Recent progress in modelling the global ocean/sea-ice circulation at eddy-permitting resolution
Résumé
With the objective of simulating the changes observed in the ocean circulation in recent
decades, and to explain the physical mechanisms responsible for these changes,
the Drakkar project has developed a hierarchy of ocean/sea-ice model configurations,
from global eddy permitting (1/4°) to North Atlantic eddy resolving (1/12°). For an improved
representation of ocean-atmophere exchanges it is important that ocean models
represent correctly the position of the major fronts. Series of sensitivity tests have
been performed with the Dakkar model configurations to carefully evaluate the impact
on model solutions of the recent state-of-the-art parameterisations and numerical
schemes. We have found significant improvements of the ocean circulation in some
cases. The results point out the influence of the momentum advection scheme, of the
partial step representation of the bottom topography, of the sub-gridscale parameterisation at eddy permitting resolution, and enlighten the need of improved side-wall and bottom boundary layer parameterisations. The influence of different freshwater flux specifications is also considered. [no pdf]