| Summary: | During several years of the last decade, the hydrological properties of the Atlantic inflow through the Strait of Gibraltar were monitored at a station located over the Moroccan continental shelf south of Camarinal sill. The station, deployed and maintained by the Centre Oceanologique de Marseille in collaboration with SHOMAR (Morocco) was part of the HydroChanges monitoring network sponsored by the CIESM1 and collected a good quality set hydrological observations at 80 m depth from 2003 to the end of 2008, when the scientific equipment was lost. In an interesting paper, Millot (2007) analyzed the time subseries spanning from 2003 to early 2007 and showed an indisputable seasonal signal in the Atlantic inflow and a trend of the salinity of the Atlantic water that was flowing toward the Mediterranean Sea at the depth of the station. Since the inflowing water comes from the Gulf of Cadiz, any signal detected in the inflow must be present in that area, a fact that has inspired the present work, which makes use of different experimental (ARGO Global Marine Atlas, Altimetry, QuickScat winds, and the whole time series at Camarinal), re-analysis (NCEP-NCAR) and numerical (ECCO model) data to address the topic. The seasonal local signals of temperature and salinity in the Gulf of Cadiz, both of them neatly depicted in the analyzed data, show up different origins. The temperature oscillation is accounted for by the surface heat flux to a very great extent (more than 80%), while the salinity signal is not sensitive to any surface flux at all, but to advective fluxes. ARGO Global MarineI Atlas and ECCO model data strongly suggests that the seasonal fluctuations of the position and extension of the North Atlantic Subtropical Gyre are driving the seasonal salinity signal observed in the Gulf of Cadiz, which is later advected into the Mediterranean Sea through the Strait of Gibraltar. The important conclusion to be drawn is that the interannual variations of the seasonal fluctuations of the Gyre will generate short-term ...
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