Saildrone autonomous vessel begins Southern Ocean carbon survey
An uncrewed, wind-powered Saildrone has embarked on a 22,000km circumnavigation of Antarctica to collect critical data on ocean and atmospheric carbon.
An autonomous orange vessel, resembling a large kayak, has left Hobart on a 22,000km journey around Antarctica to monitor carbon dioxide. The seven-metre, uncrewed craft is propelled by powerful westerly winds and solar energy on a mission expected to last seven to nine months.
Dr Elizabeth Shadwick, a principal research scientist at the CSIRO, said the vessel would travel east from Hobart towards New Zealand. It will eventually pass through the Drake Passage between South America and Antarctica, then travel past South Africa before returning to its starting point. The route is seven times the distance between Sydney and Perth. The vessel, built by the US maritime company Saildrone, is designed for extreme conditions. It has a heavy keel to keep it upright, a rudder for steering, and a fixed solar sail above the surface. Saildrone monitors it remotely via satellite, checking in regularly and able to nudge it if necessary. The day after deployment, it already encountered eight-metre waves and 35-knot winds. "It’s already been bashed around pretty heavily," Shadwick said. "It’s quite a robust little device." It may also face freezing temperatures, seals, and albatrosses.
Scientific purpose and data collection
The mission aims to measure how much carbon dioxide the Southern Ocean absorbs from the atmosphere. The vessel will collect data on wind speed, atmospheric pressure, solar radiation, ocean temperature, salinity, chlorophyll, and carbon dioxide levels in both water and air. Dr Elizabeth Shadwick notes the ocean absorbs about a third of human-caused emissions every year, with the Southern Ocean playing a significant role. Crewed research vessels only cover a limited area, but this autonomous craft will gather data over a far greater distance and time, including during the polar winter. Scientists can access the information in near real time via a mission portal.
Dr Pep Canadell, a chief research scientist at the CSIRO, provided context on the global carbon cycle. For every tonne of carbon dioxide released by burning fossil fuels, about 500kg were removed by ocean and forest sinks, he said. Understanding future changes to this ocean service is critical. Ocean carbon absorption could be altered by warming waters, shifting westerly winds, melting ice, acidification, and the ozone hole. Tracking carbon uptake helps model these processes and detect any decline. A significant drop in the ocean's absorption capacity would create a larger challenge for global emission reduction efforts.
Fleet expansion and data accessibility
This vessel is the first in a planned fleet of four. The other three are scheduled for launch at three-monthly intervals. The fleet will be deployed across the Southern, Pacific, Atlantic, and Indian Oceans, with a particular focus on winter periods. After the vessel returns, all collected data will undergo thorough quality checks before being archived and made available for further scientific research.
