The Open-Ocean Side of the Malvinas Current in Argo Floats and 24 Years of Mercator Ocean High-Resolution (1/12) Physical Reanalysis

Camila Artana (1) , Jean-Michel Lellouche (2) , Nathalie Sennéchael (1) , Christine Provost (1)

1 ABC - Austral, Boréal et Carbone
2 Mercator Océan

Downstream of Drake Passage, the northern branches of the Antarctic Circumpolar Current, the Polar Front and the Subantarctic Front, veer northward and the latter forms the Malvinas Current (MC). The MC flows along the continental slope up to 38°S where it loops southward as the Malvinas Return Flow. Using 24 years of Mercator Ocean physical reanalysis outputs and Argo float data, we explore the open‐ocean side of the MC. We observe the occurrence of blocking events at 49°S, a region where the MC is exposed to the warm and salty anticyclonic anomalies propagating westward along the steep slope of the Malvinas Escarpment. During these events, the MC is cut off from its source, and the MC transport is considerably reduced at 49°S. The open‐ocean side of the MC is regularly supplied with cold polar waters from the Polar front.The polar waters accumulate and recirculate between the MC and the Malvinas Return Flow. The water characteristics of the recirculation region change over time. The recirculation region hosts significantly lighter and fresher waters during the period 1997–2003 compared with prior and later years. The 1997–2003 salinity minimum in the recirculation region corresponds to a period with reduced feeding events at 49°S.

Domaines: Océanographie

Camila Artana, Jean-Michel Lellouche, Nathalie Sennéchael, Christine Provost. The Open-Ocean Side of the Malvinas Current in Argo Floats and 24 Years of Mercator Ocean High-Resolution (1/12) Physical Reanalysis. Journal of Geophysical Research. Oceans, 2018, 123 (11), pp.8489-8507. ⟨10.1029/2018JC014528⟩. ⟨hal-02190735⟩