We explore the interaction of mesoscale eddies in the Lofoten Basin of the Norwegian Sea using the GLORYS 12v1 eddy-resolving reanalysis. The Lofoten Basin is the area of the intensive ocean-atmosphere interactions and many mesoscale eddies are formed due to instabilities of the branches of the Norwegian Current. We describe the spatial distribution of kinetic energy, relative vorticity, and Okubo-Weiss parameter during the eddy interaction. Using the approach of turbulent theory, we study the exchange of related eddy kinetic energy (KmKe" role="presentation">KmKeKmKeKmKe) and show a strong dependence from a width of window averaging. The KmKe" role="presentation">KmKeKmKeKmKe fluxes describe features of interactions between parts of eddies and indicate a difference in the stability of the parts. The most stable parts have positive values of KmKe" role="presentation">KmKeKmKeKmKe. They can transfer energy to the less stable parts. In other words, the positive values of KmKe" role="presentation">KmKeKmKeKmKe mean transport of kinetic energy from the main fluxes to turbulent pulsations. We demonstrate that the field of relative vorticity of one anticyclonic eddy merging with another one consists of three parts with alternating signs of KmKe" role="presentation">KmKeKmKeKmKe. The parts look like two concentric rings surrounding the central part of the eddy. The sign of each part corresponds to gain or loss of kinetic energy. We detect the positive values of KmKe" role="presentation">KmKeKmKeKmKe for both the external ring and the central part of the eddy. For the middle ring of the eddy, KmKe" role="presentation">KmKeKmKeKmKe is negative. This demonstrates the tendency to the stability of the structure as the result of the merging. And vice versa, positive values of KmKe" role="presentation">KmKeKmKeKmKe break the eddy into two parts when splitting.
Lofoten Basin, mesoscale eddies, vortex interaction, splitting, merging, turbulence, kinetic energy fluxes
1. Alexeev, V. A., V. V. Ivanov, I. A. Repina, et al. (2016) , Convective structures in the Lofoten Basin based on satellite and Argo data, Izv. Atmos. Ocean. Phys., 52, no. 9, p. 1064-1077, https://doi.org/10.1134/S0001433816090036
2. Bashmachnikov, I., T. Belonenko, P. Kuibin, et al. (2018) , Pattern of vertical velocity in the Lofoten vortex (the Norwegian Sea), Ocean Dynamics, 68, no. 12, p. 1711-1725, https://doi.org/10.1007/s10236-018-1213-1
3. Bashmachnikov, I. L., T. V. Belonenko, P. A. Kuibin (2017a) , The application of the theory of the columnar Q-vortex with helical structure to the description of the dynamic characteristics of the Lofoten vortex of the Norwegian sea, Vestn. St. Petersburg Un-ta, Earth Sciences, 62, no. 3, p. 221-336, https://doi.org/10.21638/11701/spbu07.2017.301 (in Russian)
4. Bashmachnikov, I. L., et al. (2017b) , On the vertical structure and stability of the Lofoten vortex in the Norwegian Sea, Deep-Sea Res. I, 128, p. 1-27, https://doi.org/10.1016/j.dsr.2017.08.001
5. Belonenko, T. V., I. L. Bashmachnikov, et al. (2017) , On the Vertical Velocity Component in the Mesoscale Lofoten Vortex of the Norwegian Sea, Izvestiya, Atmospheric and Oceanic Physics, 53, no. 6, p. 641-649, https://doi.org/10.1134/S0001433817060032
6. Blindheim, J., S. \\Osterhus (2013) , The Nordic Seas, Main Oceanographic Features, The Nordic Seas: An Integrated Perspective, H. Drange, T. Dokken, T. Furevik, R. Gerdes and W. Berger (eds.), p. 11-39, American Geophysical Union (AGU), Washington D.C, https://doi.org/10.1029/158GM03
7. Bloshkina, E. V., V. V. Ivanov (2016) , Convective structures in the Norwegian and Greenland Seas based on simulation results with high spatial resolution, Proceedings of the Hydrometeorological Research Center of the Russian Federation, 361, p. 146-168 (In Russian)
8. Broecker, W. (1991) , The Great Ocean Conveyor, Oceanography, 4, no. 2, p. 79-89, https://doi.org/10.5670/oceanog.1991.07
9. Carton, X. (2001) , Hydrodynamical modeling of oceanic vortices, Surveys in Geophysics, 22, no. 3, p. 179-263, https://doi.org/10.1023/A:1013779219578
10. Chen, Y., J. Karstensen, et al. (2019) , Representation of selected mesoscale eddies in the eastern tropical Atlantic in an ocean re-analysis model and in a 3D ocean reconstruction, Geophysical Research Abstracts, 21, p. EGU2019-17929-1
11. Dong, C. D., J. McWilliams, A. F. Shchepetkin (2007) , Island wakes in deep water, Journal of Physical Oceanography, 37, p. 962-981, https://doi.org/10.1175/JPO3047.1
12. Fedorov, A. M., I. L. Bashmachnikov, T. V. Belonenko (2019) , Winter convection in the Lofoten Basin according to ARGO buoys and hydrodynamic modeling, Vestn. St. Petersburg Un-ta, Earth Sciences, 64, no. 3, p. 491-511, https://doi.org/10.21638/spbu07.2019.308 (In Russian)
13. Isachsen, P. E. (2011) , Baroclinic instability and eddy tracer transport across sloping bottom topography: How well does a modified Eady model do in primitive equation simulations?, Ocean Modell., 39, p. 183-199, https://doi.org/10.1016/j.ocemod.2010.09.007
14. Isachsen, P. E. (2015) , Baroclinic instability and the mesoscale eddy field around the Lofoten Basin, J. Geophys. Res., 120, no. 4, p. 2884-2903, https://doi.org/10.1002/2014JC010448
15. Isern-Fontanet, J., E. García-Ladona, J. Font (2003) , Identification of marine eddies from altimetric maps, Journal of Atmospheric and Oceanic Technology, 20, no. 5, p. 772-778, https://doi.org/10.1175/1520-0426(2003)20%3C772:IOMEFA%3E2.0.CO;2
16. Kamidaira, Y., Y. Uchiyama, S. Mitarai (2017) , Eddy-induced transport of the Kuroshio warm water around the Ryukyu Islands in the East China Sea, Continental Shelf Research, 143, p. 206-218, https://doi.org/10.1016/j.csr.2016.07.004
17. Köhl, A. (2007) , Generation and Stability of a Quasi-Permanent Vortex in the Lofoten Basin, J. Phys. Oceanogr., 37, p. 2637-2651, https://doi.org/10.1175/2007JPO3694.1
18. Kurian, J., F. Colas, X. Capet, et al. (2011) , Eddy properties in the California current system, J. Geophys. Res.: Oceans, 116, p. C08027, https://doi.org/10.1029/2010JC006895
19. Lozier, M. S. (2010) , Deconstructing the Conveyor Belt, Science, 328, no. 5985, p. 1507-1511, https://doi.org/10.1126/science.1189250
20. Okubo, A. (1970) , Horizontal dispersion of floatable particles in the vicinity of velocity singularities such as convergences, Deep Sea Research and Oceanographic Abstracts, 17, no. 3, p. 445-454, https://doi.org/10.1016/0011-7471(70)90059-8
21. S\\oiland, H., L. Chafik, T. Rossby (2016) , On the long-term stability of the Lofoten Basin Eddy, J. Geophys. Res. Oceans, 121, p. 4438-4449, https://doi.org/10.1002/2016JC011726
22. Starr, V. (1966) , Physics of Negative Viscosity Phenomena. Earth and Planetary Science Series Earth and Planetary Science Series, 256 pp., McGraw-Hill, New York
23. Volkov, D. L., A. A. Kubryakov, R. Lumpkin (2015) , Formation and variability of the Lofoten basin vortex in a high-resolution ocean model, Deep-Sea Res. I, 105, p. 142-157, https://doi.org/10.1016/j.dsr.2015.09.001
24. Volkov, D. L., T. V. Belonenko, V. R. Foux (2013) , Puzzling over the dynamics of the Lofoten Basin - a sub-Arctic hot spot of ocean variability, Geophys. Res. Lett., 40, no. 4, p. 738-743, https://doi.org/10.1002/grl.50126
25. Weiss, J. (1991) , The dynamics of enstrophy transfer in two-dimensional hydrodynamics, Physica D: Nonlinear Phenomena, 48, no. 2-3, p. 273-294, https://doi.org/10.1016/0167-2789(91)90088-Q
26. Zhmur, V. V. (2011) , Mesoscale Vortices of the Ocean, 384 pp., GEOS, Moscow (in Russian)
