Three-Dimensional Identification of the Black Sea Mesoscale Eddies according to NEMO Numerical Model Calculations

Abstract

A new method of three-dimensional identification of mesoscale eddies based on the results of the Black Sea hydrodynamics modeling is applied. It is based on identification of the closed streamlines in the velocity fields. This method and the data resulted from the NEMO calculations for 2005–2008 are used to identify more than 1000 mesoscale eddies in the basin. The results permit to define eddy characteristic trajectories, calculate spatial variability of their velocities and radii and frequency of detection of cyclones and anticyclones. The obtained results are in good agreement with the earlier published studies of the eddy characteristics derived from satellite and in situ data. The modeling results permit to investigate the features of vertical distribution of eddy characteristics. The eddies are most often detected in the 0–150 m layer (the highest detection frequency F is within 20–50 m). In the 150–300 m layer this value is two times smaller, but still is substantial. Below 300 meters F quickly decreases with depth. The analogous distribution is characteristic of the eddy radii and orbital velocity: the highest values are observed in the upper 0–150 m layer, and in the lower layers they sharply decrease with depth. The analysis of seasonal variability of the eddy characteristics shows that the anticyclonic dynamics intensifies in summer, whereas the cyclonic one – in winter, that is consistent with the previous studies. The developed method provides additional opportunities for investigating the features of the eddy generation and evolution in the Black Sea.

Keywords

mesoscale eddies, Black Sea, modeling, vertical structure, automatic identification.

Acknowledgements

The analysis of eddy characteristics and the development of method for three-dimensional automatic identification of eddies was carried out with the financial support of RFBR grant 16-05-00714. Analysis of eddies seasonal variability was supported by RFBR grant 17-05-41089. Numerical dynamics modeling was carried out with financial support the State Order No. 0827-2015-0001.

For citation

Kubryakov, A.A., Mizyuk, A.I., Puzina, O.S. and Senderov, M.V. Three-Dimensional Identification of the Black Sea Mesoscale Eddies according to NEMO Numerical Model Calculations. Physical Oceanography, [e-journal] 25(1), pp. 18-26. doi:10.22449/1573-160X-2018-1-18-26

DOI

10.22449/1573-160X-2018-1-18-26

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