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The natural geomagnetic field is constantly disturbed. The total registered effect of geomagnetic variations depends on both planetary and local processes. Planetary sources and sources in the Earth’s core respond to tidal effects. In the accepted model, the complex MHD processes in the Earth’s outer core are approximated by the assumed ring current in the equatorial plain of the liquid core. The geomagnetic variation originating as a result of tidal deformations of ring currents are ～10?4 and 0.10–1 nT in the liquid core and magnetosphere, respectively. The calculated values coincide in order of magnitude with the processed geomagnetic measurements at Paratunka observatory (Kamchatka region). 相似文献
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The effect of a thin viscous fluid–mud layer on nearshore nonlinear wave–wave interactions is studied using a parabolic frequency-domain nonlinear wave model, modified to incorporate a bottom dissipation mechanism based on a viscous boundary layer approach. The boundary-layer formulation allows for explicit calculation of the mud-induced wave damping rate. The model performed well in tests based on laboratory data. Numerical tests show that damping of high frequency waves occurs, mediated by “difference” nonlinear interactions. Simulations of 2-dimensional wave propagation over a mud “patch” of finite extent show that the wave dissipation causes significant downwave diffraction effects. 相似文献
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Wave modelling - The state of the art 总被引：2，自引：0，他引：2
The WISE Group J.-H.G.M. Alves A. Babanin K. Belibassakis M. Donelan T.H.C. Herbers P.A.E.M. Janssen I.V. Lavrenov R. Magne M. Onorato D. Resio A. Sheremet H.L. Tolman J. Wolf 《Progress in Oceanography》2007,75(4):603-674
This paper is the product of the wave modelling community and it tries to make a picture of the present situation in this branch of science, exploring the previous and the most recent results and looking ahead towards the solution of the problems we presently face. Both theory and applications are considered.The many faces of the subject imply separate discussions. This is reflected into the single sections, seven of them, each dealing with a specific topic, the whole providing a broad and solid overview of the present state of the art. After an introduction framing the problem and the approach we followed, we deal in sequence with the following subjects: (Section) 2, generation by wind; 3, nonlinear interactions in deep water; 4, white-capping dissipation; 5, nonlinear interactions in shallow water; 6, dissipation at the sea bottom; 7, wave propagation; 8, numerics. The two final sections, 9 and 10, summarize the present situation from a general point of view and try to look at the future developments. 相似文献
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Geotectonics - We have performed a comparative analysis of geological structure and geodynamic evolution of the nearly synchronous Izu–Bonin–Mariana and Aleutian island-arc systems. The... 相似文献
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We analyze the possibility of determining the masses of outer planetary satellites from their mutual gravitational perturbations via ground-based observations. Such a technique has been applied in (Emelyanov, 2005b) to determine the mass of the Jovian satellite Himalia. In this paper, we use the least-squares method to compute the errors of satellite masses inferred from simulated observations. We analyze several of the most suitable variants of groups of outer satellites of planets with maximum mutual attraction. We found that the mass of the Satumian satellite Phoebe (S9) can be refined by continuing observations of the satellite S25 Mundilfari until 2027. We show that the masses of other known outer planetary satellites cannot be determined from ground-based observations. 相似文献
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A study based on computation of D-function anomalies (method of joint gravity and magnetic data analysis) along profiles in the Bering Sea has been performed in both the Aleutian Basin with oceanic crust and the Bering continental shelf. This study revealed extended faults that affect not only the Earth’s crust but also the upper mantle. This is supported by seismic profiling. The calculated palinspastic reconstructions of the position of North America relative to “immobile” Eurasia 80, 52–50, 50–47, and 15–20 Ma ago allowed us to show that the revealed strike-slip faults are probable relics of an echeloned transform boundary between the Eurasian and North American lithospheric plates. The formation of this boundary beginning from the Late Cretaceous was apparently related to opening of the North Atalantic, which determined the large rate of displacement of North America relative to Eurasia. 相似文献