Changes in the Southern Ocean over the last two decades from Argo float measurements

The Southern Ocean (SO) plays a crucial role in connecting all the world's oceans through the Antarctic Circumpolar Current (ACC). Global ocean circulation is also affected by processes in the Southern Ocean that change the density and subduction rate of water. Argo has provided consistent and basin-wide coverage of this region over the past two decades, enabling analyses not possible with the sparse and episodic ship-based observations available earlier. This study uses the Argo float  dataset collected between 2004 and 2025  along the ACC. The data was gridded and processed using the pseudoeulerian approach; the full dataset and decadal differences were obtained for 18 sections of the SO. We will present the spatial variability of water masses in the Southern Ocean, highlighting their decadal and interannual variability and the associated large-scale spatial gradients relevant to Southern Ocean dynamics. The use of Argo float observations provides unprecedented details for examining the spatial and temporal evolution of density patterns resulting from salinity and temperature changes, with important implications for global ocean circulation and climate.