Dynamics of accumulation of heavy metals by subcolloidal fraction of bottom sediments is a result of biochemical processes in the marginal filter of the Razdol’naya River (the Amur Bay, the Sea of Japan)     

D. M. Polyakov  K. I. Aksentov 《Russian Meteorology and Hydrology》2013,38(11):776-781

Determined is the content of Fe, Mn, V, Cr, Cu, Zn, Pb, As, and Sc in the subcolloidal fraction of sediments of the Razdol’naya River marginal filter using the method of atomic emission spectroscopy. Proposed is one of the variants of separating biochemical zones with the increased content of Fe and Mn and other metals in the bottom sediments of the marginal filter: the river zone, the zone of flocculation and formation of Fe and Mn hydroxides, and the zone of biochemical metal accumulation (marine). In the sediments of the river zone and the zone of flocculation and formation of Fe and Mn hydroxides, two bottom areas are identified with the high content of the elements under study that is associated with long-term and seasonal variations of the river runoff.  相似文献   

JAMSTEC-IARC international collaboration enhancing understanding of the Arctic climate system     

Larry D. Hinzman  Tetsuo Ohata  Igor V. Polyakov  Rikie Suzuki  John E. Walsh 《Polar Science》2013,7(2):49-52

Collaborations amongst researchers from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Japan and the International Arctic research Center (IARC), University of Alaska Fairbanks (UAF), U.S., have been on-going since 1998 and resulted in a great number and magnitude of accomplishments that could not have been achieved without this close partnership. The Arctic represents an important region for Japan, the U.S. and the world, and many opportunities and challenges press for immediate understanding to enable wise decisions and policy making. We have many common interests and our countries face many common problems and goals. Addressing the tremendous scientific challenges of the Arctic requires such massive investment of manpower and resources that sharing efforts, data and working together on expeditions are in our mutual best interests.This issue presents a compilation of selected results on recent analyses conducted in the five-year (2009–2014) research term related to observational studies, model development and remote sensing applications of the Arctic Ocean, adjacent marginal seas, and the surrounding terrestrial regions. All of these studies are intended to provide a better understanding of how individual components and processes interact to form a complex and dynamic arctic system. Through these collaborations, Japanese and UAF Arctic researchers can achieve our goals of developing a quantitative understanding of the Arctic System.  相似文献   

Analysis of the Variability of Stratospheric Gases Near St. Petersburg Using Ground-Based Spectroscopic Measurements     

Virolainen  Ya. A.  Polyakov  A. V.  Timofeyev  Yu. M. 《Izvestiya Atmospheric and Oceanic Physics》2021,57(2):148-158

Izvestiya, Atmospheric and Oceanic Physics - Ozone anomalies that occur in the winter–spring period in the Northern Hemisphere have been increasingly observed in recent decades not only in...  相似文献   

Historical-geological modeling of hydrocarbon generation in the Mesozoic–Cenozoic sedimentary basin of the Kara Sea (basin modeling)     

A.E. Kontorovich  L.M. Burshtein  N.A. Malyshev  P.I. Safronov  S.A. Gus’kov  S.V. Ershov  V.A. Kazanenkov  N.S. Kim  V.A. Kontorovich  E.A. Kostyreva  V.N. Melenevskiy  V.R. Livshits  A.A. Polyakov  M.B. Skvortsov 《Russian Geology and Geophysics》2013,54(8):917-957

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Cross-correlation earthquake precursors in the hydrogeochemical and geoacoustic signals for the Kamchatka peninsula     

Gennadiy V. Ryabinin  Valeriy A. Gavrilov  Yuriy S. Polyakov  Serge F. Timashev 《Acta Geophysica》2012,60(3):874-893

We propose a new type of earthquake precursor based on the analysis of correlation dynamics between geophysical signals of different nature. The precursor is found using a two-parameter cross-correlation function introduced within the framework of flicker-noise spectroscopy, a general statistical physics approach to the analysis of time series. We consider an example of cross-correlation analysis for water salinity time series, an integral characteristic of the chemical composition of groundwater, and geoacoustic emissions recorded at the G-1 borehole on the Kamchatka peninsula in the time frame from 2001 to 2003, which is characterized by a sequence of three groups of significant seismic events. We found that cross-correlation precursors took place 27, 31, and 35 days ahead of the strongest earthquakes for each group of seismic events, respectively. At the same time, precursory anomalies in the signals themselves were observed only in the geoacoustic emissions for one group of earthquakes.  相似文献   

Assessment of the long-term safety of radioactive waste disposal: 1. Paleoreconstruction of groundwater formation conditions     

I. V. Tokarev  A. A. Zubkov  V. G. Rumynin  S. P. Pozdnyakov  V. A. Polyakov  V. Yu. Kuznetsov 《Water Resources》2009,36(2):206-213

Isotopic characteristics (δ²H, δ¹⁸O, ²³⁴U/²³⁸U, Ar, ³H) of natural and technogenically affected waters were determined in the area around the burying grounds of the Siberian Chemical Combine with the aim to assess the circulation conditions of natural waters and the safety of radioactive waste disposal in reservoir beds.  相似文献   

Vertical structure of recent arctic warming from observed data and reanalysis products     

Vladimir A. Alexeev  Igor Esau  Igor V. Polyakov  Sarah J. Byam  Svetlana Sorokina 《Climatic change》2012,111(2):215-239

Spatiotemporal patterns of recent (1979–2008) air temperature trends are evaluated using three reanalysis datasets and radiosonde data. Our analysis demonstrates large discrepancies between the reanalysis datasets, possibly due to differences in the data assimilation procedures as well as sparseness and inhomogeneity of high-latitude observations. We test the robustness of arctic tropospheric warming based on the ERA-40 dataset. ERA-40 Arctic atmosphere temperatures tend to be closer to the observed ones in terms of root mean square error compared to other reanalysis products used in the article. However, changes in the ERA-40 data assimilation procedure produce unphysical jumps in atmospheric temperatures, which may be the likely reason for the elevated tropospheric warming trend in 1979–2002. NCEP/NCAR Reanalysis data show that the near-surface upward temperature trend over the same period is greater than the tropospheric trend, which is consistent with direct radiosonde observations and inconsistent with ERA-40 results. A change of sign in the winter temperature trend from negative to positive in the late 1980s is documented in the upper troposphere/lower stratosphere with a maximum over the Canadian Arctic, based on radiosonde data. This change from cooling to warming tendency is associated with weakening of the stratospheric polar vortex and shift of its center toward the Siberian coast and possibly can be explained by the changes in the dynamics of the Arctic Oscillation. This temporal pattern is consistent with multi-decadal variations of key arctic climate parameters like, for example, surface air temperature and oceanic freshwater content. Elucidating the mechanisms behind these changes will be critical to understanding the complex nature of high-latitude variability and its impact on global climate change.  相似文献   

The Nui Chua layered peridotite-gabbro complex as manifestation of Permo-Triassic mantle plume in northern Vietnam     

G.V. Polyakov  R.A. Shelepaev  Tran Trong Hoa  A.E. Izokh  P.A. Balykin  Ngo Thi Phuong  Tran Quoc Hung  Bui An Nien 《Russian Geology and Geophysics》2009,50(6):501-516

New data on the age, composition, formation conditions, and ore-geochemical specialization of the Nui Chua layered peridotite-gabbro complex are reported. They evidence that the complex resulted from the Permo-Triassic mantle plume activity in northern Vietnam (southern framing of the Yangtze Platform). Two series of mafic and ultramafic rocks differing in ore productivity—layered (PGE-Cu-Ni) and pegmatoid (Fe-Ti-V)—have been recognized within the complex. The first estimates of the composition of their parental melts have been obtained.  相似文献   

Velocities of shallow overland flow on semiarid hillslopes          下载免费PDF全文

Viktor Polyakov  Mark A. Nearing  Jeffry Stone 《地球表面变化过程与地形》2018,43(12):2578-2583

A series of 188 rainfall plot simulations was conducted on grass, shrub, oak savanna, and juniper sites in Arizona and Nevada. A total of 897 flow velocity measurements were obtained on 3.6% to 39.6% slopes with values ranging from 0.007 m s^‐1 to 0.115 m s^‐1. The experimental data showed that shallow flow velocity on rangelands was related to discharge and ground litter cover and was largely independent of slope gradient or soil characteristics. A power model was proposed to express this relationship. These findings support the slope–velocity equilibrium hypothesis. Namely, eroding soil surfaces evolve such that steeper areas develop greater hydraulic roughness. As a result overland flow velocity becomes independent of the slope gradient over time. Our findings have implications for soil erosion modeling suggesting that hydraulic friction is a dynamic, slope and discharge dependent property. Copyright © 2018 John Wiley & Sons, Ltd.  相似文献   

Seasonal variability in Atlantic Water off Spitsbergen     

Vladimir V. Ivanov  Igor V. Polyakov  Igor A. Dmitrenko  Edmond Hansen  Irina A. Repina  Sergey A. Kirillov  Cecillie Mauritzen  Harper Simmons  Leonid A. Timokhov 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(1):1-14

A combination of 2-year-long mooring-based measurements and snapshot conductivity–temperature–depth (CTD) observations at the continental slope off Spitsbergen (81°30′N, 31°00′E) is used to demonstrate a significant hydrographic seasonal signal in Atlantic Water (AW) that propagates along the Eurasian continental slope in the Arctic Ocean. At the mooring position this seasonal signal dominates, contributing up to 50% of the total variance. Annual temperature maximum in the upper ocean (above 215 m) is reached in mid-November, when the ocean in the area is normally covered by ice. Distinct division into ‘summer’ (warmer and saltier) and ‘winter’ (colder and fresher) AW types is revealed there. Estimated temperature difference between the ‘summer’ and ‘winter’ waters is 1.2 °C, which implies that the range of seasonal heat content variations is of the same order of magnitude as the mean local AW heat content, suggesting an important role of seasonal changes in the intensity of the upward heat flux from AW. Although the current meter observations are only 1-year long, they hint at a persistent, highly barotropic current with little or no seasonal signal attached.  相似文献