Antarctic ice sheet

The Antarctic ice sheet is the largest single mass of ice on Earth.

It covers an area of almost 14 million square km and contains 30 million cubic km of ice.

Around 90 percent of the fresh water on the Earth’s surface is held in the ice sheet, an amount equivalent to 70 m of water in the world’s oceans.

In East Antarctica, the ice sheet rests on a major land mass, but in West Antarctica the bed can extend to more than 2500m below sea level.

The land would be seabed if the ice sheet were not there. Ice enters the sheet through snow and frost and leaves by calving of icebergs and melting, usually at the base but also sometimes at the surface at warm sites..

For more information about the topic Antarctic ice sheet, see the following related articles:

Ice sheet — An Ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 square kilometers (19,305 square miles).

The only current ice sheets are Antarctic and Greenland; during the last ice age at Last Glacial Maximum (LGM) the Laurentide ice sheet covered much of Canada and North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South America.

The Antarctic ice sheet is the largest single mass of ice on Earth.

The Greenland ice sheet occupies about 82% of the surface of Greenland, and if melted would cause sea levels to rise by 7.2 metres.

Estimated changes in the mass of Greenland’s ice sheet suggest it is melting at a rate of about 239 cubic kilometres (57.3 cubic miles) per year. Ice sheets are bigger than ice shelves or glaciers.

Masses of ice covering less than 50,000 square kilometers are termed an ice cap.

An ice cap will typically feed a series of glaciers around its periphery..

Antarctic ice sheet

The Antarctic ice sheet is the largest single mass of ice on Earth.

It covers an area of almost 14 million square km and contains 30 million cubic km of ice.

Around 90 percent of the fresh water on the Earth’s surface is held in the ice sheet, an amount equivalent to 70 m of water in the world’s oceans.

In East Antarctica, the ice sheet rests on a major land mass, but in West Antarctica the bed can extend to more than 2500m below sea level.

The land would be seabed if the ice sheet were not there. Ice enters the sheet through snow and frost and leaves by calving of icebergs and melting, usually at the base but also sometimes at the surface at warm sites..

Ice shelf

An ice shelf is a thick, floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface, typically in Antarctica or Greenland.

The boundary between floating ice shelf and the grounded (resting on bedrock) ice that feeds it is called the grounding line.

When the grounding line retreats inland, water is added to the ocean and sea level rises..

Larsen Ice Shelf

Larsen Ice Shelf

The Larsen Ice Shelf is a long, fringing ice shelf in the northwest part of the Weddell Sea, extending along the east coast of Antarctic Peninsula from Cape Longing to the area just southward of Hearst Island.

The Larsen Ice Shelf is a series of three shelves that occupy (or occupied) distinct embayments along the coast.

From north to south, the three segments are called Larsen A (the smallest), Larsen B, and Larsen C (the largest) by researchers who work in the area.

The Larsen A ice shelf disintegrated in January of 1995.

The Larsen B ice shelf disintegrated in February of 2002.

The Larsen C ice shelf appears to be stable. The Larsen disintegration events were unusual.

Typically, ice shelves lose mass by iceberg calving and by melting at their upper and lower surfaces.

The disintegration events are linked to the ongoing climate warming in the Antarctic Peninsula, about 0.5 °C per decade since the late 1940’s (possibly a result of global warming)..

Iceberg

An iceberg is a large piece of ice that has broken off from a snow-formed glacier or ice shelf and is floating in open water.

Since the density of pure water ice is ca.

920 kg/m3, and that of sea water ca.

1025 kg/m3, typically, around 90% of the volume of an iceberg is under water, and that portion’s shape can be difficult to surmise from looking at what is visible above the surface.

This has led to the expression “tip of the iceberg”, generally applied to a problem or difficulty, meaning that the visible trouble is only a small manifestation of a larger problem..

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~ by richart123 on June 25, 2008.

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