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2.
abtract The paper concentrates on the structure and synoptic variability of the meteorological, hydrophysical and chemical fields in the Somali continental shelf area during summer monsoon. Tidal front is shown to be a typical element of the water stratification in the studied area, whose state and dynamics thoroughly in.quence the fisheries situations. It has been found out that commercial aggregations of fishes regularly pooled up and dispersed in the frontal zone, depending on the natural synoptic-scale processes taking place. Translated by Vladimh" A. Puchkin.  相似文献   

3.
A numerical experiment with assimilation of hydrological observational data from a survey in October 2007 on the northwestern shelf of the Black Sea was carried out using the hydrodynamic model with nonlinear equations of motion, equations of heat and salt advection, and data assimilation. The results of this calculation are compared with thermohydrodynamic fields obtained without taking into account temperature and salinity measurements. It is shown that allowance for the observation data leads to qualitative and quantitative differences in the structure of the hydrophysical fields. Mesoscale eddies and intense jet streams that agree with satellite observations were found in the field of currents and were investigated. These eddies are not resolved in low-resolution field experiments.  相似文献   

4.
Results of the studies of the spatiotemporal variability in the hydrophysical and hydrodynamical structure of the shelf area and its dependence on the water dynamics of the deep-water zone of the Black Sea off Gelendzhik are presented and discussed. The field materials were collected in early October of 2006 with the use of traditional and new measurement techniques. A combined analysis of on-line satellite oceanological information, data of onboard surveys, and data time series of the vertical profiling of the hydrophysical characteristics at a moored buoy station was performed.  相似文献   

5.
Two numerical experiments on reconstructing velocity fields, sea level, temperature, and salinity were conducted with account for real atmospheric forcing in autumn 2007 using the Marine Hydrophysical Institute (MHI) hydrodynamic model with an open boundary (northwestern shelf) adjusted to the coastal region of the Black Sea. A high spatial resolution of 500 m and 1.6 km was used, while the bottom topography had a resolution of ~1.6 km. The higher spatial resolution made it possible to reconstruct detailed mesoscale and submesoscale structures of the hydrophysical fields in the upper and deep layers over the northwestern shelf and to obtain quantitative and qualitative characteristics of eddies and jets that are more accurate compared to previous calculations. It was shown that improvement of the spatial resolution up to a few hundred meters makes it possible to take into account the detailed bottom topography and shape of the coastline in the numerical model, which in turn yields a more accurate quantitative and qualitative reconstruction of the mesoscale and submesoscale properties of coastal circulation.  相似文献   

6.
This paper presents the main results of processing the data obtained in the study of hydrophysical processes during multidisciplinary monitoring of the anthropogenic impact on the coastal basin of Mamala Bay (Oahu Island, Hawaii). The results of the hydrophysical measurements carried out in August–September of 2002–2004 using stationary moorings and dropped and towed ship sensors were analyzed as the initial data. On the basis of these measurements, spatiotemporal, statistical, and spectral characteristics of different hydrophysical parameters of the marine envrionement in the basin of Mamala Bay were calculated, including three-dimensional components of the velocity vectors, the spectra of different components of velocities, the spectra of temperature fluctuations, and the characteristics of internal waves. The variability of the temperature fields and the correlation of the tidal phenomena with the temperature measurements and fluctuations caused by internal waves were analyzed. The materials and methods of the oceanographic studies and the results of the analysis of the meteorological and hydrological conditions are presented. The results obtained are used for a multidisciplinary analysis of the satellite and sea truth data.  相似文献   

7.
Distribution of Sea of Azov water on the Crimean shelf and its penetration into the Gulf of Feodosia result in significant changes in the hydrophysical and hydrochemical structure of the water area. This inflow is also estimated as a major source of anthropogenic pollution in the region. At the same time, the Gulf of Feodosia is one of the least investigated areas of Russian Black Sea coast. The paper focuses on the hydrophysical structure of the Gulf of Feodosia and southeastern part of the Crimean shelf. The results of a field survey in May 2015 made it possible to reveal the presence of Sea of Azov water in the gulf and describe its thermohaline properties, along with the character of distribution. It is shown that contamination of Sea of Azov water in the gulf could mostly be determined by the synoptic dynamic processes in the area rather than by the seasonal variability of discharge in the Kerch Strait. The possible influence of the distribution of Sea of Azov water on the formation of cyclonic gyres in the coastal area of the region is indirectly confirmed by in situ measurements.  相似文献   

8.
We consider the decadal evolution of the Black-Sea ecosystem on the basis of a three-dimensional coupled model consisting of the Black-Sea circulation model and a biogeochemical block. The circulation model is based on the widely used POM (Princeton Ocean Model) model. The calculated hydrophysical fields are interpolated then to levels of the biogeochemical model, which covers the upper 150-m layer. We demonstrate the close relationship between the interannual variation of hydrophysical fields and the evolution of the main elements of the ecosystem. The period under consideration (1992–2001) is characterized by the warming of the Black-Sea upper layer, which can be traced by the trend of a growing surface temperature. It follows from the results of modeling that the process of warming is also revealed in the subsurface hydrophysical characteristics and the dynamics of the main elements of the Black-Sea ecosystem.  相似文献   

9.
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.  相似文献   

10.
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.  相似文献   

11.
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.  相似文献   

12.
We analyze the seasonal variability of the climatic hydrophysical fields of the Black Sea reporduced in three numerical experiments carried out according to the model of circulation. The numerical predictions are performed for a period of 12.5 yr on the basis of the hydrological data accumulated in 1983–1995. The monthly average climatic fields of the current speed are reconstructed according to the data on the climatic fields of temperature and salinity by the method of hydrodynamic adaptation (standard). It is shown that, in prognostic calculations, the seasonal variability of temperature and salinity is qualitatively close to the “standard” dependence. At the same time, the quantitative difference between the climatic behavior of the model and the standard dependence may be significant. The annual cycle of the currents is characterized by the intensification of the Main Black-Sea Current in winter. The structure of the hydrophysical fields of the sea in the model becomes much more realistic if it is based on the actual hydrological data. Translated by Peter V. Malyshev and Dmitry V. Malyshev  相似文献   

13.
Field studies performed at the Shirshov Institute of Oceanology, Russian Academy of Sciences (SIO RAS), Black Sea hydrophysical polygon in 2012 are illustrated. The variations in the vertical distribution of the hydrophysical characteristics (water temperature, salinity, and density, as well as current velocity) in the upper 200-m layer of the Black Sea above the continental slope in the cold season, obtained using an Aqualog autonomous profiler on a moored buoy station, have been analyzed. It has been established that the position of the permanent pycno-halocline and the hydrosulphuric zone upper boundary intensively oscillate with a characteristic period of 5–10 days. These oscillations cause short-period variations in the thickness of the oxigenated layer by 20–40 m, which reaches one-third of the total thickness of the layer. Measurements performed with autonomous stations (bottom ADCP, thermochain) at the experimental subsatellite polygon in the Gelendzhik coastal zone, as well as meteorological, ship, and satellite data obtained during the catastrophic rains and flooding on July 6–7, 2012, and afterward, have been simultaneously analyzed. It has been established that a catastrophic flow of turbid fresh water into the sea caused the formation of a belt of freshened (by 1.0–2.7 psu) less dense water with a high suspension concentration on the shelf and the upper continental slope. This water formed a quasi-geostrophic northwestward along-shore current, the velocity of which reached 40–50 cm/s. Therefore, the freshened and turbid water mostly escaped from the Gelendzhik region northwestward for two days after the flood, and the remaining water became free of suspension owing to its settlement during approximately the same period. The fields of the current velocity and suspension concentration in a submesoscale cyclonic eddy, identified on the satellite image, were measured at the hydrophysical polygon. It has been established that a high (when compared to the background values) suspension concentration in the surface-water layer in an eddy is related to intense upwelling at the eddy center and the rising of suspension (apparently phytoplankton) from the thermocline layer, where the suspension concentration is maximal.  相似文献   

14.
A numerical model of online forecasting Black Sea currents   总被引:1,自引:0,他引:1  
A numerical three-dimensional nonlinear model of the hydrophysical fields of the Black Sea is presented. The properties of model discrete equations are described. The results of test experiments on the choice of model finite-difference approximations and parameters (as applied to the online forecasting of currents) are given. The results of prognostic calculations of the hydrophysical fields of the Black Sea are given for the period of March 31, 2005, to September 26, 2006. These results show that this numerical model with consideration for real atmospheric forcing can yield a satisfactory forecast of the parameters of the upper layers of the sea for 18 months of model time.  相似文献   

15.
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.  相似文献   

16.
The results of research into the seasonal variability of hydrothermodynamic characteristics of the Black Sea are presented. These have been obtained using field data on the fields of temperature, salinity, and wind, and by mathematical modelling. The seasonal variability of the current and heat content fields and of the cold intermediate layer and other hydrophysical characteristics is discussed.Translated by Mikhail M. Trufanov.  相似文献   

17.
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.  相似文献   

18.
The Black Sea shelf is a region of intense manifestation of various dynamical processes. Under the influence of different natural forces, eddy-wave phenomena develop here, which influence the general circulation of sea waters, biological productivity, and the condition of the engineering structures. Modern numerical models allow us to simulate and analyze the processes of the joint dynamics of marine circulation and large-scale waves. In this work, we study the spatiotemporal spectral characteristics of the sea level and velocity fluctuations formed due to atmospheric forcing and tidal potential. The hydrophysical fields are calculated using the Institute of Numerical Mathematics, Russian Academy of Sciences (INM RAS), σ model based on primitive equations. We use the CORE data as atmospheric forcing at the sea surface; the tidal potential is described by the semidiurnal lunar constituent M2. Analyzing the simulation results makes it possible to emphasize that accounting for the semidiurnal tidal potential not only improves the accuracy of the sea-level calculation at coastal stations, but also generates subinertial baroclinic oscillations previously found in the Black Sea from the data of in situ observations.  相似文献   

19.
A parallel version of the NEMO complex ocean circulation model has been implemented for the Black Sea basin; the results of circulation numerical modeling with a high spatial resolution are presented. Analysis of the spatial variability is performed for the reconstructed hydrophysical fields in 2005–2008. The resulting simulated spatial variability characteristics of the sea surface temperature are compared with available satellite observational data.  相似文献   

20.
On the basis of the data of the complex oceanographic experiment carried out in the course of the second Ukrainian Antarctic expedition in March 1998, we study the structure and kinematics of waters in the region of the archipelago of Argentine Islands. The regularities of thermohaline stratification of waters are discovered. We determine the most important environmental parameters premoting the variability of hydrophysical fields on time scales varying from several days up to a week, analyse the data of actual observations over the currents, and estimate the relative contribtions of diurnal and semidiurnal tidal waves to the total dispersion of hydrophysical parameters of the environment. The residual currents are filtered out. We propose a hypothesis about the mechanism of their formation. Various types of tidal currents are revealed and the directions of propagation of diurnal and semidiurnal tidal waves are determined. Translated by Peter V. Malyshev and Dmitry V. Malyshev  相似文献   

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