On the influence of Subtropical Mode Water on the South Atlantic Ocean

• Published in: Journal of marine systems 2018-09, Vol.185, p.13-24
• Main Authors: Souza, Arthur Gerard Quadros de, Kerr, Rodrigo, Azevedo, José Luiz Lima de
• Format: Article
• Language: English
• Subjects: Agulhas rings; Indian Ocean; Mixing processes; South Atlantic Central Water; Thermocline
• ISSN: 0924-7963; 1879-1573
• DOI: 10.1016/j.jmarsys.2018.04.006

We investigate the spatiotemporal variability of the source water masses (i.e., varieties of Subtropical Mode Water – STMW) that contribute to the South Atlantic Central Water (SACW) in the South Atlantic Ocean. Thus, the composition of the SACW layer is updated. For this investigation, we applied an optimum multiparameter (OMP) analysis and used the conservative and semi-conservative parameters available from the World Ocean Database and Argo floats for the South Atlantic Ocean. The STMW18 (at upper levels) sourced in the central and eastern regions of the South Atlantic and the STMW12 (at lower levels) sourced at the boundaries of the South Atlantic Subtropical Front are the main contributors to the SACW. Although also important, the contribution of STMW14 (sourced in the Brazil-Malvinas Confluence zone) is regionally confined by the Brazil Current recirculation gyre. The contributions from Subtropical Indian Mode Water (SIMW) increased westward along the Agulhas Corridor, while the contribution from STMW12 decreased. The relatively low contribution from SIMW matches the results of previous studies regarding the influence of these waters in the climatology of the South Atlantic Ocean. However, it cannot be ignored, since the results bring new light to further investigations of the mixing processes in the ocean interior of the South Atlantic Ocean. •The sources of South Atlantic Central Water (SACW) are investigated.•The contribution of the STMW14 to the SACW is regionally confined by the Brazil Current recirculation gyre.•The relative contribution of the AAIW and the SIMW to the SACW increases from east to west.•The influence of the SIMW in the climatological structure of the SACW is relatively small but not negligible.