77°51′33″S61°17′57″W / 77.85917°S 61.29917°W /-77.85917; -61.29917
TheFilchner–Ronne Ice Shelf orRonne–Filchner Ice Shelf is anAntarctic ice shelf bordering theWeddell Sea.
The seaward side of the Filchner–Ronneice shelf is divided into Eastern (Filchner)79°00′S40°00′W / 79.000°S 40.000°W /-79.000; -40.000 and the larger Western (Ronne)78°30′S61°00′W / 78.500°S 61.000°W /-78.500; -61.000 sections byBerkner Island. The whole ice shelf covers some 430,000 km2, making it the second largest ice shelf in Antarctica (and on Earth), after theRoss Ice Shelf. It grows perpetually due to a flow of inland ice sheets. From time to time, when the shearing stresses exceed the strength of the ice, cracks form and large parts of the ice sheet separate from the ice shelf and float off and disperse asicebergs. This is known ascalving.
The Ronne ice shelf is the larger and western part of the Filchner–Ronne ice shelf. It is bounded on the west by the base of theAntarctic Peninsula (Graham Land withZumberge Coast andOrville Coast) andEllsworth Land. CommanderFinn Ronne, USNR, leader of theRonne Antarctic Research Expedition (RARE) in 1947–48, discovered and photographed a strip along the entire northern portion of this ice shelf in two aircraft flights in November and December 1947. He named it the "Lassiter Shelf Ice" and gave the name "Edith Ronne Land" to the land presumed to lie south of it. In 1957–58, the US-IGY party atEllsworth Station, under now Captain Ronne, determined that the ice shelf was larger than previously charted, that it extends southward to preempt most of "Edith Ronne Land". Inasmuch as Capt. James Lassiter's name has been assigned to a coast ofPalmer Land, theAdvisory Committee on Antarctic Names (US-ACAN) approved the name Ronne Ice Shelf for this large ice shelf, on the basis of first sighting and exploration of the ice shelf by Ronne and parties under his leadership. The shelf is therefore named forEdith Ronne, the wife of Finn Ronne and RARE Expedition member.
The Filchner ice shelf is the eastern part of the Filchner–Ronne ice shelf. It is bounded on the west by Berkner Island and on the east byCoats Land. The east part of this shelf was discovered in January–February 1912 by theGerman Antarctic Expedition underWilhelm Filchner. Filchner named the feature forKaiser Wilhelm, but the Emperor requested it be named for its discoverer. The shelf is nourished primarily by theSlessor Glacier, theRecovery Glacier, and theSupport Force Glacier, all located east of Berkner Island.
In 2021,sponges and other unidentified suspension feeders were reported to have been found growing on a boulder under the western margin of the Filchner ice shelf, close to Berkner Island, at a depth of 1,233 m (872 of which were ice), 260 km from open water.[1]
In October 1998, theiceberg A-38 broke off the Filchner–Ronne ice shelf. It had an extent of roughly 150 by 50 km and was thus larger thanDelaware. It later broke up again into three parts. A similar-sized calving in May 2000 created an iceberg 167 by 32 km in extent, dubbed A-43 – the disintegration of this is thought to have been responsible for the November 2006 sighting of several large icebergs from the coast of theSouth Island ofNew Zealand, the first time since 1931 that any icebergs had been observed from the New Zealand mainland. A large group of small icebergs (the largest some 1000 metres in length) was seen off the south-east coast of the island, with one of them drifting close enough to shore to be visible from the hills above the city ofDunedin. If these were indeed the remnants of this calving, then over the course of five and a half years they had travelled slowly north and also east over about half the globe, a journey of some 13,500 km.[2]
From January 12 and January 13, 2010, an area of sea ice larger than the state ofRhode Island, or one-seventh the size ofWales, broke away from the Ronne–Filchner Ice Shelf and shattered into many smaller pieces. TheModerate-Resolution Imaging Spectroradiometer (MODIS) on NASA'sAqua andTerra satellites captured this event in this series of photo-like images.[3]
In May 2021,Iceberg A-76 broke off the northwest corner of the shelf. At 4320 km2,[4] it is larger thanMallorca, several times larger thanIceberg A-74 which calved in the same year, or approximately 14% the size ofBelgium.
The ice of the Filchner–Ronne ice shelf can be as thick as 600 m; the water below is about 1400 m deep at the deepest point.
The international Filchner–Ronne Ice Shelf Programme (FRISP) was initiated in 1973 to study the ice shelf.[5]
A study published inNature in 2012 by scientists from theAlfred Wegener Institute for Polar and Marine Research in Germany, and funded by theIce2Sea initiative, predicts the disappearance of the 450,000 km2 (170,000 sq mi) vast ice shelf in Antarctica by the end of the century which could – indirectly – add up to 4.4 mm (0.17 in) of rise of sea level each year.[6]
This article incorporatespublic domain material from"Filchner Ice Shelf".Geographic Names Information System.United States Geological Survey.
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