Numerical Study of the Interaction Between an Internal Tide and Mesoscale/Submesoscale Turbulence

Abstract:

Interactions between internal tides and mesoscale eddies are believed to be responsible for the incoherency of internal tides observed globally. This incoherency complicates the analysis of future high resolution altimetric missions (SWOT, COMPIRA). Attempts at quantifying the product of these interactions have been achieved with models of the ocean global circulation. These models resolve however the first few vertical modes of internal tide and their ability to represent interactions between internal tides and balanced circulation has to be tested against controlled high resolution numerical simulations. We present here first attempts in order to study such interactions in a controlled idealized setting. High resolution (1 km horizontal grid size) numerical simulations of mesoscale/submesoscale turbulence are produced by destabilizing a baroclinic jet in a zonally-periodic channel. An plane wave internal tide is generated inside the domain thanks to a localized wave-maker and propagates through the mesoscale/submesoscale turbulence. We quantify the level of incoherency of the internal tide and study how this level depends on the modal structure of the internal tide and the intensity of the mesoscale/submesoscale turbulence.