The energetics of internal tides at the Luzon Ridge

Abstract

Three-dimensional simulations of the M2 and K1 internal tides using the MIT General Circulation Model (MITgcm) configured for the Luzon Ridge are presented. The energetics of M2 and K1 internal tides are studied by analyzing the full barotropic and baroclinic energy budgets and the barotropic and baroclinic kinetic energy budgets. The conversion rate of M2 tide is also investigated using the approximate expression by Nycander (J Geophys Res 110:C10028, 2005). The results show that about 15.10 GW is transferred from the M2 barotropic tide to the M2 baroclinic tide at the Luzon Ridge, which is about 88% of the loss by the barotropic tide. The net baroclinic energy flux is about 4.46 GW, and the total dissipation is about 11.33 GW. Additionally, it is found that the potential energy changes are small in the full energy budget when comparing the result between the full barotropic and baroclinic energy budgets and the barotropic and baroclinic kinetic energy budgets. The expression by Nycander (J Geophys Res 110:C10028, 2005) is found to be sensitive to the model resolution, but may underestimate the conversion rate at the Luzon Ridge at high resolution compared with the model results.