NYC Gazette

An autonomous underwater vehicle, deployed by an international research team to monitor a glacier in Antarctica, has yielded the first detailed maps of the underside of an ice shelf, revealing clues to future sea level rise.

The findings are reported in the journal Science Advances.

“We have previously used satellite data and ice cores to observe how ice shelves change over time,” explains Anna Wåhlin, a professor of oceanography at the University of Gothenburg and the paper’s lead author. “By navigating the submersible into the cavity, we were able to get high-resolution maps of the ice underside. It’s a bit like seeing the back of the moon for the first time.”

“Our ability to project the future of the global coastline from rising sea levels in a warming world critically depends on data we obtain from beneath Antarctic ice shelves,” adds David Holland, a professor at New York University’s Courant Institute of Mathematical Sciences and one of the paper’s authors.

The scientists programmed Ran, an autonomous underwater vehicle, to dive into the cavity of Dotson Ice Shelf, 350 meters thick and located in West Antarctica, and scan the ice above it with an advanced sonar system. Dotson Ice Shelf is considered to have a potentially large impact on future sea level rise due to its size and location.

Over 27 days, the submarine traveled more than 1,000 kilometers (620 miles) back and forth under the glacier, reaching 17 kilometers (10.5 miles) into the cavity in order to capture phenomena surrounding it.

Using data captured by Ran, scientists measured currents below the glacier for the first time and identified why the western part of Dotson Ice Shelf melts so quickly. Ran’s maps showed that strong underwater currents erode its base rapidly and that there is very high melt at vertical fractures extending through the glacier.

However, findings also revealed new patterns on the glacier base that raise troubling questions. The base is not smooth but features peaks and valleys with formations resembling sand dunes. Researchers suggest these may have been formed by flowing water influenced by Earth’s rotation.

“Earth’s rotation is critical to understanding most phenomena in the climate system, notably hurricanes and other severe-weather phenomena,” says Holland. “It seems these exotic under-ice features are also intimately controlled and shaped by Earth’s spinning.”

“The maps that Ran produced represent huge progress in our understanding of Antarctica's ice shelves,” adds Karen Alley, a glaciologist from the University of Manitoba and co-author of the paper. “We’ve had hints of how complex ice-shelf bases are, but Ran uncovered a more extensive picture than ever before."

Much fieldwork for this study was conducted in 2022 when Holland led a team to install a mooring beneath Dotson Ice Shelf using innovative engineering techniques involving drilling through ice with hot water drills. This allowed continuous data collection over two years.

“For the first time, we combined data collected from an autonomous underwater vehicle sampling at one point in time but covering a large area under an ice shelf with data from a mooring installed through hot water drilling,” notes Holland. “These dual methods provided spatially comprehensive yet temporally continuous data.”

The research was supported by grants from entities including The National Science Foundation.

Additional media contact:

Anna Wåhlin

Professor of Oceanography at University of Gothenburg

+46 (0)766-18 28 66

anna.wahlin@marine.gu.se