@article{fdi:010066263,
  title = {{O}n effective resolution in ocean models},
  author = {{S}oufflet, {Y}ves and {M}archesiello, {P}atrick and {L}emarie, {F}. and {J}ouanno, {J}ulien and {C}apet, {X}. and {D}ebreu, {L}. and {B}enshila, {R}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he increase of model resolution naturally leads to the representation of a wider energy spectrum. {A}s a result, in recent years, the understanding of oceanic submesoscale dynamics has significantly improved. {H}owever, dissipation in submesoscale models remains dominated by numerical constraints rather than physical ones. {E}ffective resolution is limited by the numerical dissipation range, which is a function of the model numerical filters (assuming that dispersive numerical modes are efficiently removed). {W}e present a {B}aroclinic jet test case set in a zonally reentrant channel that provides a controllable test of a model capacity at resolving submesoscale dynamics. {W}e compare simulations from two models, {ROMS} and {NEMO}, at different mesh sizes (from 20 to 2 km). {T}hrough a spectral decomposition of kinetic energy and its budget terms, we identify the characteristics of numerical dissipation and effective resolution. {I}t shows that numerical dissipation appears in different parts of a model, especially in spatial advection-diffusion schemes for momentum equations ({ME} dissipation) and tracer equations ({APE} dissipation) and in the time stepping algorithms. {E}ffective resolution, defined by scale-selective dissipation, is inadequate to qualify traditional ocean models with low-order spatial and temporal filters, even at high grid resolution. {H}igh-order methods are better suited to the concept and probably unavoidable. {F}ourth-order filters are suited only for grid resolutions less than a few kilometers and momentum advection schemes of even higher-order may be justified. {T}he upgrade of time stepping algorithms (from filtered {L}eapfrog), a cumbersome task in a model, appears critical from our results, not just as a matter of model solution quality but also of computational efficiency (extended stability range of predictor-corrector schemes). {E}ffective resolution is also shaken by the need for non scale-selective barotropic mode filters and requires carefully addressing the issue of mode splitting errors. {P}ossibly the most surprising result is that submesoscale energy production is largely affected by spurious diapycnal mixing ({APE} dissipation). {T}his result justifies renewed efforts in reducing tracer mixing errors and poses again the question of how much vertical diffusion is at work in the real ocean.},
  keywords = {{E}ffective resolution ; {S}pectral budget ; {B}aroclinic jet ; {N}umerical ; dissipation},
  booktitle = {},
  journal = {{O}cean {M}odelling},
  volume = {98},
  numero = {},
  pages = {36--50},
  ISSN = {1463-5003},
  year = {2016},
  DOI = {10.1016/j.ocemod.2015.12.004},
  URL = {https://www.documentation.ird.fr/hor/fdi:010066263},
}