![]() ![]() It broke into parts with the mother berg dubbed A-68A. The name "A-68" was assigned by the US National Ice Center. Historical data shows that many icebergs that break off from the Antarctic Peninsula reach South Georgia and the South Sandwich Islands. The calving of A-68 reduced the overall size of the Larsen C shelf by 12 percent. With a surface area of 5,800 square kilometres (2,200 sq mi), twice the size of Luxembourg, over a quarter the size of Wales, and larger than Delaware, it was one of the largest recorded icebergs, the largest being B-15 which measured 11,000 square kilometres (4,200 sq mi) before breaking up. By 16 April 2021, no significant fragments remained. Iceberg A-68 was a giant tabular iceberg adrift in the South Atlantic, having calved from Antarctica's Larsen C ice shelf in July 2017. Iceberg A-68 on 20 July 2017 The drift of Iceberg A-68A from 1 May 2018 to 26 August 2018 We will be using the capabilities of the Copernicus Sentinels to closely monitor the behaviour and stability of the remaining Brunt Ice Shelf.Antarctic iceberg from the Larsen C Ice Shelf in July 2017 A-68A on 18 November 2020 “A typical accompaniment to such strain release events and removal of pinning of an ice shelf front by bottom features such as McDonald Bank which forms the McDonald Ice Rumples may be an acceleration in the velocity of ice flowing into the ice shelf. Mark explained, “The calving of iceberg A74, and latest separation, now focuses attention back onto the Halloween crack – whose extension could contribute to further destabilisation of the Brunt Ice Shelf. ![]() If Brunt now experiences an acceleration, it could influence the behaviour of other cracks in the area. ![]() The calving of ice bergs from an ice shelf has been observed to be followed by adjustment in the flow of ice into the ice shelf. Spotted by Sentinel-1 imagery, it has already drifted away from the Brunt Ice Shelf into the Weddell Sea. In February 2021, another giant berg, around 1270 sq km, broke off from the northern section of Brunt. Routine monitoring from satellites offers unparalleled views of events happening in remote regions and show how ice shelves are actively responding to changes in ice dynamics, air and ocean temperatures. Our science and operational teams continue to monitor the ice shelf in real-time to ensure it is safe, and to maintain the delivery of the science we undertake at Halley.” Meanwhile the combination of summer images from Sentinel-2 and availability of year-round and winter monitoring by Sentinel-1 radar placed the pattern of strain and propagation of an ice shelf fracture under the worldwide public microscope.”ĭominic Hodgson, BAS glaciologist, added, “This calving event has been expected and is part of the natural behaviour of the Brunt Ice Shelf. “Thanks to Copernicus, coupled with in-situ and airborne measurements made by the British Antarctic Survey, the safety of the Halley Base has been preserved. The northward propagation of Chasm 1 and timely decision for BAS to move the Halley Base to safer ground have been accompanied by what has been perhaps the most detailed and longest duration scrutiny of events leading to natural calving from an Antarctic ice shelf. The station is currently around 20 km from the line of rupture and there are currently 21 staff working on the station to maintain power supplies and facilities that keep the scientific experiences operating throughout winter.ĮSA’s Mark Drinkwater said, “After several years of iceberg calving watch, the long-awaited separation of the Brunt iceberg A-81 has finally taken place. The research station was relocated in 2017 to a more secure location after the ice shelf was deemed unsafe. BAS’s Halley VI Research Station, where glaciologists have been monitoring the behaviour of the ice shelf, has remained unaffected by the calving event. The split was first reported by the British Antarctic Survey (BAS) as having occurred on 22 January between 19:00 and 20:00 UTC during a spring tide. Icebergs are traditionally identified by a capital letter indicating the Antarctic quadrant in which they were originally sighted, followed by a sequential number, then, if the iceberg breaks into smaller pieces, a sequential letter suffix. The new iceberg is anticipated to be named A-81 with the smaller piece to the north likely identified as either A-81A or A-82. It was only a matter of time that Chasm 1, which had been dormant for decades, would meet with the Halloween Crack, first spotted on Halloween 2016. Glaciologists have monitored the many cracks and chasms that have formed in the thick Brunt Ice Shelf, which borders the Coats Land coast in the Weddell Sea sector of Antarctica, for years. The timing of the calving event, although unexpected, had long been anticipated. Radar images capture new Antarctic mega-iceberg ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |