On the nature of the Khvalynian transgression of the Caspian Sea

This paper presents a reconsideration of the hypothesis that the Khvalynian transgression of the Caspian Sea resulted from an abundant inflow of meltwaters from Siberian proglacial lakes through the Aral Sea and via the Uzboi channel and may be considered as a prototype of Noah’s Flood. A thorough analysis of the evidence suggested by the proponents of this hypothesis revealed a lack of factual substantiation; there are no facts indicating the existence of the Aral flow-through lake or of the Siberian proglacial water supply to the Caspian Sea. The spatial distribution of the mollusk fauna provides no support for the view that the Khvalynian transgression was essentially influenced by thawing of ice sheets on the Russian Plain. The Khvalynian transgression, though geologically short-term, could not be an analogue of Noah’s catastrophic flood. The sea level rose at a rate of a few centimeters per year for a few thousand years; this interval covered the lifetimes of many generations of the Caspian coast inhabitants. The Khvalynian water overflowing via the Manych Strait into the Pontian basin provided an even smaller influence. It resulted in flooding of the middle part of the Black Sea shelf, in a 30-m sea level rise, and in a water salinity increase by 5‰.     

Modelling of the ecosystem of the Black-Sea shelf zone near the estuary of the Danube

We analyze the results of numerical calculations performed according to the three-dimensional interdisciplinary model of an ecological system of the Black-Sea shelf zone near the estuary of the Danube. The complete system of equations of hydrothermodynamics is solved together with transport equations of the advection-diffusion-reaction type used to describe the transformation of a substance (nitrogen) between the components of the characteristic vectors of the ecosystem: plankton, detritus, and biogenic elements (nitrates). We describe the distinctive features of the circumcontinental distribution of components obtained as a result of numerical experiments and present arguments for the conclusion that the ecosystem of the Danube estuary water area plays the role of a buffer zone between the press of the Danubian biogenic pollutions and the neighbouring areas of the shelf zone and open sea. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

The influence of the bottom contour on the deformed state of the ice cover due to the motion of the submarine

The authors have previously determined that the effectiveness and failure pattern of the ice cover caused by flexural-gravity waves generated by a submerged body motion near the bottom ice can greatly depend on the depth of the water area. In its turn, the presence of a ledge on the ice surface may affect a wave propagation pattern. This paper presents an experimental study of the bottom contour influence on the deflection and length of flexural-gravity waves. The authors describe a numerical model for the analysis of the deformed state of ice caused by hydrodynamic loads due to a submarine motion, taking into account the bottom contour. The experiments are carried out in the ice tank. The results of calculations and experiments are compared.     

Modelling of the ecosystem on the shelf of the Republic of Guinea

Three mathematical models are considered: a two-dimensional model for calculating the concentration fields of the ecosystem components on the shelf of the Republic of Guinea, a pointwise model for the annual variation of the components, and a two predators-prey model. These models are used to study the effect of hydrodynamic conditions on the state of the shelf ecosystem and for research into the causes which distort the balance between marketable and unmarketable fish.Translated by Mikhail M. Trufanov.     

Model of the post-Cenozoic evolution of the cryolithozone of the shelf of the western part of the Laptev Sea

The analysis of the structure of the cryolithozone, facies, and thicknesses of the Quaternary sediments and the results of the physicochemical mathematical modeling of the modern shelf of the western part of the Laptev Sea support the influence of the Late Pleistocene glaciations on the heat conditions and the distribution of the permafrost in the area. A ～200-m thick glacier formed under aerial conditions from atmospheric precipitation represented the metamorphosed snow cover. According to the modeling, the long-living (from 60?50 to 10?4 ky) glacier reduced the thickness of the permafrost rocks in the reviewed shelf area for 280–360 m. The Holocene marine transgression additionally decreased the thickness from 50–140 m on the inner shelf to 220–350 m on the outer shelf. The modern submarine cryolithozone 450-0 m thick is wide-spread in the studied region from the coast to the shelf boundary (isobaths of 130–140 m), where it pinches out at a distance of ～380 km from the coast at a depth of ～250 m above the sea level.     

Investigation of the fields of concentration of the suspension on the northwest shelf of the Black Sea in the case of roiling of the bottom sediments by a moving cyclone

The processes of roiling of the bottom sediments, diffusion transport of the suspension, and its repeated sedimentation on the northwest shelf of the Black Sea caused by a moving cyclone are studied by using a numerical sigma-coordinate model. It is supposed that bottom sediments are formed by particles of the same type. We determine the regions of the most intense rise of the suspension, directions of its transport by the flows of water, and the vertical profiles of concentration of suspended bottom sediments in different regions. In particular, it is shown that the distribution of suspended substances at a distance of 1 m from the bottom reflects the location of the active and inactive centers of erosion. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 1, pp. 3–20, January–February, 2007.     

Towards the modeling of the ditching of a ground-effect wing ship within the framework of the SPH method

Ditching often takes place for a ground-effect wing (WIG) ship. During the ditching, the extreme load developed by water impacts may cause damages to structures, posing a great threat to the safety of crew and passengers. In the paper, a weakly compressible smoothed particle hydrodynamics (SPH) model combined with enhanced numerical techniques has been adopted to tackle the ditching problems. In order to handle the motion of a rigid body in the three-dimensional ditching problems, the six degrees-of-freedom (6-DOF) equations of motion are incorporated into the SPH scheme. The accuracy of the SPH model is validated through two benchmarks, respectively, the two-dimensional wedge water entry and the three-dimensional stone-skipping. The former is aimed to validate the prediction of pressures during the free surface impact while the latter is a good case for testing the coupling motions of the rigid body. Furthermore, the ditching of the real scale WIG ship under different conditions is simulated with the established SPH model, through which some useful conclusions are drawn.     

Regularities of the formation of the granulometric composition of the bottom and beach deposits of the Anapa bay bar

As a result of the field studies conducted in 2010 of the spatial and temporal variability of the granulometric composition of the bottom and beach deposits of the southern part of the Anapa bay bar, the tendency of a decrease in the average size of the particles under the southward flow of the deposits of the coastal zone was revealed. The comparison of the data obtained in 1949, 1979, and 2010 shows that the average diameter of the particles in the deposits of the underwater slope also gradually decreases over the time. It was established that, with the decreasing of the particle sizes down to 0.1 mm, their nonrecoverable deposition to a depth of more than 7 m increases. Since, in the southern edge of the Anapa bay bar, over 70% of the bottom and about 60% of the beach deposits are represented by fractions smaller 0.16 mm, at this site the mass deposition of the sand material to a depth occurs. Based on the data obtained, the particle size of the sandy material recommended for the restoration of the beaches of the southern part of the Anapa bay bar was determined.     

On the problem of the formation of the Greenland sea convective gyre

The transformation of the interfaces of a rotating three-layer fluid is described through a simple hydrodynamic model using the shallow-water approximation. Using the Greenland sea gyre as an example, it is shown that a cyclonic circulation results in the oncoming deflection of the upper and lower layers, which favours the development of deep convection.Translated by Mikhail M. Trufanov.     

Features of the distribution of the taxonomic diversity of bivalve fauna in the northern part of the Pacific Ocean

Among the components of biological diversity such as taxonomic richness and ecological diversity (distribution of species with respect to their abundance), one should also distinguish the taxonomic diversity as a function of taxonomic richness and evenness of the distributions of taxa of lower ranks over those of higher rank. In the direction from the high latitudes to the tropics, the taxonomic richness and Shannon’s index of taxonomic diversity regularly increase, while the taxonomic evenness, on the contrary, decreases. Toward the north, a relatively small number of mass species become better manifested; they are approximately even over a few genera and families. In warm waters, more common is the existence of a relatively large number of families, which strongly differ in the number of species; each of the latter features low abundance parameters. The meridional asymmetry in the distribution of the taxonomic richness and diversity reveals itself in the higher values of these parameters in the northeast of the Pacific Ocean as compared to their values at the same latitudes in the northwest; in the former case, the trend of latitudinal variations in the taxonomic diversity is poorer expressed.     

Analysis of inequalities between the fishing capacities of the fleets of the European union

In the period 1983-2007, The European Union controlled the evolution of the capacity of its fishing fleet through the so-called Multi-Annual Guidance Programmes (MAGPs). As a result, The European Union reduced the number of fishermen, fishing vessels, gross tonnage and power. However, the end of this period saw an increase in the average size of the fishing vessel and a reduction in crew size. The new “average fishing-vessel” was a more technologically advanced vessel with a greater fishing capacity and a higher degree of autonomy. The aim of the study presented here is to determine the degree of inequality to be found between the fishing capacities of the fleets of the European Union, and to verify whether the evolution of the “average fishing-vessel” responds to a homogenous trend shared by all of the fishing fleets of the European Union or whether it is in fact more unequal. The study formalises a methodology, using Theil indices, which enables the inequalities found between the capacities of the fishing fleets during the period of application of the MAGP adjustment polices to be analysed. The study uses data on fishermen, boats and tonnages from 13 countries of the European Union and results are obtained for the inequality indices of the average size of the fishing vessels, their degree of technological advance and their average crews.     

《京都议定书》的缺陷分析

自我加强型（self—enforcing）机制是促进气候变化国际协议中各缔约国积极参与温室气体减排的最为关键的激励机制，然而却是《京都议定书》这一国际协议所最欠缺的，致使诸多缔约国消极应对，甚至单方面退出协议，令协议至今难以有效实施。因此如何建立并完善自我加强型的激励机制是《京都议定书》在未来的机制和内容改进中应关注的重要研究领域。作为这个研究领域的1个关键的前提条件，必须对目前议定书存在的缺陷和问题具有充分和深入的认识。     

Abnormality of the monsoon wind in the sea area along the southeastern coast of China and the response of the northern area of the South China Sea during the ENSO events

Variations of monsoon wind field in the sea area along the southeastern coast of China during the ENSO events and its influence on the sea level and sea surface temperature (SST) are explored mainly on the basis of the data of monthly mean wind at 850 hPa and five coastal stations during 1973-1987. The results from the analyses of the data and theoretical estimation show that the southwest wind anomalies appeared in the study area during the events, and northeast wind anomalies occurred in general before the events. With the coastline of the area being parallel basically to the direction of the wind, an Ekman transport will result in an accumulation of the water near the coast or a departure of the water from the coast. As a result , the sea level and SST there will be affected markedly. During the events, southwest wind will intensify in the summer, and northeast wind will weaken in the winter. Their total effect is that a large negative anomaly of the sea level and SST will occur. The estimations indi     

日本南部黑潮与黑潮延伸体路径状态关联性的定量分析

日本南部黑潮存在多种路径模态:近岸非大弯曲路径、离岸非大弯曲路径和大弯曲路径。黑潮延伸体的路径存在两种典型模态:收缩态和伸展态。从地理位置看, 日本南部黑潮和黑潮延伸体是相邻的, 但它们的路径状态是否存在关联一直存在争议。本文基于卫星观测的海表高度资料和长期的海洋高分辨率再分析资料, 对日本南部黑潮和黑潮延伸体路径状态之间的关联性进行定量分析, 结果表明:日本南部黑潮和黑潮延伸体的路径状态存在一定的关联。当日本南部黑潮处于近岸非大弯曲和大弯曲路径时, 黑潮延伸体主要处于伸展态; 当日本南部黑潮处于离岸非大弯曲时, 黑潮延伸体处于伸展态和收缩态的比例相当。进一步分析表明, 黑潮流轴处于伊豆海脊的位置部分决定了上述关系, 可能存在其他因素调制了两者的关联性。     

Specific Features of the Influence of the Lower Boundary of a Waveguide on the Angular Structure of the Sound Field in the Shelf Zones in the Northwest Part of the Black Sea

We analyze the possibility of existence of critical angles of incidence of sound waves along two paths of propagation of sound typical of the northwest shelf of the Black Sea from the viewpoint of the characteristics of the lower boundary of a waveguide and the space and time structure of the field of sound velocity. The lower boundary of the waveguide may possess the property of acoustic transparency both in the case of a subsurface sound channel and under the conditions of negative refraction if the bottom is formed by fine-aleurite silts responsible for significant losses in the process of propagation of sound. The angles of total internal reflection exist for bottoms formed by shell rocks under all hydrological conditions typical of this region. At the same time, for bottoms formed by fine-aleurite silts, these angles exist only for a certain vertical structure of the field of sound velocity, which enables one to use the range of angles in which the losses caused by the reflections of sound waves from the bottom can be neglected.     

Influence of the dynamics of currents on the hydrophysical structure of the waters and the vertical exchange in the active layer of the Black Sea

An analysis of the data of measurements of the fine structure and microstructure fluctuations of hydrophysical fields in the upper 200-m layer of the Black Sea carried out using CTD profilers and a Baklan free falling microstructure and turbulence profiler revealed the existence of a positive correlation between the intensity of the fine structure and microstructure fluctuations and the dynamics of the currents. On the other hand, the level of the fine structure and microstructure fluctuations reflects the rate of the vertical turbulent exchange. It was shown that, in the case of the absence of the Black Sea Rim Current (BSRC) jet or clearly manifested mesoscale eddy structures, the vertical turbulent exchange in the pycnocline is weak, while, in the opposite case, it is stronger. The results obtained support the supposition that the interbasin dynamics play an important role in the maintenance of the rate of small-scale mixing in the pycnocline and halocline and provide the vertical transport of dissolved oxygen from the cold intermediate layer into the deeper layers of the sea.     

Estimates of the characteristics of the horizontal turbulent exchange in the northwestern part of the Pacific Ocean

Estimates of the characteristics of the horizontal turbulent exchange (coefficients of horizontal exchange, scales of deviations of the velocity of geostrophic currents from the background flows, and horizontal scales of perturbations) in the upper ocean layer were obtained on the basis of the data of expeditions held in 1978 and 1980 in the northwestern part of the Pacific Ocean. It is shown that the characteristics of the horizontal turbulent exchange strongly depend on the structure of the background flows, and one of the causes of their variability is related to tropical cyclones. A tendency to a decrease (to different degrees) of the turbulent coefficients in the wake of a tropical cyclone is noted.     

On the possible mechanism of the intensification of the vertical exchange in the ocean during earthquakes

In recent years, some papers reported events of the lowering of the temperature of the sea surface subsequent to earthquakes. This paper is devoted to a discussion of the possible mechanism of the intensification of the mixing of seawater under earthquakes. The possible role of the intensive turbidity flows that are sometimes generated in the near-bottom layer over a sloping bottom subsequent to earthquakes is discussed. The estimates made on the basis of a semiempirical theory of turbulence show that the shear currents caused by these flows can lead to a fast turbulization and mixing of rather thick water layers.     

入海河口生态预警监测站设立意义浅析

入海河口是河流和海洋生态系统的过渡带,陆源生态敏感因素入海将极大地影响近岸海域的生态状况。因此,入海生态敏感因素监测是海岸带生态保护和生态防灾减灾的重要基础,也是促进海洋经济可持续发展的关键一环。然而,当前我国入海河口生态预警监测系统的建立尚处于起步阶段,与发达国家之间还存在较大差距。文章从入海河口生态状况对海域生态系统健康的影响入手,总结了国内外入海河口海洋生态预警监测技术的发展历程、建设情况和应用方向,探讨了建设入海河口生态预警监测站的生态意义和系统发展方向。     

On the stability of the moments of the maximum entropy wind wave spectrum

The stability of some current wind wave parameters as a function of high-frequency cut-off and degrees of freedom of the spectrum has been numerically investigated when computed in terms of the moments of the wave energy spectrum.From the Pierson-Moskovitz wave spectrum type, a sea surface profile is simulated and its wave energy spectrum is estimated by the Maximum Entropy Method (MEM). As the degrees of freedom of the MEM spectral estimation are varied, the results show a much better stability of the wave parameters as compared to the classical periodogram and correlogram spectral approaches. The stability of wave parameters as a function of high-frequency cut-off result the same as obtained by the classical techniques.