la source du matériel, on constate une diminuation de la grosseur des grains vers le centre du bassin.Au centre se développait un lac de playa hypersaline de faible profondeur, qui était souvent, desséché. Vers la bordure il existait une régime fluviatile (braided rivers). Une influence marine n'est décelable ni au centre ni dans la partie occidentale du bassin. Il y a de nombreux niveaux oolithiques (Rogenstein) qui peuvent être correlés sur de grandes distances. Leur plus grande répartition se trouve au sud de l'axe du bassin. Ils se sont vraisemblabement déposés de façon isochrone. La formation des oolites eut lieu quand l'eau était sursaturée en carbonate et pendant la diminuation ou même l'absence de la sédimentation clastique.L'analyse facielle suggère un apport clastique discontinu, controllé par les soulèvements variables de la bordure du bassin. La formation des oolithes et des stromatolithes est liée aux movements de l'activité tectonique minimale.

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Time patterns of polarization currents generated in measuring the electrical conductivity of rocks     

Josef Bochníček  Marcela Laštovičková  Reviewer A. Janáčková 《Studia Geophysica et Geodaetica》1982,26(4):412-415

amamuu aau m¶rt;a uu mn¶rt;mu n¶rt; nu u mnama, m num , naa, m uau nuau nmu um a mam uu.  相似文献   

Numerical solution of the two-dimensional inverse geomagnetic induction problem     

Václav Červ  Josef Pek  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1981,25(1):69-80

Summary An effective numerical approach to the solution of the two-dimensional inverse geomagnetic induction problem using the linearization method is presented. The numerical realization of the inversion is based on Marquardt's algorithm, for which the solution of the direct problem and the partial derivatives of this solution with respect to the electrical parameters of the medium are computed by the finite difference method. Theoretical models are studied and numerical results are presented.  相似文献   

Geochemical heterogeneity and isotope geochemistry of natural attenuation processes in a gasoline-contaminated aquifer at the Hnevice site,Czech Republic     

Barbora Topinkova  Kamil Nesetril  Josef Datel  Ondrej Nol  Petr Hosl 《Hydrogeology Journal》2007,15(5):961-976

The geochemical processes, water–rock interactions and stable isotopes distribution (δ¹³C of DIC and δ¹⁸O and δ³⁴S of \({\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}} \)) were investigated in the gasoline-contaminated aquifer at the Hnevice site, 50  km northwest of Prague, Czech Republic. Diesel, gasoline and oil leaks originate from a large fuel storage area causing heavy contamination of the saturated and unsaturated zones in an area of about 0.7  km². Groundwater investigations were conducted using five multilevel sampler wells with emphasis on redox parameters and degradation by-products and a solid-phase study focused on iron speciation and determination of principal and secondary minerals. Based on the study of groundwater and solid-phase geochemistry, four different geochemical zones were described. Zone I is thought to be background consisting of an aerobic aquifer and the absence of reduced species in significant concentrations. Zone II is situated in the plume core with methanogenic, sulphate and iron-reducing conditions accompanied by ankerite and kutnahorite precipitates and significant depletion of the oxidation capacity of the aquifer. Zone III is a mixing (corona) zone, situated at the fringe of the plume with high biodegradation rates and Fe(III)-precipitants. In zone IV, reoxidation of Fe(II) minerals (with e.g. the occurrence of psilomelane and cornelite) is typical.  相似文献   

Abrupt deglaciation on the northeastern Tibetan Plateau: evidence from Lake Qinghai   总被引：4，自引：0，他引：4  

Xiuju Liu  Steven M. Colman  Erik T. Brown  Andrew C. G. Henderson  Josef P. Werne  Jonathan A. Holmes 《Journal of Paleolimnology》2014,51(2):223-240

We inferred the climate history for Central Asia over the past 20,000 years, using sediments from core QH07, taken in the southeastern basin of Lake Qinghai, which lies at the northeastern margin of the Tibetan Plateau. Results from multiple environmental indicators are internally consistent and yield a clear late Pleistocene and Holocene climate record. Carbonate content and total organic carbon (TOC) in Lake Qinghai sediments are interpreted as indicators of the strength of the Asian summer monsoon. Warm and wet intervals, associated with increased monsoon strength, are indicated by increased carbonate and TOC content. During the glacial period (~20,000 to ~14,600 cal year BP), summer monsoon intensity remained low and relatively constant at Lake Qinghai, suggesting cool, dry, and relatively stable climate conditions. The inferred stable, cold, arid environment of the glacial maximum seems to persist through the Younger Dryas time period, and little or no evidence of a warm interval correlative with the Bølling–Allerød is found in the QH07 record. The transition between the late Pleistocene and the Holocene, about 11,500 cal year BP, was abrupt, more so than indicated by speleothems in eastern China. The Holocene (~11,500 cal year BP to present) was a time of enhanced summer monsoon strength and greater variability, indicating relatively wetter but more unstable climatic conditions than those of the late Pleistocene. The warmest, wettest part of the Holocene, marked by increased organic matter and carbonate contents, occurred from ~11,500 to ~9,000 cal year BP, consistent with maximum summer insolation contrast between 30°N and 15°N. A gradual reduction in precipitation (weakened summer monsoon) is inferred from decreased carbonate content through the course of the Holocene. We propose that changes in the contrast of summer insolation between 30°N and 15°N are the primary control on the Asian monsoon system over glacial/interglacial time scales. Secondary influences may include regional and global albedo changes attributable to ice-cover and vegetation shifts and sea level changes (distance from moisture source in Pacific Ocean). The abruptness of the change at the beginning of the Holocene, combined with an increase in variability, suggest a threshold for the arrival of monsoonal rainfall at the northeastern edge of the Tibetan Plateau.  相似文献   

Footprint Estimation for Multi-Layered Sources and Sinks Inside Canopies in Open and Protected Environments     

Tomer Duman  Josef Tanny  Uri Dicken  Mario B. Siqueira  Gabriel G. Katul 《Boundary-Layer Meteorology》2015,155(2):229-248

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Surface currents in British Columbia coastal waters: Comparison of observations and model predictions     

William R. Crawford  Josef Y. Cherniawsky  Patrick Cummins 《大气与海洋》2013,51(3):255-280

Abstract

Observations of the motion of ocean surface drifters are used to evaluate numerical simulations of surface currents in the region of Queen Charlotte Sound on the West Coast of Canada. More than 30 surface Argos drifters were deployed in the spring and summer of 1995, revealing daily average currents of 10 to 40 cm s^–1 near the coast of Vancouver Island in summer, and less than 10 cm s^–1 in mid‐sound. Wind observations in this region are provided by a network of weather buoys. Comparison of daily average drifter velocities and winds shows that the drifters moved at 2 to 3% of the wind speed, and at about 30 degrees to the right of the wind.

A complex transfer function is computed between daily wind and drifter vectors using least squares techniques. The ratio of variance in the least squares residual currents to the variance of observed drifter currents is denoted γ². A percent goodness‐of‐fit is defined as g(γ²) = 100(1 – γ²), and is 42% for the case of daily winds and drifter currents. Drifter‐measured currents are compared with two numerical simulations of surface currents: Fundy5, a steadystate baroclinic model based on historical water property measurements in summer, and the Princeton Ocean Model (POM), a prognostic, baroclinic model forced by the measured winds. Fundy5 by itself provides a goodness‐of‐fit of only 3%, whereas POM has g(γ²) = 42%. The combination of Fundy5 plus daily wind gives g(γ²) = 43%. Although the prognostic model performs only as well as the winds by themselves, it simulates the near shore currents more accurately and reproduces the speeds and veering in the surface Ekman layer on average without bias. Residual currents unexplained by POM are likely due to advection of water masses into this region and horizontal inhomogeneities in the density field that are not input to the model, as well as to Stokes drift of wind waves and to net Lagrangian tidal motion not represented by the model.  相似文献   

Risk occurrences of damaging frosts during the growing season of vegetables in the Elbe River lowland,the Czech Republic     

Vera Potop  Pavel Zahraniček  Luboš Türkott  Petr Štěpánek  Josef Soukup 《Natural Hazards》2014,71(1):1-19

This study has, for the first time, analysed in detail the risk occurrences of the last spring frost, first fall frost and the length of the frost-free period during the growing season of vegetable crops at a high horizontal resolution of 10 km in the Elbe River lowland in the Czech Republic. The daily minimum air temperature from 116 grid points throughout the studied area for the period 1961–2011 was used. The daily values of minimum air temperature ranges of 0 to ?1.1 °C, ?1.2 to ?2.2 °C and below ?2.2 °C were considered to constitute mild, moderate and severe frost intensities, respectively. Firstly, the spatiotemporal variability of the date of the last spring frost, the date of the first fall frost and the length of the frost-free period in the Elbe River lowland is provided. Secondly, the estimation of the probability of a later date in the spring and an earlier date in the fall for various severe frost events and the length of the frost-free period is determined. Third, the changes in the timing of the last and first frosts of the three severities, as well as the length of the frost-free period, are evaluated. From 1961 to 2011, the Elbe River lowland has experienced a decrease in the number of frost days, while the length of the frost-free period between the last spring frost and the first fall frost has increased. The temporal evolution of the frost-free period anomalies displays two distinct periods: a shortening of the frost-free period in the 1960s and an intensified lengthening of the frost-free period since the 1980s. Whereas the latest spring frost has ended on an earlier date across the Elbe River lowland, the first frost date in the fall has generally been delayed to a later date. The dates of the last spring frost have advanced by ?0.21 days per year on average. The fall dates are delayed up to 0.18 days per year, whereas the frost-free period is lengthening by up to 0.39 days per year on average. However, regional frost series suggests that the frost-free period exhibits a large amount of inter-annual variability. In terms of the growth of field vegetables, a late spring frost remains a risk factor, but the degree of risk has decreased. There is a 25 % chance of the occurrence of dangerous spring frosts during the planting of field vegetables after 3rd May, but after 15th May, the risk is only 10 %.  相似文献   

The spatial distribution of the lignite qualitative parameters and variant estimates of coal reserves: the Czech Part of the Vienna Basin     

Jan Jelínek  František Staněk  Lukáš Vebr  Josef Honěk 《International Journal of Earth Sciences》2014,103(4):1113-1123

The aim of this article is to inform about the spatial distribution of the lignite qualitative parameters and total lignite reserves in the Czech Part of the Vienna Basin—The South Moravian Lignite Coalfield (SMLC). The total reserves were estimated on the basis of several composed variant digital models of individual seams in four partial area of SMLC. Calculations of the reserves resulted from the identified spatial distribution of chemical-technological parameters obtained from the thousands analysis of samples taken from more than 4,000 exploration works. The basic model of the deposit was so-called geological model characterising genetic evolution of the deposit and defines the spatial positions of the coal seams. Subsequently developed variant economical models spatially define the selected areas by the quality of lignite expressed by the limits of ash yield. Based on the created models, it was found that in the past just 3–7 % (depending on the variant model) of the total lignite reserves SMLC had been extracted. The presented geological reserves are currently using the existing mining technologies only partially mineable.  相似文献