Surface effects related to the flow of a nonuniformly stratified fluid around obstacles

Doklady Earth Sciences -     

Paradoxes of geoelectrics

The problem of energy paradoxes revealed in geoelectrics are discussed. The experimental facts illustrating the anomalous energy characteristics of the magnetotelluric (MT) field are presented. An attempt is made to interpret these anomalies from the standpoint of directional analysis. Two three-layer models corresponding to the situation |Q| > 1 and \(\widetilde {{S_z}} < 0\) are found by the numerical modeling. The possibility of accounting for the observed paradoxes within the resonance model “heterogeneous plane wave—layered medium” is discussed.     

Character of turbulence in the boundary regions of the Earth’s magnetosphere

The statistical features of the magnetic field and ion flux fluctuations in the boundary regions of the Earth’s magnetosphere have been studied on different timescales based on the Interball satellite measurements. Changes in the form and parameters of the probability density function have been studied for the periods when the satellite was in the solar wind plasma, different magnetosheath regions, and the turbulent boundary layer (TBL) at the polar cusp outer boundary. Variations in the probability density function maximum (P ₀) and the kurtosis value as characteristics of the turbulence property evolution on different timescales have been studied. Two asymptotic regimes of P ₀, which are characterized by different power laws, have been found. The structural functions of different orders and the types of diffusion processes in different regions, depending on time variations in the generalized diffusion coefficient, have been studied in order to analyze the character of diffusion processes. For the magnetosheath regions, TBL, and polar cusp, it has been found that the diffusion coefficient increases in the course of time (i.e., the regime of superdiffusion has been obtained). In the foreshock region before the main shock, turbulent processes are described by the Kolmogorov model of classical diffusion.     

Dielectric spectroscopy of oil-bearing rocks at 0.05–16 GHz

We have measured the dielectric spectra of sand and bentonite mixtures with oil and saline water (NaCl solution) in the frequency range from 50 MHz to 16 GHz at 22 °C. The measured spectra were compared with predictions in terms of the generalized refractive mixing dielectric model (GRMDM), and the respective error was estimated as a check of the model applicability to describe oil-bearing formations. The results may be useful in developing new methods of electromagnetic logging.     

Effect of wave action of a two-layer flow on underwater obstacles

A force action caused by the generation of internal waves in the vicinity of a density jump layer in a marine medium and exerted on underwater obstacles streamlined by a two-layer flow has been studied as part of a theoretical model. A horizontal element of an engineering structure, for example, a transport pipeline, which is modeled by a point dipole, is selected as an underwater obstacle. The integral representations for the wave resistance and the lift force are obtained. The characteristic features of variation in the hydrodynamic reactions to the streamlined obstacle, as well as the conditions of their significant intensification are revealed.     

ROY—A multiscale magnetospheric mission

The scientific rationale of the ROY multi-satellite mission addresses multiscale investigations of plasma processes in the key magnetospheric regions with strong plasma gradients, turbulence and magnetic field annihilation in the range from electron inertial length to MHD scales.The main scientific aims of ROY mission include explorations of:

(a)

turbulence on a non-uniform background as a keystone for transport processes;

(b)

structures and jets in plasma flows associated with anomalously large concentration of kinetic energy; their impact on the energy balance and boundary formation;

(c)

transport barriers: plasma separation and mixing, Alfvenic collapse of magnetic field lines and turbulent dissipation of kinetic energy;

(d)

self-organized versus forced reconnection of magnetic field lines;

(e)

collisionless shocks, plasma discontinuities and associated particle acceleration processes.

In the case of autonomous operation, 4 mobile spacecrafts of about 200 kg mass with 60 kg payload equipped with electro-reactive plasma engines will provide 3D measurements at the scales of 100-10000 km and simultaneous 1D measurements at the scales 10-1000 km. The latter smaller scales will be scanned with the use of radio-tomography (phase-shift density measurements within the cone composed of 1 emitting and 3 receiving spacecrafts).We also discuss different opportunities for extra measurement points inside the ROY mission for simultaneous measurements at up to 3 scales for the common international fleet.Combined influence of intermittent turbulence and reconnection on the geomagnetic tail and on the nonlinear dynamics of boundary layers will be explored in situ with fast techniques including particle devices under development, providing plasma moments down to 30 ms resolution.We propose different options for joint measurements in conjunction with the SCOPE and other missions:

•

simultaneous sampling of low- and high-latitudes magnetopause, bow shock and geomagnetic tail at the same local time;

•

tracing of magnetosheath streamlines from the bow shock to near-Earth geomagnetic tail;

•

passing “through” the SCOPE on the inbound orbit leg;

•

common measurements (with SCOPE and other equatorial spacecraft) at distances of ∼ few thousand km for durations of ∼several hours per orbit.

The orbit options and scientific payload of possible common interest are discussed in this work, including FREGAT cargo opportunities for extra payload launching and the “Swarm” campaigns with ejection of nano- and pico-satellites.     

Dielectric Model of Thawed and Frozen Organic Soil at the AMSR Radiometer Frequency

Izvestiya, Atmospheric and Oceanic Physics - In this paper, we develop a simple single-frequency dielectric model of thawed and frozen arctic soil for a frequency of 6.9 GHz. The model is developed...     

Arsenic content in water and bottom sediments in the areas of chemical weapon dumps in the Bornholm basin of the Baltic Sea

Data are considered on samples taken during the 2006–2008 expeditions from the water and bottom sediments in the areas where chemical weapon was dumped in the Bornholm basin. Arsenic concentration is detected with the X-ray fluorescence analysis and inversion voltammetry. Results are under consideration of the enhanced arsenic content and their relation to arsenic-bearing toxic agents. It is pointed out that arsenic contamination is local in character and at present is of no serious hazard to the natural environment.     

INTERPRETATION OF ECOLOGICAL-SOIL CHARACTERISTICS OF WOODED STEPPE ZONE IN THE CENTRAL RUSSIAN UPLAND

The authors describe how remote sensing imagery can be employed in the identification of different types of chernozem soils in a predominantly agricultural zone (forest steppe), where natural vegetation (normally one of the best vegetation indicators) has been largely displaced by farm fields. A multi-stage methodology is outlined whereby small-scale imagery is used to delineate large regions of similar bioclimatic-geologic characteristics, from which areas of similar soil formation conditions are distinguished. Multispectral and multitemporal space imagery then is employed to detect less salient ecological-soil differences that can affect phototone and image texture. Translated by Edward Torrey, Alexandria, VA 22308 from: G. V. Dobrovol'skiy and V. L. Andronikov, eds., Aerokosmicheskiye metody v pochvovedenii i ikh ispol'zovaniye v sel'skom khozyaystve: sbornik nauchnykh trudov [Remote Sensing Methods in Soil Science and Their Utilization in Agriculture: A Collection of Scientific Works]. Moscow: Nauka, 1990, pp 103–109.     

Deep structure of the crust beneath the Sea of Okhotsk inferred from 3D seismic density modeling

Potential field anomalies of the Sea of Okhotsk region are analyzed for compiling a map of the basement’s tectonic structures. A 3D density model of the Earth’s crust is constructed using seismogeological and experimental-petrophysical data, which made it possible to obtain a visual image of main structures of the region reflecting the observable geophysical anomalies. The obtained data allow a domain located in the central part of the Sea of Okhotsk beyond the limits of the exclusive economic zone of the Russian Federation to be considered as a natural continuation of the continental shelf since the latter is structurally similar to western Kamchatka. The deep structural boundaries rise beneath the large sedimentary Deryugin and Tinro basins, which is characteristic of petroliferous basins.