Influence of the Madagascar Ridge on Eddy Variability in the Agulhas Current System: A Modelling Study

A regional ocean model was used to study the influence of the Madagascar Ridge on the circulation and eddy variability in the Agulhas Current system. In the control experiment, the model was run with a realistic bathymetry, whereas in the idealized run the bathymetry was modified by flattening Madagascar Ridge. When the Ridge was suppressed, no obvious changes were observed in the large-scale circulation. However, integrated transports revealed an excess of about 10 Sv (1 Sv = 106 m3s-1) in the recirculation of the greater Agulhas Current system. Dynamic and statistically (p < 0.05) significant changes were observed at the mesoscale variability. Composite analysis of the radial distribution of the eddy azimuthal velocity, surface height, and relative vorticity within the Ridge domain in the experiments revealed that the presence of the Madagascar Ridge determines the emergence of a secondary class of large anticyclonic eddy types in the region, the “Madagascar rings”.

Keyword(s)

anticyclonic rings, control and idealized numerical model simulation experiment, flow variability, integrated volume transport, madagascar ridge, mesoscale eddies

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Halo Issufo, Raj Roshin Pappukutty, Penven Pierrick, Lamont Tarron, Ansorge Isabelle, Johannessen Johnny A. (2024). Influence of the Madagascar Ridge on Eddy Variability in the Agulhas Current System: A Modelling Study. ESS Open Archive. INPRESS. https://doi.org/10.22541/essoar.171345241.14142243/v1, https://archimer.ifremer.fr/doc/00889/100099/

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