Geomorphologic map of the 1<Superscript>st</Superscript> Mutnaya River,Southeastern Kamchatka,Russia     

Gheorghe Romanescu  Sergey Chalov  Cristian Constantin Stoleriu  Alin Mihu-Pintilie  Silvia Eleonora Angileri  Yulia Kuznetsova  Mariaelena Cama  Michael Maerker 《山地科学学报》2017,14(12):2373-2390

The Kamchatka Peninsula–situated in the Pacific “Ring of Fire”–has 29 active and over 400 extinct volcanoes. Since it is situated in the northeastern extremity of Russia, in subarctic climate, the volcanic landforms are overprinted by the 446 glaciers. This research focuses on the 1^stMutnaya catchment which drains the southern slopes of two active volcanoes: Avachinsky and Koryaksky. Those volcanoes are a permanent threat for the cities of Petropavlovsk and Elizovo, which are the 2 of 3 cities of the peninsula. Hence, most of the studies carried out in the area dealt with the natural hazards and only few focus on landscape evolution. Thus, the purpose of this study was to elaborate a cartographic approach which integrates classic geomorphology with state of the art GIS and remote sensing techniques. As result, different landforms and related processes have been analysed and included in the first general geomorphologic map of the 1^stMutnaya catchment.  相似文献   

Genotoxic potential of copper oxide nanoparticles in the bivalve mollusk <Emphasis Type="Italic">Mytilus trossulus</Emphasis>     

Victor P. Chelomin  Valentina V. Slobodskova  Maksim Zakhartsev  Sergey Kukla 《中国海洋大学学报(英文版)》2017,16(2):339-345

Copper oxide nanoparticles (CuO-NPs) are among the most widely used metal oxide nanoparticles, which increases the chance of their being released into the marine environment. As the applications of these particles have increased in recent years, their potential impact on the health of marine biota has also increased. However, the toxicological effects of these NPs in the marine environment are poorly known. In the present study, the DNA damaging potential of CuO-NPs in the marine eastern mussel Mytilus trossulus was evaluated and compared to that of dissolved copper exposures. Genotoxicity was assessed by the single cell gel electrophoresis (comet) assay in mussel gill and digestive gland cells. The results showed that copper in both forms (CuO-NPs and dissolved copper) was accumulated to different extents in mussel tissues. The mussel exposed to the dissolved copper attained higher concentrations of copper in the gills than in the digestive gland. In contrast to these results, it was found that CuO-NPs could induce much higher copper accumulation in the digestive gland than in the gills. A clear and statistically significant increase in DNA damage was found in both tissues of the Cu-exposed group compared to the control mussels. Our results indicated that the CuO-NP exposure produced remarkable effects and increased DNA damage significantly in mussel gill cells only. It should be noted that the digestive gland cells were prone to accumulation following CuO-NPs when compared to the gill cells, while the gill cells were more sensitive to the genotoxic effects of CuO-NPs. These results also suggested the need for a complete risk assessment of engineered particles before its arrival in the consumer market.  相似文献   

Statistical modeling of relative variations in the critical frequencies of the ionospheric F region     

Yu. K. Kalinin  N. P. Sergeenko  A. L. Dzvonkovskaya  V. A. Kuznetsov  T. D. Platonov  V. V. Velichko 《Geomagnetism and Aeronomy》2010,50(1):64-68

Relative variations in the critical frequency of the ionospheric F, region are considered as one of the main sources of information about the characteristics of plasma inhomogeneities in the region of the main ionization maximum and as a substantial factor responsible for the statistics of the decameter signal parameters on radio paths with different lengths. The functions defined on finite intervals are also used in statistical modeling in addition to the available methods. Such a consideration made it possible to remove a restriction, peculiar to previous models, in the form of the requirement that the fourth statistical invariant—excess— should be positive. This makes the generalized statistical model more universal, which is of special importance for high4atitude radio paths. The specified mo del more adequately corresponds to the experimental data, which are characterized by finite intervals where the quantities are measured.  相似文献   

Nonlinear structure‐enhancing filtering using plane‐wave prediction*     

Yang Liu  Sergey Fomel  Guochang Liu 《Geophysical Prospecting》2010,58(3):415-427

Attenuation of random noise and enhancement of structural continuity can significantly improve the quality of seismic interpretation. We present a new technique, which aims at reducing random noise while protecting structural information. The technique is based on combining structure prediction with either similarity‐mean filtering or lower‐upper‐middle filtering. We use structure prediction to form a structural prediction of seismic traces from neighbouring traces. We apply a non‐linear similarity‐mean filter or an lower‐upper‐middle filter to select best samples from different predictions. In comparison with other common filters, such as mean or median, the additional parameters of the non‐linear filters allow us to better control the balance between eliminating random noise and protecting structural information. Numerical tests using synthetic and field data show the effectiveness of the proposed structure‐enhancing filters.  相似文献   

Wind-driven diversion of summer river runoff preconditions the Laptev Sea coastal polynya hydrography: Evidence from summer-to-winter hydrographic records of 2007–2009     

Igor A. Dmitrenko  Sergey A. Kirillov  Thomas Krumpen  Mikhail Makhotin  E. Povl Abrahamsen  Sascha Willmes  Ekaterina Bloshkina  Jens A. Hölemann  Heidemarie Kassens  Carolyn Wegner 《Continental Shelf Research》2010

This paper examines the role of atmospheric forcing in modifying the pathways of riverine water on the Laptev Sea shelf, using summer-to-winter hydrographic surveys from 2007 to 2009. Over the two consecutive winter seasons of 2007–2008 and 2008–2009 in the area of the winter coastal polynya, our data clearly link winter surface salinity fields to the previous summer conditions, with substantially different winter salinity patterns preconditioned by summer atmospheric forcing. In the summer of 2007, dominant along-shore westerly winds in the cyclonic regime force the Lena River runoff to flow eastward. In contrast, in the summer of 2008, dominant along-shore easterly winds over the East Siberian Sea and on-shore northerly winds over the Laptev Sea in the anticyclonic regime lock the riverine water in the vicinity of the Lena Delta. Over the coastal polynya area in the southeastern Laptev Sea these patterns precondition a surface salinity difference of 8–16 psu between the winters of 2008 and 2009. Overall, this indicates a residence time of at least half a year for riverine water on the Laptev Sea shelf. Future climate change associated with an enhanced summer cyclonicity over the eastern Arctic may turn more riverine water eastward along the eastern Siberian coast, resulting in weaker vertical density stratification over the Laptev Sea shelf, with possible impact on the efficiency of vertical mixing and polynya dense water production.  相似文献   

Late Pleistocene and Holocene vegetation and climate records from Lake Kotokel, central Baikal region     

Koji Shichi  Hikaru Takahara  Sergey K. Krivonogov  Elena V. Bezrukova  Kenji Kashiwaya  Akihide Takehara  Toshio Nakamura 《Quaternary International》2009,205(1-2):98

Climatically driven Late Pleistocene and Holocene vegetation changes were reconstructed based on pollen records from the sediments of Lake Kotokel and Cheremushka Bog, located on the eastern shore of Lake Baikal. The described paleoenvironmental record has higher resolution than records collected from Lake Baikal and unites individual events identified in prior studies of bottom and onshore cores. Remarkable shifts in landscapes and expansions of index plants are as follows. Forest tundra and/or forest steppe landscape with birch, spruce, Artemisia, and Poaceae prevailed at ca. 50–25 ¹⁴C kyr BP. Tundra and/or steppe vegetation dominated by Artemisia and Poaceae was typical for the Last Glacial Maximum. The expansion of shrub birch and willow occurred at ca. 15.5 ¹⁴C kyr BP. Two peaks of spruce expansion at ca. 47.5–42.4 ¹⁴C kyr BP (Karginian time) and at ca. 14.5–13 ka (Bølling-Allerød warm intervals) suggest that the condition were more humid than today. A slight increase in Artemisia at ca. 11–10.5 ¹⁴C kyr BP (13–12 ka) was indicative of the Younger Dryas event. An expansion of birch forests with fir at ca. 12–6.4 ka suggests higher humidity. The currently dominant Scots and Siberian pine forests with birch expanded since 6.4 ka.  相似文献   

Horizontal Motions of Water in the Vicinity of a Tsunami Source     

Mikhail A. Nosov  Anastasia V. Moshenceva  Sergey V. Kolesov 《Pure and Applied Geophysics》2013,170(9-10):1647-1660

Because it is based on an initial seismic analysis and preset criteria, tsunami forecast often fails in assessment of tsunami danger. The level of danger can be determined more or less reliably only when observed sea level data became available. Along with the sea level data, i.e., vertical motions of free water surface, we suggest considering horizontal motions of water that accompany the formation and the propagation of a tsunami. The amplitude of horizontal motions is normally much higher than the amplitude of the vertical motions. Detection of the horizontal motions may provide tsunami warning centers with additional in situ data that can be used for estimation of tsunami strength. In this study, taking the 2011 Tohoku-Oki event as an example, horizontal motions of water in the vicinity of the tsunami source are theoretically examined by means of dynamic and static numerical models developed within the framework of linear shallow-water approximation. It is shown that in the vicinity of the tsunami source within a wide area of about 0.5 million square kilometers, the amplitude of horizontal motions exceeded 10 m, whereas in some shallow-water areas the amplitude amounted to hundreds of meters. Possible methods of in situ detection of the horizontal motions are discussed.  相似文献   

GLOBAL ATLASES: A NEW STAGE IN THE GEOGRAPHIC AND CARTOGRAPHIC STUDY OF NATURE AND RESOURCES     

V. M. Kotlyakov  A. A. Lyutyy  A. A. Velichko  N. N. Dreyer  I. N. Il'yina  I. I. Spasskaya 《地理信息系统科学与遥感》2013,50(1):20-30

This article examines the objectives, structure, content, and scientific significance of three new major world atlases being prepared for publication by the Institute of Geography of the USSR Academy of Sciences in cooperation with other organizations. Translated from: Izvestiya Akademii Nauk SSSR, seriya geograficheskaya, 1988, No. 3, pp. 22-30 by Jay K. Mitchell, PlanEcon, Inc., Washington, DC 20005.  相似文献   

Natural carbon nanofibers in graphite     

Tatyana Grygoryevna Shumilova  Sergey Ivanovich Isaenko  Farid Karibovich Divaev  Junji Akai 《Mineralogy and Petrology》2012,104(3-4):155-162

  相似文献   

Effect of Ocean Spray on Vertical Momentum Transport Under High-Wind Conditions   总被引：1，自引：0，他引：1  

Yevgenii Rastigejev  Sergey A. Suslov  Yuh-Lang Lin 《Boundary-Layer Meteorology》2011,141(1):1-20

Two mathematical models are proposed detailing the influence of ocean spray on vertical momentum transport under high-wind conditions associated with a hurricane or severe storm. The first model is based on a turbulent kinetic energy (TKE) equation and accounts for the so-called lubrication effect due to the reduction of turbulence intensity. The second model is based on Monin–Obukhov similarity (MOS) and uses available experimental data. It is demonstrated that the flow acceleration is negligible for wind speeds below a certain critical value due to the fact that the spray volume concentration is low for such speeds. For wind speeds higher than the critical value, the spray concentration rapidly increases, which results in significant flow acceleration. Both models produce qualitatively similar results for all turbulent flow parameters considered. It was found that the MOS-based model tends to predict a noticeably stronger lubrication effect than the TKE-based model, especially for lower wind speeds. The results of model calculations are in very good agreement with available experimental data for the spray production values near the upper bound. It is also shown that neither the value of the turbulent Schmidt number in the TKE-based model nor the choice of a stability profile function affects the spray-laden flow dynamics significantly.  相似文献