Pareto Joint Inversion of 2D Magnetotelluric and Gravity Data — Towards Practical Applications     

Katarzyna Miernik  Adrian Bogacz  Adam Kozubal  Tomasz Danek  Marek Wojdyła 《Acta Geophysica》2016,64(5):1655-1672

In this paper, a Pareto inversion based global optimization approach, to obtain results of joint inversion of two types of geophysical data sets, is formulated. 2D magnetotelluric and gravity data were used for tests, but presented solution is flexible enough to be used for combination of any kind of two or more target functions, as long as misfits can be calculated and forward problems solved. To minimize dimensionality of the solution, space and introduce straightforward regularization Sharp Boundary Interface (SBI) method was applied. As a main optimization engine, Particle Swarm Optimization (PSO) was used. Synthetic examples based on a real geological model were used to test proposed approach and show its usefulness in practical applications.  相似文献   

A protoceratopsid skeleton with an associated track from the Upper Cretaceous of Mongolia     

Grzegorz Nied?wiedzki  Tomasz SingerGerard D. Gierliński  Martin G. Lockley 《Cretaceous Research》2012,33(1):7-10

The Djadokhta Formation of the Gobi Desert is known for the number and diversity of dinosaur and other vertebrate bones and skeletons found there, but only theropod, hadrosaur and supposed ankylosaurid footprints have been reported from this stratum. Dinosaur footprints are also noted from the Nemegt Formation, and occur as typical dinosaur track accumulations (tracksites). An articulated protoceratopsid skeleton - specimen ZPAL Mg D-II/3 - was collected by the Polish-Mongolian Expedition of 1965 from the Djadokhta Formation of Flaming Cliffs in Mongolia. Recently, the natural cast of a tetradactyl digitigrade footprint was found underneath the pelvic girdle while the skeleton and matrix were being prepared. This is possibly the first find of a dinosaur track in close association with an articulated skeleton. Although Protoceratops is an extremely common dinosaur in Mongolia, its footprints have never previously been reported from the Late Cretaceous of the Gobi Desert.  相似文献   

Adaptive Smoothing Method For Computer Derivation of K-Indices     

Krzysztof Nowo&#;y&#;ski  Tomasz Ernst  Jerzy Jankowski 《Geophysical Journal International》1991,104(1):85-93

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Late‐Holocene wind‐field evolution at the southern Baltic coast as revealed by GPR data from the Mrzeżyno dunefield,NW Poland     

Tomasz Żuk  Paweł Sydor  Gregory H. Sambrook Smith 《Boreas: An International Journal of Quaternary Research》2017,46(3):470-485

All dunes within a dunefield usually show a similar response to the wind regime. However, in the late‐Holocene coastal dunefield in NW Poland the surface topography suggests that slipface orientation may vary significantly with distance from the coast, which is rarely reported in the literature. The dunefield was stabilized with forest in the mid‐19th century, preserving a unique record of atmospheric circulation in the South Baltic region at the end of the Little Ice Age. To elucidate the Holocene processes occurring along the study site a pseudo‐3D GPR data set was collected. Six grids of parallel GPR lines combined with 400 m of GPR profiles (2D) were collected across the dunefield and displayed using GOCAD for interpretation and geostatistical analysis. The geophysical data revealed that the larger dunes almost entirely consist of steeply laminated facies. Most importantly the pseudo‐3D data, supported by geostatistical estimates of strata dip directions, revealed the existence of three zones parallel to the coastline with the mean dip direction almost perpendicular to the coast in the northern coastal strip and almost parallel to it in the southern part. Spreads of the dip directions in pseudo‐3D GPR data sets recorded on the stoss slopes of dunes and crests suggested initial deposition on transverse dunes, which later were transformed into barchanoid dunes. This can probably be linked to changes in the wind regime, i.e. reduction in velocity of the northern and northwestern winds leading to reduced sediment supply from the coast. While the data provide a new interpretation of Holocene dunefield dynamics at this site, they also suggest that the minimum number of pseudo‐3D GPR grids required to establish general trends using geostatistical analysis should be at least 10, with even more data needed at larger, or more complex dunefields.  相似文献   

Desiccation shrinkage of non‐clayey soils: multiphysics mechanisms and a microstructural model     

Liang Bo Hu  Hervé Péron  Tomasz Hueckel  Lyesse Laloui 《国际地质力学数值与分析法杂志》2013,37(12):1761-1781

Analysis of macroscopic desiccation shrinkage experiments indicates that most, but not all of the shrinkage during drying occurs while soil is still saturated. Shrinkage practically ceases and air starts to penetrate the soil, when the water content is still quite high, for example, above 20% for the tested soils. The remaining, unsaturated drying process occurs with a much‐reduced shrinkage rate. In this context, we examine data of the pore system evolution as represented by the mercury porosimetry experimental results. The process is then modeled as a two‐stage process of deformation and evacuation of a two‐tube vessel system driven by the external evaporation flux. In the first stage, Poiseuille flow occurs through the vessels. The amount of water evaporated in this stage equals to the reduction of volume of the vessel through the deformation of its walls. This stage ends when a negative water pressure (suction) required to further deform the vessel reaches a critical value at which air enters the pore space. Two physical interpretation of such threshold are discussed. In the subsequent stage, evaporation proceeds with a receding liquid/vapor interface starting from the open end, incrementally emptying the vessel but with a marginal water flow and vessel deformation. The leading variables of the process are identified, and a quantifiable multiphysics meso‐scale scenario of models is established. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Hydrometeorological dataset (2014–2019) from the high Arctic unglaciated catchment Fuglebekken (Svalbard)     

Tomasz Wawrzyniak  Marta Majerska  Marzena Osuch 《水文研究》2021,35(1):e13974

In this study, a hydrometeorological dataset of unglaciated High Arctic catchment is presented. The time series encompasses air temperature, precipitation, wind speed, relative humidity, and runoff data from 2014 to 2019. Meteorological data come from continuous meteorological monitoring carried out at the Hornsund station located in SW Spitsbergen. Flow in the Fuglebekken stream was measured using a portable flowmeter Nivus PCM-F with Active Doppler sensor. Continuous hydrometeorological monitoring in polar environments is crucial for the understanding processes controlling the water circulation in the catchments. Inter- and intra- annual variability of the provided variables gives an insight into river functioning. The data set is provided in an open-access PANGAEA repository (https://doi.pangaea.de/10.1594/PANGAEA.921921), in three time intervals (6, 12, and 24 hours). It may serve as the input to rainfall-runoff hydrological models, and allows multi-model parameter estimation and validation. It can be used in a variety of research topics, including streamflow projections, and more generally in examining Arctic ecosystems and climate change impact studies.  相似文献   

Machine cataloging of impact craters on Mars     

Tomasz F. Stepinski  Michael P. Mendenhall 《Icarus》2009,203(1):77-74

This study presents an automated system for cataloging impact craters using the MOLA 128 pixels/degree digital elevation model of Mars. Craters are detected by a two-step algorithm that first identifies round and symmetric topographic depressions as crater candidates and then selects craters using a machine-learning technique. The system is robust with respect to surface types; craters are identified with similar accuracy from all different types of martian surfaces without adjusting input parameters. By using a large training set in its final selection step, the system produces virtually no false detections. Finally, the system provides a seamless integration of crater detection with its characterization. Of particular interest is the ability of our algorithm to calculate crater depths. The system is described and its application is demonstrated on eight large sites representing all major types of martian surfaces. An evaluation of its performance and prospects for its utilization for global surveys are given by means of detailed comparison of obtained results to the manually-derived Catalog of Large Martian Impact Craters. We use the results from the test sites to construct local depth-diameter relationships based on a large number of craters. In general, obtained relationships are in agreement with what was inferred on the basis of manual measurements. However, we have found that, in Terra Cimmeria, the depth/diameter ratio has an abrupt decrease at ∼38°S regardless of crater size. If shallowing of craters is attributed to presence of sub-surface ice, a sudden change in its spatial distribution is suggested by our findings.  相似文献   

Dinosaur- and mammal-bearing aeolian and associated deposits of the Upper Cretaceous in the Gobi Desert (Mongolia)   总被引：1，自引：0，他引：1  

Ryszard Gradziński  Tomasz Jerzykiewicz 《Sedimentary Geology》1974,12(4):249-278

The Barun Goyot Formation (? Campanian-Maastrichtian) consists of continental red-bed type sandstones. The formation was interpreted in terms of intertonguing and/or alternating dune deposits and sediments of intermittent lakes and streams. The mega cross-stratified sandstone units which show considerable lateral continuity and little variation of foresets dip were described as buried transverse dunes. They are rather poor in animal fossils. Most dinosaurs and mammals occur in water-deposited interdune sediments. This is due to ecological differences between bare dunes and the interdune depression which had a vegetation cover.  相似文献   

History and regional development. A controversy over the ‘right’ interpretation of the role of history in the development of the Polish regions     

Tomasz Zarycki 《Geoforum》2007,38(3):485-493

There is currently a lively discussion on the role of historic memories and the re-visiting of historic legacies in post-communist countries. Using the example of Poland and its legacy of the tripartite division of the 19th century, this paper aims to illustrate how symbolic conflicts over identity politics and the interpretation of history may critically influence discourses on the debates on, and portrayals of, variations in regional development. The paper thus discusses the post-war history of Poland in the context of the so-called left-right political cleavage, and the varying related debates on the ‘quality’ of regional development as part of Poland’s post-communist restructuring. These discussions include varying projections of the nature and role of social capital and its relative ‘usefulness’ for a successful development Poland’s after communism. And there are clear political overtones to these contrasting portrayals of Poland’s history and its regionally varying legacy. Drawing on different definitions of the notion of social capital, the paper then discusses how different legacies, such as an introspective and extrovert outlook of population and institutions, and the degree of cohesion among them, circumscribes a region’s economic development prospects.  相似文献   

Identification of seismic anomalies caused by gas saturation on the basis of theoretical P and PS wavefield in the Carpathian Foredeep,SE Poland     

Kaja Pietsch  Paweł Marzec  Marcin Kobylarski  Tomasz Danek  Andrzej Leśniak  Artur Tatarata  Edward Gruszczyk 《Acta Geophysica》2007,55(2):191-208

The thin-layer build of the Carpathian Foredeep Miocene formations and large petrophysical parameter variation cause seismic images of gas-saturated zones to be ambiguous, and the location of prospection wells on the basis of anomalous seismic record is risky. A method that assists reservoir interpretation of standard recorded seismic profiles (P waves) can be a converted wave recording (PS waves). This paper presents the results of application of a multicomponent seismic survey for the reservoir interpretation over the Chałupki Dębniańskie gas deposit, carried out for the first time in Poland by Geofizyka Kraków Ltd. for the Polish Oil and Gas Company. Seismic modeling was applied as the basic research tool, using the SeisMod program based on the finite-difference solution of the acoustic wave equation and equations of motion. Seismogeological models for P waves were developed using Acoustic Logs; S-wave model (records only from part of the well) was developed on the basis of theoretical curves calculated by means of the Estymacja program calibrated with average S-velocities, calculated by correlation of recorded P and PS wavefields with 1D modeling. The conformity between theoretical and recorded wavefields makes it possible to apply the criteria established on the basis of modeling for reservoir interpretation. Direct hydrocarbon indicators (bright spots, phase change, time sag) unambiguously identify gas-prone layers within the ChD-2 prospect. A partial range of the indicators observed in the SW part of the studied profile (bright spot that covers a single, anticlinally bent seismic horizon) points to saturation of the horizon. The proposed location is confirmed by criteria determined for converted waves (continuous seismic horizons with constant, high amplitude) despite poorer agreement between theoretical and recorded wavefields.  相似文献