Publications des scientifiques de l'IRD

Cravatte Sophie, Kestenare Elodie, Eldin Gérard, Ganachaud Alexandre, Lefèvre Jérôme, Marin Frédéric, Menkès Christophe, Aucan Jérôme. (2015). Regional circulation around New Caledonia from two decades of observations. Journal of Marine Systems, 148, p. 249-271. ISSN 0924-7963.

Titre du document
Regional circulation around New Caledonia from two decades of observations
Année de publication
2015
Type de document
Article référencé dans le Web of Science WOS:000356546400020
Auteurs
Cravatte Sophie, Kestenare Elodie, Eldin Gérard, Ganachaud Alexandre, Lefèvre Jérôme, Marin Frédéric, Menkès Christophe, Aucan Jérôme
Source
Journal of Marine Systems, 2015, 148, p. 249-271 ISSN 0924-7963
The regional and near-coastal circulation around New Caledonia is investigated using a compilation of more than 20 years of observations. Velocity profiles acquired by Shipboard Acoustic Doppler Current Profiler (SADCP) during 109 research cruises and ship transits since 1991 are analyzed and compared with absolute geostrophic currents inferred from hydrographic profiles and Argo floats drifts. In addition, altimetric surface currents are used to explore the variability of the circulation at various timescales. By making the best use of the strength of these various observations, this study provides an unprecedented detailed picture of the mean circulation around New Caledonia and of its variability in the upper layers. New Caledonia, together with the Vanuatu Archipelago and the Fiji Islands, acts as a 750-km long obstacle to the westward South Equatorial Current (SEC) entering the Coral Sea. On average, the SEC bifurcates against New Caledonia's east coast into a northwestward boundary current, the East Caledonian Current, beginning east of the Loyalty Islands and extending to at least 1000 m depth, and into a weak southeastward current. The latter, the Vauban Current, flows into the Loyalty channel against the mean trade winds where it extends to at least 500 m depth. It is highly variable at intraseasonal timescales; it often reverses and its variability is mainly driven by incoming mesoscale eddies east and south of New Caledonia. West of the Island, the southeastward Alis Current of New Caledonia (ACNC) flows along the reef slope in the 0-150 m layer. It overlays a weaker northwestward current, creating an unusual coastal circulation reminiscent of the current system along the Australian west coast. The ACNC is a persistent feature of the observations, even if its transport is also strongly modulated by the presence of offshore eddies. This study highlights the fact, if needed, that a snapshot view of the currents provided by a single transect can be strongly impacted by mesoscale eddies, and should be put into context, e.g. by using simultaneous altimetric data.
Plan de classement
Dynamique des eaux [032DYNEAU]
Descripteurs
CIRCULATION OCEANIQUE ; COURANT COTIER ; COURANT GEOSTROPHIQUE ; ARCHIPEL ; RECIF BARRIERE ; ALTIMETRIE ; VITESSE ; MODELISATION ; VARIATION PLURIANNUELLE ; VARIATION SAISONNIERE
Description Géographique
PACIFIQUE ; NOUVELLE CALEDONIE
Localisation
Fonds IRD [F B010064581]
Identifiant IRD
fdi:010064581
Contact