WHOI PO

The distribution of intermediate water masses in the Southwestern Indian Ocean is a key indicator of basin-wide ocean circulation.However, our knowledge remains limited because in situ observations in this area have historically been sparse. In this talk, I present my PhD research leveraging data from the Korean Indian Ocean Study (KIOS) project, underway since 2017. KIOS combines regional-scale repeat hydrographic surveys with acontinuous subsurface mooring located at the Seychelles-Chagos Thermocline Ridge near the Mascarene Plateau. The time series reveals pronounced property shifts in the intermediate layer, characterized by distinct decreases in salinity and spicity in recent years. Complemented by Argo float observation, an Optimum Multiparameter analysis is used to evaluate the contributions of the salty Red Sea Overflow Water, the fresher Indonesian Intermediate Water and Antarctic Intermediate Water, the three water masses that compose the intermediate layerin the Indian Ocean. The results illustrate how the relative influences of these three water masses have shifted across the KIOS observational period. This talk covers ongoing work for my second thesis chapter, and I look forward to your questions and feedback.