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) and show a strong dependence from a width of window averaging. The KmKe 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. They can transfer energy to the less stable parts. In other words, the positive values of KmKe 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. 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 for both the external ring and the central part of the eddy. For the middle ring of the eddy, KmKe 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 break the eddy into two parts when splitting. KEYWORDS: Lofoten Basin; mesoscale eddies; vortex interaction; splitting; merging; turbulence; kinetic energy fluxes.
Предметные области Scopus
- Планетоведение и науки о земле (все)