排序方式： 共有32条查询结果，搜索用时 109 毫秒
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Mark S. T. Bukowinski Philip E. Wannamaker Manfred Koch Yukio Fujinawa Dr. Pradeep Talwani D. Möhlmann Andrew H. Knoll Lucia Lovison-Golob Krzysztof Haman Hanna Pawłowska Henryk Piwkowski Dr. Anthony Dore Nguyen Xuan Huy Edward R. Cook Jan Błecki Jacek Leliwa-Kopystynski Magdalena Sroczynska-Kozuchowska 《Pure and Applied Geophysics》1993,140(1):139-177
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Changes in water chemistry along the High Arctic fluvial–lacustrine system located in Wedel Jarlsberg Land in the SW Spitsbergen (Svalbard) were investigated during the summer season of 2010 and 2011. The newly formed river–lake system consists of three lakes connected with the Brattegg River. The first bathymetric measurements of these lakes were made by the authors in 2010. The Brattegg River catchment represents a partly glaciered Arctic water system. The studied lakes are characterized by low mineralization and temperature of water. The value of the electrolytic conductivity (EC) ranges from 30.2 to 50.5 μS cm?1 and the temperature of surface water from 1.5 to 7.8 °C. The temperature increase takes place downstream starting from Upper Lake to the outflow from Myrktjørna Lake. The waters of lakes have higher temperatures than the stream. The predominant ions are HCO3 ? (up to 16.5 mg L?1), Cl? (6.66–8.53 mg L?1), Ca2+ (2.40–4.45 mg L?1) and Na+ (2.65–3.36 mg L?1). The highest values of ammonium and DOC found in the lowest Myrktjørna Lake seem to be related to the presence of aquatic organisms and also birds. From the group of 10 analyzed microelements, increased concentrations of aluminum, up to almost 500 μg L?1, are present in the lakes’ water. Water isotopic composition ranges for δ18O and δ2H, from ?10.6 to ?10.9‰ and from ?70.8 to ?72.3‰, respectively. The vertical zonality of lake waters is manifested in a decrease in the temperature and increase in EC and chemical elements concentrations. 相似文献
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Frank Flechtner Karl-Hans Neumayer Christoph Dahle Henryk Dobslaw Elisa Fagiolini Jean-Claude Raimondo Andreas Güntner 《Surveys in Geophysics》2016,37(2):453-470
The primary objective of the gravity recovery and climate experiment follow-on (GRACE-FO) satellite mission, due for launch in August 2017, is to continue the GRACE time series of global monthly gravity field models. For this, evolved versions of the GRACE microwave instrument, GPS receiver, and accelerometer will be used. A secondary objective is to demonstrate the effectiveness of a laser ranging interferometer (LRI) in improving the satellite-to-satellite tracking measurement performance. In order to investigate the expected enhancement for Earth science applications, we have performed a full-scale simulation over the nominal mission lifetime of 5 years using a realistic orbit scenario and error assumptions both for instrument and background model errors. Unfiltered differences between the synthetic input and the finally recovered time-variable monthly gravity models show notable improvements with the LRI, on a global scale, of the order of 23 %. The gain is realized for wavelengths smaller than 240 km in case of Gaussian filtering but decreases to just a few percent when anisotropic filtering is applied. This is also confirmed for some typical regional Earth science applications which show randomly distributed patterns of small improvements but also degradations when using DDK4-filtered LRI-based models. Analysis of applied error models indicates that accelerometer noise followed by ocean tide and non-tidal mass variation errors are the main contributors to the overall GRACE-FO gravity model error. Improvements in these fields are therefore necessary, besides optimized constellations, to make use of the increased LRI accuracy and to significantly improve gravity field models from next-generation gravity missions. 相似文献
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A surface geochemical survey was carried on in an area with a cluster of petroleum deposits in western Poland. The largest of these accumulations is the Papro?-Cicha Góra dry gas deposit reservoired in the Rotliegend sediments. Other, similar gas deposits are: the Papro? gas field discovered in the top part of the Carboniferous formation and the Papro? W, Papro? N, and Nowy Tomy?l gas fields localized in the Zechstein Limestone reef structures. Moreover, the Papro? gas-condensate and the Jastrz?bsko oil deposits were found at shallower depths, in the Main Dolomite formation. This paper aims to analyze the variability of composition and distribution of near-surface gaseous hydrocarbons in relation to hydrocarbon accumulations reservoired in various stratigraphic units at depths. 相似文献
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Leszek R. Jaroszewicz Zbigniew Krajewski Henryk Kowalski Grzegorz Mazur Paweł Zinówko Jerzy Kowalski 《Acta Geophysica》2011,59(3):578-596
We outline the research leading to development of the Autonomous Fibre-Optic Rotational Seismograph (AFORS) and describe the
final version of the instrument. The instrument with linear changes of sensitivity keeps accuracy from 5.1 × 10−9 to 5.5 × 10−8 rad/s in the detection bandpass 1.66–212.30 Hz; it is designed for a direct measurement of rotational components emitted
during seismic events. The presented system is based on the optical part of the fibre optic gyro construction where a special
autonomous signal processing unit (ASPU) optimizes its operation for the measurement of rotation motions instead of the angular
changes. The application of a newly designed telemetric system based on the Internet allows for a remote system control, as
shown in an example of the system’s operation in Książ (Poland) seismological observatory. 相似文献
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Hard coal mining in the area of the Bytom Syncline (Upper Silesia Coal Basin, Poland) has been associated with the occurrence of high-energy seismic events (up to 109 J; local magnitude up to 4.0), which have been recorded by the local mining seismological network and regional seismological network. It has been noticed that the strongest seismic events occur when the mine longwall alignments coincide with the syncline axis. Data recorded by the improved local seismic network in the Bobrek Mine allow the estimation of the depths of the events’ hypocentres during excavation of longwall panel 3 as it approached the syncline axis. The recorded data were also used to estimate the location of the rupture surface and stress distribution in the seismic focus region. It was concluded that tectonic stresses, particularly horizontal stress components, are essential in the distribution of seismic tremors resulting from reverse faulting. The stresses induced by mining activity are only triggering tectonic deformations. The hypocentres of the strongest seismic events during mining of longwall panel 3/503 were located 300–800 m deeper than the level of coal seam 503. 相似文献
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In 2001 a surface geochemical survey was carried out in the Carpathian Foredeep, in the area between Jaros?aw and Radymno (SE Poland) where multihorizon gas deposits were discovered. These deposits accumulate microbial CH4 with small amounts of N2 and higher molecular weight gaseous hydrocarbons. Soil–gas composition in the hydrocarbon fields in the study area is relatively different from the original composition of natural gas occurring in the subsurface reservoir. In 449 analyzed soil gas samples collected from 1.2 m depth relatively low concentrations were found for CH4 (median value 2.2 ppm) and its homologues (median value of total alkanes C2–C4 – 0.02 ppm). Alkenes were encountered in 36.3% of the analyzed samples (mean value of total alkenes C2–C4 – 0.015 ppm) together with distinctly higher concentrations of H2 (maximum value – 544 ppm, mean value – 42 ppm) and CO2 (maximum value – 10.26 vol.%, mean value – 2.27 vol.%). Individual, very high concentrations of CH4 (up to about 35 vol.%) resulted from sub-surface biochemical reactions whereas higher alkanes detected in soil gases (up to about 68 ppm) originated from deep gas accumulations. Both the H2 and alkenes may be indirect indicators of deep hydrocarbon accumulations. Carbon dioxide may also be useful for hydrocarbon exploration, revealing increased concentrations in those sampling sites where CH4 concentrations are strongly depleted, presumably due to bacterial oxidation. These relationships are valid only for the study area and should not be extended as an universal principle. 相似文献
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Comparison of Daily GRACE Gravity Field and Numerical Water Storage Models for De-aliasing of Satellite Gravimetry Observations 总被引：1，自引：0，他引：1
L. Zenner I. Bergmann-Wolf H. Dobslaw T. Gruber A. Güntner M. Wattenbach S. Esselborn R. Dill 《Surveys in Geophysics》2014,35(6):1251-1266
Reducing aliasing effects of insufficiently modelled high-frequent, non-tidal mass variations of the atmosphere, the oceans and the hydrosphere in gravity field models derived from the Gravity Recovery and Climate Experiment (GRACE) satellite mission is the topic of this study. The signal content of the daily GRACE gravity field model series (ITG-Kalman) is compared to high-frequency bottom pressure variability and terrestrially stored water variations obtained from recent numerical simulations from an ocean circulation model (OMCT) and two hydrological models (WaterGAP Global Hydrology Model, Land Surface Discharge Model). Our results show that daily estimates of ocean bottom pressure from the most recent OMCT simulations and the daily ITG-Kalman solutions are able to explain up to 40 % of extra-tropical sea-level variability in the Southern Ocean. In contrast to this, the daily ITG-Kalman series and simulated continental total water storage variability largely disagree at periods below 30 days. Therefore, as long as no adequate hydrological model will become available, the daily ITG-Kalman series can be regarded as a good initial proxy for high-frequency mass variations at a global scale. As a second result of this study, based on monthly solutions as well as daily observation residuals, it is shown that applying this GRACE-derived de-aliasing model supports the determination of the time-variable gravity field from GRACE data and the subsequent geophysical interpretation. This leads us to the recommendation that future satellite concepts for determining mass variations in the Earth system should be capable of observing higher frequeny signals with sufficient spatial resolution. 相似文献