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1.
The methods of celestial mechanics can be used to construct a mathematical model for the perturbed rotational motions of the deformable Earth that can adequately describe the astrometric measurements of the International Earth Rotation Service (IERS). This model describes the gravitational and tidal influences of the Sun and Moon. Fine resonant interactions of long-period zonal tides (annual, semiannual, monthly, and biweekly) with the diurnal and semidiurnal tides are revealed. These interactions can be reliably confirmed via a spectral analysis of the IERS data. Numerical modeling of tidal irregularities of the Earth’s axial rotation was carried out, focusing on the analysis and forecasting of variations of the day length occurring within short time intervals of a year or shorter (intrayear variations). 相似文献
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S. N. Kulichkov I. P. Chunchuzov G. A. Bush V. G. Perepelkin 《Izvestiya Atmospheric and Oceanic Physics》2008,44(2):175-186
The results of experiments on the physical modeling of long-range infrasonic propagation in the atmosphere are given. Such modeling is based on the possible coincidence between the forms of the vertical profiles of the effective sound speed stratification in the atmospheric boundary layer (between 0 and 600 m for the case under consideration) and in the atmosphere as a whole (from the land surface up to thermospheric heights (about 150 km)). The source of acoustic pulses was an oscillator of detonation type. Owing to the detonation of a gas mixture of air (or oxygen) and propane, this generator was capable of producing short, powerful (the maximum acoustic pressure was on the order of 30 to 60 Pa at a distance of 50 to 100 m from the oscillator), and sufficiently stable acoustic pulses with a spectral maximum at frequencies of 40 to 60 Hz and a pulsing period of 20 to 30 s. The sites of acoustic-signal recording were located at different distances (up to 6.5 km) from the source and in different azimuthal directions. The temperature and wind stratifications were monitored in real time during the experiments with an acoustic locator—a sodar—and a temperature profiler. The data on the physical modeling of long-range sound propagation in the atmosphere are analyzed to verify the physical and mathematical models of predicting acoustic fields in the inhomogeneous moving atmosphere on the basis of the parabolic equation and the method of normal waves. A satisfactory agreement between calculated and experimental data is obtained. One more task was to compare the theoretical relations between variations in the azimuths and angles of tilting of sound rays about the horizon and the parameters of anisotropic turbulence in the lower troposphere and stratosphere with the experimental data. A theoretical interpretation of the experimental results is proposed on the basis of the theory of anisotropic turbulence in the atmosphere. The theoretical and experimental results are compared, and a satisfactory agreement between these results is noted. 相似文献
3.
I. G. Granberg V. F. Kramar R. D. Kuznetsov O. G. Chkhetiani M. A. Kallistratova S. N. Kulichkov M. S. Artamonova D. D. Kuznetsov V. G. Perepelkin V. V. Perepelkin F. A. Pogarskii 《Izvestiya Atmospheric and Oceanic Physics》2009,45(5):541-548
The studies conducted in 1991–2004 by scientists of the A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, and the Karpov Institute of Physical Chemistry yielded data on the structures of the surface air layer (to a height of 20 m) and both subinversion and inversion layers (to heights of from 800 m to 1 km), where arid aerosol is transported. One of the main objectives of the 2007 experiment was to record the space-vortex structures within a layer of 30–700 m that directly provide the removal and long-range transport of fine-dispersed (<5 µm) desert aerosol. This paper describes the organization of the Khar-Gzyr 2007 experiment (Black Lands, 2007) to study the convective removal of arid aerosol from desertificated lands, and it presents some data obtained from the remote sensing of the atmospheric boundary layer with a sodar network in the course of this experiment. The sodar network, which was developed to study a spatial structure of coherent vortices, included three identical minisodars (with carrier frequencies of 3.8 kHz) located at the apices of a triangle, each side of which was about 3.5 km, and a sodar (with a carrier frequency of 1.7 kHz). The vertical profiles of the three wind-velocity components and the characteristics of air temperature fluctuations were determined. The procedure of identifying coherent vortex structures is described. The variations in the vertical and horizontal wind-velocity components and the scales characteristic of such structures are estimated. 相似文献
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5.
Astronomy Reports - We found an oscillatory process of the Earth’s pole associated with the precession motion of the Moon’s orbit using numerical processing a series C01 of... 相似文献
6.
A numerical–analytical approach is used to investigate irregular effects in oscillations of the Earth’s pole related to variations in the Chandler and annual components. An approach to studying oscillations in the motion of the Earth’s pole based on a joint analysis of the Chandler and annual components of this motion is proposed. A transformation to a new coordinate system in which the motion of the pole is synchronous with the precession of the lunar orbit can be found in this approach. Estimates of the precision of predictions of the coordinates of the Earth’s pole taking into account additional terms due to lunar perturbations are presented.
相似文献7.
Chandler oscillations of the Earth’s pole in the presence of fluctuational dissipative perturbations
Effects of fluctuational dissipative perturbations on the Earth’s polar motion due to random components of the centrifugal potential are studied using a numerical-analytical approach. A combined model for the polar fluctuations is used to take into account stochastic components of the polar tides. Fluctuations excited at frequencies close to the Chandler frequency are analyzed using observations of sea level and the gravitional acceleration. Equations describing the correlation characteristics of the polar motions are presented. 相似文献
8.
L. D. Akulenko Yu. G. Markov V. V. Perepelkin L. V. Rykhlova 《Astronomy Reports》2009,53(11):1070-1077
The fundamental astrometric problem of high-accuracy interpolation and forecasting of the Earth’s polar motion on short time
scales from 1–2 to 10–30 days is studied. Hierarchies of interval length and parameter accuracy are established using appropriate
models for the process. Filtering algorithms are adjusted using a weighted least squares fit of measurements of the International
Earth Rotation Service (IERS). Best-fit estimates for the main features of the motion are obtained for various time intervals;
interpolations and forecasts are compared with the IERS measurements. 相似文献
9.
The subject of measuring the performance of registries has been a topic of policy discussions in recent years at the regional level due to the recasting of the European Union (EU) port state control (PSC) directive which introduces incentives for flags which perform better. Since the current method used in the EU region entails some shortcomings, it has therefore been the subject of substantial scrutiny. Furthermore, the International Maritime Organization (IMO) developed a set of performance indicators which however lacks the ability to measure compliance as set out in one of its strategic directions towards fostering global compliance. This article develops a methodology to measure flag state performance which can be applied on the regional or global level and to other areas of legislative interest (e.g. recognized organizations, Document of Compliance Companies). The proposed methodology overcomes some of the shortcomings of the present method and presents a more refined, less biased approach of measuring performance. To demonstrate its usefulness, it is applied to a sample of 207,821 observations for a 3-year time frame and compared to the current method. 相似文献
10.
I. P. Chunchuzov S. N. Kulichkov O. E. Popov V. G. Perepelkin 《Izvestiya Atmospheric and Oceanic Physics》2010,46(5):597-607
A wave theory of propagation of an acoustic pulse in a moving stratified atmospheric layer above the ground with a finite
impedance of an underlying ground surface is developed. The shapes of acoustic signals in a near-ground atmospheric waveguide,
which are formed due to temperature inversion and a vertical shear of the wind velocity, are calculated based on this theory.
These signals are compared with those measured during the experiments where vertical profiles of the wind velocity and temperature
in an atmospheric boundary layer have been continuously controlled using a sodar, a temperature profile meter, and acoustic
anemometers or thermometers mounted on a 56-meter-high mast. The joint action of a near-ground acoustic waveguide, the impedance
of the underlying surface, and a vertical layered structure of the boundary atmospheric layer on a signal shape far from the
acoustic source are studied. 相似文献