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Gavrilov B. G. Poklad Yu. V. Ryakhovsky I. A. Ermak V. M. 《Geomagnetism and Aeronomy》2022,62(1-2):98-103
Geomagnetism and Aeronomy - An experimental study was made of the dependence of the electron-density perturbations in the D?regions of the midlatitude ionosphere during solar flares on the... 相似文献
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Ryakhovskii I. A. Gavrilov B. G. Poklad Yu. V. Bekker S. Z. Ermak V. M. 《Izvestiya Physics of the Solid Earth》2021,57(5):718-730
Izvestiya, Physics of the Solid Earth - Abstract—Studying the spatiotemporal dynamics of the disturbances in the atmosphere, upper, and lower ionosphere requires integrated investigation of... 相似文献
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Gavrilov B. G. Ermak V. M. Poklad Yu. V. Ryakhovskii I. A. 《Geomagnetism and Aeronomy》2019,59(5):587-592
Geomagnetism and Aeronomy - Changes in the state of the D and E ionospheric regions lead to variations in the amplitude-phase characteristics of VLF radio signals. The existing theoretical and... 相似文献
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Gavrilov B. G. Ermak V. M. Lyakhov A. N. Poklad Yu. V. Rybakov V. A. Ryakhovsky I. A. 《Geomagnetism and Aeronomy》2020,60(6):747-753
Geomagnetism and Aeronomy - The paper presents the results of the reconstruction of the effective height h' and the slope of the profile β of the electron concentration in the D layer of... 相似文献
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We present a Lagrangian stochastic model of vertical dispersion in the convective boundary layer (CBL). This model is based on a generalized Langevin equation that uses the simplifying assumption that the skewed vertical velocity probability distribution is spatially homogeneous. This approach has been shown to account for two key properties of CBL turbulence associated with large-scale coherent turbulent structures: skewed vertical velocity distributions and long velocity correlation time. A 'linear-skewed' form of the generalized Langevin equation is used, which has a linear (in velocity) deterministic acceleration and a skewed random acceleration. 'Reflection' boundary conditions for selecting a new velocity for a particle that encounters a boundary were investigated, including alternatives to the standard assumption that the magnitudes of the particle incident and reflected velocities are positively correlated. Model simulations were tested using cases for which exact, analytic statistical properties of particle velocity and position are known, i.e., well-mixed spatial and velocity distributions. Simulations of laboratory experiments of CBL dispersion show that (1) the homogeneous linear-skewed Langevin equation model (as well as an alternative 'nonlinear-Gaussian' Langevin equation model) can simulate the important aspects of dispersion in the CBL, and (2) a negatively-correlated-speed reflection boundary condition simulates the observed dispersion of material near the surface in the CBL significantly better than alternative reflection boundary conditions. The homogeneous linear-skewed Langevin equation model has the advantage that it is computationally more efficient than the homogeneous nonlinear-Gaussian Langevin equation model, and considerably more efficient than inhomogeneous Langevin equation models. 相似文献
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A. A. Egoshin V. M. Ermak Yu. I. Zetzer S. I. Kozlov V. P. Kudryavtsev A. N. Lyakhov Yu. V. Poklad E. N. Yakimenko 《Izvestiya Physics of the Solid Earth》2012,48(3):275-286
The statistical characteristics of the intensity of VLF-LF radio signals transmitted from the midlatitude radio stations and
recorded by the receiver at the Mikhnevo geophysical observatory (54.94°N, 37.73°E; Institute of Geosphere Dynamics, Russian
Academy of Sciences) in 2007–2010 are analyzed. The experiments revealed strong variations in the intensity of radio signals
during the deep solar minimum conditions, when the medium does not experience impacts from above associated with solar and
geomagnetic activity. We relate the observed variations to the disturbances from below, which are caused by the meteorological
and wave processes occurring in the lower atmosphere. 相似文献
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A Lagrangian stochastic model for the time evolution of the velocity of a fluid particle is presented. This model is based on a one-dimensional generalized Langevin equation, and assumes the velocity probability distribution of the turbulent fluid is skewed and spatially homogeneous. This has been shown to be an effective approach to simulating vertical dispersion in the convective boundary layer. We use a form of the Langevin equation that has a linear (in velocity) deterministic acceleration and a random acceleration that is a non-Gaussian, skewed process. For the case of homogeneous fluid velocity statistics, this 'linear-skewed' Langevin equation can be integrated explicitly, resulting in an efficient numerical simulation method. Model simulations were tested using cases for which exact, analytic statistical properties of particle velocity are known. Results of these tests show that, for homogeneous turbulence, a linear-skewed Langevin equation model can overcome the difficulties encountered in applying a Langevin equation with a skewed random acceleration. The linear-skewed Langevin equation model results are compared to results of a 'nonlinear-Gaussian' Langevin equation model, and show that the linear-skewed model is significantly more efficient. 相似文献
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