The Amundsen Sea, an arm of the

Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-small ...

off Marie Byrd Land in western

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest cont ...

, lies between

Cape Flying Fish Cape Flying Fish (, also known as Cape Dart) is an ice-covered cape which forms the western extremity of Thurston Island. It was discovered by Richard E. Byrd and members of the US Antarctic Program in a flight from the USS ''Bear'' in Februa ...

(the northwestern tip of

Thurston Island Thurston Island is an ice-covered, glacially dissected island, long, wide and in area, lying a short way off the northwest end of Ellsworth Land, Antarctica. It is the third-largest island of Antarctica, after Alexander Island and Berkner Isl ...

) to the east and

Cape Dart Cape Dart () is a cape at the foot of Mount Siple on the north coast of Siple Island, just southward of Lauff Island off the Bakutis Coast, Marie Byrd Land. It was discovered in December 1940 by members of the United States Antarctic Service ...

on Siple Island to the west. Cape Flying Fish marks the boundary between the Amundsen Sea and the

Bellingshausen Sea The Bellingshausen Sea is an area along the west side of the Antarctic Peninsula between 57°18'W and 102°20'W, west of Alexander Island, east of Cape Flying Fish on Thurston Island, and south of Peter I Island (there the southern ''Vostokkys ...

. West of Cape Dart there is no named

marginal sea This is a list of seas of the World Ocean, including marginal seas, areas of water, various gulfs, bights, bays, and straits. Terminology * Ocean – the four to seven largest named bodies of water in the World Ocean, all of which have "Ocea ...

of the

between the Amundsen and Ross Seas. The Norwegian expedition of 1928–1929 under Captain

Nils Larsen Nils Larsen (19 June 1900 – 29 September 1976) was a Norwegian sea captain. Larsen is perhaps most associated with the Norvegia expeditions of Antarctica. Larsen was born in Sandar, and became a noted whaler, captaining a number of whali ...

named the body of water for the Norwegian polar explorer

Roald Amundsen Roald Engelbregt Gravning Amundsen (, ; ; 16 July 1872 – ) was a Norwegian explorer of polar regions. He was a key figure of the period known as the Heroic Age of Antarctic Exploration. Born in Borge, Østfold, Norway, Amundsen beg ...

while exploring this area in February 1929. The sea is mostly ice-covered, and the Thwaites Ice Tongue protrudes into it. The

ice sheet In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at La ...

which drains into the Amundsen Sea averages about in thickness; roughly the size of the state of Texas, this area is known as the Amundsen Sea Embayment (ASE); it forms one of the three major ice-drainage basins of the

West Antarctic Ice Sheet The Western Antarctic Ice Sheet (WAIS) is the segment of the continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere. The WAIS is classified as ...

Embayment

The ice sheet which drains into the Amundsen Sea averages about in thickness; is roughly the size of the state of Texas and the area is known as the Amundsen Sea Embayment (ASE); it forms one of the three major ice drainage basins of the

, the others being the

Ross Sea The Ross Sea is a deep bay of the Southern Ocean in Antarctica, between Victoria Land and Marie Byrd Land and within the Ross Embayment, and is the southernmost sea on Earth. It derives its name from the British explorer James Clark Ross who ...

Embayment A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, a lake, or another bay. A large bay is usually called a gulf, sea, sound, or bight. A cove is a small, circular bay with a na ...

and the

Weddell Sea The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha ...

Embayment. In March 2007, scientists studying the ASE through satellite and airborne surveys announced a significant thinning of the ASE, due to shifts in wind patterns that allow warmer waters to flow beneath the ice sheet. Some scientists have proposed that this region may be a "weak underbelly" of the

. The Pine Island and Thwaites Glaciers, which both flow into the Amundsen Sea, are two of Antarctica's largest five. Scientists have found that the flow of these glaciers has increased starting in the mid-2000s decade; if they were to melt completely, global sea levels would rise by about . Scientist have suggested that the loss of these glaciers would destabilise the entire West Antarctic ice sheet and possibly sections of the

East Antarctic Ice Sheet The East Antarctic Ice Sheet (EAIS) is one of two large ice sheets in Antarctica, and the largest on the entire planet. The EAIS lies between 45° west and 168° east longitudinally. The EAIS holds enough ice to raise global sea levels by and ...

. A study in October 2004 suggested that because the ice in the Amundsen Sea had been melting rapidly and riven with cracks, the offshore ice shelf was set to collapse "within five years". The study projected a sea level rise of from the West Antarctic Ice Sheet if all the sea ice in the Amundsen Sea melted. Measurements made by the British Antarctic Survey in 2005 showed that the ice discharge rate into the Amundsen Sea embayment was about 250 km³ per year. Assuming a steady rate of discharge, this alone is sufficient to raise global sea levels by 0.2 mm per year. A subglacial

volcano A volcano is a rupture in the Crust (geology), crust of a Planet#Planetary-mass objects, planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and volcanic gas, gases to escape from a magma chamber below the surface. On Ear ...

has also been detected in the area, just north of the Pine Island Glacier near the

Hudson Mountains The Hudson Mountains are a mountain range in western Ellsworth Land just east of Cranton Bay and Pine Island Bay at the eastern extremity of Amundsen Sea. They are of volcanic origin, consisting of low scattered mountains and nunataks that pro ...

. It last erupted approximately 2,200 years ago, indicated by widespread ash deposits within the ice, in what was the largest known eruption in Antarctica within the past 10 millennia. Volcanic activity in the region may be contributing to the observed increase of glacial flow, although currently the most popular theory amongst the scientists studying this area is that the flow has increased due to warming ocean water. This water has warmed due to an upwelling of deep ocean water which is due to variations in pressure systems, which could have been affected by

global warming In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

In January 2010, a modelling study suggested that the "tipping point" for Pine Island Glacier may have been passed in 1996, with a retreat of possible by 2100, producing a corresponding of

sea level rise Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cry ...

, although it was suggested that these estimates for timespan were conservative. However, the modelling study also states that "Given the complex, three-dimensional nature of the real Pine Island glacier ... it should be clear that the ..model is a very crude representation of reality."

Pine Island Bay

Pine Island Bay () is a bay about long and wide, into which flows the ice of the

Pine Island Glacier Pine Island Glacier (PIG) is a large ice stream, and the fastest melting glacier in Antarctica, responsible for about 25% of Antarctica's ice loss. The glacier ice streams flow west-northwest along the south side of the Hudson Mountains into Pine ...

at the southeast extremity of the Amundsen Sea. It was delineated from aerial photographs taken by United States Navy (USN) Operation HIGHJUMP in December 1946, and named by the Advisory Committee on Antarctic Names for the USS ''Pine Island'', seaplane tender and flagship of the eastern task group of USN Operation HIGHJUMP which explored this area.

Russell Bay

Russell Bay () is a rather open bay in southwestern Amundsen Sea, extending along the north sides of Siple Island,

Getz Ice Shelf The Getz Ice Shelf is the largest Antarctic ice shelf along the SE Pacific-Antarctic coastline, over long and from wide, bordering the Hobbs and Bakutis Coasts of Marie Byrd Land between the McDonald Heights and Martin Peninsula. Several lar ...

and

Carney Island Carney Island () is an ice-covered island, long and about in area, with all but its North coast lying within the Getz Ice Shelf, Antarctica. It is located between Siple Island and Wright Island along the coast of Marie Byrd Land. Carney Is ...

, from Pranke Island to

Cape Gates Cape Gates () is an ice-covered cape which marks the northwestern extremity of Carney Island along the coast of Marie Byrd Land, Antarctica. It was first mapped by United States Geological Survey from aerial photographs taken by U.S. Navy Operation ...

. It was mapped by the

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

from surveys and USN air photos, 1959–66, and named by the Advisory Committee on Antarctic Names for Admiral James S. Russell,

Vice Chief of Naval Operations The vice chief of naval operations (VCNO) is the second highest-ranking commissioned United States Navy officer in the Department of the Navy and functions as the principal deputy of the chief of naval operations and by statute, the vice chief ...

during the post 1957–58 IGY period.

References

* *

External links

Airborne Geophysical Survey of the Amundsen Embayment

Thinning ice
{{Authority control Seas of the Southern Ocean