Monitoring of the Black-Sea Dynamics Based on Satellite Technologies

We present a survey of the principles and methods of satellite monitoring of the ocean, analyze the prospects of application of the data of satellite measurements to the operative diagnostics and prediction of circulation in the Black Sea, and discuss the physical foundations of remote sensing, the possibilities of contemporary equipment aimed at the observation of the sea surface from satellites, and the applicability of satellites as retransmitters of the data of measurements from free-drifting buoys. The contemporary oceanographic investigations carried out from satellites enable one to use the accumulated data for the numerical analysis of currents in seas and oceans in the model of general circulation as well as for the creation of a system of operative diagnostics and prediction of the state of marine environment. Examples of experimental realization of elements of the system of operative diagnostics of the state of the Black Sea based on the use of the satellite data are presented and the prospects of prediction of currents in the basin are analyzed.     

Origin and development of the morphological structure of the rift zone of slow-spreading mid-ocean ridges

Due to the complex transformation of the Earth’s crust in the rift valley, the morphology of the newly formed crust is changed by that of the province of rift mountains. The main factors of the variability of the morphological structure are as follows: the tectonomagmatic cyclicity of the geodynamic processes at the spreading centers and the isostatic uplift of the rift valley floor. The interchange of magmatic and tectonic cycles determines the difference in the bathymetric levels of the isostatic equilibrium at the edges of the rift valley slopes and the beginning of the formation of the topography of the province of rift mountains. This relief represents an indepth system of ridges and valleys rhythmically interchanging in the lateral direction. The morphology of the province of rift mountaines becomes the morphology of the acoustic basement throughout the ocean floor, except for the continental margins and areas of intraplate tectonics and volcanism.     

Effect of the Geometric Characteristics of a Basin on the Space Structure of Forced Oscillations

By the method of mathematical simulation, we study the effect of changes in the width and depth of a ring-shaped basin with parabolic profile of the bottom on the space structure of waves generated by variations of atmospheric pressure periodic as a function of time. Our investigation is carried out under the assumptions of the linear theory of long waves with regard for the action of the Coriolis force. The structures of the profiles of liquid surface are compared for the cases of free and forced waves. We also establish the dependences of the period of atmospheric disturbances on the geometry of the basin for which the number of nodal points of the free-surface profile in the case of forced oscillations coincides with the number of nodal points of the profile of liquid surface in the case of free oscillations.     

Variability of the Baltic Sea level and floods in the Gulf of Finland

The statistical analysis of the long-term data on the variability of the Baltic Sea level has revealed the complicated character of the wave field structure. The wave field formed by the variable winds and the disturbances of the atmospheric pressure in the Baltic Sea is a superposition of standing oscillations with random phases. The cross spectral analysis of the synchronous observation series of the level in the Gulf of Finland has shown that the nodal lines of the standing dilatational waves are clearly traced with frequencies corresponding to the distance from the nodal line to the top of the gulf (a quarter of the wave length). Several areas of the water basin with clearly expressed resonant properties may be distinguished: the Gulfs of Finland, Riga, and Bothnia, Neva Bay, etc. The estimations of the statistical correlation of the sea level oscillations with the variation of the wind and atmospheric pressure indicate the dominant role of the zonal wind component during the formation of the floods in the Gulf of Finland. The probable reason for the extreme floods in St. Petersburg may be the resonance rocking of the eigenmode oscillations corresponding to the basic fundamental seiche mode of the Gulf of Finland with a period of 27 h when the repeated atmospheric disturbances in the Baltic Sea occur with a period of 1–2 days.     

Low-frequency variations of the Gulf-Stream transport: description and mechanisms

On the basis of the contemporary array of oceanographic and hydrometeorological data, we compute the characteristics of variations of the Gulf-Stream transport in 1950–2004. The role played by the low-frequency oscillations of vorticity of the wind field and turbulent heat fluxes in the North Atlantic in the formation of the analyzed variations is estimated. We reveal a significant (on a 5% confidence level) positive linear trend of the monthly average Gulf-Stream transport manifested in the increase in the Gulf-Stream transport by 13 Sv for the investigated period. On the basis of the established estimates, we make a conclusion that about a quarter of the interannual variations of the Gulf-Stream transport is caused by the low-frequency oscillations of vorticity of the wind field in the Subtropical Atlantic. Moreover, the Gulf-Stream transport is delayed relative to the wind oscillations by about 2 yr. An important role in the changes in the Gulf-Stream transport is played by the response of the system of west boundary currents to the quasiperiodic action of turbulent heat fluxes on the surface of the ocean connected with the North-Atlantic Oscillation. The intensification of turbulent heat fluxes in the Northern Subpolar Cyclonic Gyre and their weakening in the north part of the Subtropical Anticyclonic Gyre are accompanied by the intensification of the Gulf Stream observed after 3–5 yr. The anomalies of turbulent heat fluxes of the opposite sign are followed by weakening of the Gulf Stream also after a period of 3–5 yr. We also mention a potentially important role played the Pacific decadal oscillation in maintaining the decadal variations of the intensity of Gulf Stream. The influence of this oscillation on the Gulf-Stream transport is realized both via the changes in the wind field in different phases of oscillations and due to its influence on the heat exchange of the ocean with the atmosphere.     

Numerical analysis of the propagation and amplification of tsunami waves of seismic generation in the Sea of Azov

The numerical analysis of the evolution of tsunamis is performed for the Sea of Azov. Our calculations are carried out on a grid with steps of 500 m, as applied to seaquakes with magnitudes within the range 6–7 for 18 circular zones of generation covering almost the entire water area of the sea. It is shown that the oscillations of the sea level in the form of cellular waves are formed as a result of the wave reflections from the coasts. Small areas of the elevated activity of waves are formed in the zones of irregularity of the coastline on the north coast of the sea and in the zones of shoals in the southeast part of the basin. On the basis of the determined values of extreme elevations and lowerings of the sea level, we can make a conclusion that the tsunami hazard is quite low for the coast of the Sea of Azov.     

Numerical modeling of the influence of land–sea temperature contrasts on the atmospheric circulation in the Black-Sea region

The formation of the fields of surface winds over the Black Sea occurs under the action of numerous physical factors. One of the most important factors is the monsoon mechanism connected with the seasonal variations of buoyancy contrasts over the sea and surrounding land. To separate the effects caused by this mechanism, we performed and described the numerical experiments aimed at the evaluation of the sensitivity of the regional model of atmospheric circulation to the variations of land–sea temperature contrasts. It is shown that the influence of these effects is restricted to the lower part of the atmosphere. The presented estimates of the climatic fields of disturbances enable us to describe the monsoon mechanism specifying the seasonal variability of the field of vorticity of the wind velocities and, as a consequence, the seasonal variability of the large-scale circulation of waters in the Black Sea.     

Continental runoff of solid matter as a source of dissolved calcium in the ocean

It was found in the experiments that the transfer of calcium from the solid phase to the dissolved state took place under the interaction of terrigenous matter (bottom sediments from the freshwater lake) with the solutions modeling the interstitial waters of the sediments of high-productive regions of the ocean. This calcium might later bind the autochthonous CO₂ formed in the ocean under the oxidation of organic matter. According to the data of the three-week experiment, 1 g of the terrigenous matter evolved on average ～2.3 mg Ca²⁺ into interstitial solutions, which conforms to the involving of exclusively surface layers of the grains of the solid phase into the reaction. In view of the true rate of halmyrolysis of the grains of terrigenous silicates (a few μm/year), at the value of the continental runoff of solid matter being equal to 16 billion t/year, the amount of dissolved calcium supplied to the ocean as a result of the transformation of the terrigenous sedimentary matter at the stage of diagenesis amounts to 250–440 million t/year and over. These values are 3- to 5-fold higher that the amount of calcium in the continental runoff of dissolved matter supplied by the erosion of silicates and capable of forming carbonate sediments in the ocean under the interaction with autochthonous CO₂, unlike the calcium that is product of the dissolution of carbonate rocks.     

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.     

Correlation between the intensity of tsunami in the Black Sea and the magnitude of underwater earthquakes

We perform the analysis of tsunami waves in the shelf zone of the Crimean peninsula generated by underwater earthquakes whose epicentres are located near the lower boundary of the continental slope. For this purpose, we use a one-dimensional nonlinear dissipative numerical model of long waves. The investigated distributions of the depth of the basin correspond to four points of the south coast of the Crimean peninsula. We use the empirical dependences of parameters of the sources of tsunami waves on the magnitude of the earthquake obtained earlier for the Pacific Ocean. It is shown that the height, vertical climb, and duration of tsunami waves increase with the magnitude of the earthquake. For equal magnitudes of the earthquake, the highest tsunamis on the south coast of the Crimea are observed between Alushta and Yalta. We also deduced a generalized regression dependence of the height of tsunami waves near the coast on the magnitude of the earthquake. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

基于随机森林的复坡堤越浪量预测研究

针对复坡堤越浪量的计算问题,提出了采用随机森林算法预测越浪量的方法。首先,通过对欧洲CLASH数据集进行筛选,挑选出符合复坡堤越浪量预测的数据;其次,对数据做无量纲化处理,建立以随机森林为基础的复坡堤越浪量预测模型,并通过网格搜索(GridSearchCV)方法对模型进行调参以改善模型的性能;最后,利用决定系数R~2来评估模型的精度,并将随机森林模型与集成神经网络模型做了预测能力的对比,同时还给出了随机森林模型各个特征参数对预测精度的重要性。结果显示,随机森林模型的决定系数为92.7%,集成神经网络模型的决定系数为87.7%,表明随机森林模型对越浪量具有更强的学习和预测能力。通过对特征重要性的分析,墙顶高程对模型预测精度的影响最大,堤顶高程次之,堤脚宽度影响最小。     

海洋空间利用年度计划制度的提出与体系构建探讨

海洋空间利用年度计划是自然资源部“三定”职责之一,是应对海洋空间资源短缺、空间利用效率低、海洋资源环境损害等的有效措施。生态文明体制改革以来,国家进一步加强对自然资源的总量和规模控制,强化自然岸线保有率的约束作用,重视国土空间整治修复和围填海历史遗留问题处置。基于以上自然资源管理改革精神,研究提出了海洋空间利用年度计划...     

Formation of electrically active layers in the atmosphere with temperature inversion

The dynamics of the electric field in the planetary boundary layer (PBL) is thoroughly studied from in situ observations of the aeroelectric field and the height profiles of the wind-velocity components in the conditions of temperature inversion and incipient convection. It is established that the formation of a layer with temperature inversion is accompanied by a positive trend in the intensity of the aeroelectric field and by the generation of short-period aeroelectric pulsations. The transfer of a spatially nonuniform space charge and the formation of electrically active layers in PBL are studied by numerical modeling. The response of the electric field to the motion of the space charges simulating the coherent structures of electrogasdynamical turbulence is investigated for the vicinity of the observation point. The key parameters of the model distributions of the space charge are analyzed. The linear dimensions of the model structures range from 20 to 500 m, and the density of the transported charge varies from 0.1 to 1 nC/m³. The layer containing the model structures is located at a height of 60–300 m. It is shown that the spatial distribution and the transfer of the space charge form the dynamical component of the aeroelectric field in the surface layer. The short-period aeroelectric pulsations are induced by the transfer of the spatially heterogeneous space charge in PBL, while the positive trend is due to the accumulation of the space charge below the inversion layer. When the inversion was recorded by a sodar, the intensity of the field at the onset of the convection increased at a rate of 100 V/(m h) on average.     

一代宗师 学人楷模——怀念中国著名海洋教育家、我校首届学报主编赫崇本教授

今年是我校建校三十周年,也是我校学报创刊三十周年,正当散布在海内外的校友与全校师生员工共庆这个光辉的海洋界节日时,作者怀着十分崇敬的心情,回顾我校首届学报主编、海洋系创始人、著名海洋教育家、中国海洋科学奠基人之一赫崇本教授的卓越功绩。     

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.     

Energy features of plural tropical cyclogenesis from multispectral satellite observations

Energy features of the succession of interrelated tropical cyclones (plural cyclogenesis) in the oceans of the Southern Hemisphere (the southern part of the Indian Ocean and the southwestern part of the Pacific Ocean) over February 2008 are comprehensively analyzed on the basis of the method of combining different-scale data of the infrared and radio thermal satellite sounding. The data of infrared thermal channels of the geostationary Meteosat-7 satellite and the results of reconstruction of integral water vapor from data of the AMSR-E microwave complex of the Aqua satellite were used. The analysis showed that the region where water vapor has an increased integral concentration is the most effective channel for pumping the latent heat energy from the tropics into midlatitudes. Each cyclone captures this region from the tropical zone and retains it throughout the entire stage of its own evolution with the aid of the jet spiral bridge. The quantitative estimates of the latent energy of the central equatorial region of water vapor in the intratropical convergence zone (ITCZ) of the Indian and Pacific oceans were a basically new result, as well as the detection of considerable time variations in the latent heat associated with the ejection of coherent water-vapor regions into high latitudes by plural cyclogenesis.     

Field Study of the Space Uniformity of Meteorological and Wave Parameters in the Coastal Zone. On the Problem of Calibration of a Side-Looking Radar on the <Emphasis Type="Italic">Sich-1M</Emphasis> Satellite as an Instrument for Measuring Wind Velocity over the Sea

We study the problem of subsatellite calibration of a side-looking radar (SLR) of the Sich-1M satellite regarded as an instrument for the evaluation of the velocity of surface wind and discuss the possibility of application of the meteorological and wave parameters measured from the stationary oceanographic platform of the Experimental Department of the Marine Hydrophysical Institute (Ukrainian Academy of Sciences) for their evaluation in the remote regions of the sea. These regions can be observed with the help of the SLR without errors introduced by the appearance of the coast in elements of space resolution. To prove the indicated possibility experimentally, we perform simultaneous measurements of the water and air temperatures, wind velocity, and the characteristics of waves both from the platform and in the water area neighboring with the platform on the side of the sea at distances of up to 4.8 km. The quantitative estimates of the degree of space uniformity of the analyzed parameters are deduced under the conditions of stable inshore wind. A conclusion is made that the platform can be used for subsatellite measurements aimed at the validation and improvement of the algorithm of reconstruction of the velocity of surface wind by using the SLR of the Sich-1M satellite. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 3, pp. 31–43, May–June, 2005.     

Transformation of the ocean level under a moving area of disturbances of atmospheric pressure

Within the framework of the linear model of long waves, we study the transformations of the ocean surface under the conditions of uniform motion of a zone of disturbances of atmospheric pressure. The analysis is based on the evaluation of a two-dimensional integral appearing in the exact expression for the shape of the free surface of the ocean. It is shown that Earth’s rotation, the increase in the horizontal scale of the atmospheric anomaly, and the decrease in the depth of the basin make the displacements of the sea level smaller than those predicted by the law of inverted barometer. The motion of the baric anomalies leads to the opposite effect. In the open ocean, the displacements of its surface under a moving front are more pronounced than in the case of a moving circular anomaly of atmospheric pressure. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 3–14, March–April, 2007.     

Quasi-decadal variations in total ozone content,wind velocity,temperature, and geopotential height over the Arosa station (Switzerland)

We present the results of the analysis of the phase relationships between the quasi-decadal variations (QDVs) (in the range from 8 to 13 years) in the total ozone content (TOC) at the Arosa station for 1932–2012 and a number of meteorological parameters: monthly mean values of temperature, meridional and zonal components of wind velocity, and geopotential heights for isobaric surfaces in the layer of 10–925 hPa over the Arosa station using the Fourier methods and composite and cross-wavelet analysis. It has been shown that the phase relationships of the QDVs in the TOC and meteorological parameters with an 11-year cycle of solar activity change in time and height; starting with cycle 24 of solar activity (2008–2010), the variations in the TOC and a number of meteorological parameters occur in almost counter phase with the variations in solar activity. The periods of the maximum growth rate of the temperature at isobaric surfaces 50–100 hPa nearly correspond to the TOC’s maximum periods, and the periods of the maximum temperature correspond the periods of the decrease of the peak TOC rate. The highest correlation coefficients between the meridional wind velocity and temperature are observed at 50 hPa at positive and negative delays of ~27 months. The times of the maxima (minima) of the QDVs in the meridional wind velocity nearly correspond to the periods of the maximum amplification (attenuation) rate of the temperature of the QDVs. The QDVs in the geopotential heights of isobaric surfaces fall behind the variations in the TOC by an average of 1.5 years everywhere except in the lower troposphere. In general, the periods of variations in the TOC and meteorological parameters in the range of 8–13 years are smaller than the period of variations in the level of solar activity.