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Where and how the East Madagascar Current retroflection originates?
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  • Juliano Dani Heriniaina RAMANANTSOA,
  • Pierrick Penven,
  • Roshin P. Raj,
  • Lionel Renault,
  • Leandro Ponsoni,
  • Marek Ostrowski,
  • Ahmad Fehmi Dilmahamod,
  • Mathieu Rouault
Juliano Dani Heriniaina RAMANANTSOA
Department of Oceanography - University of Cape Town

Corresponding Author:[email protected]

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Pierrick Penven
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Roshin P. Raj
Nansen Environmental and Remote Sensing Center Bergen, Norway
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Lionel Renault
Institur de Recherche pour le Dévelopement (IRD)
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Leandro Ponsoni
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Marek Ostrowski
Institute of Marine Research
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Ahmad Fehmi Dilmahamod
GEOMAR Helmholtz Centre for Ocean Research Kiel
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Mathieu Rouault
University of Cape Town
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In-situ and remote sensing data are used to identify three states of the East Madagascar Current (EMC) southern extension: Early-Retroflection, Canonical-Retroflection and No-Retroflection. Retroflections occur 47% of the time. EMC strength regulates the retroflection state, although impinged mesoscale eddies also contribute to the retroflection formation. The Early-Retroflection is linked with the EMC volume transport. Anticyclonic eddies drifting from the central Indian Ocean to the coast favors Early-Retroflection formation, anticyclonic eddies near the southern tip of Madagascar promotes the generation of Canonical Retroflection, and No-Retroflection appears to be associated with a lower Eddy Kinetic Energy (EKE). Knowledge of the EMC retroflection state could help predicting: (1) coastal upwelling south of Madagascar, (2) the South-East Madagascar phytoplankton bloom, (3) the formation of South Indian Ocean Counter Current (SICC). The EMC retroflection status appears to have a slight noticeable impact on the Agulhas Current system.
Nov 2021Published in Journal of Geophysical Research: Oceans volume 126 issue 11. 10.1029/2020JC016203