Gliders, drifters and Argo floats, as well as a tall mooring, a Triaxus and a CTD rosette are being deployed during the ACC-SMST campaign to investigate why the planet’s strongest current that helps keep the Antarctic continent frozen is leaking warm water into the polar seas.
Three autonomous deep-sea ocean gliders will be deployed. They travel up and down the water column to a depth of 1000m and can navigate against and across the current. This enables them to detail the structure of the current. The gliders surface to transmit data and receive piloting instructions. They will be deployed for six months, sampling the ocean continuously over an area 180 kilometres north to south and an even greater distance west to east. One glider belongs to CSIRO and two to the California Institute of Technology. Once deployed, a team of pilots in Hobart (CSIRO), Pasadena (California Institute of Technology) and New York (Brown University) will manage the gliders for six months.
The 3.6km high tall mooring will be anchored by three 1-tonne anchors in the centre of the research area for 18 months. The ship with conduct experiments with other monitoring equipment around the tall mooring which is equipped with floats and 35 instruments. While the mooring is fixed, the instruments will measure the currents, temperature, salinity and oxygen continuously and capture data every 10 minutes for the 18 months.
The Triaxus is towed behind RV Investigator and has wings that allow an operator on board the ship to pilot it through the water, profiling the water to a depth of 300m. New instrumentation from Woods Hole Oceanographic Institution will provide data on the microstructure of the water, measuring velocity, temperature, salinity and turbulence. The Triaxus will be guided to coincide with the satellite as it passes overhead, to validate and complement the ocean data with satellite data.
Fifteen drifters will be deployed and will float freely with the ocean surface providing information on current trajectories and ocean dynamics, calibrated against satellite data.
Drifters deployment from R/V Investigator during the ACC-SMST campaign. Credit: Amelia Pearson.
Six Argo floats will be deployed. All six will measure temperature, salinity, dissolved oxygen and other biochemistry as they drift with currents. Three will also measure turbulence, or microstructure, of the current.
The conductivity, temperature and depth (CTD) rosette can reach the bottom of the ocean and will be deployed 130 times during the voyage. As well as measuring the current, it measures temperature, salinity, oxygen, nutrients, fluorescence, dissolved carbon and takes water samples for further analysis. Scientists will analyse for carbon absorption by the ocean and the diversity of phytoplankton.
Preparing the CTD Rosette aboard the R/V Investigator during the ACC-SMST campaign.
Learn more about the ACC-SMST campaign.