Agulhas Ring Heat Content and Transport in the South Atlantic Estimated by Combining Satellite Altimetry and Argo Profiling Floats Data

R. Laxenaire (1) , S. Speich (1) , A. Stegner (1)

1 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)

The Agulhas leakage of Indian Ocean waters into the Atlantic has been shown to be a key link in global ocean circulation and climate; an increased understanding of this process is therefore of more than just of local interest. While knowledge of the Agulhas leakage has increased over the past 30 years, the precise mechanisms at play and water properties transferred are still not sufficiently documented. This study covers the Agulhas rings heat content and transport, which contribute to the meridional overturning circulation of the global ocean during their route across the South Atlantic Ocean. By applying TOEddies, an eddy detection and tracking algorithm that takes into account eddy merging and splitting, to satellite altimetry maps combined with a colocation of the detected eddies with Argo floats vertical profiles, we are able to document the important heat anomaly characterizing Agulhas rings and their evolution across the Cape Basin and the South Atlantic Ocean. Notwithstanding that in situ data coverage is still limited at the ocean mesoscale, we have estimated an averaged Agulhas rings subsurface heat transport of 2.5 × 10^-2 PW and 1.5 × 10^-2 PW across the eastern and western South Atlantic Ocean, respectively.

Mots clés: subduction of most of the Agulhas rings in the South Atlantic; comparison of numerous methods of eddy reconstruction; new estimate of ∼0.02 PW heat flux achieved by the Agulhas ring in the South Atlantic Ocean

Domaines: Planète et Univers [physics]

R. Laxenaire, S. Speich, A. Stegner. Agulhas Ring Heat Content and Transport in the South Atlantic Estimated by Combining Satellite Altimetry and Argo Profiling Floats Data. Journal of Geophysical Research. Oceans, 2020, 125, ⟨10.1029/2019JC015511⟩. ⟨insu-03726972⟩