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Posts tagged Ice shelf

Start of Iceberg Calving Off Pine Island Glacier, Antarctica – February 6th, 2012

75.1S 100W

February 6th, 2012 Category: Climate Change, Glaciers and Ice Caps

Pine Island Glacier - January 28th, 2012

The Pine Island Glacier, visible at the center of this image, is a large ice stream flowing west-northwest along the south side of the Hudson Mountains into Pine Island Bay, Amundsen Sea, Antarctica. The image focuses on a floating ice shelf at the downstream end of Pine Island Glacier. The crack shows the start of a large iceberg calving.

The area drained by Pine Island Glacier comprises about 10 percent of the West Antarctic Ice Sheet. Satellite measurements have shown that the Pine Island Glacier Basin has a greater net contribution of ice to the sea than any other ice drainage basin in the world and this has increased due to recent acceleration of the ice stream.

The Pine Island and Thwaites Glaciers are two of Antarctica’s five largest ice streams. Scientists have found that the flow of these ice streams has accelerated in recent years, and suggested that if they were to melt, global sea levels would rise by 0.9 to 1.9 m (2 ft 10 in to 6 ft 3 in), destabilising the entire West Antarctic Ice Sheet and perhaps sections of the East Antarctic Ice Sheet.

Ice Rises Parallel the Coast of the West Antarctic Ice Sheet

75.8S 53.4W

December 16th, 2009 Category: Snapshots

Antarctica - November 30th, 2009

Antarctica - November 30th, 2009

Three ice rises appear here as long parallel lines near the edge of the West Antarctic Ice Sheet. Ice rises are rounded elevations that form where the ice shelf touches areas in the seabed that are elevated, but nevertheless below sea level.

The ice shelf flows over these higher parts of the seabed and completely covers them with ice. The ice rises formed in this manner are typically 100 to 200 meters high.

Glacier on West Coast of Greenland

February 1st, 2009 Category: Snapshots

Glacier melting on west coast of Greenland - November 30th, 2008

Glacier melting on west coast of Greenland - November 30th, 2008

Here we can see a large glacier off the western coast of Greenland, seemingly fed by three ice streams.

The largest glaciers are continental glaciers, enormous masses of ice that are not visibly affected by the landscape and that cover the entire surface beneath them, except possibly on the margins where they are thinnest.

Antarctica and Greenland are the only places where continental ice sheets currently exist. These regions contain vast quantities of fresh water.

The volume of ice is so large that if the Greenland ice sheet melted, it would cause sea levels to rise some six meters (20 ft) all around the world.

These ice sheets are further divided into sections based on characteristics. Ice shelves are areas of an ice sheet that are at the margin and are afloat. As a result they are thinner, have limited slopes and reduced velocities.

Ice streams, like the three visible in the image, are fast moving sections of an ice sheet.

source Wikipedia

Glaciers and Ice Streams in Antarctica – December 19th, 2008

December 19th, 2008 Category: Image of the day

Glaciers in Antartica - December 13th, 2008

Glaciers in Antartica - December 13th, 2008

Close-up of two glaciers

Close-up of two glaciers

This ASAR (radar) image gives a fine view of the contours of two glaciers and an ice sheet in Antartica.

A glacier is a large, slow-moving mass of ice, formed from compacted layers of snow, that slowly deforms and flows in response to gravity and high pressure.

Both glaciers in the image appear bright white as much light reflects off their icy slopes. The darker grey lines show the movement of the melting ice.

Upon opening the second close-up image, ice streams appear as lines in an ice shelf or ice sheet. An ice stream is a region of an ice sheet that moves significantly faster than the surrounding ice.

Close-up of ice sheet

Close-up of ice sheet

Ice streams are significant features of the Antarctic where they account for 10% of the volume of the ice. They are up to 50 km wide and 2 km thick. They stretch for hundreds of kilometres and account for most of the ice leaving the ice sheet and entering the ice shelf.

source Wikipedia

Icebergs Breaking Off Alexander Island, Antarctica – November 26th, 2008

November 26th, 2008 Category: Image of the day

Icebergs Breaking Off Alexander Island, Antartica - Novembe 25th, 2008

Icebergs Breaking Off Alexander Island, Antartica - Novembe 25th, 2008

This radar image allows us to see through the cloud cover that frequently hides the landscape of Antartica, giving us a clear look at icebergs breaking off Alexander Island into Wilkins Sound.

Wilkins Sound is a seaway in Antartica that is largely occupied by the Wilkins Ice Shelf, a rectangular ice shelf about 80 nautical miles long and 60 nautical miles wide (150 km by 110 km).

Alexander Island is Antartica’s largest island, with an area of 18,946 mi² (49,070 km²). It lies in the Bellingshausen Sea west of the base of the Antarctic Peninsula, from which it is separated by Marguerite Bay and George VI Sound, though the Wilkins Ice Shelf links it to the mainland.

The claim to this territory is disputed by Argentina, Chile and the United Kingdom.

By opening the full image we can see an arm of ice reaching out to Charcot Island, a nunatak. It is an island of the British Antarctic Territory, 30 miles long and 25 miles wide, which is ice covered except for prominent mountains overlooking the north coast.

source Wikipedia