материалы конференции

Ru

CITES '2019: Труды Международной молодежной школы и конференции по вычислительно-информационным технологиям для наук об окружающей среде, Москва, 27 мая-06 июня 2019 г.

2019

This study is devoted to analysis of the results of numerical modeling of the coastal circulation of the Black Sea based on the assimilation in the hydrodynamic model of temperature and salinity measurements. The fields of temperature, salinity, level and currents in the coastal region of the Black Sea (the coast of the western Crimea and in the Sevastopol region) were reconstructed with high resolution (horizontal grid ~1.6 xi.6 km and 30 vertical layers) on the basis of the hydrodynamic model and observational data of temperature and salinity at the research vessel “Experiment” in 2007. The z-coordinate three-dimensional nonlinear model of the Black Sea, which was developed at the Marine Hydrophysical Institute and adapted to the conditions of the coastal zone, was chosen as a research tool. A simplified procedure of four-dimensional analysis, based on the method of sequential optimal interpolation when the covariance functions of the temperature and salinity fields were calculated under the assumption of homogeneity and isotropy, was used to implement the procedure of assimilation of field observations. A comprehensive expedition with the aim to study oceanological processes at the end of the summer warm-up period - the beginning of the autumn cooling period was conducted on 16 - 22nd of September, 2007 by the Marine Hydrophysical Institute on the research vessel “Experiment”. The maximum depth to which probing was carried out varied from 5 to 300 m, the number of stations was 44. From the analysis of the statistical structure of the fields, a correlation radius of ~ 20 km was determined. The covariance functions of thermohaline fields were approximated by an exponential function. We considered a region of the Black Sea, limited by latitude 44.4°N, located between meridians 28.5° and 33.5° E (we used a detailed presentation of bottom topography with a resolution ~1.6 km.The choice of the horizontal coefficients of turbulent viscosity and diffusion was based on a series of specialized numerical experiments. The total period of integration of model equations 10 days (from 14 to 24 of September 2007). Along the vertical, horizontal components of the current velocity, temperature and salinity were computed at 30 depths. The vertical component of velocity was calculated for intermediate horizons. Fields of currents, temperature and salinity, obtained from model for the entire sea on a 5 x 5 km horizontal grid, were used to specify initial and the boundary conditions at the open boundary of the domain. The vertical coefficients of turbulent exchange of momentum and diffusion were calculated according to the Philander-Pacanowski approximation. We took into account the discharges of rivers. The fields of tangential wind stress, heat fluxes, short-wave radiation, precipitation and evaporation, obtained from the data of the regional atmospheric model “ALADIN”, were specified for each day on the surface of the sea. The calculated current fields were characterized by mesoscale eddies and jets. The wind regime had a great influence on the formation of circulation due to the shallowness of the area. Under the influence of the south-west wind, acting from 14th to 18th of September, the main direction of surface currents was the eastern. An anticyclonic eddie with a radius of about 15 km in the Kalamitsky Bay was reconstructed in the upper 30-meter layer, intensification of currents near cape Tarkhankut to 30 cm/s on the upper horizon was noted, a cyclonic eddy with a radius of about 10 km was generated in a layer of 10-20 m km near the city of Evpatoria. Under the influence of the northern and northeastern winds, acting from 19th to 24th of September, the main direction of surface currents was the western, the circulation features (cyclonic eddies with a radius of about 15 km) were formed, associated with the meandering of the Rim Current along the depth dump. We also note the intens

2019-12-12 15:49:00