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Communication Dans Un Congrès Année : 2019

Subsurface Fine-Scale Patterns in an Anticyclonic Eddy Off Cap-Vert Peninsula Observed From Glider Measurements

Alban Lazar
Claire Gourcuff
  • Fonction : Auteur
Xavier Capet

Résumé

Glider measurements acquired along four 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 northwest toward the Cape Verde islands. At depth, between 100 and -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- to 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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Dates et versions

hal-02401875 , version 1 (10-12-2019)

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Nicolas N. Kolodziejczyk, Pierre Testor, Alban Lazar, Vincent Echevin, Gerd Krahmann, et al.. Subsurface Fine-Scale Patterns in an Anticyclonic Eddy Off Cap-Vert Peninsula Observed From Glider Measurements. 21st EGU General Assembly, EGU, Apr 2019, Vienna, Austria. ⟨hal-02401875⟩
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