Features of the hydrological structure and circulation in the north-western Black Sea: shipboard and satellite observations in 1989–1990

The results of shipboard and satellite observations of the synoptic variability in the region of the continental slope south of the Tarkhankut Cape are considered. Ship observations revealed a two-layer circulation system of currents. An anticyclonic meander is localized within the upper mixed layer. A cyclonic disturbance, related to the main Black Sea current, occupies the water column below the seasonal thermocline. The interaction between the thermohaline fields is presumably induced by the anticyclonic atmospheric circulation. The satellite-derived images revealed a complex pattern of the large-scale dynamics of seawater over the entire north-western Black Sea.Translated by Mikhail M. Trufanov.     

Assimilation of the Data of Satellite Altimetry in an Eddy-Resolving Model of Circulation of the Black Sea

The data of satellite altimetry are used to simulate the Black-Sea circulation. The altimetry data of the TOPEX/Poseidon and ERS satellites are prepared within the framework of the NASA Ocean Altimeter Pathfinder project. The additional data processing is performed to compute the dynamic level reflecting the circulation of the Black Sea. The altimetry sea-level is assimilated in an eddy-resolving model of circulation of the Black Sea based on primitive equations. The accuracy of the obtained fields of temperature and salinity is estimated by comparing with the data of large-scale hydrographic surveys according to the ComSBlack program. The prognostic capabilities of the proposed model are estimated by comparing the obtained results with the fields computed with the help of assimilation of the altimetry data.     

Monitoring Anthropogenic Impact on Some Coastal Water Areas of the Black Sea Using Multispectral Satellite Imagery

Izvestiya, Atmospheric and Oceanic Physics - The results of comprehensive monitoring of anthropogenic impact on some coastal water areas of the Black Sea are presented. Multispectral satellite...     

Study of long-term variations in the Black Sea fields using an interdisciplinary physical and biogeochemical model

Using an interdisciplinary three-dimensional physical and biogeochemical model developed for the Black Sea, the long-term evolution of marine dynamics and ecosystem is investigated. The hydrophysical fields were calculated from a model of Black Sea circulation with assimilation of hydrographic survey and satellite measurement data from 1971 to 2001. The circulation model reproduces well processes of various scales in both space and time (particularly the seasonal course and interannual variability of main hydrophysical fields). The resulting flow fields are then used to calculate the long-term evolution of the components of the lower level of the food chain in the Black Sea ecosystem. The biogeochemical model used in the calculations is based on the nitrogen cycle and includes a parameterization of the main biological and chemical interactions and processes in the upper layer of the Black Sea. The numerical experiments indicated that the biogeochemical component of the model rather successfully reproduces the main features and evolution trends in the Black Sea ecosystem for the period under consideration: the growth in the phytoplankton biomass during eutrophication and changes in seasonal cycles of the main ecosystem components. Also, the hydrophysical processes were shown to be important for a reliable reproduction of long-term changes in the ecosystem.     

Development of means and methods of drifter technology applied to the problem of the Black Sea research

During the last ten years, autonomous drifting platforms for data collection (drifters) equipped with Argos satellite communication devices have become one of the main components for the observation system in the upper layer of the ocean and surface atmosphere. This article presents the results of the Black Sea drifter monitoring in 2002–2006 within a number of international programs and projects. During this period, about 70 drifters manufactured by NPF Marlin-Yug Ltd. (Sevastopol, Ukraine) were deployed in the western part of the Black Sea. The drifters were mainly standard barometric Lagrangian tracers and a part of them were principally new temperature profiling buoys. Unique long-term data were obtained about the circulation of the surface currents and the dynamics of the temperature stratification within the seasonal thermocline and the cold intermediate layer.     

Satellite monitoring of oil slicks on the Black Sea surface

This paper summarizes the results of perennial combined satellite monitoring of the Black Sea conducted in order to detect sea-surface oil and oil-product pollution, as well as biogenic and anthropogenic surfactant films. A joint analysis of data obtained by various remote sensing techniques has been performed. The large amount of data has resulted in generalizations and reliable statistics on the spatial and temporal variability of different film manifestations in radar images of the sea surface. Regions most severely polluted by petroleum products have been identified. A hypothesis is suggested linking the surface manifestations of certain types of polluting films with natural gas and oil seeps and mud volcanism in the Black Sea. Improvements in the reliability of interpreting satellite data are discussed.     

Spatial and temporal variability and monitoring of hydrophysical fields of the Black Sea

As part of the Russian-Ukrainian program “The Black Sea as a Simulation Model of the Ocean,” the monitoring of the marine environment is considered using modern measuring systems. On the basis of historical and contemporary observation data, we estimate the spatial and temporal scales of dominant processes in the Black Sea. We describe the main measuring systems used to monitor the structure and variability of the hydrophysical fields. Examples characterizing the specific features of the Black Sea processes are presented.     

Experience of remote monitoring in the Black Sea and the Mediterranean Sea in the optical spectrum band

The methodology of regional remote monitoring of the ocean on the basis of complex largescale studies carried out by the Marine Hydrophysical Institute of the Ukrainian SSR Academy of Sciences in the Black Sea and the Mediterranean Sea in 1987–1988 is considered. The collection of controlled parameters, ground facilities, methods of collecting and processing of satellite and subsatellite data, and features in the compilation of composition maps of the sea surface radiation temperature are discussed.Translated by Mikahil M. Trufanov.     

Study of long-term variability of Black Sea dynamics on the basis of circulation model assimilation of remote measurements

The Black Sea dynamics for two decades (1993–2012) is analyzed. The study is carried out in numerical simulation with the use of a circulation model and assimilation of satellite measurements of free surface elevations and sea-surface temperatures (SSTs). The Black Sea circulation model has a spatial resolution of 4.8 km and 35 vertical levels, which thicken toward the surface. Arrays of ERA-Interim data are used for simulating the atmospheric forcing. A set of 3D arrays of the Black Sea hydrophysical fields is calculated on a regular grid with a time resolution of 24 h. The results are analyzed and compared with available contact measurements of temperature and salinity. This comparison shows a quite good quality of the resulted hydrophysical fields of the Black Sea.     

Estimating the quality of the retrieval of the surface geostrophic circulation of the Black Sea by satellite altimetry data based on validation with drifting buoy measurements

Combined measurements of satellite altimeters make it possible to determine anomalies of the sea level of the Black Sea on a regular grid with a high spatial resolution 1/8°. In this work arrays of total geostrophic velocities of currents in the Black Sea basin are retrieved and compared with drifter measurements of current velocities for 1999–2007. The comparison is performed both for the whole array of drifter measurements (～110000 measurements) and individually for each drifter. To retrieve the velocities, two different arrays of mean dynamic topography (MDT) are used: synthetic and climatic mean dynamic topography. The comparison results demonstrate that using synthetic MDT is preferable for calculating geostrophic velocities. Velocities calculated by from satellite altimetry data agree with velocities obtained by in-situ data.     

东海赤潮遥感自动监测系统开发与应用

赤潮是最严重的海洋灾害之一,它不仅破坏海洋渔业生产、恶化海洋环境、影响滨海旅游业,而且还会影响人类健康。卫星遥感技术具有覆盖范围广、重复率高、成本低廉等优势,近年来已成为赤潮监测不可或缺的重要手段。本研究利用C++语言建立了一套赤潮遥感监测系统。该系统能自动接收和处理遥感数据,并利用赤潮水体的光谱和固有光学量特征自动提取赤潮信息。在实际业务化应用中,该系统被国家监测部门采用,在2013年4月至9月东海赤潮高发期间,该系统制作了55期赤潮遥感监测产品,用于指导船舶现场监测工作,取得了良好的应用效果。利用本系统对近年来东海发生的27次大型赤潮事件进行了发生位置和面积的提取,并与现场观测结果进行比较。结果显示,系统对大部分赤潮范围的识别有较好的效果,对赤潮识别准确度大概在80%左右。     

Upwelling in the Black Sea by the results of numerical experiments and satellite data

The paper analyses results of the numerical simulation of upwelling events in the north-western part of the Black Sea, mostly near the South Crimea. The calculations were performed using a numerical model based on primitive hydrodynamics equations. Emphasis is laid on the case when a salinity front simulating the Black Sea rim current is prescribed in the initial conditions. The interaction of the Black Sea rim current's stream with the coastline and bottom topography leads to the development of an upwelling near the Crimea's coast, even in the absence of wind forcing. The paper discusses the structure of the three-dimensional circulation of waters in the shelf area of the NW Black Sea. Numerical modelling results are matched up with the satellite data obtained by the HRPT receiving station. Translated by Vladimir A. Puchkin.     

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.     

Wave model predictions in the Black Sea: Sensitivity to wind fields

This paper evaluates the impact of using different wind field products on the performance of the third generation wave model SWAN in the Black Sea and its capability for predicting both normal and extreme wave conditions during 1996. Wind data were obtained from NCEP CFSR, NASA MERRA, JRA-25, ECMWF Operational, ECMWF ERA40, and ECMWF ERA-Interim. Wave data were obtained in 1996 at three locations in the Black Sea within the NATO TU-WAVES project. The quality of wind fields was assessed by comparing them with satellite data. These wind data were used as forcing fields for the generation of wind waves. Time series of predicted significant wave height (H_mo), mean wave period (T_m02), and mean wave direction (DIR) were compared with observations at three offshore buoys in the Black Sea and its performance was quantified in terms of statistical parameters. In addition, wave model performance in terms of significant wave height was also assessed by comparing them against satellite data.The main scope of this work is the impact of the different available wind field products on the wave hindcast performance. In addition, the sensitivity of wave model forecasts due to variations in spatial and temporal resolutions of the wind field products was investigated. Finally, the impact of using various wind field products on predicting extreme wave events was analyzed by focussing on storm peaks and on an individual storm event in October 1996. The numerical results revealed that the CFSR winds are more suitable in comparison with the others for modelling both normal and extreme events in the Black Sea. The results also show that wave model output is critically sensitive to the choice of the wind field product, such that the quality of the wind fields is reflected in the quality of the wave predictions. A finer wind spatial resolution leads to an improvement of the wave model predictions, while a finer temporal resolution in the wind fields generally does not significantly improve agreement between observed and simulated wave data.     

Subsatellite polygon for studying hydrophysical processes in the Black Sea shelf-slope zone

The first data on the creation of the subsatellite polygon on the Black Sea shelf and continental slope in the Gelendzhik area (designed in order to permanently monitor the state of the aquatic environment and biota) and the plans for maintaining and developing this polygon are presented. The autonomous measuring systems of the polygon in the composition of bottom stations with acoustic Doppler current profilers (ADCP), Aqualog robotic profilers, and thermo-chains on moored buoy stations should make it possible to regularly obtain hydrophysical, hydrochemical, and bio-optical data with a high spatial-time resolution and transmit these data to the coastal center on a real-time basis. These field data should be used to study the characteristics and formation mechanisms of the marine environment and biota variability, as well as the water-exchange processes in the shelf-deep basin system, ocean-atmosphere coupling, and many other processes. These data are used to calibrate the satellite measurements and verify the water circulation numerical simulation. It is assumed to use these data in order to warn about the hazardous natural phenomena and control the marine environment state and its variation under the action of anthropogenic and natural factors, including climatic trends. It is planned to use the polygon subsatellite monitoring methods and equipment in other coastal areas, including other Black Sea sectors, in order to create a unified system for monitoring the Black Sea shelf-slope zone.     

Reconstruction of mean dynamic topography of the Black Sea for altimetry measurements

In this study a new approach for reconstructing the Mean Dynamic Topography of the Black Sea is applied. Constant observations (SVP measurements), drifters, and data of vertical sounding of the temperature and salt content together with measurements of sea level anomalies received from Topex/Poseidon mission satellite data were used. The absolute sea level received by altimetry data using the mean dynamic topography received during work was compared to the dynamic level received according to independent marine surveys. The comparison showed that the method represented in the study permits one to define more exactly the dynamic topography of the Black Sea when compared with the studies of previous authors. The results of this study will be useful to reconstruct the areas of the geostrophic currents according to satellite altimetry.     

Marine strategy framework directive: Defining joint monitoring opportunities for the Eastern Mediterranean and the Black Sea,through dedicated decision making workshops and innovative policy tools

The Marine Strategy Framework Directive (MSFD) is an important milestone for the preservation of the European marine environment. However, Member States can find its monitoring requirements challenging, particularly where it regards the definition and implementation of joint monitoring programmes between neighbouring countries. The challenges are even greater in the Mediterranean and the Black Sea, where many countries are not members of the European Union and where Regional Sea Conventions face greater difficulties in coordinating monitoring activities. This paper presents the results from two regional workshops, within the framework of IRIS-SES project, which aimed to inform policy- and decision-makers in the Eastern Mediterranean and the Black Sea on what key stakeholders, including scientists, academia and local authorities, consider the main gaps, needs and opportunities for the MSFD joint monitoring regarding eutrophication and contaminants. It shows that a bottom-up approach, guided by structured workshops, can be a successful means of enhancing cooperation.     

Experiment of Wind Wave Parameter Research on the Black Sea Shelf

The article presents information on the current experiment of research on wind wave parameters in the Black Sea coastal zone. Two wave-meter devices are the part of the measuring equipment of the Black Sea testing site Gelendzhik of the Shirshov Institute of Oceanology (IO RAS). The integral characteristics of wind waves accumulated and obtained in real time may be in demand by experts in operational and satellite oceanography.

     

Technique for Simulation of Black Sea Circulation with Increased Resolution in the Area of the IO RAS Polygon

A numerical technique is presented for simulating the hydrophysical fields of the Black Sea on a variable-step grid with refinement in the area of IO RAS polygon. Model primitive equations are written in spherical coordinates with an arbitrary arrangement of poles. In order to increase the horizontal resolution of the coastal zone in the area of the IO RAS polygon in the northeastern part of the sea near Gelendzhik, one of the poles is placed at a land point (38.35° E, 44.75° N). The model horizontal resolution varies from 150 m in the area of the IO RAS polygon to 4.6 km in the southwestern part of the Black Sea. The numerical technique makes it possible to simulate a large-scale structure of Black Sea circulation as well as the meso- and submesoscale dynamics of the coastal zone. In order to compute the atmospheric forcing, the results of the regional climate model WRF with a resolution of about 10 km in space and 1 h in time are used. In order to demonstrate the technique, Black Sea hydrophysical fields for 2011–2012 and a passive tracer transport representing self-cleaning of Gelendzhik Bay in July 2012 are simulated.     

Data-computing technologies: A new stage in the development of operational oceanography

An analysis is given of the methods of operational oceanography based on measurements derived from satellite data, observations acquired by drifters and passing vessels, and modern simulations of marine and oceanic circulations. In addition, a historical review is conducted of the previous and current research in this field carried out in the Soviet Union, Ukraine, and Russia. A discussion is given of the principles underlying the design of an effective data-computing system (DCS) for solving the problems of operational oceanography and the implementation of the prototype system for the Black Sea within the joint research project of the Russian Academy of Sciences (RAS) and the National Academy of Sciences of Ukraine (NASU) “The Black Sea as an Ocean Simulation Model.” The effectiveness of applying the multicomponent splitting method in the construction of sea circulation models and specialized DCSs with integrated algorithms of variational assimilation of observational data is estimated. The concept of using the Black Sea as a testing site for innovations is developed. The underlying idea of the concept is the similarity of the Black Sea dynamics with processes in the oceans. The numerical Black Sea circulation models used in the project are described, their development areas are discussed, and the requirements to a Black Sea observing system are defined.