Exploring the Arctic Ocean with sailing robots

The Arctic Ocean is changing rapidly as the planet warms, but studying it presents challenges: it’s a remote area that is often covered by sea ice. As CHELLE GENTEMANN, MARISOL GARCÍA-REYES and JORGE VAZQUEZ-CUERVO explain, using autonomous solar-powered sailing robots is a safe, reliable and climate-friendly way to collect the data we need.

Here’s a scientist’s perspective on seasons in the Arctic Ocean: Sea ice covers the surface all winter, presenting research challenges. Spring brings a retreat of the ice and an opportunity to collect some data in ice-free areas. And summers are short and bright, with more open water—the perfect time to send solar-powered autonomous sailing robots, called Saildrone Explorers, out to sea to collect valuable data.

Small and agile, these robots can go where large research vessels cannot, and they can take continuous measurements for long stretches of time. From your office, a café or a couch, you can receive real-time data from the Arctic Ocean, and even change the course of the saildrone if need be. In fact, an international team of scientists is using this data right now to improve our understanding of climate change.

Saildrone Explorers are zero-emission research platforms that move around using vertical sail-like “wings” at speeds of up to 1.25 metres per second. The seven-metre narrow hull has a hard sailing wing five metres tall and a keel with a 2.5 metre draft, and weighs approximately 750 kilograms. Solar panels set into the vertical wings and hull capture energy. A battery stores the energy and powers the 16 science-grade instruments and navigation equipment. An onboard computer and antenna transmit data in real time through satellite connectivity, allowing scientists to adjust sampling patterns as interesting features present themselves.

Exploring the marginal ice zone

In 2019, a joint National Aeronautics and Space Administration (NASA) and National Oceanic and Atmospheric Administration field campaign sent five saildrones to the Arctic for 150 days. That was also the first time the saildrones were sent to the marginal ice zone. From Dutch Harbor, Alaska, the saildrones navigated north, following the retreat of the sea ice, through the Yukon River outflow plume, the Bering Strait and into the Arctic Ocean.

During the 2019 cruises, one of the saildrones stumbled into Arctic ice—literally—and we ended up with better data than we expected.

Exploring the marginal ice zone—the dynamic region between the open ocean and the sea ice edge—was always part of the plan for this cruise. Most Arctic wildlife is found in this narrow zone full of nutrients, where conditions in both the ocean and atmosphere change rapidly. However, running straight into this zone was not what we had planned.

The saildrones were carrying cameras that sent images back every six hours. From an armchair in California, the “edge” of the sea ice looked very clear on the satellite image: the saildrones appeared to be in the clear, miles away from any ice. But in reality, they weren’t following our directions and seemed to be just drifting. The next thing we saw in the downlinked images was one of the saildrones surrounded by sea ice.

After we noticed what had happened, we directed the four other saildrones in the opposite direction. Eventually, we were also able to guide the ice-enclosed saildrone to join them. We had to wait a little while, hoping it would drift out of the ice. Once we saw that we had steerage ahead for the open ocean, we sent the errant saildrone forward as fast as it would go.

It was a bit suspenseful, but we ended up obtaining data about the margins of the ice that would have been hard to get had the saildrone not ventured so close to it.

Sharing the data

The cruise ended in October 2019, and then we shifted to studying the data. To make sure anyone could use the data, we released it freely and publicly.

Since then, many articles and publications have made use of the data to advance our understanding of the Arctic Ocean and its connection to our weather and climate. Scientists have examined the upper ocean using these unique observations to look at how ocean currents, salinity and temperature shape Arctic climate dynamics. The accuracy of model and operational weather forecasts have been studied as a first step to understanding how to improve them.

All the satellite data, along with the Saildrone data, remain freely available through NASA’s Physical Oceanography Distributed Active Archive Center (PO.DAAC), allowing for collaboration among all interested scientists.

Saildrone Explorers are an exciting new source of information that we hope will continue to advance our understanding of the rapidly changing Arctic.