Underwater robot provides first detailed 3-D maps of Antarctic sea ice

A team of scientist has developed first detailed, high-resolution 3-D maps of Antarctic sea ice using an underwater robot.

Scientists from the UK, USA and Australia say the new technology provides accurate ice thickness measurements from areas that were previously too difficult to access.

Measurements made on the sea ice by drilling holes, together with visual observations from ships are critical for building a more complete picture, making it difficult to get access to thicker areas of sea ice that leaves gaps in the data, but now, with the Autonomous Underwater Vehicle (AUV) known as SeaBED, scientists have an invaluable new tool to fill this gap.

While most oceanographic survey instruments look down at the seafloor, SeaBED was fitted with upward-looking sonar in order to measure and map the underside of sea ice floes.

The AUV operated at a depth of 20 to 30 meters and was driven in a lawnmower pattern and these lines of data were merged to form high-resolution 3D bathymetric surveys of the underside of the ice.

Researcher Hanumant Singh said that putting an AUV together to map the underside of sea ice is challenging from a software, navigation and acoustic communications standpoint.

Singh added that SeaBED's maneuverability and stability made it ideal for this application where we were doing detailed floe-scale mapping and deploying, as well as recovering in close-packed ice conditions.

Co-author Dr Guy Williams said that the full 3-D topography of the underside of the ice provides a richness of new information about the structure of sea ice and the processes that created it, which is key to advancing their models particularly in showing the differences between Arctic and Antarctic sea ice.

The results are published in the journal Nature Geoscience.