Transport of bottom waters in the Kane Gap     

E. G. Morozov  R. A. Tarakanov  A. N. Demidov 《Doklady Earth Sciences》2010,433(2):1062-1066

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A spatial model of snowmelt-rainfall runoff formation of the mountain river (by the example of the Upper Kuban River)     

L. S. Kuchment  A. N. Gelfan  V. N. Demidov 《Russian Meteorology and Hydrology》2010,35(12):842-850

A spatial model is proposed of snowmelt-rainfall runoff formation of the mountain river enabling to take account of spatial inhomogeneity of the river catchment and vertical zoning of physiographic and meteorological conditions. The model describes the processes of snow cover formation at various altitudes and snow melting, infiltration into the soils, evaporation, and overland, subsurface and riverbed flows. The verification of the model was carried out from the observational data in the Kuban River basin up to the town of Armavir.  相似文献   

Density-dependent dispersion in heterogeneous porous media Part II: Comparison with nonlinear models   总被引：1，自引：0，他引：1  

Anke Jannie Landman  Ruud Schotting  Andrey Egorov  Denis Demidov   《Advances in water resources》2007,30(12):2481-2498

The results of a series of high-resolution numerical experiments are used to test and compare three nonlinear models for high-concentration-gradient dispersion. Gravity stable miscible displacement is considered. The first model, introduced by Hassanizadeh, is a modification of Fick’s law which involves a second-order term in the dispersive flux equation and an additional dispersion parameter β. The numerical experiments confirm the dependency of β on the flow rate. In addition, a dependency on travelled distance is observed. The model can successfully be applied to nearly homogeneous media (σ² = 0.1), but additional fitting is required for more heterogeneous media.The second and third models are based on homogenization of the local scale equations describing density-dependent transport. Egorov considers media that are heterogeneous on the Darcy scale, whereas Demidov starts at the pore-scale level. Both approaches result in a macroscopic balance equation in which the dispersion coefficient is a function of the dimensionless density gradient. In addition, an expression for the concentration variance is derived. For small σ², Egorov’s model predictions are in satisfactory agreement with the numerical experiments without the introduction of any new parameters. Demidov’s model involves an additional fitting parameter, but can be applied to more heterogeneous media as well.  相似文献   

On spatial filtering of low-degree global oscillations of the Sun     

A. L. Balandin  V. M. Grigoryev  M. L. Demidov 《Solar physics》1987,112(2):197-209

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Methods and Results of Numerical Modeling of Reactive Solute Transport in River Flow   总被引：1，自引：0，他引：1  

Nazarov  N. A.  Demidov  V. N. 《Water Resources》2001,28(1):34-41

The equation of advection–diffusion transport of a reactive solute in a stream is solved by different methods. Procedures for evaluating the parameters of a four-node finite-difference approximation used to numerically integrate this equation are proposed. Numerical experiments based on the developed numerical procedures, software, and models of solute transport allowed, in particular, the evaluation of the sensitivity of pollutant concentration estimates to variations in the parameters of interaction processes and hydrodynamic dispersion for a lowland river.  相似文献   

Measurement of water column primary production using photosynthesis-irradiance relations for surface phytoplankton,the vertical chlorophyll profile,and underwater light intensity     

A. B. Demidov  V. I. Gagarin  S. A. Mosharov 《Oceanology》2016,56(5):637-642

A method has been developed to measure water column integrated primary production (PP_int) in the water column using photosynthesis-irradiance relations for surface phytoplankton, the vertical profile of chlorophyll a concentration, and the underwater light intensity. Good correlation has been found for the results calculated with this method and light dependences in situ. The advantages of this method are the independence of PP_int calculation from CTD profiling and water sampling, and thus optimization (reduction) of the station working time.  相似文献   

Verification of Kara Sea primary production models with field and satellite observations     

A. B. Demidov  S. V. Sheberstov  S. V. Vazyulya  V. A. Artemiev  S. A. Mosharov  A. N. Khrapko 《Oceanology》2016,56(6):799-808

The depth-integrated model (Ψ-Mod) and depth-resolved Kara Sea model (KDRSM) of primary production in the water column were verified using field (2013–2015) and satellite (MODIS-Aqua scanner, 2007, 2011, 2013–2015) observations. The KSDRM and Ψ-Mod over- or underestimate the values of integrated primary production (IPP) in autumn by a factor of 2 and 2.5 with shipboard data as input parameters; the rootmean-square difference (RMSD) was 0.29 and 0.39, respectively. In summer, the efficiency of Ψ-Mod decreased by a factor of 1.5 (RMSD = 0.57), while the predictive capacity of the KSDRM remained the same (RMSD = 0.31). In the Laptev Sea in autumn, the KSDRM performed better than Ψ-Mod (the RMSD was 0.24 and 0.41, respectively). There was no sufficient decrease in the predictive skill of either algorithm when MODIS-Aqua data were used as input parameters. Thus, Ψ-Mod, being a simple and precise algorithm, can be recommended for evaluating the annual IPP in the Kara Sea and for studying its long-term variability using satellite data.  相似文献   

Variations of the λ525.02 nm FeI line profile over the solar disk and observations of large-scale magnetic fields     

M. L. Demidov 《Solar physics》1994,153(1-2):115-129

This paper examines the question of the influence of the 525.02 nm Fei line profile (slope of its wings) variations over the solar disk upon observations of large-scale magnetic fields (LSMF) made in this line. The study has shown that depending on the position on the disk (center-limb effect) and magnetic field parameters at the place of the observation, values of magnetic field strengths determined with proper account of the real line profile and in the usual way (by calibration using the line profile at the center of the solar disk only) can differ by 25% or more, which is of crucial importance. Observations at the Solar Telescope for Operative Predictions (STOP) of the Sayan Observatory have been used to accomplish this work.  相似文献   

Determination of moment tensor and location of microseismic events under conditions of highly correlated noise based on the maximum likelihood method          下载免费PDF全文

E.V. Birialtsev  D.E. Demidov  E.V. Mokshin 《Geophysical Prospecting》2017,65(6):1510-1526

We examine the problem of localization of a single microseismic event and determination of its seismic moment tensor in the presence of strongly correlated noise. This is a typical problem occurring in monitoring of microseismic events from a daylight surface during producing or surface monitoring of hydraulic fracturing. We propose a solution to this problem based on the method of maximum likelihood. We discuss mathematical aspects of the problem, some features and weak points of the proposed approach, estimate the required computing resources, and present the results of numerical experiments. We show that the proposed approach is much more resistant to correlated noises than diffraction stacking methods and time reverse modeling.  相似文献   

Biochemical Characteristics of Suspended Particulate Matter on a Latitudinal Transect in the North Atlantic     

N. V. Politova  A. S. Savvichev  A. A. Klyuvitkin  M. D. Kravchishina  A. B. Demidov  A. Yu. Lein  V. S. Gladyshev 《Oceanology》2018,58(4):573-582

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