~600,000 CTD hydrographic profiles from 45°S across the circumpolar Southern Ocean from 2004-2021, including Argo, MEOP, SOCCOM, and WOD18 data (ship-based CTD and gliders). Includes data only flagged as good and under ice. We follow the QC described in Wison et al. (2019) such that we remove profiles that do not capture upper ocean and surface layer processes, largely removing data from transecting seals (MEOP). Subsequently, hydrographic profiles are vertically interpolated to 2dbar bins. If you use these data, please cite it in either the data section or acknowledgements. Please also consider citing the following paper, which gives a description of the data processing, distribution, and an example of usage (water mass identification): https://doi.org/10.1029/2024JC021017