Database of Comet Polarimetry: Analysis and Some Results     

Nikolai Kiselev  Vera Rosenbush  Klaus Jockers  Sergey Velichko  Sen Kikuchi 《Earth, Moon, and Planets》2005,97(3-4):365-378

We present the electronic database (EAR-C-COMPIL-5-DB-COMET-POLARIMETRY-V1.0, NASA Planetary Data System) involving published and some unpublished results of cometary polarimetry. The database contains more than 2600 measurements of linear and circular polarization for 64 comets since 1940s. The narrow-band and wide-band measurements within the spectral region 0.3–2.2 micron are presented. The ranges of phase angles, helio- and geocentric distances of comets are 0.4–122°, 0.6–4.8 AU, 0.03–4.9 AU, respectively. We have comprised more than 60 references to the published papers and unpublished sources. The data we included are presented in a tabular format in the ASCII codes. The database can be used as the observational basis for detailed theoretical modeling, interpretation of the phase-angle and spectral dependence of polarization, classification of comets, laboratory simulating, and for selecting future space-mission targets. Analysis of the available data allowed us to summarize some observed characteristics of linearly and circularly polarized light and their phase-angle, heliocentric, spectral, and spatial dependencies.  相似文献   

Buried palaeosols of the Nevado de Toluca: an alternative record of Late Quaternary environmental change in central Mexico     

Sergey Sedov  Elizabeth Solleiro‐Rebolledo  Jorge E. Gama‐Castro  Ernestina Vallejo‐Gmez  Arelia Gonzlez‐Velzquez 《第四纪科学杂志》2001,16(4):375-389

Buried palaeosols of central Mexico, not previously analysed from a palaeopedological standpoint, have helped to develop a reliable regional model of Late Quaternary climatic change. This paper focuses upon morphological and micromorphological properties, particle‐size distribution, and extractable Fe, Al and Si of seven palaeosols (named PT1–PT7) in the vicinity of the Nevado de Toluca volcano. The characteristics of Andic Cambisol PT1, similar to those of modern soils in semi‐arid environments, indicate a drier climate in the first half of the Holocene. Humic Andosols PT2–PT4 are analogous to modern volcanic soils of humid forest environments. They show evidence that a moist palaeoclimate prevailed during marine oxygen isotope stages (OIS) 2 and 3. Luvisols PT5 and PT6, which are assumed to have formed at the end of marine OIS 5 to marine OIS 4, also indicate humid conditions. We attribute the differences between Andosols PT2–PT4 and Luvisols PT5–PT7 to variations in the duration in the pedogenesis rather than to changes in palaeoclimate. Micromorphological features of Andosol to Luvisol transition confirm that these soils form an evolutionary sequence. Being for the most part consistent with lacustrine records, the palaeosol properties do not reflect the episodes of ‘drier climate’ during the Last Glacial Maximum, however, as shown by diatom and palynological data from lake sediments. Mesoclimate variations and/or incompleteness of ‘soil memory’, reflecting mostly periods of humid pedogenesis, probably provide the reason for this disagreement. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Geochemical Baselines of Nickel and Chromium in Various Surficial Materials in the Barents Region, NW Russia and Finland     

Reijo Salminen  Igor Bogatyrev  Victor Chekushin  Sergey P. Glavatskikh  Virgilija Gregorauskiene  Heikki Niskavaara  Lubov Selenok  Markku Tenhola  Olga Tomilina 《Geostandards and Geoanalytical Research》2004,28(2):333-341

The geochemical baselines of nickel and chromium were studied from the data produced by the Barents Ecogeochemistry project, a large international regional geochemical mapping exercise. The project surveyed major and trace element distributions in stream water, organic and mineralogically-modified soil horizons, and terrestrial moss in the northwestern part of Russia and in Finland. Other materials were collected during the pilot phase and later from thirty special sites. The results on respective materials by XRF, ICP-MS and ICP-AES showed that both geological and anthropogenic factors have an influence on the geochemical baseline concentrations of Ni and Cr in organic soil and stream water. The main explanation of the observed distribution patterns in terrestrial moss is human activity, but geological factors can also affect the baselines. The variation of geochemical baselines in the mineral-rich soil horizon depends only on variations in bedrock. The mineralogy of samples mainly controls the leachability properties of soil samples.  相似文献   

Holocene environmental changes and development of Figurnoye Lake in the southern Bunger Hills, East Antarctica     

Sergey R. Verkulich  Martin Melles  Hans-Wolfgang Hubberten  Zinaida V. Pushina 《Journal of Paleolimnology》2002,28(2):253-267

The lithology, radiocarbon chronology, granulometry, geochemistry and distribution of diatoms were investigated in three sediment cores from fresh-water Figurnoye Lake in the southern Bunger Hills, East Antarctica. Our paleolimnological data provide a record of Holocene environmental changes for this region. In the early Holocene (prior to 9.0 ± 0.5 kyr BP), warm climate conditions caused intensive melting of either the floating glacier ice mass or glaciers in the immediate lake surroundings, leading to the accumulation of terrigenous clastic sediments and limiting biogenic production in the lake. From ca. 9.0 ± 0.5 to 5.5 ± 0.5 kyr BP, highly biogenic sediments dominated by benthic mosses formed, indicating more distal glaciers or snowfields. A relatively cold and dry climate during this period caused weaker lake-water circulation and, likely, occurrence of lake ice conditions were more severe than present. The distribution of marine diatoms in the cores shows that, sometime between 8 and 5 kyr BP, limited amounts of marine water episodically penetrated to the lake, requiring a relative sea-level rise exceeding 10–11 m. During the last ca. 5.5 ± 0.5 kyr BP, sedimentation of mainly biogenic matter with a dominance of laminated microbial mats occurred in the lake under warm climatic conditions, interrupted by relative coolings: the first one around 2 kyr BP and then shortly before recent time. Between ca. 5.5 and 4 kyr BP, the drainage of numerous ice-dammed lakes took place in the southern Bunger Hills and, as a result, drier landscapes have existed here from about 4 kyr BP.  相似文献   

Speciation,Size Fractionation and Transport of Trace Elements in the Continuum Soil Water–Mire–Humic Lake–River–Large Oligotrophic Lake of a Subarctic Watershed     

Svetlana M. Ilina  Sergey A. Lapitskiy  Yuriy V. Alekhin  Jérôme Viers  Marc Benedetti  Oleg S. Pokrovsky 《Aquatic Geochemistry》2016,22(1):65-95

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Fatal landslides in Europe   总被引：4，自引：3，他引：1  

Ubydul Haque  Philipp Blum  Paula F. da Silva  Peter Andersen  Jürgen Pilz  Sergey R. Chalov  Jean-Philippe Malet  Mateja Jemec Auflič  Norina Andres  Eleftheria Poyiadji  Pedro C. Lamas  Wenyi Zhang  Igor Peshevski  Halldór G. Pétursson  Tayfun Kurt  Nikolai Dobrev  Juan Carlos García-Davalillo  Matina Halkia  Stefano Ferri  George Gaprindashvili  Johanna Engström  David Keellings 《Landslides》2016,13(6):1545-1554

Landslides are a major hazard causing human and large economic losses worldwide. However, the quantification of fatalities and casualties is highly underestimated and incomplete, thus, the estimation of landslide risk is rather ambitious. Hence, a spatio-temporal distribution of deadly landslides is presented for 27 European countries over the last 20  years (1995–2014). Catastrophic landslides are widely distributed throughout Europe, however, with a great concentration in mountainous areas. In the studied period, a total of 1370 deaths and 784 injuries were reported resulting from 476 landslides. Turkey showed the highest fatalities with 335. An increasing trend of fatal landslides is observed, with a pronounced number of fatalities in the latest period from 2008 to 2014. The latter are mostly triggered by natural extreme events such as storms (i.e., heavy rainfall), earthquakes, and floods and only minor by human activities, such as mining and excavation works. Average economic loss per year in Europe is approximately 4.7 billion Euros. This study serves as baseline information for further risk mapping by integrating deadly landslide locations, local land use data, and will therefore help countries to protect human lives and property.  相似文献   

日本海百年来沉积速率及粒度指示意义     

宗娴  石学法  葛晨东  邹建军  Sergey Gorbarenko  乔淑卿  董智 《沉积学报》2016,34(3):516-522

对日本海中部、北部和西部四个深水多管沉积岩芯中的210Pb活度和沉积物粒度进行分析。结果显示百年以来大和海脊、日本海北部和西部陆坡沉积物以粉砂和黏土质粉砂为主。在日本海北部和大和海脊表层沉积物存在显著的生物扰动现象,而在西部陆坡不存在。基于恒定供给速率(CRS)模式建立了4个岩芯的年代框架,并计算了沉积速率。日本海现代平均沉积速率介于0.19~0.42 cm/a,最低值出现在大和海脊。4个岩芯中沉积物平均粒径呈现不同的分布模式,但是在1940年和1980年,沉积物粒度分布模式同时发生了改变,这可能与百年以来北太平洋十年涛动(PDO)及东亚夏季风震荡有关。  相似文献   

Particle Dispersion in the Neutral Atmospheric Surface Layer     

Sergey Belan  Vladimir Lebedev  Gregory Falkovich 《Boundary-Layer Meteorology》2016,159(1):23-40

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Barite from the Saf’yanovka VMS deposit (Central Urals) and Semenov-1 and Semenov-3 hydrothermal sulfide fields (Mid-Atlantic Ridge): a comparative analysis of formation conditions     

Nataliya P. Safina  Irina Yu. Melekestseva  Paolo Nimis  Nataliya N. Ankusheva  Anatoly M. Yuminov  Vasily A. Kotlyarov  Sergey A. Sadykov 《Mineralium Deposita》2016,51(4):491-507

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Evidence for pole switching in the magnetic cataclysmic variable BY Camelopardalis     

Paul A. Mason  Gavin Ramsay  Ivan Andronov  Sergey Kolesnikov  Nickolay Shakhovskoy  & Elana Pavlenko 《Monthly notices of the Royal Astronomical Society》1998,295(3):511-518

An analysis of X-ray and optical light curves of the magnetic cataclysmic variable (MCV) BY Cam is presented. This system is one of three MCVs in which the spin period of the white dwarf and the binary orbital period differ by ∼1 per cent. As such these 'BY Cam' stars are important objects with which to probe the field structure of the magnetic white dwarf and ultimately the nature of synchronization of AM Her binaries. We confirm asynchronous rotation of the magnetic white dwarf with respect to the binary. We find evidence that the accretion stream accretes directly on to the white dwarf as in AM Her systems, but further, the stream impacts on to different magnetic poles over the course of the beat period. We present evidence that the optical and hard X-ray light curves modulate in phase, but together they are out of phase with the soft X-ray light curve. We confirm the spin down of the white dwarf which is expected to lead to the synchronization of the spin and orbital periods of BY Cam.  相似文献