Madrid. Following the calving of the 1,500 square kilometer iceberg A-81 at the end of January 2023, the Brunt Ice Shelf is moving faster than before.
Currently it moves about 4 meters per day towards the sea, while before the landslide it moved at an average of between one and 2.5 meters. The observations were presented this week by the BAS (British Antarctic Survey) to the magazine The Cryosphere.
The Brunt is one of the most studied ice shelves in the world. Its glaciological structure is complex and the impact of landslides is often unpredictable. Researchers believe that climate change has not played a significant role in the recent acceleration of that frozen piece.
It has accelerated due to the loss of its connection to the seabed in an area known as McDonald Ice Rumples, following the calving of iceberg A-81. This connection helped stabilize the ice shelf for most of the past 67 years since it was first occupied and instrumented. It is now moving at a pace normally only measured on ice shelves fed by exceptionally fast-flowing outlet glaciers, such as Thwaites in West Antarctica.
BAS scientists are closely monitoring the situation using GPS equipment deployed on the ice and satellite data. The tracking information is used to assist operational planning at Halley Research Station, located in the most stable part of Brunt, 20 kilometers from the new ice front. In 2016, they took the precaution of relocating the research center 23 kilometers inland from the fissure (Abyss-1) that finally caused iceberg A-81 to break off, after it began to widen.
Field season will begin in November
Halley remains closed during the Antarctic winter and is currently unstaffed. BAS operations teams are planning a routine field season at the station with a team of 40 flying to the Brunt Ice Shelf in November. They will spend the season maintaining power supplies and will operate the facilities where scientific experiments are done remotely during the winter. Their work will continue until they are picked up by planes in February 2024.
BAS glaciologist Dominic Hodgson, part of the scientific team that has been studying the Brunt Ice Shelf for more than a decade, explained in a statement: “It is a dynamic situation. We expected the platform to respond to the release of the A-81. We are monitoring the acceleration and conducting further experiments to determine if and when it will reestablish contact with the sea floor. This will be evidenced by a stabilization or decrease in speed, which we can record in real time. “Our science and operations teams continue to monitor the platform to ensure it is safe and maintain the delivery of the science we carry out at Halley.”
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