PhD thesis: Submesoscale dynamics in the Western Mediterranean Sea



Photo: (from left to right) Ismael Hernandez, Evan Mason, Ananda Pascual, Damià Gomis,Esther Capó, Annalisa Bracco, Alejandro Orfila and Marca Marcos



Esporles, January 22, 2020. Maria Esther Capó Truyols has defended her doctoral thesis supervised by the doctors Alejandro Orfila Forster and Evan Mason from IMEDEA (CSIC-UIB). The event took place on January 22 at the University of Balearic Islands.



The transition from mesoscale to submesoscale dynamics is analyzed in the western Mediterranean Sea using a set of ROMS model simulations. 



The mesoscale exploration is assessed in terms of the Lorenz energy cycle (LEC), which provides a quantification of kinetic-potential energy exchange through eddy-mean flow interaction.



The patterns of energy conversion between mean and eddy kinetic and potential energy are estimated in three subregions of the domain: the Alboran Sea, Algerian Basin, and Northern Basin.



Spatial characterization of the energy conversion routes, together with the physical and dynamical characteristics of the area, hints at two principal submesoscale mechanisms being involved in maintaining balance: topographic vorticity generation (TVG) and frontogenesis (FG).



The transition toward the submesoscale is explored in the Alboran Sea by means of two nested, realistic simulations with increasing horizontal resolutions ranging from 1.5 to 0.5 km.



Unbalanced submesoscale dynamics emerge as the model resolution is increased. 



TVG is explored and quantified using the barotropic vorticity balance equation, in which the generation of vorticity through flow-topography interaction relies on contributions from both bottom stress and form drag.



FG is analyzed at an intense density front located at the eastern edge of the permanent western anticyclonic gyre (WAG) which has a structure similar to that of the climatological Almeria-Oran front.