Abstract. The Mediterranean Outflow Water (MOW) is a dense water
mass originated in the Strait of Gibraltar. Downstream of the Gulf of Cádiz,
the MOW forms a reservoir region west of the Iberian continental slopes at a
buoyant depth of approximately 1000 m. This region plays a key role as the
main centre where the MOW is mixed and distributed into the North Atlantic.
The seafloor in this area is characterized by the presence of a complex
bathymetry with three abyssal plains separated by mountain chains. Although
the topographic features do not reach the surface, they influence ocean
flows at intermediate and deep ocean layers, conditioning the distribution
and circulation of MOW. The Copernicus Marine Environmental Monitoring Service (CMEMS) Iberian–Biscay–Ireland (IBI) ocean reanalysis is used to provide a detailed view of the
circulation and mixing processes of MOW near the Iberian and African
continental slopes. This work emphasizes the relevance of the complex
bathymetric features defining the circulation processes of MOW in this
region. The high resolution of the IBI reanalysis allows us to make a
description of the mesoscale features forced by the topography. The
temperature, salinity, velocity, transport, and vorticity fields are
analysed to understand the circulation patterns of MOW. The high-resolution
circulation patterns reveal that Horseshoe Basin and the continental
slope near Cape Ghir (a.k.a. Cap Rhir or Cabo de Aguer) are key areas controlling the mixing processes of MOW
with the surrounding water masses, mainly North Atlantic Central Water (NACW)
and Antarctic Intermediate Water (AAIW). The water mass
variability is also analysed by means of composite analysis. Results
indicate the existence of a variability in the MOW tongue which retracts and
expands westwards in opposition to the movement of the underlying North
Atlantic Deep Water.