Evidence of Mediterranean Water dipole collision in the Gulf of Cadiz
| Type | Article | ||||||||
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| Date | 2014-08 | ||||||||
| Language | English | ||||||||
| Author(s) | L'Hegaret Pierre1, 2, Carton Xavier1, 2, Ambar Isabel3, Menesguen Claire 1, 2, Hua Bach Lien1, 2, Cherubin Laurent4, Aguiar Ana5, Le Cann Bernard1, 2, Daniault Nathalie1, 2, Serra Nuno6 |
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| Affiliation(s) | 1 : UBO UEB, LPO, Brest, France. 2 : IFREMER, Brest, France. 3 : Univ Lisbon, Ctr Oceanog, P-1699 Lisbon, Portugal. 4 : Florida Atlantic Univ, HBOI, Ft Pierce, FL USA. 5 : Univ Lisbon, Inst Dom Luiz, P-1699 Lisbon, Portugal. 6 : Univ Hamburg, Inst Meereskunde, Hamburg, Germany. |
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| Source | Journal Of Geophysical Research-oceans (0148-0027) (Amer Geophysical Union), 2014-08 , Vol. 119 , N. 8 , P. 5337-5359 | ||||||||
| DOI | 10.1002/2014JC009972 | ||||||||
| WOS© Times Cited | 28 | ||||||||
| Abstract | A collision of Mediterranean Water dipoles in the Gulf of Cadiz is studied here, using data from the MedTop and Semane experiments. First, a Mediterranean Water eddy (meddy) was surveyed hydrologically in November 2000 southwest of Cape Saint Vincent. Then, this meddy drifted northeastward from this position, accompanied by a cyclone (detected only via altimetry), thus forming a first dipole. In February 2001, a dipole of Mediterranean Water was measured hydrologically just after its formation near Portimão Canyon. This second dipole drifted southwestward. The western and eastern meddies had hydrological radii of about 22 and 25 km, respectively, with corresponding temperature and salinity maxima of (13.45°C, 36.78) and (11.40°C, 36.40). Rafos float trajectories and satellite altimetry indicate that these two dipoles collided early April 2001, south of Cape Saint Vincent, near 35°30′N, 10°15′W. More precisely, the eastern meddy wrapped around the western one. This merger resulted in an anticyclone (a meddy) which drifted southeastward, coupled with the eastern cyclone. Hydrological sections across this final third resulting dipole, performed in July 2001 in the southern Gulf of Cadiz, confirm this interaction: the thermohaline characteristics of the final meddy can be tracked back to the original structures. The subsequent evolution of this dipole was analyzed with Rafos float trajectories. A numerical simulation of the interaction between the two earlier dipoles is also presented. We suggest that these dipole collisions at the Mediterranean Water level may represent a mechanism of generation of the larger meddies that finally leave the Gulf of Cadiz. | ||||||||
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