Ice Shelf


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Related to Ice Shelf: Larsen B Ice Shelf

ice shelf

[′īs ‚shelf]
(oceanography)
A thick sheet of ice with a fairly level or undulating surface, formed along a polar coast and in shallow bays and inlets, fastened to the shore along one side but mostly afloat and nourished by annual accumulation of snow and by the seaward extension of land glaciers.

Ice Shelf

 

a glacier that is floating or partially resting on the bottom and flowing from the shore into the sea in the form of a plate that diminishes in thickness toward the edge and terminates in a cliff.

The ice shelf is a continuation of land ice sheets. More rarely, it is formed by the accumulation of snow on sea ice and by the cementing together of accumulations of icebergs by snow and ice. Ice shelves are found almost exclusively in Antarctica. Their total area is 1,460,000 sq km; the volume is about 0.6 million cu km; and the thickness varies from 200–1,300 m at the land edge to 50–400 m at the sea edge. The accumulation area usually encompasses the entire upper surface and the coastal section of the lower surface where ice forms; in the marginal zone the ice melts on the bottom (up to 1 m per year). A large part of the loss occurs from the breaking off of icebergs (a volume at times of thousands of cu km). The rate of movement of the ice shelf, which increases toward the edge, varies from 300–800 m to 1,800 m and more per year. (The largest ice shelf is the Ross Ice Shelf.)

REFERENCES

Shumskii, P. A. “Oledenenie Antarktidy.” In the collection Osnovnye itogi izucheniia Antarktiki za 10 let. Moscow, 1967.
Atlas Antarktiki, vol. 2. Leningrad, 1969.
References in periodicals archive ?
The Fimbul Ice Shelf - located along eastern Antarctica in the Weddell Sea - is the sixth largest of the forty-three ice shelves that dapple Antarctica's perimeter.
Scientists hadn't expected currents to bring much food to the site under the ice shelf, says Riddle.
Adelie penguins fully recolonized the Ross Sea coast only 8,000 years ago, after the most recent ice age ended, following the retreat of the ice shelf to near its present location.
The projections show that similar levels of melt may occur across coastal Antarctica near the end of this century, raising concerns about future ice shelf stability.
Satellite images reveal that a crack in Larsen C rapidly extended tens of kilometers across the ice shelf in 2014.
The study predicts that what remains of the once-prominent ice shelf, a thick floating platform of ice, most likely will "disintegrate completely" before the end of this decade.
A team led by Ala Khazendar of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, found the remnant of the Larsen B Ice Shelf is flowing faster, becoming increasingly fragmented and developing large cracks.
Earlier gains in East Antarctic ice shelf volume observed earlier ceased after about 2003, according to the data.
The team's work will centre on "Larsen C" a long, fringing ice shelf in the north-west part of the Weddell Sea, extending along the east coast of Antarctic Peninsula, covering and area two and half times the size of Wales.
Professor Bryn Hubbard and Dr David Ashmore, from the Department of Geography and Earth Sciences' Centre for Glaciology in Aberystwyth, will be joined by colleagues from Swansea University on the Larsen C ice shelf when they fly off at the beginning of next month.
The glacier is currently experiencing significant acceleration, thinning and retreat that is thought to be caused by 'ocean-driven' melting; an increase in warm ocean water finding its way under the ice shelf.
The team discovered that oceanic melting of the ice shelf into which the glacier flows decreased by 50 percent between 2010 and 2012, and this may have been due to a La Nina weather event.