Observed Characteristics and Vertical Structure of Mesoscale Eddies in the Southwest Tropical Pacific

Type Article
Date 2018-04
Language English
Author(s) Keppler LydiaORCID1, 2, 3, Cravatte SophieORCID4, Chaigneau Alexis4, Pegliasco Cori4, Gourdeau Lionel4, Singh Awnesh1
Affiliation(s) 1 : USP, PaCE SD, Suva, Fiji.
2 : Max Planck Inst Meteorol, Ocean Earth Syst, Hamburg, Germany.
3 : IMPRS ESM, Hamburg, Germany.
4 : Univ Toulouse, CNRS, CNES, IRD,LEGOS,UPS, Toulouse, France.
Source Journal Of Geophysical Research-oceans (2169-9275) (Amer Geophysical Union), 2018-04 , Vol. 123 , N. 4 , P. 2731-2756
DOI 10.1002/2017JC013712
WOS© Times Cited 31
Keyword(s) mesoscale eddies, southwest Pacific, argo floats, satellite altimetry

In the Southwest Pacific Ocean, waters transit from the subtropical gyre before being redistributed equatorward and poleward. While the mean pathways are known, the contribution to the mixing and transport of the water from mesoscale eddies has not been comprehensively investigated. In this research, satellite altimetry data, combined with an eddy detection and tracking algorithm is used to investigate the distribution and surface characteristics of mesoscale eddies in this region of complex bathymetry (10 degrees S-30 degrees S, 140 degrees E-190 degrees E). Detected eddies are then colocalized with in situ data from Argo floats to determine their vertical structure and the effect of eddies on the water masses. The numerous islands affect the eddy behavior as most eddies are formed in the lee of islands, propagate westward and decay when encountering shallow bathymetry. Eddies are sparse and short-lived in the tropical area north of Fiji, impacting only the top 200 meters of water. They do not appear to be able to trap and transport waters in this region. In the Coral Sea, a region of lateral shear between currents transporting waters of different origins, eddies are more numerous and energetic. They affect the water properties down to at least 500 m depth, and anticyclonic eddies trap water to approximate to 200 m, contributing to the upper thermocline waters mixing and transport. South of New Caledonia, mesoscale eddies are ubiquitous, with typical lifetimes longer than 5 months. They affect the temperature, salinity, and velocities down to approximate to 1,000 m depth, and weakly contribute to the mixing of lower thermocline waters.

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Keppler Lydia, Cravatte Sophie, Chaigneau Alexis, Pegliasco Cori, Gourdeau Lionel, Singh Awnesh (2018). Observed Characteristics and Vertical Structure of Mesoscale Eddies in the Southwest Tropical Pacific. Journal Of Geophysical Research-oceans, 123(4), 2731-2756. Publisher's official version : https://doi.org/10.1002/2017JC013712 , Open Access version : https://archimer.ifremer.fr/doc/00489/60039/