Subsurface fine scale patterns in an anticyclonic eddy off Cap-Vert peninsula observed from glider measurements

Type Article
Date 2018-09
Language English
Author(s) Kolodziejczyk NicolasORCID1, 2, Testor Pierre1, Lazar Alban1, Echevin Vincent1, Krahmann Gerd3, Chaigneau Alexis4, Gourcuff Claire1, Wade Malick5, Faye Saliou6, Estrade Philippe7, Capet Xavier1, 8, Mortier Laurent1, Brehmer Patrice8, Schuette Florian3, Karstensen Johannes3
Affiliation(s) 1 : Univ Paris 06, Sorbonne Univ UPMC, CNRS, IRD,MNHN,LOCEAN Lab, Paris, France.
2 : Univ Brest, LOPS Lab, CNRS, IRD,Ifremer,IUEM, Rue Dumont dUrville, Plouzane, France.
3 : Helmholtz Ctr Ocean Res Kiel GEOMAR, Kiel, Germany.
4 : Univ Toulouse, LEGOS, CNRS, CNES,IRD,UPS, Toulouse, France.
5 : Univ Gaston Berger, Lab Sci Atmosphere & Ocean, St Louis, Senegal.
6 : Ctr Rech Oceanog Dakar Thiaroye, Inst Senegalais Rech Agr, Dakar, Senegal.
7 : UCAD, LPAOSF, IRD, Dakar, Senegal.
8 : Inst Rech Dev, Dakar, Senegal.
Source Journal Of Geophysical Research-oceans (2169-9275) (Amer Geophysical Union), 2018-09 , Vol. 123 , N. 9 , P. 6312-6329
DOI 10.1029/2018JC014135
WOS© Times Cited 4
Keyword(s) submesoscale, stirring, tropical Atlantic, meoscale eddy, glider measurements, OMZ
Abstract

Glider measurements acquired along 4 transects between Cap‐Vert Peninsula and the Cape Verde archipelago in the eastern tropical North Atlantic during March‐April 2014 were used to investigate fine‐scale stirring in an anticyclonic eddy. The anticyclone was formed near 12°N off the continental shelf and propagated north‐west towards the Cape Verde islands. At depth, between 100‐400 m, the isolated anticyclone core contained relatively oxygenated, low salinity South Atlantic Central Water, while the surrounding water masses were saltier and poorly oxygenated. The dynamical and thermohaline subsurface environment favored the generation of fine‐scale horizontal and vertical temperature and salinity structures in and around the core of the anticyclone. These features exhibited horizontal scales of O(10‐30 km) relatively small with respect to the eddy radius of O(150 km). The vertical scales of O(5‐100 m) were associated to density‐compensated gradient. Spectra of salinity and oxygen along isopycnals revealed a slope of around k‐2 in the 10‐100 km horizontal scale range. Further analyses suggest that the fine‐scale structures are likely related to tracer stirring processes. Such mesoscale anticyclonic eddies and the embedded fine‐scale tracers in and around them could play a major role in the transport of South Atlantic Central Water masses and ventilation of the North Atlantic Oxygen Minimum Zone.

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Kolodziejczyk Nicolas, Testor Pierre, Lazar Alban, Echevin Vincent, Krahmann Gerd, Chaigneau Alexis, Gourcuff Claire, Wade Malick, Faye Saliou, Estrade Philippe, Capet Xavier, Mortier Laurent, Brehmer Patrice, Schuette Florian, Karstensen Johannes (2018). Subsurface fine scale patterns in an anticyclonic eddy off Cap-Vert peninsula observed from glider measurements. Journal Of Geophysical Research-oceans, 123(9), 6312-6329. Publisher's official version : https://doi.org/10.1029/2018JC014135 , Open Access version : https://archimer.ifremer.fr/doc/00450/56162/