Wave Theory

Wave Theory

History

In the Moscow period of Marine Hydrophysical Institute of the USSR Academy of Sciences, theoretical modeling of wave processes in the World Ocean was carried out in the Laboratory of Wave and Current Theory, headed by a leading scientist in the field of mathematics, hydromechanics and wave theory, corresponding member of the USSR Academy of Sciences L.N. Sretensky. During this period, Doctors of physical and mathematical sciences S.S. Voight and Ya.I. Sekerzh-Zenkovich, Ph.D’s (Phys.-Math.) Z.K. Grigorash, T.Ya. Sekerzh-Zenkovich, A.S. Stavrovsky, P.N. Uspensky, L.G. Lebedkin and others participated in the wave studies of the Institute. After the institute transfer to Sevastopol, in 1968 in the hydrology department a group of employees engaged in wave research was created. Subsequently, it was reorganized into a structural unit – Wave Theory Department. Since 1975, it was headed by the corresponding member of NAS of Ukraine L.V. Cherkesov. Since 2016, the Department is headed by Dr.Sci. (Phys.-Math.) S.G. Demyshev.

Major research directions

  • The study of free and forced waves in a homogeneous and stratified fluid.
  • Calculation and analysis of dynamic and energy characteristics of mesoscale and submesoscale eddies, jet currents and fronts in the Black Sea circulation, studying the possible mechanisms of their formation.
  • Research of deep-sea dynamics of the Black Sea, constructed on the basis of hydrodynamic model comparison with the measurement data.
  • Reconstruction and analysis of small-scale circulation features in the Black Sea coastal region based on a four-dimensional algorithm for assimilation of observational data in a numerical model of dynamics.
  • Study of the structure of hydrophysical and energy fields in the coastal and deep sea areas of the Sea of Marmara based on processing available observational data and numerical modeling.
  • The solution of inverse problems of distribution of impurity various types in the Black Sea.

Department Staff

The department has 10 employees in the following positions:

  • 1 Chief Research Associate, Dr.Sci. (Phys.-Math.);
  • 1 Senior Research Associate, Ph.D. (Phys.-Math.);
  • 1 Research Associate, Ph.D. (Phys.-Math.);
  • 5 Junior Research Associates, no degree;
  • 1 Senior Software Engineer;
  • 1 Technician.

Head of the Department: Dr.Sci. (Phys.-Math.) Sergey G. Demyshev.

The most significant results of the work

  1. A software complex for processing hydrological survey data was adapted for the Black Sea coastal zone, which allows us to reconstruct the continuous spatial-temporal circulation pattern and variability of thermohaline characteristics. A number of polygon surveys based on the hydrodynamic model with the assimilation of hydrological observation data were processed. This provided more accurate description of mesoscale and submesoscale features of hydrophysical fields (eddies, jets, frontal zones, areas of upwellings and downwellings).
  2. With an improvement in spatial resolution of several hundred meters and taking into account the fine structure of the bottom topography and coast line orography, a more accurate quantitative and qualitative reconstruction of mesoscale and submesoscale coastal eddies and jets was obtained. Based on numerical forecasting experiments of 350 m, 500 m, 1.6 km resolution and with regard to real atmospheric impact, the mesoscale and submesoscale features of circulation on the northwestern shelf, near the Southern Coast of Crimea (SCC) and the Caucasian and Anatolian coasts are calculated.
  3. When comparing the fields of current velocities and the spatial distribution fields of energy budget components, the main mechanisms for generating coastal mesoscale and submesoscale eddies in the Black Sea are determined: 1) horizontal velocity shift resulting from negative work of wind force and/or as a result of coastal inhomogeneities affecting coastal currents (Southern Coast of Crimea, Caucasus and Anatolian coasts); 2) baroclinic instability resulting from the intensification of the of the buoyancy force work at the SCC and the northwestern shelf (NWS); 3) a change in pressure over the topographic features of the bottom relief (NWS).
  4. Qualitative and quantitative assessments of the deep sea circulation features of the Black Sea for different years (2006, 2010, 2011 and 2013) were obtained. The results of numerical experiments were validated using field observations on temperature and salinity (ship measurements, ARGO buoys). Quasiperiodic formation of synoptic and mesoscale currents and eddies in the lower layers of the sea was determined.
  5. A long-term (20 years) forecast of the Sea of Marmara currents without taking into account atmospheric effect showed that the main features of its circulation are formed under effect of the Bosporus and Dardanelles. Vertically, in the density field a clearly pronounced two-layer structure is observed. In the upper 20 - 25 meter layer, an S - shaped jet stream is formed, which separates two anticyclonic formations. When spatial resolution is improved and atmospheric effects are taken into account, the example of 2008 shows that in the sea upper layer the mesoscale eddies can form directly under effect of wind force and as a result of baroclinic instability of currents. The generation of sub-mesoscale gyres in coastal areas is mainly affected by the processes of baroclinic instability. As a result of less dense Black Sea waters inflow, an increase in horizontal gradients in the density field and, as a consequence, the development of eddy formation processes were observed in the Bosporus region.
  6. Within the framework of long wave theory, a study of the resonance properties of a system of Sevastopol bays was carried out. The problem was solved numerically for the basins with real topography and analytically for model rectangular basins of constant and variable depth having parameters of a number of Sevastopol Bays. In all the bays the oscillations with periods of 50 min, 22 min, and 15.6 min, corresponding to the first three natural periods of the Sevastopol Bay modes are generated.
  7. A modified variational algorithm for identifying the transport model parameters is constructed. The implementation of the adjoint equations method for a model of passive admixture transport in the Black Sea with a high degree of discretization provided an identification of possible pollution sources in the areas of the Kerch Strait and the Heracles Peninsula.

The department employees participate in research work of the State Program for the Development of Science and Technology of the Russian Federation until 2020 under projects 0827-2019-0002 “Development of operational oceanology methods based on interdisciplinary studies of formation and evolution processes of marine environment and mathematical modeling using the data from remote and contact measurements” (Code “Operational Oceanology”), 0827-2019-0003 “Basic research of oceanologic processes determining state and evolution of marine environment under effect of natural and anthropogenic factors, based on observation and modeling methods” (code “Oceanologic processes”), 0827-2019-0004 “Comprehensive interdisciplinary studies of oceanologic processes that determine the functioning and evolution of ecosystems of the coastal zones of the Black and Azov Seas” (code “Coastal Studies”), as well as RFBR projects.

The results of the department’s work are presented by employees at international and all-Russian conferences, published in high-ranking journals included in the citation databases Web of Science and Scopus.

Recent publications

  1. Demyshev S.G. The work of the main forces in the annual-averaged and seasonal-averaged energy balance of the Black Sea circulation // Journal of Physics: Conference Series. – 2018. – V.1128 (1). – 012141. DOI: 10.1088/1742-6596/1128/1/012141. (WoS)
  2. Demyshev S.G., Dymova O.A. Numerical analysis of the Black Sea currents and mesoscale eddies in 2006 and 2011 // Ocean Dynamics. 2018. – 68 (10). – P. 1335-1352. doi.org/10.1007/s10236-018-1200-6.(WoS)
  3. Demyshev S.G., Dymova O.A. Computing complex for modeling of the Black Sea state // IOP Conference Series: Earth and Environmental Science. – 2018. – Vol.211(1). – 012082. doi:10.1088/1755-1315/211/1/012082 (WoS)
  4. Demyshev S.G., Evstigneeva N.A. Simulations of Hydrophysical Fields with High Spatial Resolution over the Northwestern Shelf of the Black Sea // Oceanology. – 2018. – Vol. 58, No. 2. P. 164–174. (WoS)
  5. Demyshev S., Evstigneeva N. (2018) Reconstruction of Hydrophysical Fields in the Coastal Region of the Black Sea on the Basis of Hydrodynamic Model with Assimilation of Observational Data. In: Karev V., Klimov D., Pokazeev K. (eds) Physical and Mathematical Modeling of Earth and Environment Processes. PMMEEP 2017. Springer Geology. Springer, Cham. P. 138-147 https://doi.org/10.1007/978-3-319-77788-7_15. (SCOPUS)
  6. Demyshev S.G., Kochergin V.S. and Kochergin S.V. Using the Variational Approach and Adjoint Equations Method Under the Identification of the Input Parameter of the Passive Admixture Transport Model // Physical and Mathematical Modeling of Earth and Environment Processes - 3rd International Scientific School for Young Scientists, Ishlinskii Institute for Problems in Mechanics of Russian Academy of Science, Springer International Publishing AG, part of Springer Nature 2018, Chapter 7. P. 51 – 61. ISSN 2197-9545, ISBN 978-3-319-77787-0, https://doi.org/10.1007/978-3-319-77788-7 (WoS)
  7. Dymova O.A. Mesoscale variability of the Black Sea circulation by the simulation results in 2011 and 2016 // Journal of Physics: Conference Series. – 2018. – Vol.1128(1). – 012143. 10.1088/1742-6596/1128/1/012143 (WoS)
  8. Kremenchutskii D.A., Dymova O.A., Batrakov G.F., Konovalov S.K. Numerical simulation of the intra-annual evolution of beryllium-7 (7Ве) in the surface layer of the Black Sea // Environmental Science and Pollution Research. 2018. – Vol. 25(11). P. 11120-11127. https://doi.org/10.1007/s11356-018-1269-y (WoS)
  9. Markova N.V. Variability of the Black Sea deep-water circulation based on hydrophysical reanalysis results / IOP Conf. Series: Journal of Physics: Conf. Series 1128 (2018) 012145. DOI: 10.1088/1742-6596/1128/1/012145 (WoS)

Contacts

Wave Theory
FSBSI FRC MHI
2, Kapitanskaya St.
299011, Sevastopol
Russian Federation