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Laboratoire d'études en Géophysique et océanographie spatiales |  |
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Laboratoire d'études en Géophysique et océanographie spatiales | |
| HAL: hal-00655768, version 1 |
| DOI: 10.1029/2011JC007477 |
| Detailed view |  Export this paper |
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| Journal of Geophysical Research 116 (2011) C12044 |
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| From the western boundary currents to the Pacific Equatorial Undercurrent: Modeled pathways and water mass evolutions |
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| Mélanie Grenier 1Sophie Cravatte 1 |
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| (2011-12-30) |
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| The hydrological and geochemical properties of the waters constituting the Pacific Equatorial Undercurrent (EUC) determine the properties of the equatorial cold tongue. Understanding and quantifying the various EUC origins is therefore of prime importance. For this purpose, a high-resolution (1/4°) interannual oceanic simulation was analyzed from the western tropical Pacific boundaries to 140°W, using a Lagrangian framework. Waters from the Low-Latitude Western Boundary Currents (LLWBCs) transiting from Vitiaz Strait (the main contributor), from Solomon Strait, and via the Mindanao Current were identified as the principal sources to the EUC. Waters conveyed by the interior ocean off equator are negligible till 180°E. The LLWBCs' waters represent 87% of the EUC transport at 156°E out of which the New Guinea Coastal Undercurrent (NGCU) is as large as 47%. The EUC meridional distribution suggests that the waters originating from Solomon Strait and Mindanao Current mostly remain in the hemisphere from which they originate. Contrastingly, Vitiaz Strait waters are found in both hemispheres. The vertical EUC distribution shows that the lower layer of the EUC is mainly composed of Vitiaz Strait waters. Finally, the source transport distributions were characterized, at their origin and within the EUC, as a function of density. These distributions showed that waters flowing through Vitiaz Strait at densities higher than those of the EUC (down to sigma = 27.2 kg m-3) undergo a diapycnal mixing and lighten during their journey to join the EUC. This lightening supports the suggestion that the NGCU is a major source for the EUC geochemical enrichment. |
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| 1: | Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) |
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CNRS : UMR5566 – Institut de recherche pour le développement [IRD] – CNES – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III |
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| 2: | Laboratoire de physique des océans (LPO) |
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CNRS : UMR6523 – Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) – INSU – Université de Bretagne Occidentale [UBO] – Institut de recherche pour le développement [IRD] – Institut Universitaire Européen de la Mer (IUEM) |
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| 3: | Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN) |
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Institut de recherche pour le développement [IRD] – INSU – CNRS : UMR7159 – Université Pierre et Marie Curie [UPMC] - Paris VI – Muséum National d'Histoire Naturelle (MNHN) |
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| 4: | Laboratoire des écoulements géophysiques et industriels (LEGI) |
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CNRS : UMR5519 – Université Joseph Fourier - Grenoble I – Institut polytechnique de Grenoble (Grenoble INP) |
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| ECOLA OLVAC GEOMAR |
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| Subject | : | Environmental Sciences |
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| Attached file list to this document: | |||||
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| hal-00655768, version 1 | |
| http://hal.archives-ouvertes.fr/hal-00655768 | |
| oai:hal.archives-ouvertes.fr:hal-00655768 | |
| From: Francois Lacan | |
| Submitted on: Monday, 2 January 2012 11:59:12 | |
| Updated on: Monday, 11 March 2013 11:23:58 | |
