Topographic eddy generation in the Mediterranean Water outflow

N. Serra, R.H. Käse and I. Ambar

In a process modeling perspective, the bottom-following coordinates ocean model ROMS is used to study the Mediterranean Water (MW) outflow processes at high-resolution in the Gulf of Cadiz. The variability of the salt transport in the dense plume near the bottom is shown to depend on a process of cyclogenesis occurring in the layers above the MW. The model shows the generation of MW eddies (meddies) to take place, in accordance with observations, downstream of the Portimão Canyon, which plays an important role in determining the MW Undercurrent characteristics further downstream. The meddies are at times generated in the form of baroclinic dipoles, which are ejected perpendicularly to the Undercurrent. The role of the bottom topography in the generation mechanisms is discussed as well as the eddy contribution to the MW salt flux in the North Atlantic. Recent observational findings are presented to support the modeling results.