Monitoring the Southern Ocean

The main objective of the SURVOSTRAL project is to MONITOR different physical parameters in the AuSTRAL Ocean with long-term hydrological measurements. SURVOSTRAL started in 1992-1993, and since then the ocean heat content in the first 800 m and the surface salinity have been measured regularly on a repeated line (6-10 times a year) between Tasmania and Antarctica. These measurements form the longest time series of seasonal and interannual variations of these parameters in the Southern Ocean, and are therefore a key value for quantifying oceanic changes in this key climate region.

The overall objectives are as follows:
– A monitoring of the seasonal, interannual and decadal variability of the heat content of the Southern Ocean and its response to changes in atmospheric heat fluxes.
– A study of surface salinity and its relationship with the freshwater balance in the Southern Ocean.
– Study of the transport and structure of the Antarctic Circumpolar Current (ACC).
– Study of the variation of the different thermal and haline fronts.
– Study of the role of oceanic eddies in the flow of mass, heat and salt through the CCA.

The SURVOSTRAL project uses the regular rotations of the supply vessel ASTROLABE between Hobart and Terre Adélie. This transit enhancement program is based on high spatial resolution XBT and thermosalinograph measurements. Participating in this project supported by IPEV: LEGOS (France), CSIRO (Australia) and the Scripps Institution of Oceanography (USA). SURVOSTRAL is currently integrated into CLIVAR and the scientific valorisation is financed by TOSCA (CNES).