The first uranium-thorium dating of the Middle Neopleistocene peat in West Siberia     

F. E. Maksimov  S. A. Laukhin  Kh. A. Arslanov  V. Yu. Kuznetsov  G. N. Shilova  S. B. Chernov  I. E. Zherebtsov  S. B. Levchenko 《Doklady Earth Sciences》2010,433(1):915-919

For a sample from the roof of peat (0–2 cm) located in a reference section for the Middle Neopleistocene in West Siberia near the village of Krivosheino, we obtained an exorbitant value of ¹⁴C date ≥53.9 ka B.P. (LU-6024). In the peat proper, the ²³⁰Th/U dates obtained by the isochronous method are 195.2 ± 10.8/9.1 ka B.P. for the L/L model and 204.1 ± 17/13 ka B.P. for the TSD model. The palynospectra of the peat characterize, from the bottom up, birch forests with fir and spruce participation; then spruce forests with fir; next spruce-cedar forests, similar to the middle taiga subzone. In the clay, the following palynospectra have been examined: forb-gramineous grasslands and light forests with spruce and Betula fruticosa. In the upper part of clays, the palynospectra reflect the evolution of swampy, birch, light forests with spruce participation. The conclusion is made that the studied part of the section formed at the end of the Samarovo Ice Age and in the last third of the Taz Ice Age. The break in sedimentation related to the erosion contact covers a part of the Samarovo Ice Age and the first two-thirds of the Taz Ice Age.  相似文献   

The origin and evolution of relict larch stands on Shikotan Island (Lesser Kuril Ridge) in the Holocene     

N. G. Razzhigaeva  N. I. Belyanina  L. A. Ganzei  Kh. A. Arslanov  S. B. Chernov 《Geography and Natural Resources》2013,34(2):179-184

Palynological and geochronological data have been used to ascertain the time history of a unique natural-territorial complex — the relict larch stands that have persisted in the southeastern part of Shikotan Island since the Late Pleistocene. The study revealed the development stages of landscapes. Factors favoring vegetation conservation in the refugium are discussed.  相似文献   

Exploring the deep (International library series)     

Andrei Aksyonov  Alexander Chernov 《Ocean Engineering》1980,7(1):195

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Estimation of the characteristics of the thermodynamic structure of waters in the Newfoundland energy-active zone based on the results of four-dimensional analysis     

V. V. Knysh  V. A. Moiseenko  V. V. Chernov 《Physical Oceanography》1991,2(1):19-28

The seasonal and interannual variability of the heat and dynamic characteristics of the ocean is analysed based on the results of four-dimensional analysis of measurements taken in the Newfoundland energy area during 1982–1986. The horizontal and vertical large-scale circulation of waters is considered in the interaction with the quasi-steady anticyclonic eddy. Data are supplied on the response of the results of four-dimensional analysis to the initial conditions and the bulk measurement data.Translated by Mikhail M. Trufanov.  相似文献   

Atlas of Channel Deformations in the Lower Volga     

V. V. Ivanov  V. N. Korotaev  N. A. Rimskii-Korsakov  A. V. Chernov 《Water Resources》2006,33(5):535-542

A methodology for compiling the electronic “Atlas of Channel Deformations in the Lower Volga,” its contents, and the materials used for its compilation are described. Analysis of published data and field observations made by the authors is used to examine long-term variations in channel deformations in the period of 1914–2001 and to forecast the development of the channel in the Lower Volga in the 21st century.  相似文献   

A comparative analysis of zebra-pattern structures at frequencies from 20 to 7000 MHz     

G. P. Chernov 《Astronomy Reports》2004,48(10):853-870

A joint analysis of several recent solar type IV radio outbursts with zebra structures and fiber bursts in their dynamical radio spectra is carried out using all available ground-based and satellite data (Yohkoh, SOHO, TRACE). Zebra structures and fiber bursts were observed at frequencies from 20 to 6500 MHz. The main relative spectral parameters and degree of circular polarization of the zebra structures and fiber bursts are nearly the same. The relative width of the zebra structures varies only slightly with frequency (≈0.003–0.005); the radio emission is radiated in the ordinary mode. New data on centimeter-wavelength zebra structures and fiber bursts testifies that they are analogous to similar structures observed at meter wavelengths. A double-plasma-resonance model for the zebra structures based on the observational dependences for the electron density and magnetic field yields a frequency dependence for the frequency separation between stripes that does not agree with the observations. Fine structure was observed together with the rise into the corona of new, hot magnetic loops, in which instabilities associated with high-frequency and low-frequency plasma waves develop. The frequency range of the fine structure in the dynamical spectra is probably determined by the extent of these new loops in the corona. The continuous transition of the fiber bursts into zebra structures and vice versa testifies to a single origin for these two structures. All the main properties of the stripes in emission and absorption can be explained if they are associated with interactions between electrostatic plasma waves and whistlers. It is possible to obtain realistic values for the magnetic-field strength of B≈160 G at a plasma level of about 3 GHz in this model.  相似文献   

Numerical experiments on estimating the accuracy of four-dimensional analysis of hydrophysical fields using a quasi-geostrophic model of currents     

V. V. Chernov 《Physical Oceanography》1992,3(1):43-52

The relationship between the results of four-dimensional (4-D) analysis and the approximations employed in the assimilation scheme, as well as the initial fields, is studied. The contribution made by a procedure of correcting the horizontal velocities by theT, S data to the increase of the quality of the data obtained is estimated. Numerical experiments were carried out on the data of measurements made in the observation site located in the Newfoundland energy-active zone in August 1985.Translated by Mikhail M. Trufanov.  相似文献   

Unusual stripes in emission and absorption in solar radio bursts: Ropes of fibers in the meter wave band     

G. P. Chernov 《Astronomy Letters》2008,34(7):486-499

Based on data from the spectrographs of IZMIRAN and Tremsdorf station (Astronomical Institute, Potsdam), we analyze the ropes of narrow-band fibers in the spectra of solar radio bursts in the meter wave band by invoking events of satellite data (SOHO/LASCO, EIT, MDI) for the analysis. We consider in detail basic properties of the ropes in four events in comparison with previously known data. The fibers in ropes are more commonly observed with an overlap in time and frequency, but occasionally (more often at the end of the ropes) they can follow with a separation in time. The fiber duration and recurrence period seldom remain stable and, in general, increase from 0.3–0.5 s at the beginning to several seconds at the end of the rope. The relative values of the instantaneous and total fiber frequency bandwidths change only slightly in different events; δ f / f ≈ 0.003–0.005 and Δf / f ≈ 0.02–0.03. Most of the ropes exhibit a low-frequency absorption. The fibers in ropes are similar to ordinary intermediate drift bursts (fiber bursts), but they drift in a narrow frequency band and have a more frequent recurrence in some events. The ropes of fibers are usually observed in the time interval when the shock front catches up with the leading edge of a coronal mass ejection. Under the condition of a unified approach to interpreting the ropes of fibers in all events, their basic properties can be explained in terms of the model of fiber bursts. The connection of fibers with the developed zebra pattern is shown within the framework of a unified approach to the formation theory of stripes in emission and absorption in the model on whistlers.  相似文献   

Whistlers in the solar corona and their relevance to fine structures of type IV radio emission     

G. P. Chernov 《Solar physics》1990,130(1-2):75-82

This short report concerns a general consideration of whistler manifestations in fine structures, including possible trajectories of obliquely propagating whistlers, the role of quasilinear diffusion and an interpretation of new observations. A whistler ray tracing and kinetic whistler growth rates under arbitrary angles to the magnetic field in the solar corona were calculated. Different regimes of a whistler instability yield divers elements of fine structures: different stripes in emission and absorption or millisecond pulsations, moreover, zebra-stripes can convert into fiber bursts and inversely. A new explanation of low-frequency absorption in fibers is proposed: it is connected with an attenuation of plasma-wave instability due to the fast electron diffusion by whistlers. Rope-like chains of fiber bursts are explained by a periodic whistler instability in a magnetic reconnection region.  相似文献   

Paleoclimates and chronology of the middle Würm megainterstadial on the West Siberian Plain     

S. A. Laukhin  Kh. A. Arslanov  G. N. Shilova  F. Yu. Velichkevich  F. E. Maksimov  V. Yu. Kuznetsov  S. B. Chernov  T. V. Tertychnaya 《Doklady Earth Sciences》2006,411(2):1457-1461

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