Geostrophic adjustment of linear disturbances in two-component media

The linear problem of geostrophic adjustment in a rotating stratified medium is generalized to the case of binary mixtures stratified with respect to both the temperature and admixture concentration (such as, for example, saline seawater and humid air). It is shown that, if the initial ageostrophicity is related to the temperature and/or admixture concentration disturbances, the evolution of the fields of these substances may qualitatively differ from the classical solutions of the adjustment problems. For example, in the course of adjustment, jumps in the temperature and salinity may be retained and enhanced, in contrast to those in the velocity, pressure, and buoyancy. The latter are smoothed by the adjustment process and are distributed over relatively spacious areas with horizontal sizes of the order of the Rossby scale. The initial thermal pulse may lead to the development of a temperature disturbance with a significantly greater amplitude and/or opposite sign and to an intensive disturbance in the admixture concentration.     

Numerical experiments on estimating the accuracy of the methods of solution of the Kalman smoothing problems

The model numerical experiments on estimating the accuracy of two methods for solving the problem of Kalman smoothing, both iteration and precise, are described on the basis of a simple equation for the passive admixture transport. Some quantitative estimations are given.Translated by Mikhail M. Trufanov.     

Variational Approach to the Problems of Planning of Experiments and Identification of the Input Parameters of Hydrodynamic Models According to the Data of Measurements

We discuss the computational properties of variational algorithms of mastering the data of measurements and convergency of iterative procedures of search for an optimum distribution of the input parameters of a model and consider the model of transfer of a passive admixture. The algorithm of identification is based on the variational principles, solving the conjugate problem, and minimization of the functional of quality of a prediction. We carry out the analytic verification of the efficiency of the algorithm and discuss the problems of optimum planning of experiments from the viewpoint of conditionality of the problem of identification that is being solved.     

Unsteady Chains of Wave Structures and Anomalous Transport of Passive Admixture in a Barotropic Jet Flow

Izvestiya, Atmospheric and Oceanic Physics - The anomalous transport of passive admixture is studied when unsteady chains of wave structures with closed streamlines are excited in a barotropic jet...     

On the effect of spray on the dynamics of the marine atmospheric surface layer in strong winds

A nonlinear analytical model of the near-water air layer is considered. In the model, the effect of spray droplets on turbulent exchange is taken into account through their effect on density stratification. To close the system of equations, a semiempirical turbulence theory in the Kolmogorov-Monin form is used. Unlike previous publications, we use an alternative closure scheme that seems more appropriate. A version is also proposed for generalizing the model to the case where heavy admixture particles (spray droplets) make a dominant contribution to the average density of a medium. This model allows a general analytical solution that, in principle, describes non-linear effects such as a decrease in the effective friction and “self-closure” of the heavy admixture in the near-surface layer because of turbulence suppression due to the strengthening of stratification stability. As the current data show, however, the intensity of spray production is probably insufficient to explain the recently discovered phenomenon of the aerodynamic-drag decrease (saturation) in storm winds.     

Chaotic Advection of a Passive Admixture in a Circular Barotropic Jet Flow

Izvestiya, Atmospheric and Oceanic Physics - The chaotic advection of a passive admixture during the excitation of chains of vortex structures in circular barotropic flows with a complex two-jet...     

Analytical Model of Density Currents Arising during the Sedimentation of a Heavy Admixture

Izvestiya, Atmospheric and Oceanic Physics - The horizontally inhomogeneous distribution of a heavy admixture in a fluid (gaseous) medium in the field of gravity means the presence of a horizontal...     

Geostrophic adjustment and frontogenesis in stratified two-component media

A nonlinear problem of geostrophic adjustment in an ideal rotating two-component fluid in the field of gravity is studied analytically. The stratification of the fluid’s density is composed of its temperature stratification and stratification of the concentration of an admixture (in particular, these are salt seawater and moist air). Stationary states, which are reached after the adjustment process is terminated, are found with the use of Lagrange conservation laws. If the amplitudes of smooth initial disturbances are sufficiently large, discontinuity surfaces can appear in the course of evolution. Allowance for a two-component character of the medium makes qualitative properties of such surfaces especially varied. For example, a jump may be strongly marked in the field of one substance alone. It is shown that, if the initial ageostrophic property is related to temperature and/or admixture-concentration disturbances, the evolution of the fields of these substances can differ qualitatively from classical solutions to adjustment problems. For example, in the course of adjustment, the initial heat pulse can lead to the formation of a stationary temperature disturbance with a larger amplitude and/or the opposite sign. During the evolution of a smoothed temperature “step,” nonmonotonic distributions of temperature whose amplitudes are much greater than the amplitude of the initial step may appear. Some of such effects can manifest themselves even in a linear approximation.     

Approximation of the estimate error covariance function: Verification of the accuracy and generalization for the case of cross-covariance functions

Generalization of the approximation for the autocovariance function of estimate error, used frequently in four-dimensional analysis of the ocean's hydrophysical fields, is suggested for cross-covariance functions. It is shown that the principal properties of the covariance function of error estimate are not then violated. Approximation accuracy is studied through numerical experimentation using the two-dimensional equation for passive admixture transport as an example.Translated by V. Puchkin.     

Chaotic transport and mixing of a passive admixture by vortex flows behind obstacles

A two-layer nonviscous model of chaotic advection in a unidirectional pulsating running current above a delta-shaped underwater elevation is considered. The property of local stability is used and a characteristic similar to the cumulative Lyapunov exponent is introduced that makes it possible to determine the range of regular and chaotic particle behavior. The estimates obtained using this characteristic are for clarifying passive admixture transport in analog model problems. Knowledge of the maximum chaotization region boundary is important for oceanology in view of interpreting point vortices as a model of distributed vortices. The criterion based on using the cubic Hamiltonian approximation for a nonlinear resonance model is introduced to estimate the limiting boundary of the regular region.     

用数学形态学变换提取地性线的一种方法

地性线是非常重要的地形结构信息,应用领域十分广阔。采用单纯的矢量方法提取的地性线往往不连续,比较零碎。阐述了利用数学形态学的流域分割算法提取地性线的原理,介绍了基于等高线,采用矢量栅格混合算法提取地性线的具体步骤,最后,给出了结论,实验结果表明,采用本文提出的算法是可行的,提取的地性线有较好的连续性。     

Precious and nonferrous metals in the ferromanganese crusts of the central Sea of Okhotsk

Thin mineral grains of nonferrous and precious metals (Ag, Au, Cu, Ni, Pb, Sn, Zn, Sb, Ti, W, Mo, and Ce) were revealed for the first time by SEM and microprobe studies of polished sections of iron-manganese crusts from the Sea of Okhotsk. The metals form native and intermetallic compounds; less frequently they form mineral oxides or sulfides. The conclusion was drawn that the main part of the native minerals represents a mechanical admixture in the ferromanganese crusts.     

Chemical composition of Aegean Sea sediments

The partial composition of 241 sediment samples from the Aegean Sea, determined for Ca, Mg, Al, Ti, Fe, Mn, Ni, Cr, Pb, Cu, and Zn, can be largely explained by admixture of terrigenous components of variable composition and biogenic components poor in minor elements. Cr and Pb appear to be enriched owing to the occurrence of mafic rocks and minor Pb mineralisation onshore. Variations in elemental abundances within the Aegean Sea can generally be accounted for by differences in depositional environment, except at Sounion where anomalous concentrations of Pb and Zn are probably associated with onshore mining activity.     

Quaternary phosphatized limestones with initial Fe-Mn mineralization from the Kammu Seamount (Milwaukee Seamounts, northern Pacific)

Phosphatized biogenic limestones and phosphorites with initial Fe-Mn mineralization dredged from the summit surface of the Kammu Seamount (Milwaukee Seamounts, northwestern Pacific) are studied. The rocks are largely composed of nannofossils and planktonic foraminifers with an admixture of benthic foraminifers, bryozoans, and other organic remains, presumably including bacterial ones. The nannofosssil and foraminiferal assemblages indicate the Quaternary age of the sediments, and their phosphatization is consistent with the phosphatization age determined previously based on nonequilibrium uranium (within the limits of 1 My). The age of phosphatization and the Fe-Mn mineralization in the sediments from Pacific seamounts that young implies the dependence of these ore-forming processes on oceanic environments favorable for ore accumulation rather than on their age.     

Lagrangian analysis of mixing and transport of water masses in the marine bays

The Lagrangian approach to studying the mixing and transport of a passive admixture in marine bays and gulfs based on the methods of a theory of dynamic systems is developed. This approach is employed to investigate the lateral mixing and transport of waters in the Peter the Great Bay, Japan Sea, using a velocity field of the predictive numerical hydrodynamic circulation model of a synoptic scale. It is shown that the Lagrangian characteristics, such as the maximum accumulated Lyapunov exponent, the time of particle stay in the bay, particle relative displacements, and the number of cyclonic and anticyclonic rotations, allow us to describe the movement of water masses, the character of mixing, and chaos in the Bay. In integrating the advection equations forward and backward in time, maps showing a number of particle arrivals to different regions of the Bay make it possible to establish corridors through which particles leave and enter the Bay.     

Composition of ferromanganese nodules from Riga Bay (Baltic Sea)

An average sample of ferromanganese nodules from Riga Bay was investigated by analytical electron microscopy coupled with atomic absorption, neutron activation, and ICP-MS methods. It is established that the nodules consist of colloform and poorly crystallized Fe and Mn hydroxides with an admixture of dispersed inclusions of better crystallized particles allowing revealing their mineralogical nature by the microdiffraction method. The major mineral phases are ferroxigite and Fe-vernadite with subordinate magnetite, asbolane, and todorokite. The chemical composition of the nodules is dominated by iron followed by cobalt and lead, while nickel, molybdenum, and tungsten associate with the manganese phase. The concentration of several minor elements in the Riga Bay nodules is slightly lower as compared with their average values for the entire Baltic Sea; some elements such as silver, bismuth, cadmium, niobium, tin, and thallium were never analyzed before.     

Hydrothermal manganese mineralization in the Peterbourgskoye ore field (North Atlantic)

The manganese crust covered by pelagic sediment was recovered from the 3 km depth from the Peterbourgskoye ore field located on the eastern flank of the Mid-Atlantic Ridge. The crust comprises a platy brittle aggregate 1–5 cm thick made of black heterogeneous and partly porous material. The inner structure consists of aggregated parallel microplaits several micrometers to 0.2 mm thick consisting of well-crystallized bisnessite with a minor admixture of colloform vernadite. The chemical composition of the crust is dominated by manganese (more than 60% MnO) with minor iron (1.7% Fe₂O₃) and somewhat notable sodium and sulfur. The trace element composition is characterized by very high molybdenum, moderate gallium and uranium, and very low values of 40 other trace elements. Compared to previous publications, the composition of this crust is fairly different from the average values previously defined for hydrothermal crusts. On the other hand, it is rather close to some crusts recovered from subsea volcanoes in the Sea of Japan.     

Simulation of surge phenomena and transformation of the admixture field in the Sea of Azov in the presence of stationary currents

Using a three-dimensional nonlinear mathematical model, we study the processes of transfer and diffusion of contaminants in the Sea of Azov in the presence of stationary currents. Changes in the sea level, surge phenomena, and the direction and velocity of stationary currents caused by winds with different maximum velocities are analyzed. We estimate the region of applicability of the linear approximation and the choice of the value of integration steps over space and time coordinates. It is shown that the growth of the maximum wind velocity increases the contaminated domains and the time of complete dispersion of the admixture. Solutions obtained in the linear approximation differ slightly from those obtained by using the nonlinear model for wind velocities up to 5 m/sec. Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 52–68, July–August, 2008.     

Ecology of benthic foraminifers in the littoral zone of Iturup Island

The composition and abundance of present-day benthic foraminifers in the littoral zone of Iturup Island are examined. The littoral zone is surveyed on the sides of both the Sea of Okhotsk and the Pacific Ocean. The greatest species diversity and the maximum foraminifer abundance were observed on the bench and at the sites of attachment of seaweeds and aquatic plants on silted sands and on sands with an admixture of coquina, silt, and detritus from the adjacent coast. The minimum diversity and abundance are confined to the mouths of rivers and creeks; over rocky plates, where sediments cannot be retained and there are no attached seaweeds and aquatic plants; and in areas not protected from wind-wave action. It was stated that the foraminifer assemblages on the sides of the Sea of Okhotsk and the Pacific Ocean differ both in their species diversity and in their population density over the littoral zone. A morphological comparison between the species Buccella granulata and B. inusitata from different areas of the Sea of Okhotsk and the Pacific Ocean is presented.     

Population structure of the Korean gizzard shad, <Emphasis Type="Italic">Konosirus punctatus</Emphasis> (Clupeiformes,Clupeidae) using multivariate morphometric analysis

The gizzard shad, Konosirus punctatus, is one of the most important fish species in Korea, China, Japan and Taiwan, and therefore the implementation of an appropriate population structure analysis is both necessary and fitting. In order to clarify the current distribution range for the two lineages of the Korean gizzard shad (Myoung and Kim 2014), we conducted a multivariate morphometric analysis by locality and lineage. We analyzed 17 morphometric and 5 meristic characters of 173 individuals, which were sampled from eight localities in the East Sea, the Yellow Sea and the Korean Strait. Unlike population genetics studies, the canonical discriminant analysis (CDA) results showed that the two morphotypes were clearly segregated by the center value “0” of CAN1, of which morphotype A occurred from the Yellow Sea to the western Korean Strait with negative values, and morphotype B occurred from the East Sea to the eastern Korean Strait with positive values even though there exists an admixture zone in the eastern Korean Strait. Further studies using more sensitive markers such as microsatellite DNA are required in order to define the true relationship between the two lineages.