Scientists Propose Network of Autonomous Vehicles to Observe Ocean Surface

A new paper from an international team of more than 50 researchers, including four from UC San Diego’s Scripps Institution of Oceanography, proposes the creation of a global observing network of autonomous vehicles roving the ocean surface. Such a network of so-called uncrewed surface vehicles (USVs) could transform how scientists understand the critical boundary layer where the ocean meets the atmosphere, ushering in improvements in weather forecasting, climate research and marine ecosystem monitoring.

The proposed network of USVs would be analogous to the Argo network of roughly 4,000 drifting robotic floats that are focused on collecting data from the ocean’s interior.

“Argo provides an incredible view of the ocean interior. Now we are trying to do that for the air-sea interface,” said Luc Lenain, co-author of the study and director of Scripps’ Air-Sea Interaction Research Laboratory. “We feel the technology is there and these vehicles are ready to make a huge contribution to science.”

The study, published March 6 in Frontiers in Marine Sciences, also compiles research showing how USVs are currently being used to collect data and the diversity of designs and technologies that enable these capable machines.

The ocean surface is the site of important exchanges of energy and chemistry between the ocean and the atmosphere. 

“The weather that disrupts our lives and waters our crops often originates from interactions between the atmosphere and the ocean,” said Sarah Gille, co-author of the study and a physical oceanographer at Scripps. “Understanding air-sea interactions is key for improving our ability to forecast extreme weather to enhance public safety and protect property.”

But despite its importance, this boundary between the air and sea is not regularly observed in detail – especially in regions that are remote or perilous. 

Current observation systems struggle to capture the complex, rapidly changing dynamics at the ocean surface. Buoys and fixed moorings are too sparse or, in the case of Argo, are not focused on the ocean surface; ships are not cost-effective for remote locations and can be unsafe for crew in stormy seas; and most satellites are not well positioned to observe small-scale, fast-moving processes. This data gap hampers scientists’ ability to forecast severe weather, understand climate change and track carbon dioxide uptake by the oceans.

USVs, by contrast, can be powered by the sun and can utilize wave and wind energy for propulsion, allowing them to remain at sea for long periods of time and return themselves to port if they are in need of repairs. USVs can simultaneously measure dozens of variables while traversing thousands of kilometers (hundreds of miles) of open ocean or operate in hurricanes and near sea ice where traditional methods struggle, all while transmitting high-resolution data in near real-time. 

Lenain’s lab operates a fleet of USVs called Wave Gliders – named for their use of wave energy for propulsion – with sensors to record troves of data on the wind, waves and weather at the sea surface. For Lenain and other researchers interested in studying interactions between air and sea, the smaller physical profile of the Wave Gliders offers practical advantages for collecting these data compared to ships. 

“The form factor of a large research vessel creates wind and wave interference, which reduces the accuracy of our measurements,” said Lenain. “The smaller size of our Wave Gliders reduces that interference, and improves the quality of our data.”  

Beginning in 2022, the research team behind this paper conducted a review of 200 datasets collected via USVs and 96 scientific studies from the past decade to evaluate the capabilities and potential of these autonomous platforms. The authors created maps using data from USV manufacturers and researchers to show where these sea-faring robots have been used to observe the sea surface and where they have yet to venture. 

The analysis revealed that USVs have successfully measured 33 different variables spanning physical, biogeochemical, biological and ecological processes at the ocean-atmosphere boundary. 

“This paper shows the potential value of a global scale network of uncrewed surface vehicles to observe and characterize the complex interactions that occur between the ocean and the atmosphere,” said Lenain. “The technology is ripe for this and there is a strong scientific need for these observations, especially in the high latitudes and remote parts of the ocean.”

The authors argue that creating a global USV observation network would significantly enhance humanity’s ability to forecast severe weather events, improve climate models, monitor carbon dioxide uptake by the oceans and support interdisciplinary marine research.

The team is now working to secure an endorsement from the UN Ocean Decade program and the Global Ocean Observing System. Lenain indicated that an endorsement from the Global Ocean Observing System would be an important stamp of approval for the proposed USV observing network as the researchers behind the proposal begin to seek funding. 

“Observing systems like this are funded through contributions of multiple countries,” said Gille. “This paper provides a baseline for conversations in each country about where they can make sensible and meaningful contributions.”

Other next steps include developing international standards for data collection and sharing, building partnerships between scientists, data managers and USV manufacturers, as well as developing a legal framework for operating autonomous vessels in international waters. 

Verena Hormann and Laurent Grare of Scripps Oceanography also co-authored the study.