Analysis of Seasonal Energy Characteristics of the Marmara Sea Upper Layer Dynamics

Purpose. The aim of the work is to assess the role of the basic forces in formation of the dynamic structures of the upper layer in the Marmara Sea in different hydrological seasons. Methods and Results. The numerical model developed in Marine Hydrophysical Institute, Russian Academy of Sciences, was used to calculate the hydrodynamic and energy characteristics of the sea circulation. The horizontal spatial resolution was 1.22 × 0.83 km, 18 horizons were used vertically, and the time step was 0.5 min. The characteristics of the waters inflowing through the Bosporus and Dardanelles straits corresponded to the available observational data. On the sea surface, the daily average fields of tangential wind stress, heat fluxes, precipitation and evaporation for 2008 were preset; these parameters were calculated using the regional atmospheric model MM5. Spatial distributions of the vortex structures and the corresponding energy flows in the upper sea layer for different seasons were considered. Having been analyzed, the average seasonal spatial distributions of the current velocity fields and the components of the kinetic energy budget showed that during the year, the vortices in the upper sea layer were formed mainly by two mechanisms. In the central part of the sea, generation of a large-scale anticyclone and its seasonal variability are basically conditioned by the wind forcing, whereas formation and evolution of coastal cyclonic eddies are caused by the buoyancy force. In the fields where the buoyancy, pressure and friction forcing takes place, the zones of local extremes are distinguished. Two of them are the areas of water inflow through the Bosphorus and Dardanelles straits. The strongest variability is observed in the Bosporus region that is certainly conditioned by the fact that the inflowing Black Sea waters have a decisive influence on seasonal nature of the Marmara Sea circulation. The extreme values in the other zones are the result of the coastline structure heterogeneities, that leads to formation of the coastal eddies, the energy source for which is the available potential energy. Conclusions. Analysis of the results of the performed numerical experiment makes it possible to conclude that in the upper layer of the Marmara Sea, formation and variability of the central anticyclone are conditioned by the wind forcing, while those of the coastal cyclones – by the buoyancy effect.

Vertical Distribution of Phosphates in the Black Sea Based on the Expeditionary Data, 2016–2019

Purpose. The purpose of the study is to analyze the features of vertical distribution of phosphates and dissolved organic phosphorus (Porg) in the Black Sea at the present period. Methods and Results. The data obtained by the scientists of Marine Hydrophysical Institute in the Black Sea within the economic zone of Russia in 2016–2019 were used. At more than 200 deep-sea stations, a cassette of 12 bathometers (the Seabird-Electronics STD-instrument) was applied for taking hydrochemical samples at certain isopycnic surfaces, usually at σt = 16.30; 16.25; 16.20; 16.20; 16.15; 16.10; 16.05; 16.00; 15.95; 15.90; 15.80; 15.50, 14.0 kg/m3. At the coastal shallow-water stations, samples were taken at the 10 m intervals. Such a scheme permitted to carry out vertical sampling in the upper mixed layer and in the suboxic zone (including its upper boundary) with possible minimum of phosphates, to determine the depth of hydrogen sulfide formation and the location of the phosphates concentration maximum in the upper part of the anaerobic zone. Conclusions. From the surface to isopycn σt = 14.4 kg/m3, the content of phosphates and Porg does not exceed 0.1 µM; below this isopycnic surface, the phosphates concentration begins to increase, whereas of Porg remains at the same level. At all the profiles of the phosphates vertical distribution, the phosphates concentration minimum was recorded near the isopycnic surface σt = 15.8 kg/m3, and its maximum – near the isopycnic surface σt = 16.2 kg/m3. The minimum content of phosphates varied within 0–1.5 µM; in 2016–2017 the phosphates concentration maximum did not exceed 8 µM; in 2018, in many cases, it was higher than 12 µM, and once, near the Kerch Strait, it exceeded 17 µM. Increase in the magnitude of the maximum phosphates concentration (in the previous studies in 1988–2013, it did not exceed 8 µM) is assumed to be related to installation of the supports for constructing the Kerch Bridge.

Preface

The origins of the Conference start from 1970 in the Soviet Union, Novosibirsk. It was organized by Kutateladze Institute of Thermophysics SB RAS. The name of the conference was «Actual problems of thermophysics and physical hydrodynamics». The conference has been organized under this name up to 2015. The conference chairs were academicians of RAS V. E. Nakoryakov, S. V. Alekseenko and D. M. Marckovich. Peer reviewed proceedings of the conference have been published in the format of printed books. In 2016 the conference is reorganized in a new format with a shorter name: «Thermophysics and physical hydrodynamics» (TPH2021). The proceedings of the renewal Conference were published in the Journal of physics: conference series. The conference was held jointly with the scientific youth school «Thermophysics and Physical Hydrodynamics: Modern Challenges» (TPHMC2021). The scientific school is a lecture intensive. Invited lecturers – famous scientists and specialists from all over Russia talk about the achievements of their groups, teams, organizations. The subsequent work of young scientists in the sections of TPH2021 provides an opportunity to look at the challenges facing science in detail, ask questions, and get answers that can give an impetus to the development of their own research. The conference takes place in Sevastopol, a beautiful and honor city in Crimea on the bank of the Black Sea. Ministry of Science and Higher Education of the Russian Federation, Siberian Branch of the Russian Academy of Sciences, National Committee on Heat and Mass Transfer RAS, Lavrentyev Institute of Hydrodynamics SB RAS, Novosibirsk State University, Novosibirsk State Technical University, Marine Hydrophysical Institute RAS, and Sevastopol State University are among other conference organizers besides Kutateladze Institute of thermophysics. The present Conference covers the following topics: heat transfer and hydrodynamics in single phase flows, hydrodynamics and heat and mass transfer in multiphase flows, phase transitions, reacting flow dynamics, detonation processes, numerical methods in thermophysics and physical hydrodynamics, techniques of thermophysics and hydrodynamics experiment, thermophysical properties of substances, heat and mass transfer on micro- and nanoscales, electrophysical phenomena in gaseous and liquid media, heat transfer and hydrodynamics in industrial processes and environment protection. There are more than 180 participants. The proceedings contain 137 papers grouped by topic. The scientific committee appreciates the enormous work of the editorial board and reviewers in the preparation of this volume. We would like to express our sincere thanks to all authors for their research contributions, and to organizers of the conference for their valuable spadework, especially to specialists of MKS LLC.

Mathematical Modeling the Dynamics of the Bottom Sediments Granulometric Composition in the Balaklava Bay Affected by the Wind Waves

Purpose. Based on the mathematical modeling methods, influence of the wind waves on redistribution of the sand fractions in the semi-closed estuary-type water area is estimated using the Balaklava Bay as an example. Methods and Results. A two-dimensional version of the XBeach model with a constant grid spacing 10 m was used. The characteristics of wind waves were preset using the JONSWAP spectrum implying fixed height, wave period and various combinations of the wave direction. The calculations were carried out for a storm event lasting about 12 hours once a year. The in-situ data on the particle size distribution in the bottom sediments resulted from the monitoring observations performed by the Marine Hydrophysical Institute, Russian Academy of Sciences, in the Balaklava Bay region was used in the numerical experiments. Conclusions. The results of modeling showed that the basic determining factors regulating the sediments movement were the depth and the bottom slope. It is noted that changing of the bottom inclination angle between the isobaths 6–7 and 7–8 m leads to deposition of the large and medium fractions, and in the area between the isobaths 9–10 and 10–12 m – to accumulation of fine sand. It was revealed that in the Balaklava Bay water area, the main redistribution of sand material caused by the storm waves took place within the southern basin, as well as at the bay exit in the coastal zone of the Megalo-Yalo Bay. This is primarily determined by the features of the Balaklava Bay coast orography, namely, the knee-shaped narrowness separating the northern and southern basins. Nevertheless, in the isolated northern part of the Balaklava Bay being affected by the storm waves, insignificant dynamics of sand material was observed. The fractions of bottom sediments are redistributed from the western coast to the central part of the basin and to the eastern coast of the bay.

MARINE FORECAST FOR THE EASTERNMOST PART OF THE BLACK SEA

Modelling and forecasting of dynamic processes and distribution of various substances of anthropogenic and natural origin in coastal and shelf zones of the seas and oceans are of great interest due to the high anthropogenic load of these zones. The aim of this paper is to present some examples of modelling and short-term forecasting of dynamic fields – the current, temperature and salinity in the easternmost Black Sea covering Georgian sector of the Black Sea and adjacent water area using a high-resolution regional model of the Black Sea dynamics. The z-level regional model is based on a full system of ocean hydro-thermodynamics equations and is nested in the basin-scale model of the Black Sea dynamics of Marine Hydrophysical Institute (Sevastopol). To solve the model equation system, a numerical algorithm based on the splitting method is used. Calculations show that circulation processes in the easternmost water area of the Black Sea are characterized by a permanent alternation of different circulation modes with the formation of mesoscale and submesoscale eddies throughout the year, which significantly affect the formation of thermohaline fields; atmospheric wind forcing substantially determines not only the peculiarities of the sea surface horizontal circulation, also the vertical structure of the current field.

DISSOLVED ORGANIC MATTER IN THE WATER OF THE ABRAMOV BAY (CRIMEA) IN SUMMER OF 2019

Based on data of the monitoring carried out by Marine Hydrophysical Institute in summer of 2019, the structure and the pattern of temporal variations in the field of concentration of dissolved organic matter (DOM) in the Abramov Bay (Crimea) are revealed. The response of the DOM concentration field to the atmospheric synoptic processes is monitored. The variation patterns of the analyzed field structure under conditions of intensive desalination of the coastal zone by storm water, as well as under influence of upwelling and typical wind conditions for summer are determined. Statistical data on the DOM concentration variability in the Abramov Bay apex are presented.

The main objects of anthropogenic impact on the Kerch strait water environment according to hydrooptical and hydro-chemical observation data

Based on expeditionary data of Marine Hydrophysical Institute (MHI, Sevastopol) and Southern Research Institute of Marine Fisheries and Oceanography (YugNIRO, Kerch), the main objects of economic activity that have anthropogenic impact on the Kerch Strait waters and adjacent areas of the Sea of Azov and the Black Sea are identified. These are ports, cargo terminals, dump zones, raid transshipment points, etc. Results obtained by optical methods were compared with those of long-term standard hydrochemical complex observations of water pollution in the studied region.

Features of the Oceanological Values Fields in the Sivash Bay (The Sea of Azov)

Purpose. The study is aimed at revealing the structural regularities and variability of the fields of temperature, salinity, the colored dissolved organic matter and total suspended matter concentrations, and also the factors that form them in the Sivash Bay. Besides, the results obtained are to be compared with the already known features of the fields of the values under investigation which are typical of the Azov-Black Sea coastal zone; and the response in the considered fields to the North Crimean Canal damming is to be assessed. Methods and Results. Based on the data of 8 expeditions carried out by Marine Hydrophysical Institute in 2013–2016, the structural regularities and variability of the fields of temperature, salinity, the colored dissolved organic matter and total suspended matter concentrations, and the factors that form the fields of these values in the Sivash Bay were revealed. The quantitative indicators of changes in the fields of the considered values, which arose after the North Crimean Canal was dammed, are represented. Conclusions. In the region under study, a number of constantly acting factors that determine formation of special, not typical of the coastal area, features of the oceanological values fields are identified, namely: the influence of the Azov Sea and the North Crimean Canal waters, the rivers inflowing to the water area of the Sivash western coast, the isolated lakes, the swampy shallow bays and the isolated, relatively deep, parts of the coastline. Three years after the North Crimean Canal was dammed, in the northwestern Sivash salinity increased by 20 PSU. The opinion that Sivash is not a typical sea bay, but a connected with the Azov Sea reservoir with the signs of a salt swamp is confirmed

PROFESSOR VOIT'S CHAIR IS A WORK OF A LIFETIME. THE CENTURY FROM BIRTHDAY OF SERGEY SERGEEVICH VOIT (1920–1989)

The article is dedicated to the centenary of the birth of Professor Sergei Voit. During his lifetime he held title of an Honored Worker of Science and Technology of the Russian Federation, a Laureate of the USSR State Prize, Doctor of Science in Physics and Math, Professor of the Moscow Institute of Physics and Technology (MIPT) since 1964. During the period of 1961–1963 he served as Deputy Director for research at the Marine Hydrophysical Institute, Sebastopol. Subsequently he became the Head of the Wave Theory Cabinet at the Shirshov Institute of Oceanology, Moscow, and in 1967 he founded the Chair of Ocean Thermohydromechanics at MIPT and became its first chairperson. A brilliant theoretician in thermohydrodynamics of the ocean, he published over 100 scientific articles. He made a fundamental contribution to the study of the dynamics of ocean waves. His work on the generation of tsunami and the appearance of elastic waves in the ocean floor made it possible to come closer to the practical solution of the problem of tsunami prediction and protection.