(ORDO NEWS) — The Brunt ice shelf in Antarctica began to move more actively after the calvation of iceberg A-81 occurred at the end of January 2023. According to observations published in the journal Cryosphere , the rate of seaward movement of the shelf is about 4 m (13 ft) per day, compared to the previous average speed of 1-2.5 m (3-8 ft) per day.
The Brunt Shelf is one of the best studied ice shelves in the world due to its complex glaciological structure and unpredictable scour events. However, the researchers believe climate change was not a significant factor in the recent acceleration. Instead, the loss of connection between the ice shelf and the seafloor in an area known as the Macdonald Ice Mounds, caused by the A-81 iceberg rupture, played a major role in increasing the movement.
Over the past 67 years, connectivity to the seafloor has helped stabilize the Brunt Ice Shelf since its first occupation and instrumental survey. It is now moving at speeds typically seen on ice shelves fed by fast-flowing outlet glaciers, such as the Thwaites Glacier in West Antarctica.
To closely monitor the situation, British Antarctic Survey (BAS) scientists have placed GPS equipment on the ice and are using satellite data. These observations help plan operational work at the Halley Research Station, located on the most stable part of the Brunt Ice Shelf, approximately 20 km from the new ice front.
In 2016, BAS took precautionary measures by moving the Halley research station 23 km inland from the crack (Chasm-1) that eventually led to the fracture of iceberg A-81. Halley Research Station is currently closed for the Antarctic winter and its staff are absent. However, BAS task forces are already planning a normal field season on Halley, with a 40-person team due to fly to the Brunt Ice Shelf in November 2023.
During the field season, the team will focus on maintaining power sources and equipment to enable scientific experiments to be conducted remotely throughout the winter. Their work will continue until the aircraft are collected in February 2024.
Professor Dominic Hodgson, a glaciologist at BAS who has been studying the Brunt Ice Shelf for more than a decade, acknowledges the dynamic nature of the situation. He says: “We expected the ice shelf to respond to the A-81 washout. We are monitoring the acceleration and conducting further experiments to determine if and when the ice shelf will regain contact with the seafloor. This would be indicated by a stabilization or reduction in ice speed.” shelf, which we will be able to record in real time.”
Hodgson stresses the importance of monitoring the ice shelf to ensure the safety and continuation of scientific research on Halley. Efforts by BAS and others will provide valuable insights into the behavior of ice shelves and their response to swelling events.
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