Saildrone Completes First Autonomous Circumnavigation of the Southern Ocean

A Saildrone unmanned surface vehicle (USV) completed the first autonomous circumnavigation of the Southern Ocean on August 3, 2019, delivering an unprecedented set of in-situ data collected during the 196-day journey. The Saildrone USV, known as SD 1020, carried ASVCO2 and ADCP sensors to measure atmospheric and dissolved pCO2 (carbon flux), dissolved oxygen, water temperature, and pH, and the speed and direction of ocean currents, in addition to the standard sensor suite, which collects a variety of variables including wind speed and direction, sea surface temperature, chlorophyll, and salinity.

Saildrone (SD 1020) approaching Point Bluff, New Zealand in stormy conditions after finishing the first Saildrone Antarctic Circumnavigation.

The mission was launched from Southport in Bluff, New Zealand, on January 19, 2019, and returned to the same port after sailing over 11,879 nautical miles (22,000 km) around Antarctica. During the mission, the vehicle survived freezing temperatures, 15-meter waves, 130 km/h winds, and collisions with giant icebergs.

Saildrones are built to perform in the harshest ocean conditions on the planet. They are seven meters long with a five-meter-tall carbon composite wing and are powered exclusively by the wind for forward propulsion and solar to run the onboard sensors, computers, and cameras. SD 1020 was deployed with a shorter “square” wing designed especially for conditions in the Southern Ocean: 15-meter waves, 130 km/h winds, and icebergs.

Saildrones (SD 1022 and SD1023) being deployment to the Southern Ocean with shorter "square" wing design.

Over the course of the mission, SD 1020 rendezvoused with profiling floats, which are part of the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) project, and moored buoys to take reference measurements.

“These crossovers provide great opportunities for validation and context between two very different and complementary datasets. Sustaining both of these types of observations will be extremely helpful for improving our understanding of the Southern Ocean’s role in the global carbon budget and I can’t wait to dive into this new dataset,” said Nancy Williams, Assistant Professor at the University of South Florida College of Marine Science.

Mission map showing completed Antarctic Circumnavigation track.

Data from the mission is available to the scientific community in NetCDF format on Saildrone’s new data portal, (DSC). Scientists and researchers to download and analyze this data set. To download hourly and minutely data, users will be required to complete a free registration form; daily data is available without registration.

To learn more, visit

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