A team of researchers has announced that their unmanned submarine captured detailed images of an underwater glacier, but the vehicle has since gone missing.
Earlier this January, scientists from the University of Gothenburg in Sweden revisited the Dotson Ice Shelf in Antarctica. They aimed to replicate initial surveys conducted in 2022 by deploying an underwater drone named ‘Ran’ beneath the Dotson ice shelf in West Antarctica.
The Dotson ice shelf, a floating sheet of ice connected to a landmass between Martin Peninsula and Bear Peninsula, was initially mapped by the US Geological Survey in January 1947 using aerial photographs.
The University of Gothenburg’s team has employed advanced underwater technology for mapping the ice shelf. The drone, Ran, was equipped to scan the ice above using “an advanced sonar system,” according to the university’s website.
Ran was tasked with diving into the cavity of the Dotson ice shelf. It remained underwater for 27 days, covering over 1,000 kilometers back and forth under the glacier, and 17 kilometers into the cavity.
The mission yielded significant results.
The underwater drone successfully produced the “first detailed maps of the underside of a glacier.”
The images revealed “new patterns on the glacier base,” indicating that the surface “is not smooth but features a landscape with peaks, valleys, plateaus, and formations resembling sand dunes.”
“The researchers hypothesize that these may have been formed by flowing water under the influence of Earth’s rotation,” the study added.
The mapping also indicated that the glacier “melts faster where strong underwater currents erode its base.”
“Using the submersible, scientists were able to measure the currents below the glacier for the first time and prove why the western part of Dotson Ice Shelf melts so fast. They also see evidence of very high melt at vertical fractures that extend through the glacier.”
Detailed maps of a glacier’s underside are critical for providing “clues to future sea level rise.”
Anna Wåhlin, Professor of Oceanography at the University of Gothenburg and lead author of the study, explained that teams have “previously used satellite data and ice cores to observe how glaciers change over time.”
However, using the underwater drone allowed them “to get high-resolution maps of the ice underside,” which she described as “a bit like seeing the back of the moon.”
Karen Alley, a glaciologist from the University of Manitoba and co-author of the study, said the maps created by Ran “represent a huge progress in our understanding of Antarctica’s ice shelves” and offer “a more extensive and complete picture than ever before.”
Wåhlin highlighted that there aren’t “many uncharted areas left on Earth,” making Ran’s exploration of the depths below the ice even more thrilling. Unfortunately, the expedition also resulted in Ran going missing.
Wåhlin stated, “Experience from over 40 missions below ice gave us confidence but in the end the challenging environment beat us,” she said.
Despite Ran’s disappearance, the data collected from the mission has provided researchers with “a lot of new data” to examine more closely.
Wåhlin concluded, “It is clear that many previous assumptions about melting of glacier undersides are falling short. Current models cannot explain the complex patterns we see. But with this method, we have a better chance of finding the answers.”
“Better models are needed to predict how fast the ice shelves will melt in the future. It is exciting when oceanographers and glaciologists work together, combining remote sensing with oceanographic field data. This is needed to understand the glaciological changes taking place – the driving force is in the ocean.”
“[…] Although we got valuable data back, we did not get all we had hoped for. These scientific advances were made possible thanks to the unique submersible that Ran was. This research is needed to understand the future of Antarctica’s ice sheet, and we hope to be able to replace Ran and continue this important work.”