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| Le Traon, Pierre-yves; Demey, P. |
| Two years of Geosat data (November 1986 to December 1988) for the Azores-Madeira region of the North Atlantic are analyzed. The objective is to study the eddy field associated with the terminal retroflection of the Azores current. The rms variability of sea level anomaly is 4 to 8 cm, with maximum values between 33-degrees and 35-degrees-N being associated with the Azores current and located on its northern flank. Higher energy is observed during winter and during the year November 1987 to November 1988. Analysis of velocities at crossovers reveals anisotropy with larger meridional velocity variances. This is the signature of meanders and/or eddies elongated in the north-south direction. The eddy-mean flow interaction is studied through the analysis of the... |
| Tipo: Text |
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| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00079/18985/16626.pdf |
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| Larnicol, Gilles; Le Traon, Pierre-yves; Ayoub, N; Demey, P. |
| We describe the circulation and mean sea lever variations of the Mediterranean Sea from 2 years of TOPEX/POSEIDON altimetric data. It is first shown that the response of the Mediterranean Sea to atmospheric pressure forcing is close to an inverse barometer (except at high frequencies) which means that the adjustment is accompanied by a flow through the Straits of Sicily and Gibraltar. We then use TOPEX/POSEIDON to study the mean sea level variations, representing steric effects and integrated large-scale changes of the mass of the Mediterranean Sea. We observe an annual cycle with a fast drop during winter, Steric effects account for about half of the observed variations. The remaining signal is believed to be driven by evaporation minus precipitation (E -... |
| Tipo: Text |
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| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00079/18979/16625.pdf |
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| Demey, P. |
| We show various synoptic estimates of the North Atlantic Current (NAC) eddy field in a domain 450 x 350 km at 52.5-degrees-N 25.0-degrees-W in the theoretical path of the NAC. Temperature, salinity, and surface streamfunction estimates are derived from the AthenA hydrological data collected in the summer of 1988. These estimates are discussed and compared with two surface streamfunction estimates obtained from Geosat altimetric measurements: one statistical, and the other resulting from quasi-geostrophic assimilation. The estimates show a frontal structure associated with a jet, sharply separating cold and fresh water to the north from warmer and saltier water to the south. Temperature and salinity values on both sides of the front are consistent with... |
| Tipo: Text |
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| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/00101/21240/18855.pdf |
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