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631.
The solar wind–magnetosphere coupled system is characterized by dynamical processes. Recent works have shown that nonlinear couplings and turbulence might play a key role in the study of solar wind–magnetosphere interaction processes.Within this framework, this study presents a statistical analysis aimed to investigate the relationship between solar wind MHD turbulence and geomagnetic activity at high and low latitudes as measured by the AE and SYM-H indices, respectively. This analysis has been performed for different phases of solar cycle 23. The state of turbulence was characterized by means of 2-D histograms of the normalized cross-helicity and the normalized residual energy. The geomagnetic response was then studied in relation to those histograms.The results found clearly show that, from a statistical point of view, solar cycle 23 is somewhat peculiar. Indeed, good Alfvénic correlations are found unexpectedly even during solar activity maximum. This fact has implications on the geomagnetic response as well since a statistical relationship is found between Alfvénic fluctuations and auroral activity. Conversely, solar wind turbulence does not seem to play a relevant role in the geomagnetic response at low latitudes. 相似文献
632.
Estimating hydrological characteristics in the Amu Darya River basin under climate change conditions
N. A. Agal’tseva M. V. Bolgov T. Yu. Spektorman M. D. Trubetskova V. E. Chub 《Russian Meteorology and Hydrology》2011,36(10):681-689
Under consideration are results of solving the problem of the river water content estimation under conditions of uncertainties
of climate change forecasts and the catchment state with a reference to the Amu Darya River basin. When constructing regional
climate models, one selected a multimodel approach using the results of several global models and a statistical downscaling
method that made the climate scenarios more detailed. The estimates demonstrated that in the medium- and long-term perspective,
the Amu Darya River runoff is expected to decrease. As a result of the Bayesian ideology application, using the calculations
got with a total probability formula, a prognostic probability curve of an annual river runoff supply of the basin rivers
was derived based on different weights given to the estimates of a mean value for different climate scenarios. Prognostic
characteristics of the annual runoff for the Amu Darya basin rivers are estimated in a form acceptable for hydrologic and
hydroeconomic application. 相似文献
633.
Considered is a dangerous ice phenomenon developing in the Neva River during its freezing, the formation of the intrawater
ice resulting in the corking of water intakes, and ice jams causing a sharp water runoff decrease downstream of them and floods.
Described are the forecasting techniques of the intrawater ice formation intensity, peak ice jam water levels, and thickness
of ice jams. 相似文献
634.
The numerical global self-consistent model of the Earth’s thermosphere, ionosphere and protonosphere (GSM TIP), which makes
it possible to calculate all the main parameters of the near-Earth plasma, is used to calculate the total electron content
(TEC). Calculations have been performed along the radiosignal propagation trajectory between a surface receiving point and a GPS
satellite. The TEC value calculated from the satellite data have been compared with such a “true model” TEC value for magnetically quiet conditions of the spring equinox and moderate solar activity. The relative errors in determining
the satellite data-based TEC for two European (Troms have been calculated. It has been indicated that an increase in the number of satellites not always
results in an increase in accuracy of the TEC value measured on satellites. 相似文献
635.
A new version of the STRUCTON (2009) computer model is proposed for the simulation of the molecular mass distributions (MMD)
characterizing the diversity of anions in silicate melts depending on their polymerization and temperature. In contrast to
earlier versions, the new version of the model accounts for disproportionation reactions of Q
n
species and makes use of their proportions in the statistical simulations of the origin of real Si-O complexes. The new potentialities
of the STRUCTON program package are illustrated by its application to studying the structural-chemical characteristics of
melts in the Na2O-SiO2 system along its liquidus line, including the points of eutectics and phase transitions at 0.333 ≤ $
N_{SiO_2 }
$
N_{SiO_2 }
< 0.500. This problem is solved with the use of a temperature-composition dependence of polymerization constants K
p
Na in the Toop-Samis approximation. The variations in K
p
Na were proved to be as large as three orders of magnitude due to both the temperature effect at a constant composition and
the composition effect at a constant temperature. The results of the MMD simulations on the liquidus show that the concentration
of the SiO44− ion strongly decreases, and the proportion of chain species increases compared to those at a stochastic distribution. The
concentration of the Si2O76− anion reaches its maximum (∼42%) at 40 mol % in the liquid, i.e., the composition of Na6Si2O7. At $
N_{SiO_2 }
$
N_{SiO_2 }
> 0.40, this ion dominates over the SiO44− monomer. More silicic melts with $
N_{SiO_2 }
$
N_{SiO_2 }
≥ 0.45, are dominated by (Si
n
O3n
)3n− ring species, and the concentrations of these species are related as (Si3O9)6− > (Si4O12)8− > (Si5O15)10−. The maximum concentration of these flat rings also occurs near the composition of stoichiometric metasilicate with Si/O
= 0.333. The comparison of the dependence of the average size of anions i
av and the average number of their species on depolymerization indicates that a change in the proportion of Q
n
species in melt at decreasing temperature results in structural restyling and an increase in the average size of Si-O complexes.
The average number of anion species thereby decreases compared to that in a stochastic MMD. The results presented in this
publication direct the progress in the thermodynamic theory of silicate melts to a new avenue that makes use of the capabilities
and advantages of the ion-polymer model, the theory of associated solutions, spectroscopic data, and the experimental study
of variations in oxide activities depending on composition and temperature. 相似文献
636.
A. A. Kadik N. A. Kurovskaya Yu. A. Ignat’ev N. N. Kononkova V. V. Koltashev V. G. Plotnichenko 《Geochemistry International》2011,49(5):429-438
It is assumed in the theories of Earth formation that the composition of gases extracted by primary planetary magmas is formed
by the large-scale melting of the early mantle, which occurred in the presence of a metallic Fe phase. The molten Fe metal
and silicate materials underwent gravitational migration, which affected the fractionation of siderophile elements. Volatile
compounds had to form simultaneously in the zones of large-scale melting of the early Earth; their compositions were controlled
by interaction with silicate and metallic melts. This process remains poorly understood. 相似文献
637.
638.
639.
Mixed-layer corrensite-chlorites and their formation mechanism in the glauconitic sandstone-clayey rocks (Riphean, Anabar Uplift) 总被引:1,自引:0,他引:1
V. A. Drits T. A. Ivanovskaya B. A. Sakharov B. B. Zviagina N. V. Gor’kova E. V. Pokrovskaya A. T. Savichev 《Lithology and Mineral Resources》2011,46(6):566-593
The paper presents the first detailed mineralogical, structural, and crystal-chemical characteristics of the mixed-layer corrensite-chlorites
from the glauconitic sandy-clayey rocks that make up the bottom (0.10 m) of a basal member (1.50 m) of the lower subformation
of the Yusmastakh Formation (Riphean, Anabar Uplift, North Siberia). Like the overlying mudstones (1.40 m) in the basal member,
these rocks are generally transformed up to the deep catagenesis level and included in a thick dolomite sequence. In mudstones
represented by the dioctahedral micas, the corrensite-type minerals are observed as traces. 相似文献
640.
O. V. Postnikova A. V. Postnikov E. S. Konoval’tseva V. G. Toporkov S. I. Savchenko 《Lithology and Mineral Resources》2011,46(5):447-456
Basic regularities of secondary processes in reservoir rocks of the Yarakta Horizon are described with rocks in the Yarakta
field as example. To achieve the formulated goal, we elucidated rock types in the studied section, its structure and distribution
of reservoir rocks, as well as types of secondary alterations and their influence on filtration-capacity properties. The studies
revealed that reservoir rocks of the Yarakta Horizon were formed on an alluvial-deltaic plain on the southeastern slope of
the Nepa-Botuoba anteclise. The pore space of reservoir rocks is determined by conditions of their formation and peculiarities
of secondary alterations. Maximal filtration-capacity values are characteristic of gritstones, as well as coarse-grained and
inequigranular sandstones developed in the lower and middle parts of the Yarakta Horizon. The intergranular space of reservoir
rocks in the lower part of the reservoir is substantially “healed” by secondary processes (regeneration, dolomitization, sulfatization,
and salinization), probably, due to the gravitational seepage of stratal fluids, mineralization of which increased with time. 相似文献