Search

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. [ABSTRACT FROM AUTHOR]

The locations of possible earthquake occurrence (magnitudes М ≥ 6) have been determined for mountainous Crimea and the adjacent sea shelf, including the continental slope zone. The earthquake-generating structures were assumed to be intersections of morphostructural lineaments as found by morphostructural zoning. The measurement of geological and geophysical characteristics was followed by applying a decision rule that was derived previously using the CORA-3 pattern recognition algorithm in order to find possible locations of М ≥ 6 earthquakes in the Caucasus. The results corroborate the high seismic potential for the Yalta area where two events with magnitudes of 6.0 and 6.8 occurred in 1927, as well as indicating the possibility of М ≥ 6 earthquakes in other areas in mountainous Crimea and in the adjacent Black Sea area where no such events have yet been recorded. [ABSTRACT FROM AUTHOR]

The original method is presented for parameterization of surface wind-driven currents in the Black Sea using drifters, altimetry, and wind data. Buoys velocities for the cases with small time variability of the altimetry-derived geostrophic currents were parameterized as a function of the amplitude coefficient b and rotation angle a between wind and residual current direction at drifter drogue depth ∼ 15 m. The results show that the variability of a and b for different cases is very high: angle a changes from 10 to 90° to the right, amplitude coefficient b varies from 0.01 to 0.03. At the same time, it is shown that amplitude coefficient b and rotation angle a on 15 m depth are not independent parameters and there is a robust dependence between them. Using quasi-Ekman theory and the revealed dependence, we can determine parameterization for wind-driven currents exactly on the surface. As a result, we found that wind-driven currents at z = 0 m are directed on b = 13° to the right of wind direction with amplitudes equal to k = 2.8 % of wind velocity. It is important that these parameters did not depend on Ekman layer depth and can be used under different ocean conditions. This parameterization is used to compute the total surface currents and determine the trajectories of oil slick propagation observed on satellite images. Comparison shows that the presented method can be successfully used to predict floating objects trajectories basing on the satellite data. [ABSTRACT FROM AUTHOR]

This paper presents the results of long-term in situ and satellite measurements at shelf areas adjacent to the estuaries of the small rivers of the Russian coast of the Black Sea (Mezyb, Pshada, Vulan, Tuapse, Bitkha, Sochi, Cudepsta, Mzymta). The quantitative characteristics of the response of the hydrophysical and hydrochemical fields at the sea shelf on the influence of the continental river discharge are presented for each of these areas. A number of indicators of the water quality (the concentrations of the nitrate and nitrite forms of nitrogen, the phosphorus, the silica, the dissolved oxygen, the value of the total alkalinity and pH, the mineral and organic suspended matter, and the chlorophyll a) are considered in the context of the anthropogenic and terrigenous influence. In this paper, the emphasis was placed on the Mzymta River plume at the shelf area adjacent to the city of Sochi, where the measurements were repeatedly performed during the spring flooding conditions in the period from 2007 until 2012. The interannual variability of the water quality indicators and the seasonal and short-term variability of the area and the configuration of the plume, which transports suspended matter and anthropogenic pollution, were considered. [ABSTRACT FROM AUTHOR]

This paper presents new results of the research and development project on the moored profiler Aqualog aimed at multidisciplinary studies and ecological monitoring of the marine environment. The data on the profiler's operation are summarized based upon the field experiments in the northeastern Black Sea in 2011. An important scientific result obtained by using the profiler during the experiments was the discovery of the countercurrent below the Black Sea Rim Current in the layer between the 500 m and 900 m depth. [ABSTRACT FROM AUTHOR]

The results of long-term measurements (16 months) of the current's velocity in the Black Sea coastal zone near Golubaya Bukhta (Blue Bay) by a bottom mounted acoustic Doppler current profiler (ADCP) are presented and discussed. It was found that the alongshore component of the current dominates and its absolute value is an order of magnitude larger than the absolute value of the normal to the shore component. The annual average value of the alongshore current's velocity is close to zero. A well pronounced oscillatory mode of the alongshore current's velocity is revealed. This mode is characterized by quasi-periodic changes in the direction of the alongshore current. The maximal amplitudes of the unidirectional alongshore current's velocity are observed with a time scale from several hours to several days. [ABSTRACT FROM AUTHOR]

The results of observations of submesoscale eddies (with a diameter of 2-8 km) on the narrow Black Sea shelf are presented. These observations were carried out in the Gelendzhik region in the autumn seasons of 2007-2008 using traditional and new methods of hydrophysical investigations. The mechanisms of generation of such eddies are discussed. [ABSTRACT FROM AUTHOR]

National Oceanic and Atmospheric Administration (NOAA) Advanced Very-High Resolution Radiometer (AVHRR) imagery (1993, 1998), along with attendant daily meteorological information from seaports and available hydrographic information from different years, was used to investigate the structure and evolution of mesoscale anticyclonic eddies in the northwestern Black Sea, and their role in shelf/deep basin water exchange. In the summer of 1993, two anticyclonic eddies with diameters of 90 and 55 km coexisted without coalescence for 1.5 months over a wide and relatively gentle part of the northwestern continental slope. The directions of the eddies'' movements inside this zone (speed of movement up to 16 cm/s) were likely determined by the interaction between eddies themselves, and by the Rim Current meandering and forcing. For June–August of 1998, three such eddies have been traced in the sea surface temperature (SST, AVHRR) and chlorophyll a (SeaWiFS) fields. The largest anticyclone with a diameter of 90 km moved during 3 months southwestward from the wide slope region west of Sevastopol to the area of narrower slope southeast of Cape Kaliakra with a mean speed of about 3 cm/s. Together with nonstationary associated elements (cyclones at the eddies'' peripheries, entrained and ejected jets), anticyclonic eddies determine water exchange processes in a large area of the western Black Sea between 43–45°N and 29–33°E. They transport chlorophyll-rich coastal waters to the deep basin, westerly winds being favorable to the process. [Copyright &y& Elsevier]

Mesoscale dynamics in the northeastern Black Sea in Autumn 1993 and 1997 is considered on the basis of analysis of the NOAA AVHRR imagery together with relevant hydrographic measurements and meteorological information. Over the course from 6 September to 8 October 1997, five near-shore anticyclonic eddies (NAEs) about 40 km in diameter were observed within the region between Tuapse and the Kerch Strait, their movement speed reaching about 15 cm/s at separate parts of their trajectories. Separation of an NAE (NAE-1) from the coast in the region of a widening shelf/slope west of Novorossiysk and its transformation into deep-sea eddy was traced. Lifetime of the anticyclone was no less than 1 month, its mean offshore speed was about 4.3 cm/s. According to the SeaWiFS data, the increased chlorophyll a concentration (compared with the mean concentration at the center of the eastern part of the sea) was observed on 8 October 1997 in four “young” NAEs after an intense precipitation, the decreased one at the same time occurred in NAE-1, which was depleted of supply by shelf waters. In Summer 1993, a large NAE (about 95 km in diameter) was observed in the region between Tuapse and Gelendzhik. Evolution of the eddy from 3 June to 8 November 1993 was traced. Lifetime of the eddy exceeded 5 months. Its mean offshore speed to the southwest since its separation from the coast (around 17 August) in the Novorossiysk region was about 1.2 cm/s. The difference between dynamic situations in the same season (autumn) of 2 years, 1997 and 1993, was likely associated with peculiarities of atmospheric circulation and related intensity of cyclonic circulation in the Black Sea. [Copyright &y& Elsevier]