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81.
K. Schneider-Carius 《Pure and Applied Geophysics》1949,15(3-4):236-241
Ohne Zusammenfassung 相似文献
82.
Wiener optimal filtering of GRACE data 总被引:4,自引:0,他引:4
We present a spatial averaging method for Gravity Recovery and Climate Experiment (GRACE) gravity-field solutions based on
the Wiener optimal filtering.
The optimal filter is designed from the least-square minimization of the difference between the desired and filtered signals.
It requires information about the power spectra of the desired gravitational signal and the contaminating noise, which is
inferred from the average GRACE degree-power spectrum. We show that the signal decreases with increasing spherical harmonic
degree j with approximately j−b, where b = 1.5 for GRACE data investigations. This is termed the Second Kaula rule of thumb for temporal variations of the
Earth’s gravity field. The degree power of the noise increases, in the logarithmic scale, linearly with increasing j.
The Wiener optimal filter obtained for the signal model with b = 1.5 closely corresponds to a Gaussian filter with a spatial
half width of 4° (∼440 km). We find that the filtered GRACE gravity signal is relatively insensitive to the exponent b of
the signal model, which indicates the robustness of Wiener optimal filtering. This is demonstrated using the GFZ-GRACE gravity-field
solution for April 2004. 相似文献
83.
A. J. Kappos I. G. Gidaris K. I. Gkatzogias 《Bulletin of Earthquake Engineering》2012,10(4):1237-1266
Currently available displacement-based design (DBD) procedures for bridges are critically evaluated with a view to identifying extensions and/or modifications of the procedure, for it to be applicable to final design of a fairly broad class of bridges. An improved direct DBD procedure is presented, including a suite of comprehensive design criteria and proper consideration of the degree of fixity of the pier top. The design of an overpass bridge (originally designed to a current European Code), applying the improved ‘direct’ displacement-based design (DDBD) procedure is presented and both ‘conventional’ and displacement-based designs are assessed using non-linear response-history analysis (NLRHA); comparisons are made in terms of both economy and seismic performance of the different designs. It is seen that DDBD provided a more rational base shear distribution among piers and abutments when compared to the force-based design procedure and adequately captured the displacement pattern, closely matching the results of the more rigorous NLRHA. 相似文献
84.
M.?A.?LevitanEmail author T.?N.?Gelvi K.?V.?Syromyatnikov K.?D.?Chekan 《Geochemistry International》2018,56(4):304-317
Lithofacies zoning is described for the first time for the Neo- and Eopleistocene of the Bering Sea. Four lithofacies sedimentation zones are distinguished: (I) terrigenous; (II) siliceous–terrigenous; (III) siliceous, and (IV) volcanoterrigenous ones. Corresponding maps were treated using Ronov volumetric method to quantify sedimentation parameters for distinguished lithofacies zones (subzones) and types of Pleistocene sediments. It was revealed that terrigenous sediments predominate over other sediments. Accumulation of the terrigenous sediments was more intense (by 1.4 times) in the Neopleistocene than in the Eopleistocene. The sedimentation rate of siliceous sediments of the Bowers Ridge in the Eopleistocene was two times higher than in the Neopleistocene. 相似文献
85.
86.
K. Cehak 《Meteorology and Atmospheric Physics》1963,13(3-4):343-359
Zusammenfassung Es werden Gleichungen abgeleitet, mittels derer man aus dem Energiespektrum des Windes die Häufigkeit von Böen bestimmter Größe und bestimmter Mindestgröße, die Größe der häufigsten Böenspitze und einen mittleren Abstand zwischen zwei Böenstößen berechnen kann. Die Theorie wird an einem Beispiel erläutert.
Mit 4 Textabbildungen 相似文献
Summary Equations are derived which allow the calculation of frequencies of gusts with a velocity equal or larger than a given amount, of the velocity of the most frequent gust, and of a mean interval between two gusts out of the power-spectrum of wind. The theory is illustrated by an example.
Résumé L'auteur établit des formules permettant de calculer les grandeurs suivantes en partant du spectre énergétique du vent: Fréquence des rafales de force ou de force maximale déterminées, force des rafales les plus fréquentes ainsi que le temps moyen séparant deux rafales. Il démontre sa théorie par un exemple.
Mit 4 Textabbildungen 相似文献
87.
A general method for representing the flow properties in the three-dimensional boundary layers around ship hulls of arbitrary shape is described. It makes use of an efficient two-point finite-diffirence schem to solve the boundary-layer equations and includes an algebraic eddy-viscosity representaion of the Reynolds-stress ternsor. The numericzal method contains novel and desirable features and allows the calculation of flows in which the circumferential velocity component contains regions of flow reversal across the boundary layer. The inviscid pressure distribution is determined with the Douglas-Neumann method which, if necessary, can conveniently allow for the boundary-layer displacement surface. To allow its application to ships, and particularly to those with double-elliptic and flat-bottomed hulls, a non-orthogonal coordinate system has been developed and is shown to be economical, precise and comparatively easy to use. Present calculations relate to zero Froude number but they can be extended to include the effects of a water wave and local regions of flow separation which may stem from bulbous-bow geometries. 相似文献
88.
Comprehensive distribution patterns of physical and chemical characteristics have been obtained from a series of cruises in Liverpool Bay. The marked feature of these distributions was their temporal variability, suggesting that the surface residual circulation is also temporally variable. The influence of wind stress upon the circulation pattern and hence water quality of this sea area is illustrated. 相似文献
89.
A. F. Morozov B. N. Khakhaev O. V. Petrov V. I. Gorbachev G. V. Tarkhanov L. D. Tsvetkov Yu. M. Erinchek A. M. Akhmedov V. A. Krupenik K. Yu. Sveshnikova 《Doklady Earth Sciences》2010,435(1):1483-1486
A thick (200 m) rock salt mass covering Late Archean granitoids was exposed for the first time in the Early Proterozoic volcanogenic-sedimentary
formations in the Onega trough of the east Baltic Shield by the Onega parametric well. The mineral composition of salts, their
geochemical features, and the isotopic composition of carbonate carbon and oxygen have been studied. After fluid inclusions
present in salts, their metamorphism temperature and isotopic composition of helium and argon were determined. The obtained
results give evidence of the fact that rock salts and magnesites associated with them were formed in an evaporate basin with
participation of deep crustal processes. The age of the underlying granitoids (2.716 ± 9 Ma) is determined using the Pb—Pb
method. 相似文献
90.
Doklady Earth Sciences - Distribution density functions for the sensitivity of a three-coil sounder are constructed as the weighted mean rock volume between the in-phase surfaces of running... 相似文献