排序方式： 共有26条查询结果，搜索用时 62 毫秒
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G. I. Gorchakov A. V. Karpov V. M. Kopeikin A. V. Sokolov D. V. Buntov 《Doklady Earth Sciences》2016,467(1):314-319
Quasi-horizontal trajectories of salting sand grains were found using high-speed video-recording in the desertified territory of the Astrakhan region. The sizes and displacement velocities of the saltating sand grains were determined. A piecewise logarithmic approximation of the wind profile in a quasi-stationary wind–sand flow is suggested, which is consistent with the data of observations and modeling. It was established that, in the regime of stationary saltation, the wind profile in the lower saltation layer of the wind–sand flow depends only slightly on the wind profile variations in the upper saltation layer. The vertical profiles of the horizontal wind component gradient in a quasi-stationary wind–sand flow were calculated and plotted. It was shown using high-speed video recording of the trajectory of a sand grain with an approximate diameter of 95 μm that the weightlessness condition in the desertified territory of the Astrakhan region in a stationary wind–sand flow is satisfied at a height of approximately 0.15 mm. The electric parameters of a wind–sand flow, which can provide for compensation of the force of gravity by the electric force, were estimated. In particular, if the specific charge of a sand grain is 100 μC/kg, the force of gravity applied to the sand grain can be compensated by the electric force if the vertical component of the electric field in a wind–sand flow reaches approximately 100 kV/m. It was shown that the quasi-horizontal transport of sand grains in the lower millimeter saltation layer observed in the desertified territory can be explained by the joint action of the aerodynamic drag, the force of gravity, the Saffman force, the lift force, and the electric force. 相似文献
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Gorchakov G. I. Kopeikin V. M. Karpov A. V. Gushchin R. A. Datsenko O. I. Buntov D. V. 《Izvestiya Atmospheric and Oceanic Physics》2022,58(5):466-475
Izvestiya, Atmospheric and Oceanic Physics - Measurements of electric currents of saltation in the wind-sand flux and currents caused by the wind transport of dust aerosol particles have been... 相似文献
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Gorchakov G. I. Kopeikin V. M. Karpov A. V. Gushchin R. A. Datsenko O. I. Buntov D. V. 《Doklady Earth Sciences》2022,505(1):483-488
Doklady Earth Sciences - Using the measurement data in a wind–sand flux on the desertified areas of Astrakhan oblast and Kalmykia, it has been established that the time variability of... 相似文献
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V. V. Kopeikin 《Geomagnetism and Aeronomy》2014,54(1):117-126
Spectral measurements of radiowaves emitted by artificial ball lightning are presented. The measurements were carried out using two different facilities: a pulsed power generator (PPG) and a three-contour Tesla transformer. The results of these measurements confirm the hypothesis that ball lightning is a self-oscillator of high-voltage pulses in the radio range. 相似文献
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A prolonged timing of millisecond pulsars has revealed low-frequency uncorrelated (infrared) noise, presumably of astrophysical
origin, in the pulse arrival time (PAT) residuals for some of them. Currently available pulsar timing methods allow the statistical
parameters of this noise to be reliably measured by decomposing the PAT residual function into orthogonal Fourier harmonics.
In most cases, pulsars in globular clusters show a low-frequency modulation of their rotational phase and spin rate. The relativistic
time delay of the pulsar signal in the curved spacetime of randomly distributed and moving globular cluster stars (the Shapiro
effect) is suggested as a possible cause of this modulation. Extremely important (from an astrophysical point of view) information
about the structure of the globular cluster core, which is inaccessible to study by other observational methods, could be
obtained by analyzing the spectral parameters of the low-frequency noise caused by the Shapiro effect and attributable to
the random passages of stars near the line of sight to the pulsar. Given the smallness of the aberration corrections that
arise from the nonstationarity of the gravitational field of the randomly distributed ensemble of stars under consideration,
a formula is derived for the Shapiro effect for a pulsar in a globular cluster. The derived formula is used to calculate the
autocorrelation function of the low-frequency pulsar noise, the slope of its power spectrum, and the behavior of the σz statistic that characterizes the spectral properties of this noise in the form of a time function. The Shapiro effect under
discussion is shown to manifest itself for large impact parameters as a low-frequency noise of the pulsar spin rate with a
spectral index of n = −1.8 that depends weakly on the specific model distribution of stars in the globular cluster. For small impact parameters,
the spectral index of the noise is n = −1.5. 相似文献
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S. A. Sitnov G. I. Gorchakov M. A. Sviridenkov V. M. Kopeikin T. Ya. Ponomareva A. V. Karpov 《Izvestiya Atmospheric and Oceanic Physics》2013,49(9):1006-1018
The evolution of smoke plume over European Russia (ER) during the massive forest and peatbog fires of summer 2010 has been studied using observations of aerosol optical depth (AOD) from MODIS instruments (both Aqua and Terra platforms), objective analysis of meteorological fields performed at the Russian Hydrometeorological Research Center, NCEP/NCAR reanalysis, as well as upper air data. A relation between the structure inhomogeneities of the AOD field and regional atmospheric circulation has been found. It is shown that, on August 5–9, 2010, the maximum of smoke pollution did complete turn around Moscow, while remaining at a distance of 200 to 650 km from the megacity. Both regionally averaged shortwave aerosol radiative forcings (ARFs) at the top and the bottom of the atmosphere are estimated for the period of extreme smoke pollution over ER. The spatial distributions of ARF values over the territory of the region and the estimates of the local and spatially distributed thermal effects of smoke aerosol are given. It is shown that, on August 5–9, 2010, the spatial distribution of AOD and the calculated thermal effects of smoke aerosol were in agreement with the spatial distributions of air-temperature anomalies observed in the lower 1.5-km layer of the atmosphere. MODIS’s AOD data obtained during the wildfires were validated by AOD observations from the CIMEL sun photometer operated at the AERONET station Zvenigorod. 相似文献
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