Impacts of mesoscale activity on the water masses and circulation in the Coral Sea
Résumé
The climatological vision of the circulation within the Coral Sea is today well established with
the westward circulation of two main jets, the North Caledonian Jet (NCJ) and the North Vanuatu Jet (NVJ)
as a consequence of the separation of the South Equatorial Current (SEC) on the islands of New Caledonia,
Vanuatu, and Fiji. Each jet has its own dynamic and transports different water masses across the Coral Sea.
The influence of mesoscale activity on mean flow and on water mass exchanges is not yet fully explored in
this region of intense activity. Our study relies on the analysis of in situ, satellite, and numerical data. Indeed,
we first use in situ data from the Bifurcation cruise and from an Argo float, jointly with satellite-derived
velocities, to study the eddy influence on the Coral Sea dynamics. We identify an anticyclonic eddy as
participating in the transport of NVJ-like water masses into the theoretical pathway of NCJ waters. This
transfer from the NVJ to the NCJ is confirmed over the long term by a Lagrangian analysis. In particular, this
numerical analysis shows that anticyclonic eddies can contribute up to 70–90% of the overall eddy transfer
between those seemingly independent jets. Finally, transports calculated using S-ADCP measurements
(0–500 m) show an eddy-induced sensitivity that can reach up to 15 Sv, i.e., the order of the transport of the
jets.
Domaines
Océan, AtmosphèreOrigine | Fichiers éditeurs autorisés sur une archive ouverte |
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