RT Conference Proceedings
T1 On the origin of the seasonal and interannual T-S variability of the inflow through the Strait of Gibraltar
A1 García-Lafuente, Jesús
A1 Naranjo-Rosa, Cristina Belén
A1 Sánchez, Ricardo
A1 Sánchez-Garrido, José Carlos
A1 Sammartino, Simone
K1 Gibraltar (Estrecho)
K1 Corrientes marinas
AB During several years of the last decade, the hydrological properties of the Atlantic inflow through theStrait of Gibraltar were monitored at a station located over the Moroccan continental shelf south ofCamarinal sill. The station, deployed and maintained by the Centre Oceanologique de Marseille incollaboration with SHOMAR (Morocco) was part of the HydroChanges monitoring network sponsoredby the CIESM1 and collected a good quality set hydrological observations at 80 m depth from 2003 tothe end of 2008, when the scientific equipment was lost. In an interesting paper, Millot (2007) analyzedthe time subseries spanning from 2003 to early 2007 and showed an indisputable seasonal signal in theAtlantic inflow and a trend of the salinity of the Atlantic water that was flowing toward the MediterraneanSea at the depth of the station. Since the inflowing water comes from the Gulf of Cadiz, any signaldetected in the inflow must be present in that area, a fact that has inspired the present work, which makesuse of different experimental (ARGO Global Marine Atlas, Altimetry, QuickScat winds, and the wholetime series at Camarinal), re-analysis (NCEP-NCAR) and numerical (ECCO model) data to address thetopic.The seasonal local signals of temperature and salinity in the Gulf of Cadiz, both of them neatly depictedin the analyzed data, show up different origins. The temperature oscillation is accounted for by thesurface heat flux to a very great extent (more than 80%), while the salinity signal is not sensitive to anysurface flux at all, but to advective fluxes. ARGO Global MarineI Atlas and ECCO model data stronglysuggests that the seasonal fluctuations of the position and extension of the North Atlantic SubtropicalGyre are driving the seasonal salinity signal observed in the Gulf of Cadiz, which is later advected intothe Mediterranean Sea through the Strait of Gibraltar. The important conclusion to be drawn is thatthe interannual variations of the seasonal fluctuations of the Gyre will generate short-term trends of theseawater properties observed in the Gulf of Cadiz (intra–decadal variability) and, hence, in the Strait.Actually, the ECCO database indicates that such a short-term trend of the Gyre position to be displacedto the east took place during the same years as the salinity trend in the inflow reported by Millot (2007).Thus the salinification mentioned by this author would have its origin in the large scale dynamics of theNorth Atlantic Subtropical Gyre, since the more to the east the Gyre reaches, the easier will be to findsaltier water in the Gulf of Cadiz. To this regard it is worth noting that the trend of the North AtlanticSubtropical Gyre to be displaced to the east stopped in year 2007, which coincides with the end ofthe short-term trend that was being detected by the monitoring station. Millot’s analyses embraced theperiod from February 2003 to February 2007, which ended before the trend changed, and he could notenvisage that change.As far as the salinity of the inflow is a fundamental ingredient of the thermohaline circulation of theMediterranean Sea, the understanding of the mechanism that causes the interannual variability of theseasonal pattern of the North Atlantic Subtropical Gyre would be critical for studies of the interannualvariability of the Mediterranean Sea circulation. The issue is currently under study although large scalewind field in the North Atlantic is the most likely candidate.
YR 2014
FD 2014-06-18
LK http://hdl.handle.net/10630/7691
UL http://hdl.handle.net/10630/7691
LA eng
NO Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.
DS RIUMA. Repositorio Institucional de la Universidad de Málaga
RD 19 ene 2026