29/11/2023
Researchers are using machine learning to analyze satellite radar data to identify icebergs in the Southern Ocean around Antarctica to better understand their life cycle and environmental impact.
Icebergs may seem exotic and far away, but as anyone who has seen the Titanic will tell you, they can have a profound effect on us when we least expect it. Just last week, the world's largest iceberg, called A23a, which is more than twice the size of Greater London, broke free from the seabed after nearly three decades aground and is drifting north in the Antarctic Ocean. Meanwhile, many thousands of smaller icebergs are constantly breaking off from the Antarctic ice shelf and floating into the sea.
The effect of all these icebergs is not only that they pose a danger to shipping. As they melt over decades, they release cold fresh water and nutrients that can alter local ecology, as well as the complex dynamics of ocean circulation, sea ice collapse, and even global sea levels.
The problem is that all those chunks of ice bobbing around like a giant mint julep are so numerous and moving so erratically that they're hard to identify, much less track. To help with this, a team of scientists funded by the Alan Turing Institute used the Synthetic Aperture Radar (SAR) from ESA's Sentinel-1 satellites, which can scan icebergs day and night in all weather conditions.
The radar data is not new, but it uses an unsupervised artificial intelligence algorithm to analyze readings collected between October 2019 and September 2020, which revealed nearly 30,000 icebergs of about 1 km² (0.4 mi²) or less in the Amundsen Sea at to the west Antarctica at the calving front of Thwaites Glacier.
It is hoped that by accurately detecting and tracking icebergs, it will be possible to create a digital counterpart of the Antarctic sea, leading to a better understanding of the complex physics of how the ocean, ice and atmosphere interact with each other.
"The technology we used to develop this instrument is already quite widely used in medical imaging, so we are excited to apply the same technology to the complex features seen in SAR satellite images of the polar oceans," said Ben Evans of British Antarctic Survey. Survey (BAS) AI Lab: “The method we used is as accurate as other alternative iceberg detection methods, and outperforms most of them, without the need for human intervention. This means it can be easily scaled beyond our research and even provide near-real-time monitoring.”
