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1.
Doklady Earth Sciences - A model of the Earth’s cooling, which describes the formation of a solid core, is considered. Its formation enhances the convection due to additional energy sources... 相似文献
2.
M. Yu. Reshetnyak 《Solar System Research》2014,48(3):182-193
Using the Lagrangian approach, the author considered the temporal evolution of an ensemble of interacting magnetohydrodynamic cyclones, obeying equations of the Langevin type, in a rotating medium. The problem is topical for fast-rotating convective objects: cores of planets and a number of stars, where the Rossby numbers are much less than unity and the geostrophic balance of forces is observed. In this work, results of simulation are given both for the two-dimensional case, when axes of cyclones can rotate only in the vertical plane, and for the three-dimensional case when the axes are rotating by two angles. It is shown that a change in the heat flux on the shell boundary impacts the frequency of reversals of the mean dipole magnetic field, which agrees with results of simulation in three-dimensional models of a planetary dynamo. Applications of the model for the giant planets are considered, and an explanation of certain episodes of the geomagnetic field in the past is offered. 相似文献
3.
M. Yu. Reshetnyak 《Geomagnetism and Aeronomy》2009,49(4):542-549
The interaction between Fourier waves, which results in energy transfer over the spectrum, has been considered using the Boussinesq model in a plane layer during rapid rotation as an example. It has been indicated that the wave triangle spectrum strongly differs on the scales shorter (longer) than the scale of a cyclonic turbulence leading mode. 相似文献
4.
M. Yu. Reshetnyak 《Izvestiya Physics of the Solid Earth》2007,43(8):642-652
A dynamo model for an incompressible liquid in a rectangular rapidly rotating box is considered. The model is based on a pseudospectral method adapted for multiprocessor technology. The effect of rotation in Boussinesq models on some of the basic characteristics of flows is studied: the spatial form of fields, helicity generation, and spectra of fields. A mechanism stabilizing the magnetic field rise associated with the transition of the system to a nonlinear regime is analyzed separately. The results obtained in the paper provide deeper insights into the processes of magnetoconvection in the cores of planets. 相似文献
5.
M. Yu. Reshetnyak 《Astronomy Reports》2017,61(9):783-790
A three-dimensional model for thermal convection with a dynamo in a rotating planar layer heated from below is used to investigate the behavior of the mean kinetic and current helicities. In spite of the presence of gravity and rotation, which introduce anisotropy into the system, the components of the helicity determined from the field components in the directions tangent and normal to the boundary have similar values. The existence of a separation by scale, when the current helicity has different signs on different spatial scales, is demonstrated. The number of regions where the sign of the helicity does not coincide with the sign of its mean value in that region is estimated (～43?45% of the total number of regions). The estimates presented are relevant for interpretations of observations of solar activity and analysis of the properties of rotating magnetohydrodynamical turbulence. 相似文献
6.
Izvestiya, Atmospheric and Oceanic Physics - This paper considers a sequential selection of parameters in a model of cooling of the Earth’s core. The model describes the evolution from the... 相似文献
7.
A. M. Nikanorov L. P. Sokolova O. S. Reshetnyak M. Yu. Kondakova A. O. Danilenko 《Russian Meteorology and Hydrology》2010,35(4):281-288
The results of calculation and analysis of the inflow of dissolved chemical substances to the estuarine area of the Northern
Dvina River are considered. Based on the long-term regime hydrochemical information of the State Service of Observation and
Monitoring of the Natural Environmental State, the anthropogenic load of dissolved chemical substances on the estuarine area
and on the estuarine coastal water is estimated per inflow volumes. The extent of the water environment pollution of the near-delta
part of the Northern Dvina River and its delta is estimated. The distribution of pollutant inflow among arms and channels
in delta is under consideration. 相似文献
8.
M. Yu. Reshetnyak 《Izvestiya Physics of the Solid Earth》2014,50(4):467-473
The three-dimensional dynamo model in the fast-rotating plane layer heated from below is considered. The transition from the linear generation of the magnetic field to the nonlinear generation is studied. With the use of the wavelet analysis, it is demonstrated how the spatial spectra of the kinetic and magnetic energies, as well as the hydrodynamic, magnetic, cross-, and current helicity, vary in time. The scenarios of the suppression of α-effect (α-quenching) by the magnetic field are suggested. 相似文献
9.
A. M. Nikanorov L. I. Minina V. A. Bruzgalo L. S. Kosmenko M. Yu. Kondakova O. S. Reshetnyak A. O. Danilenko 《Water Resources》2016,43(5):791-802
Many-year variations of water pollution and the state of more than two hundred of rivers (or their segments) in different latitudinal zones in European Russia are estimated. In accordance with latitudinal zonality, space and time trends in variations of water quality and the state of rivers are identified. By the level of water pollution, most river ecosystems (or their segments) were classified as polluted and very polluted, very polluted and dirty, dirty and very dirty. A tendency toward water quality improvement could be seen in the recent decade. More than 50% of the examined river ecosystems are at the transitional state of passing from natural (and/or equilibrium) to crisis state. 相似文献
10.
M. Yu. Reshetnyak 《Izvestiya Physics of the Solid Earth》2012,48(4):326-334
The eigenvalue problem for Parker’s dynamo model is considered. We study how the intensity of convection in the liquid core
of the Earth affects the generation of the geomagnetic field with different directions of latitudinal field propagation. The
scenarios of transition of the geomagnetic field from frequent to rare reversals are suggested. 相似文献