Sustained Observation of the Southern Ocean

The Sustained Observation of the Southern Ocean (SO-SO) project addresses critical observational gaps in monitoring the Southern Ocean’s role in regulating global climate. This region accounts for approximately 70% of the excess heat absorbed by the world’s oceans annually and exerts a profound influence on atmospheric CO2 concentrations, yet remains one of the most poorly observed and understood components of the Earth system. SO-SO will establish a comprehensive, multi-parameter observational framework along the transects of the French icebreaker Astrolabe, which supplies the Antarctic base Dumont d’Urville five times annually. Building on the legacy of previous successful IPEV programs (SURVOSTRAL, MINERVE, and SOCISSE), SO-SO will unify the Astrolabe’s temperature, salinity, carbon, and water stable isotope measurements into a coherent scientific framework to study the interdependence of the heat, carbon, and freshwater cycles. This integrated approach will enable unprecedented insights into how these parameters covary across spatial scales (from mesoscale to basin-wide) and temporal scales (from seasonal to multidecadal). The project contributes to French national observing services (SNO SSS and SNO COOL) and international programs including WOCE/CLIVAR, GOSUD, SOCAT and GOA-ON, strengthening international collaboration between French, Australian, and US partners. SO-SO will also represent a French contribution to the international Antarctica InSync program to be carried out in 2027-2030, a regionally endorsed action of the United Nations Decade of Ocean Science for Sustainable Development (2021-2030).