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 ?
By assessing the health of the ice shelf, the scientists can gauge how much climate change has affected the region.
We can use this research to help determine where to place instruments to observe ocean currents that circulate beneath the ice shelf. These observations can then guide computer models to predict how the Ross Ice Shelf and the West Antarctic Ice Sheet will change as our climate warms.
A team from Cambridge University spent several years investigating how the Ross Ice Shelf's north-west sector interacted with the ocean beneath it.
The iceberg, measuring over 1,500 square kilometres -- which is twice the size of New York City -- is expected to break away from the Brunt Ice Shelf in as little as a few months, when two large cracks which have been growing over the past seven years meet.
'It is not yet clear how the remaining ice shelf will respond following the break, posing an uncertain future for scientific infrastructure and a human presence on the shelf that was first established in 1955,' the scientists wrote.
This has led to several icebergs breaking off from the continent in recent years, the biggest of which separated from the Larsen C Ice Shelf in July, 2017, and was approximately the size of Delaware.
Another recent example was the 2017 calving of a Delaware-sized iceberg from the Larsen C ice shelf that broke away from the Antarctic Peninsula.
Dr Evans said the favourable sea-ice conditions next to the Larsen-C Ice Shelf changed towards the end of the planned science time.
Winds blowing across snow dunes on Antarctica's Ross Ice Shelf cause the massive ice slab's surface to vibrate, producing a near-constant set of seismic "tones" scientists could potentially use to monitor changes in the ice shelf from afar, according to new research.
"The calving of this iceberg leaves the Larsen C ice shelf reduced in area by more than 12 percent, and the landscape of the Antarctic Peninsula changed forever," the team added.
The calving of the iceberg, which is likely to be named A68, reduces the size of the Larsen C Ice Shelf by around 12% and will change the landscape of the Antarctic Peninsula forever, the scientists said.