Sensitivity of the mesoscale quasi-geostrophic turbulence to the numerical advection scheme: application to an Antarctic Ocean channel dynamics

The interactions of mesoscale eddies cause the potential enstrophy (the variance of potential vorticity) to be transferred toward small scales. To prevent a pileup of potential enstrophy at the grid size scale, models should dissipate the enstrophy. This can be done explicitly or implicitly via the...

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Bibliographic Details
Main Author: NOVI, LYUBA
Other Authors: Salvetti, Maria Vittoria
Format: Text
Language:Italian
Published: Pisa University 2015
Subjects:
Online Access:http://etd.adm.unipi.it/theses/available/etd-03272015-131318/
Description
Summary:The interactions of mesoscale eddies cause the potential enstrophy (the variance of potential vorticity) to be transferred toward small scales. To prevent a pileup of potential enstrophy at the grid size scale, models should dissipate the enstrophy. This can be done explicitly or implicitly via the the advection scheme. We explore the second choice and compare a set of schemes (2nd order MUSCL type, the ROMS one and two 5th order ones including a WENO). The comparison is done with a 3D QG model in a forced-dissipated turbulent regime. We assess the behavior with resolution. We nd a significant impact of the advection scheme on the turbulence, likely due to the inverse cascade of kinetic energy. We are able to diagnose the spectral signature of the implicit dissipation for each scheme. This reveals and explains why the eddy kinetic energy can so dramatically dier from one scheme to the other. Statistically convergence is also assessed, as well as robustness with c . In conclusion this work is aimed at exploring the eects of implicit dissipation in the eddy resolving regime.