The meridional transport of salt is computed in a global eddy-resolving numerical model (1/12° resolution) in order to improve our understanding of the ocean salinity budget. A methodology is proposed that allows a global analysis of the salinity balance in relation to surface water fluxes, without defining a "freshwater anomaly" based on an arbitrary reference salinity. The method consists of a decomposition of the meridional...

Observations and numerical simulations have shown that the meridional overturning circulation (MOC) exhibits substantial variability on sub- to interannual timescales. This variability is not fully understood. In particular it is not known what fraction of the MOC variability is caused by processes such as mesoscale ocean eddies and waves which are ubiquitous in the ocean. Here we analyse twin experiments performed with a glob...

Four global ocean/sea-ice simulations driven by the same realistic 47-year daily atmospheric forcing were performed by the DRAKKAR group at 2°, 1°, &frac12°, and ¼° resolutions. Simulated mean sea-surface heights (MSSH) and sea-level anomalies (SLA) are collocated over the period 1993–2004 onto the AVISO dataset. MSSH fields are compared with an inverse estimate. SLA datasets are filtered and compared over various time and spa...

The dynamical role of geothermal heating in abyssal circulation is reconsidered using three independent arguments. First, we show that a uniform geothermal heat flux close to the observed average (86.4 mW m−2) supplies as much heat to near-bottom water as a diapycnal mixing rate of ~10−4 m2 s−1 – the canonical value thought to be responsible for the magnitude of the present-day abyssal circulation. This parity raises the possi...

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 ¼° 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 transpor...

An eddying global model is used to study the characteristics of the Antarctic Circumpolar Current (ACC) in a streamline-following framework. Previous model-based estimates of the meridional circulation were calculated using zonal averages: this method leads to a counter-intuitive poleward circulation of the less dense waters, and underestimates the eddy effects. We show that on the contrary, the upper ocean circulation across...