Penduff T. auteur aut IRD Le Sommer J. auteur aut IRD Barnier B. auteur aut IRD Treguier A.M. auteur aut IRD Molines J.M. auteur aut IRD Madec Gurvan auteur aut IRD text journalArticle eng The combined use of partial steps and of an energy-enstrophy conserving momentum advection scheme was shown by Barnier et al. (2006) to yield substantial improvements in the surface solution of the DRAKKAR Œ° global sea-ice/ocean model. The present study extends this investigation below the surface with a special focus on the Atlantic and reveals many improvements there as well: e.g. more realistic path, structure and transports of major currents (Gulf Stream, North Atlantic Current, Confluence region, Zapiola anticyclone), behavior of shedded rings, narrower subsurface boundary currents, stronger mean and eddy flows (MKE and EKE) at depth, beneficial enhancement of cyclonic (anticyclonic) flows around topographic depressions (mountains). Interestingly, adding a no-slip boundary condition to this improved model setup cancels most of these improvements, bringing back the biases diagnosed without the improved momentum advection scheme and partial steps (these biases are typical of other models at comparable or higher resolutions). This shows that current-topography interactions and full-depth eddy-admitting model solutions can be seriously deteriorated by near-bottom sidewall friction, either explicit or inherent to inadequate numerical schemes. specialized 032 4 3 491-528 2007 https://www.documentation.ird.fr/hor/PAR00002830 https://www.documentation.ird.fr/hor/PAR00002830 Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2009-03-20 2017-08-23 PAR00002830 fre