Petrochemistry of Cenozoic basalts and associated rocks in the Baikal rift zone   总被引：1，自引：0，他引：1  

A.I. Kiselev  H.A. Golovko  M.E. Medvedev 《Tectonophysics》1978,45(1):49-59

The main episode of Cenozoic volcanic activity occurred simultaneously with formation of the Sayan—Baikal uplift, before the rift depressions were initiated. Volcanism and rifting in this region have developed as independent processes, connected with each other only by an ultimate primary mantle energy source. The volcanic regions do not coincide with the rift depressions, except in the Tunka graben.Chemical features of the volcanics show that during the entire period of volcanic activity there was a complex alternation of basaltic lavas of alkaline, intermediate and tholeiitic composition. Both alkaline and subalkaline lavas are distributed over the entire volcanic region, excepting the Tunka depression where tholeiitic lavas are predominant. However, there is neither mineralogical nor chemical evidence for the existence of two separate magma types within the Baikal rift zone.Judging by the presence of high-pressure, lherzolitic megacrysts of clinopyroxene, and to a lesser extent titaniferous biotite and amphibole in alkaline basalts, variations of lava chemistry are connected with high-pressure fractionation of initial melts, which was more complete for sources outside the rift zone. The predominance of tholeiitic lavas in the Tunka depression is likely to have been caused by a higher degree of partial melting and quick ascent of magma to the surface, facilitated by a high geothermal gradient under the depression where crustal extension is taking place.  相似文献   

Polarization and brightness opposition effects for the E-type Asteroid 64 Angelina     

Vera K. Rosenbush  Nikolai N. Kiselev  Klaus Jockers  Yuriy S. Efimov 《Icarus》2005,178(1):222-234

We present new polarimetric and photometric observations of the high-albedo Asteroid 64 Angelina in the UBVRI wavebands at phase angles ranging from 0.43° to 13.02° during oppositions in 1995, 1999, and 2000/2001. The polarization opposition effect has been observed in the form of a sharp peak of negative polarization with amplitude of about −0.4% centered at αmin≈1.8°, which is superimposed on the regular negative polarization branch. The amplitude of the polarization opposition effect appears to be apparition-dependent. Our photometric data confirm the early detected by Harris et al. [1989. Phase relations of high-albedo asteroids: The unusual opposition brightening of 44 Nysa and 64 Angelina. Icarus 81, 365-374] of a very strong and unusually narrow opposition spike, i.e., brightness opposition effect, for Angelina. Thus, 64 Angelina is the first asteroid for which both the polarization opposition effect and the brightness opposition effect have been detected. We observed that the polarization opposition effect as well as the regular negative polarization branch depends on the wavelength of scattered light, but in different manners. In addition, the colors B-V and V-R show little phase-angle dependence, while the color U-B increases with increasing phase angle, thus indicating that the amplitude of the brightness opposition effect is larger in the U band and almost the same in the B, V, and R bands. It appears that all colors indices begin to increase with decreasing phase angle to zero. The composite lightcurve computed with a period of 8.752 h has amplitude of 0.13 magnitude.  相似文献   

Polarimetry of the E-type asteroid 64 Angelina     

S. V. Zaitsev  N. N. Kiselev  V. K. Rosenbush  S. V. Kolesnikov  K. A. Antonyuk 《Kinematics and Physics of Celestial Bodies》2014,30(3):155-160

Results of polarimetric observations of a high-albedo asteroid 64 Angelina obtained in the phase-angle range from 0.8° to 24.3° are presented. The observations were carried out in the period from September 28 to October 9, 2008, and on November 15, 2011, and September 18, 2012, with the 1.25-m and 2.6-m telescopes of the Crimean Astrophysical Observatory equipped with a five-color double-beam photopolarimeter and a single-channel photometer-polarimeter, respectively. Our observations confirm the polarimetric opposition effect in asteroid 64 Angelina at small phase angles and well agree with the other observations. The obtained results are discussed in terms of the currently available models of the light scattering by regolith surfaces.  相似文献   

Influence of solar wind on ozone and circulation in the middle atmosphere: A model study     

V. A. Zubov  E. V. Rozanov  A. V. Shirochkov  L. N. Makarova  T. A. Egorova  A. A. Kiselev  Yu. E. Ozolin  I. L. Karol  W. K. Schmutz 《Doklady Earth Sciences》2006,408(4):595-598

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Non-geometrical waves–are there any? An asymptotic description of some 'non-geometrical' phenomena in seismic wave propagation     

Vasily M. Babich  Aleksey P. Kiselev 《Geophysical Journal International》1989,99(2):415-420

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<Emphasis Type="Italic">R/S</Emphasis> analysis of the <Emphasis Type="Italic">Dst</Emphasis> index     

B. V. Kiselev 《Geomagnetism and Aeronomy》2017,57(3):326-334

The paper addresses estimation of the Hurst exponent for time series of the hourly values of the Dst index for the period from 1957 to 2011. It is found that the Hurst exponent is 0.79–0.94 for yearly intervals and 0.8–1.0 for monthly intervals. Based on R/S graphs, the Dst cycles are identified; they range from 3–4 months to 2.2 years and from 8.5 to 22 years in length. It is shown that a Dst time series can be quite satisfactorily described by an α-stable Levy process.  相似文献   

Reduction of short-lived atmospheric pollutant emissions as an alternative strategy for climate-change moderation     

I. L. Karol’  A. A. Kiselev  E. L. Genikhovich  S. S. Chicherin 《Izvestiya Atmospheric and Oceanic Physics》2013,49(5):461-478

The current state of studies on short-lived atmospheric constituents (greenhouse gases and aerosols) is reviewed. They have short atmospheric lifetimes (from several days to a few years) and can significantly affect the environment and climate. We propose reducing the emissions of these constituents as an alternative to the reduction of man-made carbon dioxide releases. We consider methane, hydrofluorocarbons, tropospheric ozone, and various aerosols (primarily, black carbon); discuss their atmospheric sources and destruction mechanisms; evaluate their content, atmospheric emissions, and climate impacts; and recommend efficient actions for the nearest future.  相似文献   

GEOGRAPHIC FORECASTING AND MAPPING     

A. N. Kiselev 《地理信息系统科学与遥感》2013,50(2):93-114

The author outlines general principles and methods of predictive or forecast mapping in the USSR, more specifically the use of maps in support of geographic forecasting, i.e., prediction of relationships involved in matter, energy, and other flows of ecosystem components. Maps are employed in all stages of geographic forecasting, particularly to identify spatial patterns which can be extrapolated in space or time and used to predict distributions that are difficult or impossible to determine directly, as well as to graphically portray these expected distributions. A scheme for classifying forecast maps in terms of their orientation in time and space is presented. Translated from: Prognoznoye blogeograficheskoye kartografirovaniye: regional'nyy aspekt, Moscow: Nauka, 1985, pp. 6-24.  相似文献   

Indices of the factors that form climate changes of different scales     

I. L. Karol’  A. A. Kiselev  V. A. Frol’kis 《Izvestiya Atmospheric and Oceanic Physics》2011,47(4):415-429

Radiative forcing, the global warming potential, and the recently proposed global temperature potential are widely used not only in scientific studies but also in a number of economic and political evaluations of the effects of an increase in the contents of greenhouse gases and aerosols and other factors that form climate and its changes. New indices have appeared, and, to calculate them, information is required on the quantitative characteristics of the climate system’s components—current and expected—within standard periods of 20, 100, and 500 years. The calculations of some of these indices and potentials require consideration for variations in the rate of energy exchange between the atmosphere and the underlying surface (ocean) within the indicated periods. This leads to a more general problem of analyzing the sensitivity of the climate system to external (radiative) forcing and its response to such a forcing for the conditions of both stationary (equilibrium) and nonstationary “greenhouse” climates. A brief review of the few existing studies of such a response is given.  相似文献   

Achromatic interfero-coronagraph with variable rotation shearing for studying extrasolar planets     

P. N. Frolov  I. I. Akhmetov  B. B. Shkurskii  I. V. Gvozdovskii  A. V. Kiselev  O. I. Korablev  A. V. Tavrov 《Solar System Research》2013,47(6):477-486

Direct observation of exoplanets will make it possible to clarify many principal questions connected both with extrasolar planets and planetary systems and to measure atmospheric spectra of the planets. Obtaining an exoplanet image not distorted by the light from a star is at the cutting edge of present-day optical technologies owing to the combination of tremendous brightness contrasts and small angular distances between the planet and star. To observe the exo-Earth, it is necessary to weaken the brightness of the parent star image by 9–10 orders of magnitude (in the optical and near-IR ranges). To compensate the influence of the atmosphere, ground-based (e.g., 8–10 m) telescopes intended for observing exoplanets are equipped with adaptive optics systems, the spatial and temporal resolutions of which are not yet sufficient. A meter-class space telescope equipped with a star coronagraph will make it possible to observe the nearest exoplanets. In this paper, an improved tool for star coronagraphy is considered, namely, the achromatic interferometric coronagraph with a variable rotational shear. It is fabricated according to the optical scheme of the common path interferometer for studying extrasolar planets by direct observations. Theoretical and experimental estimations for the main characteristics of the scheme were carried out. Laboratory experimental measurements were carried out on a coronagraph model.  相似文献