NZ scientists awed at buoys' 6500km, year-long journey

The buoys being deployed from Niwa research vessel RV Tangaroa last February. Photo / MetOcean Solutions

Solar-powered wave buoys dropped in the world's strongest ocean current have drifted an incredible 6500km in just a year, wowing Kiwi oceanographers.

In February 2018, MetOcean Solutions deployed five solar powered wave buoys – called Spotters - in the Southern Ocean as part of a collaboration with Spoondrift and the Defence Technology Agency.

A year later, these buoys have travelled more than 6500km and were currently crossing the stormy waters of the Drake Passage, the body of water between South America's Cape Horn and the South Shetland Islands.

The Southern Ocean programme was helping understand waves in the region and their impact on the climate system.

"The buoys were deployed in the Southern Ocean, home to the strongest current on Earth; the Antarctic Circumpolar Current," said the operation's leader, MetOcean Solutions' technical support liaison Dr Aitana Forcén-Vázquez.

"The Southern Ocean is the circular ocean that flows uninterrupted around Antarctica and occupies almost one quarter of all the world's oceans.

"It plays an important role in the climate system, cycling heat, carbon and nutrients. Persistent storms and the lack of landmass in the Southern Ocean result in large fetches and strong winds - ideal conditions for generating large waves."

MetOcean Solutions' science development manager Dr Tom Durrant said the waves generated in this region had far reaching effects, contributing significantly to the wave climate in all the major ocean basins.

"The New Zealand West Coast, for example, is periodically battered by large swell systems generated in Southern Ocean storms."

It was the first time that this kind of wave buoy has been deployed in the Southern Ocean.

Scientists saw it as the perfect scenario to test the response of this new technology in an energetic open ocean.

This map illustrates the buoys' 6500km drift across the bottom of the world. Image / MetOcean Solutions

If effective, they could revolutionise the way we monitored remote ocean basins through a constellation of drifting buoys.

"These buoys are surprisingly easy to deploy, very light and easy to handle, and can be lowered into the water by hand using a line," Forcén-Vázquez said.

"As a result, you can deploy them in almost any kind of conditions, which greatly facilitates Southern Ocean operations."

Spoondrift developed the Spotter buoy as a citizen sensor to drive distributed ocean sensing and democratised data access.

"The Spotter buoy is designed to be easy to use, low-cost and solar-powered," Spoondrift chief executive Tim Janssen said.

"From the Spotter Dashboard the user can access data and change settings on the device.

The current generation Spotters have a battery protection feature that triggers a hibernation mode during extreme temperatures and extended periods of darkness in the Southern Ocean winter.

"Spoondrift continuously innovates its technology to simplify deployments and provide high-latitude options to ensure continuous data acquisition in extreme conditions."

In addition to the five drifting buoys, MetOcean operated the world's southernmost open ocean moored buoy which last year recorded the highest wave – climbing a massive 23.8m high - in the Southern Hemisphere.