Adekule Ajayi, Julien Le Sommer, Laurent Brodeau, Brian K. Arbic, Guillaume Serazin, Aurelie Albert, Такая Учида , Patrice Klein

Understanding how kinetic energy (KE) is exchanged across scales and eventually dissipated remains a key question in physical oceanography. Recent theoretical works suggests that both quasi-balanced submesoscale motions and internal gravity waves (IGWs) could play a role in fluxing KE towards dissipation. How these classes of motions actually provide a route to dissipation in the ocean is still debated. This study investigates the impact of IGWs generated by tidal motions on cross-scale KE exchanges at mid-latitude. Our analysis is based on the output of two realistic submesoscale permitting ocean model simulations of the North Atlantic Ocean, run respectively with and without tidal forcing. These twin experiments permit investigation of how tidally-forced IGWs modify the KE variance, cross-scale exchanges, and associated seasonality. Our results show that, in the presence of externally-forced IGWs, KE transfer towards dissipative scales is enhanced in summertime both at the surface and in the ocean interior.