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21.
The structure of the mid- and high-latitude ionosphere during the November 2004 storm event obtained from GPS observations 总被引:1,自引:1,他引:1
Andrzej Krankowski Irk I. Shagimuratov Lubomir W. Baran Galina Yakimova 《Acta Geophysica》2007,55(4):490-508
GPS data from the International GNSS Service (IGS) network were used to study the development of the severe geomagnetic storm
of November 7–12, 2004, in the total electron content (TEC) on a global scale. The TEC maps were produced for analyzing the
storm. For producing the maps over European and North American sectors, GPS measurements from more than 100 stations were
used. The dense network of GPS stations provided TEC measurements with a high temporal and spatial resolution. To present
the temporal and spatial variation of TEC during the storm, differential TEC maps relative to a quiet day (November 6, 2004)
were created.
The features of geomagnetic storm attributed to the complex development of ionospheric storm depend on latitude, longitude
and local time. The positive, as well as negative effects were detected in TEC variations as a consequence of the evolution
of the geomagnetic storm. The maximal effect was registered in the subauroral/auroral ionosphere during substorm activity
in the evening and night period. The latitudinal profiles obtained from TEC maps for Europe gave rise to the storm-time dynamic
of the ionospheric trough, which was detected on November 7 and 9 at latitudes below 50°N. In the report, features of the
response of TEC to the storm for European and North American sectors are analyzed. 相似文献
22.
23.
Żelaźniewicz Andrzej Marheine Dirk Oberc-Dziedzic Teresa 《International Journal of Earth Sciences》2003,92(2):185-194
A Variscan foreland in western Poland comprises two NW-trending basement highs, which are concealed under Carboniferous through Triassic strata of the Fore-Sudetic Monocline (FSM). Both highs consist of multiply deformed quartz-sericite - albite - chlorite phyllites of unknown protolith age. 40Ar/39Ar laser probe dating of white micas in up to 0.5-mm-thick mica layers, which form the S2 axial-plane foliation in phyllites of the Wolsztyn-Leszno High, yielded an age of 340.1DŽ.6 Ma for the lower greenschists facies metamorphism and probably also for the F2 folding. This deformation was associated and followed by thrusting, which brought about the basement highs. The latter delivered clasts to overlying late Viséan-early Namurian flysch basin that was mainly sourced from the Saxothuringian Sudetes in which most of the deformation occurred between 345-335 Ma. The FSM basement may represent an independent terrane, referred to as the Wielkopolska terrane, belonging to the Armorican Terrane Assemblage. 相似文献
24.
Yong Il Lee Hyoun Soo Lim Ho Il Yoon Andrzej Tatur 《Quaternary Science Reviews》2007,26(25-28):3167-3178
Several reworked tephra layers in gravity-flow deposits are present in lacustrine core sediments collected from Hotel and Rudy Lakes on King George Island, South Shetland Islands, maritime sub-Antarctica. This study tests the values of tephra for establishing regional tephrochronologies for lakes in ice-covered landscapes in the vicinity of volcanoes. The tephra record is more abundant in a long Hotel Lake core (515 cm long). This study uses volcanic glass samples from five tephra layers of Hotel Lake and from one tephra layer of Rudy Lake. Morphologically, tephras are mixtures of basaltic and pumice shards, both having various degrees of vesicularity. Major element analyses of glass shards reveal that the majority of the glass fragments belong to basic glass (<60 wt% SiO2), compositionally ranging from basalt to low-silica andesite and subalkaline series medium-K tholeiites, probably sourced from Deception Island located 130 km southwest of King George Island. Less than 20% of tephra belongs to silicic glass and occurs in three tephra horizons E of Hotel Lake. However, source volcano(es) for about 10% of basic tephra and silicic tephra are not readily identified from nearby volcanic centers. Except for the studied tephra in Rudy Lake, all tephra samples in Hotel Lake are not ashfall deposits but reworked and redeposited pyroclasts derived from retreating ice sheet, resulting in the occurrence of geochemically equivalent tephra samples in different tephra horizons. The dating of the studied tephra horizons represents the timing of deglaciation rather than that of volcanic eruptions. The result of this study implies that combined with sedimentological information more chemical criterion is necessary to study tephrochronology and regional correlation and to understand paleoenvironmental changes using tephra. 相似文献
25.
Earth, Moon, and Planets - 相似文献
26.
On hyperelasticity for clays 总被引:1,自引:0,他引:1
Under purely elastic conditions a constitutive model for clays should be conservative. This can be achieved by using a hyperelastic stress–strain relation derived from an elastic potential. To circumvent problems connected with formulation of a suitable potential a simple concept of back-stress elasticity is proposed. Several elastic models are critically reviewed, two of which had been originally incorrectly classified as hyperelastic. A novel elastic potential which can be used to generate various hyperelastic models is proposed. Its salient feature is that the resulting stiffness is a homogeneous function of order 1 with respect to stress. An example of Mathematica calculation with tensorial differentiation is enclosed (Wolfram S. Mathematica. A system for doing mathematics by computer. Addison-Wesley Publishing, 1988). © 相似文献
27.
Andrzej Kijko 《Pure and Applied Geophysics》1977,115(4):1011-1021
Summary Seven optimal networks consisting of 4 to 10 stations are compared for a given region, where velocity-depth profiles and the distribution of seismic intensity are known. Assuming that the standard error of arrival time is
t
=0.05 s and the standard errors of the parameters of velocity-depth profiles are equal to 5% of their values, the average standard errors of the origin time
and focus coordinates
are estimated. The application of optimum methods to the planning of seismic networks in the Lublin Coal Basin is presented, and maps of standard errors of origin time
, depth
and epicenter (
xy
) for the case of an optimum network of 6 seismic stations are given. 相似文献
28.
On the basis of thermodynamic calculations, diagrams of metastable electrochemical equilibria of the system copper-potassium ethylxanthate-water, at 25°C were constructed. The equilibria equations and diagrams for the total activity of [EtX?] + [HEtX] + 2 [(EtX)2] (equalling 10?1, 10?4 and 10?7 mol/dm3), are presented. The practical conclusions resulting from these diagrams for the flotation of native copper are discussed. 相似文献
29.
30.
Andrzej J. Maciejewski Maria Przybylska 《Celestial Mechanics and Dynamical Astronomy》2011,110(1):17-30
We consider the planar problem of three bodies which attract mutually with the force proportional to a certain negative integer
power of the distance between the bodies. We show that such generalisation of the gravitational three-body problem is not
integrable in the Liouville sense. 相似文献